TY - JOUR
AU - Devant, M.
AB - Abstract A total of 240 Holstein bulls (121 ± 2.0 kg initial BW; 99 ± 1.0 d of age), from 2 consecutive fattening cycles, were randomly allocated in 1 of 6 pens and assigned to 1 of the 3 treatments consisting of different concentrate feeder designs: a control feeder with 4 feeding spaces (CF), a feeder with less concentrate capacity (CFL), and a single-space feeder with lateral protections (SF). Each pen had a straw feeder and a drinker. All animals were fed a high-concentrate diet for ad libitum intake. Concentrate consumption was recorded daily using a computerized feeder, straw consumption was recorded weekly, and BW was recorded every 14 d. Animal behavior was registered on d 1, 3, 5, 8, and 14 and every 28 d by scan sampling. Eating behavior at concentrate feeders was filmed on d 12, 125, and 206. On d 7, 120, and 204, samples of rumen contents were collected for measurement of pH and VFA and blood samples were obtained to analyze NEFA, haptoglobin, glucose, and insulin. Animals were slaughtered after 223 d, and HCW and lesions of the rumen wall and liver were recorded. The accumulative concentrate consumption per animal tended (P = 0.09) to be greater with CF than with CFL and SF. Also, CV of concentrate consumption was greater (P < 0.01) for SF than for CF or CFL. However, feeder design did not influence the other performance and carcass data. Also, no differences among treatments in rumen wall evaluation and liver abscesses were observed. At 7 and 204 d of study, SF bulls had greater (P < 0.05) rumen pH compared with CF and CFL bulls. On d 7, the acetate to propionate ratio from SF was greater (P < 0.05) than for CFL or CF. At d 7, NEFA of SF were greater (P < 0.05) compared with CF and CFL. Bulls fed with CF have the greatest (P < 0.01) concentrate disappearance velocity followed by bulls fed with CFL and finally by bulls fed with SF, and this was associated with different feeding behaviors. Bulls on SF spent more time (P < 0.05) eating straw and exhibited fewer (P < 0.05) displacements at concentrate feeder than CF and CFL bulls. The CFL bulls exhibited (P < 0.01) more attempted mounts and tended (P = 0.10) to exhibit more completed mounts than CF bulls. In conclusion, both alternative feeder designs (CFL and SF) are good strategies to reduce total concentrate consumption without impairing performance, rumen health, or animal welfare in Holstein bulls fed high-concentrate diets. However, at the beginning, there was evidence that animals fed using SF had problems with adaptation. INTRODUCTION In Mediterranean countries in beef feeding systems, concentrate and straw are both fed for ad libitum intake in separate self-feeders resulting in a concentrate to straw ratio of 90 to 10 (Devant et al., 2000; Mach et al., 2009), differing from the most common world feeding systems, fence line bunk feeding with a total mixed ration. In recent years, prices of ingredients have increased drastically, a circumstance that has forced producers to look for alternatives beyond the formulation. A single-space feeder with lateral barriers has been used to record individual concentrate intakes for research purposes (Devant et al., 2012; Marti et al., 2013), and total concentrate consumed by the cattle was less than in previous studies (Mach et al., 2006; Devant et al., 2010) without impairing growth. So, it was hypothesized that the single-space feeder with lateral barriers could reduce feed consumption and feed costs compared with self-feeders with multiple feeding spaces. However, reducing the feeder space to animal ratio could increase effort to obtain feed and competition to access feed (Huzzey et al., 2006; González et al., 2008), and increased eating rate could negatively affect rumen health (Sauvant et al., 1999; González et al., 2008), as greater fluctuations in rumen pH and consumption can lead to rumen acidosis and liver abscesses (Fulton et al., 1979; Stock et al., 1987, 1990). Moreover, feed adjustment at the feeder (amount of feeder pan coverage) can affect time spent eating, competition at the feeder, and feed wastage (Gonyou, 1999) and, in turn, feed efficiency as observed in swine (Bergstrom et al., 2012; Myers et al., 2012). So another alternative to improve feed efficiency in beef would be the reduction of feeder depth. The present study evaluated the effect of feeder design on concentrate consumption, growth rate, feed efficiency, eating pattern, animal behavior, welfare, rumen health, and carcass traits in Holstein bulls fed high-concentrate diets. MATERIALS AND METHODS Cattle, Feeding, and Housing Animals were reared under commercial conditions in a farm owned by Agropecuaria Montgai SL (Lleida, Spain) and were managed following the principles and specific guidelines of the Institut de Recerca i Tecnologia Agroalimentàries Animal Care Committee. Two hundred forty male Holstein calves (121 ± 2.0 kg initial BW; 99 ± 1.0 d of age) in 2 consecutive fattening cycles (120 animals each cycle) were used in a replicated study, which was conducted in a commercial farm with 6 pens. Pens were totally covered and measured 12 by 6 m (72 m2 per pen), with a space availability of 3.6 m2 per animal, and were deep bedded with straw. Each pen had 36 m2 of resting area and 36 m2 of feeding area in the front with the concentrate feeder, a separate straw feeder (3 m long by 1.12 m wide by 0.65 m deep; 7 feeding spaces), and a water bowl. Animals were randomly allocated in 1 of 6 pens and assigned to 1 of the 3 different concentrate feeder designs (20 animals per pen): 1) a control feeder with 4 feeding spaces (CF), a concentrate feeder capacity of 200 kg, and a feeder depth of 0.6 m (Fig. 1a); 2) a feeder (like CF) with less concentrate capacity (CFL; 45 kg) and a feeder depth of 0.15 m (Fig. 1b); and 3) a single-space feeder with lateral protections (SF), a concentrate feeder capacity of 10 kg, and a feeder depth of 0.15 m (Fig. 1b). Concentrate feeders were manufactured in stainless steel, which were elevated at 0.80 m from the floor but had different features of design (dimensions of feeder): CF was 1.9 m long, 0.6 m wide, and 0.6 m deep, with a feeder capacity of 200 kg of concentrate and stanchions defining 4 feeding spaces (35 cm inside distance; Fig. 2); CFL was 1.9 m long, 0.6 m wide, and 0.15 m deep, with a feeder capacity of 45 kg of concentrate and stanchions defining 4 feeding spaces (35 cm inside distance; Fig. 3); and SF was 0.5 m long by 0.26 m wide by 0.15 m deep, with a feeder capacity of 10 kg of concentrate, protected by 2 lateral barriers (1.4 m long by 0.8 m high) forming a chute, the inside diameter of which could be regulated from 42 to 72 cm wide (Fig. 4). Animals fed with SF were adapted for the first 4 d of the study by widening the chute to facilitate feeder access (adaptation period). After these first days, the width of the chute was adjusted 3 times during the study to adapt the entrance to the animal size providing sufficient space to eat comfortably. At d 5 of study, the width of chute was fixed at 42 cm, at d 25 it was 55 cm, and at d 120 it was widened to 72 cm. Figure 1. View largeDownload slide Schedule of a cross-sectional cut of the control feeder (a) and the control feeder with limited concentrate level or the single feeder with lateral barriers (b). The trough depth is indicated. Figure 1. View largeDownload slide Schedule of a cross-sectional cut of the control feeder (a) and the control feeder with limited concentrate level or the single feeder with lateral barriers (b). The trough depth is indicated. Figure 2. View largeDownload slide Control feeder. Concentrate feeder with 4 feeding spaces and 200 kg of trough capacity. (a) Top view and (b) front view. Figure 2. View largeDownload slide Control feeder. Concentrate feeder with 4 feeding spaces and 200 kg of trough capacity. (a) Top view and (b) front view. Figure 3. View largeDownload slide Control feeder with limited feeder capacity. Concentrate feeder with 4 feeding spaces and 45 kg of trough capacity. (a) Top view and (b) front view. Figure 3. View largeDownload slide Control feeder with limited feeder capacity. Concentrate feeder with 4 feeding spaces and 45 kg of trough capacity. (a) Top view and (b) front view. Figure 4. View largeDownload slide Single feeder. Single feeder with lateral protections and a trough capacity of 10 kg. (a) Top view and (b) front view. Figure 4. View largeDownload slide Single feeder. Single feeder with lateral protections and a trough capacity of 10 kg. (a) Top view and (b) front view. Feed Consumption and Performance All animals were fed a commercial concentrate (Table 1), formulated according to the NRC (1996) recommendations. For the initial 130 d of the study, animals were fed the grower concentrate, and from 131 d of study to the end of the study, they were fed the finisher concentrate. Also, animals had ad libitum access to wheat straw (3.5% CP, 1.6% ether extract, 70.9% NDF, and 6.1% ash; DM basis) and fresh water. A sample from each concentrate batch was collected and was analyzed for DM, CP, NDF, ash, and ether extract. Table 1. Ingredients and nutrient composition of the experimental concentrates   Concentrate    Grower  Finisher    Fattening cycle  Item  First  Second  First  Second  Ingredient, % of DM      Corn  43.0  40.7  33.4  48.5      Soybean hulls  15.0    17.0  3.0      Soybean meal    4.3    4.0      Canola meal    3.0          Corn dried distillers grains  14.0  10.0  14.0  12.0      Corn grits    17.0  15.0  17.0      Lupin meal  13.3            Wheat middlings  11.8  21.8  3.9  12.3      Pea meal      9.4        Palm oil  1.2  1.3  3.0  1.8      Sunflower meal      3.0        Calcium carbonate  1.2  1.4  0.8  0.9      White salt  0.3  0.3  0.3  0.3      Vitamin–mineral premix1  0.2  0.2  0.2  0.2  Nutrient composition, % of DM      Ash  5.00  4.71  5.38  4.47      CP  16.33  15.15  15.58  14.38      Ether extract  6.73  9.09  7.05  7.88      NDF  28.21  27.45  21.61  20.42      NFC2  43.73  43.60  50.38  52.85      ME, Mcal/kg  2.88  2.88  3.01  3.00    Concentrate    Grower  Finisher    Fattening cycle  Item  First  Second  First  Second  Ingredient, % of DM      Corn  43.0  40.7  33.4  48.5      Soybean hulls  15.0    17.0  3.0      Soybean meal    4.3    4.0      Canola meal    3.0          Corn dried distillers grains  14.0  10.0  14.0  12.0      Corn grits    17.0  15.0  17.0      Lupin meal  13.3            Wheat middlings  11.8  21.8  3.9  12.3      Pea meal      9.4        Palm oil  1.2  1.3  3.0  1.8      Sunflower meal      3.0        Calcium carbonate  1.2  1.4  0.8  0.9      White salt  0.3  0.3  0.3  0.3      Vitamin–mineral premix1  0.2  0.2  0.2  0.2  Nutrient composition, % of DM      Ash  5.00  4.71  5.38  4.47      CP  16.33  15.15  15.58  14.38      Ether extract  6.73  9.09  7.05  7.88      NDF  28.21  27.45  21.61  20.42      NFC2  43.73  43.60  50.38  52.85      ME, Mcal/kg  2.88  2.88  3.01  3.00  1SinuvitTerneros Final (Sinual S.L., Sallent, Spain): vitamin and mineral premix containing, per kilogram of DM: 4,500 kIU of vitamin A, 1,000 kIU of vitamin D3, 22.5 g of vitamin E, 0.5 g of vitamin B1, 1 g of vitamin B2, 5 mg of vitamin B12, 2.5 g of vitamin B3. 15 g of Mn, 3 g of Cu, 30 g of Zn, 0.5 g of Co, 0.5 g of I, 0.1 g of Se, 1 g of butylated hydroxytoluene, and 1 kg of calcium carbonate as excipient. 2NFC = nonfiber carbohydrates [calculated as 100 – (CP + ash + NDF + ether extract)].. View Large Table 1. Ingredients and nutrient composition of the experimental concentrates   Concentrate    Grower  Finisher    Fattening cycle  Item  First  Second  First  Second  Ingredient, % of DM      Corn  43.0  40.7  33.4  48.5      Soybean hulls  15.0    17.0  3.0      Soybean meal    4.3    4.0      Canola meal    3.0          Corn dried distillers grains  14.0  10.0  14.0  12.0      Corn grits    17.0  15.0  17.0      Lupin meal  13.3            Wheat middlings  11.8  21.8  3.9  12.3      Pea meal      9.4        Palm oil  1.2  1.3  3.0  1.8      Sunflower meal      3.0        Calcium carbonate  1.2  1.4  0.8  0.9      White salt  0.3  0.3  0.3  0.3      Vitamin–mineral premix1  0.2  0.2  0.2  0.2  Nutrient composition, % of DM      Ash  5.00  4.71  5.38  4.47      CP  16.33  15.15  15.58  14.38      Ether extract  6.73  9.09  7.05  7.88      NDF  28.21  27.45  21.61  20.42      NFC2  43.73  43.60  50.38  52.85      ME, Mcal/kg  2.88  2.88  3.01  3.00    Concentrate    Grower  Finisher    Fattening cycle  Item  First  Second  First  Second  Ingredient, % of DM      Corn  43.0  40.7  33.4  48.5      Soybean hulls  15.0    17.0  3.0      Soybean meal    4.3    4.0      Canola meal    3.0          Corn dried distillers grains  14.0  10.0  14.0  12.0      Corn grits    17.0  15.0  17.0      Lupin meal  13.3            Wheat middlings  11.8  21.8  3.9  12.3      Pea meal      9.4        Palm oil  1.2  1.3  3.0  1.8      Sunflower meal      3.0        Calcium carbonate  1.2  1.4  0.8  0.9      White salt  0.3  0.3  0.3  0.3      Vitamin–mineral premix1  0.2  0.2  0.2  0.2  Nutrient composition, % of DM      Ash  5.00  4.71  5.38  4.47      CP  16.33  15.15  15.58  14.38      Ether extract  6.73  9.09  7.05  7.88      NDF  28.21  27.45  21.61  20.42      NFC2  43.73  43.60  50.38  52.85      ME, Mcal/kg  2.88  2.88  3.01  3.00  1SinuvitTerneros Final (Sinual S.L., Sallent, Spain): vitamin and mineral premix containing, per kilogram of DM: 4,500 kIU of vitamin A, 1,000 kIU of vitamin D3, 22.5 g of vitamin E, 0.5 g of vitamin B1, 1 g of vitamin B2, 5 mg of vitamin B12, 2.5 g of vitamin B3. 15 g of Mn, 3 g of Cu, 30 g of Zn, 0.5 g of Co, 0.5 g of I, 0.1 g of Se, 1 g of butylated hydroxytoluene, and 1 kg of calcium carbonate as excipient. 2NFC = nonfiber carbohydrates [calculated as 100 – (CP + ash + NDF + ether extract)].. View Large An automated system was used to register concentrate consumption by recording the feed disappearance within an interval of time. Each pen was equipped with a scale that consisted of 4 load cells (Utilcell, Barcelona, Spain) where the feeder was suspended. The scales were programmed to transmit the feed weight at 1-min intervals or when weight change was detected to a Programmable Logic Controller (Allen-Bradley model 1769-L35E; Rockwell Automation,, Milwaukee, WI) and finally displayed by a personal computer with a software application (Voltec, Lleida, Spain). The computer recorded initial and final feed weight with its corresponding initial and final time. The negative values of concentrate consumption, which were usually caused by eating action belonging to animals (scratching) or when feed was added inside the feeder, were removed from the data set by computer filters. The scales were calibrated weekly. All feeders were designed to be refilled automatically to ensure continuous feed availability. The refilling system was common for all feeders (Fig. 5). The dispensing tube capacity had the same dimensions in all feeders and the dispensing tube was always full. The scale under the feeder continuously registered the weight, and when it detected that the dispensing tube was empty (by weight difference), the dispensing tube was automatically refilled with concentrate contained in the intermediate dispensing hoppers, so that the level of concentrate in the trough (trough depth) was continuously maintained. The amount of straw offered to each pen was recorded weekly to estimate the total amount of straw consumed; however, because straw was also used for bedding, these data are only guiding data. Animals were weighed every 14 d throughout study, and calculations used full BW data. Figure 5. View largeDownload slide The refilling system is common for all feeders. The dispensing tube capacity has the same dimensions in all feeders and the dispensing tube is always full. The scale under the feeder continuously registers the weight; when it detects that the dispensing tube (stainless steel half-tube, 2 m long and radius of 20.5 cm) is empty (by weight difference), the dispensing tube is automatically refilled with concentrate contained in the intermediate dispensing hoppers (in red) so that the level of concentrate at the trough (limited by the lower end of the dispensing tube and the trough depth) is continuously maintained. Figure 5. View largeDownload slide The refilling system is common for all feeders. The dispensing tube capacity has the same dimensions in all feeders and the dispensing tube is always full. The scale under the feeder continuously registers the weight; when it detects that the dispensing tube (stainless steel half-tube, 2 m long and radius of 20.5 cm) is empty (by weight difference), the dispensing tube is automatically refilled with concentrate contained in the intermediate dispensing hoppers (in red) so that the level of concentrate at the trough (limited by the lower end of the dispensing tube and the trough depth) is continuously maintained. Animal Behavior To analyze the general activity (standing, lying, eating concentrate and straw, drinking, and ruminating) in the pen and social behavior (nonagonistic, agonistic, and sexual interactions) of animals, a scan sampling procedure was used. Records correspond to total counts of each activity in a pen (Mounier et al., 2005). Animal behavior was recorded on d 1, 3, 5, 8, 14, and 26 and every 28 d throughout the study from 0830 to 1100 h by scan sampling as described by Rotger et al. (2006), Robles et al. (2007), Mach et al. (2008), and Marti et al. (2010). The scan sampling method describes a behavior exhibited by an animal at a fixed time interval (Colgan, 1978). Two pens were observed at the same time, and whereas social behavior (Table 2) was scored during 2 continuous sampling periods of 15 min, general activities (Table 3) were scored using 2 scan samplings of 10 s at 5 min intervals (Mach et al., 2008). This recording procedure (15 min) was repeated twice during the morning. Table 2. Description of the social behavioral categories recorded Item  Definition  Nonagonistic interactions      Self-grooming  Defined as nonstereotypied licking of its own body or scratching with a hind limb or against the fixtures      Social behavior  When a bull was licking or nosing a neighboring bull with the muzzle or horning      Oral behavior  The act of licking or biting the fixtures  Agonistic interactions      Fighting  When bulls pushed vigorously head against head      Butting  When 1 bull pushed vigorously its head against any part of another bull's body      Displacement  When 1 bull shoved itself between 2 other animals or between an animal and a wall or any equipment      Chasing  When 1 bull made another animal flee by following fast or running behind it      Chasing-up  When 1 bull used forceful physical contact against a resting animal that made the receiver rise  Sexual interactions      Flehmen  Upper lip reversed      Attempted mounts  Head on the back of another animal      Completed mounts  Forelimbs on the back of another animal  Stereotypies        Oral stereotypies  Tongue rolling, stereotyped licking, or biting on certain bars or sites in the stall  Item  Definition  Nonagonistic interactions      Self-grooming  Defined as nonstereotypied licking of its own body or scratching with a hind limb or against the fixtures      Social behavior  When a bull was licking or nosing a neighboring bull with the muzzle or horning      Oral behavior  The act of licking or biting the fixtures  Agonistic interactions      Fighting  When bulls pushed vigorously head against head      Butting  When 1 bull pushed vigorously its head against any part of another bull's body      Displacement  When 1 bull shoved itself between 2 other animals or between an animal and a wall or any equipment      Chasing  When 1 bull made another animal flee by following fast or running behind it      Chasing-up  When 1 bull used forceful physical contact against a resting animal that made the receiver rise  Sexual interactions      Flehmen  Upper lip reversed      Attempted mounts  Head on the back of another animal      Completed mounts  Forelimbs on the back of another animal  Stereotypies        Oral stereotypies  Tongue rolling, stereotyped licking, or biting on certain bars or sites in the stall  View Large Table 2. Description of the social behavioral categories recorded Item  Definition  Nonagonistic interactions      Self-grooming  Defined as nonstereotypied licking of its own body or scratching with a hind limb or against the fixtures      Social behavior  When a bull was licking or nosing a neighboring bull with the muzzle or horning      Oral behavior  The act of licking or biting the fixtures  Agonistic interactions      Fighting  When bulls pushed vigorously head against head      Butting  When 1 bull pushed vigorously its head against any part of another bull's body      Displacement  When 1 bull shoved itself between 2 other animals or between an animal and a wall or any equipment      Chasing  When 1 bull made another animal flee by following fast or running behind it      Chasing-up  When 1 bull used forceful physical contact against a resting animal that made the receiver rise  Sexual interactions      Flehmen  Upper lip reversed      Attempted mounts  Head on the back of another animal      Completed mounts  Forelimbs on the back of another animal  Stereotypies        Oral stereotypies  Tongue rolling, stereotyped licking, or biting on certain bars or sites in the stall  Item  Definition  Nonagonistic interactions      Self-grooming  Defined as nonstereotypied licking of its own body or scratching with a hind limb or against the fixtures      Social behavior  When a bull was licking or nosing a neighboring bull with the muzzle or horning      Oral behavior  The act of licking or biting the fixtures  Agonistic interactions      Fighting  When bulls pushed vigorously head against head      Butting  When 1 bull pushed vigorously its head against any part of another bull's body      Displacement  When 1 bull shoved itself between 2 other animals or between an animal and a wall or any equipment      Chasing  When 1 bull made another animal flee by following fast or running behind it      Chasing-up  When 1 bull used forceful physical contact against a resting animal that made the receiver rise  Sexual interactions      Flehmen  Upper lip reversed      Attempted mounts  Head on the back of another animal      Completed mounts  Forelimbs on the back of another animal  Stereotypies        Oral stereotypies  Tongue rolling, stereotyped licking, or biting on certain bars or sites in the stall  View Large Table 3. Description of the general activities recorded Item  Definition  Eating  Eating (concentrate or straw) was defined as when the animal had its head into the feeder and was engaged in chewing. An observation was defined as eating when the bull was eating from the feed bunk with its muzzle in the feed bunk or chewing or swallowing food with its head over the bunk.  Drinking  Drinking was recorded when the animal had its mouth in the water bowl. An observation was recorded as drinking when the bull was with its muzzle in the water bowl or swallowing the water.  Ruminating  Ruminating included the regurgitation, mastication, and swallowing of the bolus.  Lying  Lying was recorded as soon as the animal was not standing on its 4 legs, independently of any activity the animal might perform.  Standing  Standing was recorded when the animal was standing on its 4 legs, independently of any activity the animal might perform.  Item  Definition  Eating  Eating (concentrate or straw) was defined as when the animal had its head into the feeder and was engaged in chewing. An observation was defined as eating when the bull was eating from the feed bunk with its muzzle in the feed bunk or chewing or swallowing food with its head over the bunk.  Drinking  Drinking was recorded when the animal had its mouth in the water bowl. An observation was recorded as drinking when the bull was with its muzzle in the water bowl or swallowing the water.  Ruminating  Ruminating included the regurgitation, mastication, and swallowing of the bolus.  Lying  Lying was recorded as soon as the animal was not standing on its 4 legs, independently of any activity the animal might perform.  Standing  Standing was recorded when the animal was standing on its 4 legs, independently of any activity the animal might perform.  View Large Table 3. Description of the general activities recorded Item  Definition  Eating  Eating (concentrate or straw) was defined as when the animal had its head into the feeder and was engaged in chewing. An observation was defined as eating when the bull was eating from the feed bunk with its muzzle in the feed bunk or chewing or swallowing food with its head over the bunk.  Drinking  Drinking was recorded when the animal had its mouth in the water bowl. An observation was recorded as drinking when the bull was with its muzzle in the water bowl or swallowing the water.  Ruminating  Ruminating included the regurgitation, mastication, and swallowing of the bolus.  Lying  Lying was recorded as soon as the animal was not standing on its 4 legs, independently of any activity the animal might perform.  Standing  Standing was recorded when the animal was standing on its 4 legs, independently of any activity the animal might perform.  Item  Definition  Eating  Eating (concentrate or straw) was defined as when the animal had its head into the feeder and was engaged in chewing. An observation was defined as eating when the bull was eating from the feed bunk with its muzzle in the feed bunk or chewing or swallowing food with its head over the bunk.  Drinking  Drinking was recorded when the animal had its mouth in the water bowl. An observation was recorded as drinking when the bull was with its muzzle in the water bowl or swallowing the water.  Ruminating  Ruminating included the regurgitation, mastication, and swallowing of the bolus.  Lying  Lying was recorded as soon as the animal was not standing on its 4 legs, independently of any activity the animal might perform.  Standing  Standing was recorded when the animal was standing on its 4 legs, independently of any activity the animal might perform.  View Large Eating Behavior To study the effect of feeder design on eating behavior at the feeder, the feeding area was filmed for 24 h at the beginning (d 12), in the middle (d 125), and at the end (d 206) of the experiment using digital cameras (Sony CSM-BV420; Sony Corp., Barcelona, Spain) that filmed the feeding area of each pen. Videotapes were processed by continuous recording of the activities performed by animals at the concentrate feeders. Only 12 h of recordings (0600 to 1800 h) were used to create a data set, because the quality of the night recordings was not always acceptable. Activities recorded included eating concentrate, waiting time to access to the feeder, and displacements at the feeder. These activities were registered by simultaneously recording for each activity the time duration (min), the number of animals involved, and the frequency of activity. Rumen Samples Samples of rumen contents (10 mL) from each animal were collected in the morning on d 7, 120, and 204 by rumenocentesis for pH and VFA determination. The order in which pens were sampled was random to avoid the effect sampling time on rumen data. Rumenocentesis was conducted with a 14-gauge, 140-mm needle (Abbocath-T; Hospira, Madrid, Spain) inserted into the ventral sac of the rumen approximately 15 to 20 cm caudal–ventral to the costocondral junction of the last rib. Rumen liquid pH was immediately measured with a portable pH meter (Crison pH25; Crison Instruments SA, Barcelona, Spain). Following Jounay (1982), a 4-mL rumen sample was mixed with 1 mL of a solution containing 0.2% (wt/wt) of mercuric chloride, 2% (wt/wt) orthophosphoric acid, and 0.2% (wt/wt) of 4-methylvaleric acid (internal standard) in distilled water and stored at –20°C until subsequent VFA analyses. Blood Samples Blood samples for each animal were collected on d 7, 120, and 204 via tail or jugular venipuncture using Vacutainer tubes and 18 gauge needles. One blood sample (10 mL) was harvested into a Vacutainer tube with spray-dried clot activator (BD Vacutainer, Franklin Lakes, NJ) for insulin, NEFA, and haptoglobin concentration analysis; a second blood sample (4 mL) was collected into a Vacutainer tube with sodium fluoride and potassium oxalate (BD Vacutainer) for glucose analysis. All blood samples were centrifuged at 1,500 × g at 4°C for 15 min, and serum was decanted and stored at –20°C until further analyses. Carcass Quality On d 217 of the study and onward, animals were randomly selected from each pen and transported to a commercial slaughterhouse (Mercabarna, Barcelona, Spain) by truck. Transport distance was less than 150 km and the waiting time until slaughter was less than 12 h. Animal transport was organized in 3 different loads without mixing animals from different treatments and pens. Before each loading, animal BW was recorded. Animals were stunned using a captive-bolt pistol and dressed according to commercial practices. Immediately following slaughter, HCW was recorded, and the degree of carcass conformation and fatness were graded according to the (S)EUROP categories (EU Regulation No. 1208/81 and 1026/91) and into EU classification system into 1.2.3.4.5 (EU Regulation No. 1208/81), respectively. The conformation class designated by the letter “S” (superior) describes carcasses with all profiles extremely convex, and with exceptional mucle development (double-muscled carcass type), whereas the conformation classified as “E” (excellent) describes carcasses with all profiles convex to super-convex, and with exceptional muscle development, and the conformation classified as “U” (very good) describes carcasses with profiles on the whole convex, and with very good muscle development. The carcasses classified as “R” (good) present profiles, on the whole, straight and with good muscle development. Carcasses classified as “O” (fair) present profiles straight to concave and with average muscle development, and carcasses classified as “P” (poor) present all profiles concave to very concave with poor muscle development. In addition, the degree of fat cover describes the amount of fat on the outside of the carcass and in the thoracic cavity. The class of fat cover classified as 1 (low) describes none to low fat cover, and the class of fat cover classified as 5 (very high) describes an entire carcass covered with fat and with heavy fat deposits in the thoracic cavity. Dressing percentage was calculated dividing on HCW by BW before slaughter. Rumen and Liver Macroscopic Evaluation Rumens were divided into areas according to Lesmeister et al. (2004) to examine the presence of ulcers and presence of clumped papillae (Nocek et al., 1984). Also, rumens were classified from 1 to 5 depending on the color, being “5” a black colored rumen and “1” a white colored rumen (González et al., 2001). Liver abscesses were classified according to Brown et al. (1975). Chemical Analyses Feed samples were analyzed for DM (24 h at 103°C), ash (4 h at 550°C), CP by the Kjeldahl method (method 981.10; AOAC, 1995), NDF according to Van Soest et al. (1991) using sodium sulfite and α-amylase, and ether extract by Soxhlet with a previous acid hydrolysis (method 920.39; AOAC, 1995). Rumen VFA concentration was analyzed with a semicapillary column (15 m by 0.53 mm i.d. and 0.5-µm film thickness; TRB-FFAP; Teknokroma, Barcelona, Spain) composed of 100% polyethylene glycol esterified with nitroterephtalic acid, bonded and cross-linked phase, using a CP-3800-GC (Varian, Inc., Walnut Creek, CA). Plasma glucose concentration was determined following the hexokinase method (Tietz, 1995; intra- and interassay CV of 0.6 and 3.0%, respectively), and serum insulin concentration was determined using Porcine Insulin RIA (kit PI-12K; Millipore, Billerica, MA) with intra- and interassay CV of 4.8 and 5.8%, respectively. Plasma NEFA concentration was determined by the colorimetric enzymatic test ACS-ACOD-MEHA (acyl-CoA-synthetase/acyl-CoA-oxidase/3-methyl-N-ethyl-N-β-hydroxyethyl-aniline) method (NEFA C; Wako Chemicals, Neuss, Germany; with an intra- and interassay CV of 2.7 and 4.8%, respectively). Haptoglobin was determined by the hemoglobin binding method with the use of a commercial haptoglobin colorimetric assay (Assay Phase Range; Tridelta Development Limited, Maynooth, Ireland); the intra- and interassay CV were 4.1 and 11.2%, respectively. Calculations and Statistical Analyses The frequency of each social behavior was obtained by summing by day, pen, and scan, and they were transformed into the root of the sum of each activity plus 1 to achieve a normal distribution. The percentage of each general activity was averaged by day, pen, and scan, and it was transformed into natural logarithms to achieve a normal distribution. Serum metabolites and pH data were transformed into natural logarithms to achieve a normal distribution. The means presented in the tables correspond to back-transformed data, and SEM and P-values correspond to the ANOVA analyses of the transformed data. The occupancy time of concentrate feeder (min) and total waiting time to access to the feeder (min) were calculated as the sum of total time performing these activities per day and pen. The number of bulls eating concentrate and number of visits at concentrate feeder were averaged by pen and day. Number of displacements at the feeder were summed by pen and by hour and divided by total time analyzed to express as frequency of displacements per hour. Feeder occupancy and waiting time data were expressed as the percentage of time devoted to these activities from total daily time of video recording analyzed (12 h). All eating behavior data were corrected by the number of animals within the pen for each filming period. The pen was considered the experimental unit for all statistical analysis (n = 4), with animals considered sampling units. Hence, a power analysis was conducted to check if 4 replicates per treatment would be sufficient to detect differences in feed consumption. The power analyses was conducted for the primary outcome variable (concentrate consumption) using the SD of this parameter between pens observed in previous studies under same experimental conditions (Devant et al., 2012; Marti et al., 2013), an α of 0.05, and a power of 0.80. The power analysis indicated at least that 3 replicates (pens) per treatment were necessary to detect expected differences among treatments. An expected 10% in total concentrate consumption difference among treatments was expected; this expectation was based on previous studies data (Devant et al., 2012; Marti et al., 2013). To the extent that individual measurements on animals were possible, animals were included in the analyses as sampling unit and not as experimental unit (like a repeated measure typically seen with several determinations on the same animal over time). This allowed the use of covariate measurements on the animals (sampling units). So the covariate adjustments were done on the individual animals. Consumption, performance, and eating and animal behavior data were analyzed using a mixed-effects model with repeated measures (version 9.2; SAS Inst., Inc., Cary, NC). The model included initial full BW as a covariate; treatment, period (14 d for consumption and performance data; 3 times throughout the study for eating behavior data; weekly for first month and 28 d for the remaining of study for animal behavior data), and their interaction as fixed effects; and pen and fattening cycle as random effects. Period was considered a repeated factor, and pen nested within treatment was subjected to 3 variance–covariance structures: compound symmetry, autoregressive order 1, and unstructured. The covariance structure that yielded the smallest Schwarz's Bayesian information criterion was considered the most desirable analysis. Rumen and serum metabolites were analyzed using mixed-effects ANOVA with repeated measures (version 9.2; SAS Inst., Inc.). The model was the same as the previous one, but sampling time (time of the day when the animal was sampled) was also included as a covariate for pH and VFA data. Initial full BW, age, final BW, and carcass data were analyzed using a mixed-effects model (version 9.2; SAS Inst., Inc.) including treatment as a fixed effect and pen and fattening cycle as a random effects. Carcass conformation and fatness, rumen wall macroscopic evaluation and liver lesions data, and animal health records were analyzed with the PROC FREQ of SAS with a χ2 distribution (version 9.2; SAS Inst., Inc.). Significance was established at P < 0.05, and trends were discussed as P ≤ 0.10. RESULTS Animal Health Records Thirteen animals were removed from the study due to health problems (2 bulls from the CF treatment, 6 bulls from the CFL treatment, and 5 bulls from the SF treatment). During first month after entrance, 2 animals from the CF and CFL treatments died from unknown causes and 2 others from SF group were removed for inability to adapt to the feeding system. In the second month of the study, 1 bull from the CFL treatment died because of bloat. The remaining of animals were sent to the slaughterhouse before the end of study: 3 bulls from the CFL treatment due to weight loss, 4 animals as a result of chronic pneumonia (1 from the CF treatment, 1 from the CFL treatment, and 2 from the SF treatment), and 1 bull from the SF treatment due to chronic lameness. No differences (P > 0.10) among fattening cycles and treatments were found in health problems. Consumption, Performance, and Carcass Quality Daily concentrate consumption (6.2 ± 0.17 kg of DM/d) and straw consumption (0.7 ± 0.07 kg of DM/d) were not affected by feeder design (Table 4). However, cumulative concentrate consumption per animal throughout the study tended (P = 0.09) to be greater in CF (1,322 ± 19.3 kg of DM) than in CFL (1,264 ± 19.3 kg of DM) and SF (1,234 ± 19.3 kg of DM). Also, feeder design did not influence ADG (1.51 ± 0.035 kg/d) and feed efficiency (0.25 ± 0.005 kg/kg). However, CV of concentrate consumption was greater (P < 0.01) in SF bulls (8.7 ± 0.75%) than in CF (7.7 ± 0.75%) and CFL (7.3 ± 0.75%) bulls. Table 4. Performance and concentrate consumption of Holstein bulls fed a high-concentrate diet with different concentrate feeder designs for 214 d of study   Treatment1    P-value2  Item  CF  CFL  SF  SEM  Trt  Per  Trt × Per  Days of study, d  214.5  214.5  214.5  0.00  1.00      Initial age, d  98.9  99.3  99.3  8.23  0.96      Initial BW, kg  121.1  120.7  121.0  7.61  0.32      Final BW, kg  449.8  445.4  441.4  3.27  0.20      Concentrate DM consumption      Mean, kg/d  6.4  6.2  6.0  0.17  0.15  <0.01  0.84      CV, %  7.7b  7.3b  8.7a  0.75  0.01  <0.01  0.44      Accumulative concentrate DM consumption after 214 d, kg  1,322  1,264  1,234  19.3  0.09          Straw DM consumption, kg/d  0.7  0.7  0.7  0.07  0.80  <0.01  0.28      ADG, kg/d  1.54  1.50  1.49  0.035  0.44  <0.01  0.98      Gain to concentrate ratio, kg/kg  0.25  0.25  0.26  0.005  0.40  <0.01  0.99    Treatment1    P-value2  Item  CF  CFL  SF  SEM  Trt  Per  Trt × Per  Days of study, d  214.5  214.5  214.5  0.00  1.00      Initial age, d  98.9  99.3  99.3  8.23  0.96      Initial BW, kg  121.1  120.7  121.0  7.61  0.32      Final BW, kg  449.8  445.4  441.4  3.27  0.20      Concentrate DM consumption      Mean, kg/d  6.4  6.2  6.0  0.17  0.15  <0.01  0.84      CV, %  7.7b  7.3b  8.7a  0.75  0.01  <0.01  0.44      Accumulative concentrate DM consumption after 214 d, kg  1,322  1,264  1,234  19.3  0.09          Straw DM consumption, kg/d  0.7  0.7  0.7  0.07  0.80  <0.01  0.28      ADG, kg/d  1.54  1.50  1.49  0.035  0.44  <0.01  0.98      Gain to concentrate ratio, kg/kg  0.25  0.25  0.26  0.005  0.40  <0.01  0.99  a–cMeans within a row with different superscripts are differ (P < 0.05). 1Treatments were different concentrate feeder design. CF = a control feeder with 4 feeding spaces; CFL = a feeder with less concentrate capacity; SF = a single-space feeder with lateral protections. 2Fixed effects were treatment (Trt), period (Per), and interaction between treatment and period (Trt × Per). View Large Table 4. Performance and concentrate consumption of Holstein bulls fed a high-concentrate diet with different concentrate feeder designs for 214 d of study   Treatment1    P-value2  Item  CF  CFL  SF  SEM  Trt  Per  Trt × Per  Days of study, d  214.5  214.5  214.5  0.00  1.00      Initial age, d  98.9  99.3  99.3  8.23  0.96      Initial BW, kg  121.1  120.7  121.0  7.61  0.32      Final BW, kg  449.8  445.4  441.4  3.27  0.20      Concentrate DM consumption      Mean, kg/d  6.4  6.2  6.0  0.17  0.15  <0.01  0.84      CV, %  7.7b  7.3b  8.7a  0.75  0.01  <0.01  0.44      Accumulative concentrate DM consumption after 214 d, kg  1,322  1,264  1,234  19.3  0.09          Straw DM consumption, kg/d  0.7  0.7  0.7  0.07  0.80  <0.01  0.28      ADG, kg/d  1.54  1.50  1.49  0.035  0.44  <0.01  0.98      Gain to concentrate ratio, kg/kg  0.25  0.25  0.26  0.005  0.40  <0.01  0.99    Treatment1    P-value2  Item  CF  CFL  SF  SEM  Trt  Per  Trt × Per  Days of study, d  214.5  214.5  214.5  0.00  1.00      Initial age, d  98.9  99.3  99.3  8.23  0.96      Initial BW, kg  121.1  120.7  121.0  7.61  0.32      Final BW, kg  449.8  445.4  441.4  3.27  0.20      Concentrate DM consumption      Mean, kg/d  6.4  6.2  6.0  0.17  0.15  <0.01  0.84      CV, %  7.7b  7.3b  8.7a  0.75  0.01  <0.01  0.44      Accumulative concentrate DM consumption after 214 d, kg  1,322  1,264  1,234  19.3  0.09          Straw DM consumption, kg/d  0.7  0.7  0.7  0.07  0.80  <0.01  0.28      ADG, kg/d  1.54  1.50  1.49  0.035  0.44  <0.01  0.98      Gain to concentrate ratio, kg/kg  0.25  0.25  0.26  0.005  0.40  <0.01  0.99  a–cMeans within a row with different superscripts are differ (P < 0.05). 1Treatments were different concentrate feeder design. CF = a control feeder with 4 feeding spaces; CFL = a feeder with less concentrate capacity; SF = a single-space feeder with lateral protections. 2Fixed effects were treatment (Trt), period (Per), and interaction between treatment and period (Trt × Per). View Large Carcass data are presented in Table 5. Feeder design did not affect slaughter BW (461 ± 10.3 kg), HCW (247 ± 4.7 kg), dressing percentage (53.6 ± 0.29%), carcass conformation (97.3% classified as “O”), and carcass fatness (65.6% classified as “2”). Table 5. Carcass characteristics from Holstein bulls fed a high-concentrate diet with different concentrate feeder designs after a 223-d fattening period   Treatment1      Item  CF  CFL  SF  SEM  P-value  No.  76  72  72      Days of study, d  223.1  223.1  223.1  1.26  1.00  Slaughter age, d  322.2  322.5  321.9  6.55  0.93  Slaughter BW, kg  464.8  462.8  456.5  10.30  0.21  HCW, kg  249.7  247.9  244.1  4.70  0.15  Dressing percentage, %  53.7  53.6  53.5  0.29  0.78  Conformation,2 %      P  1.3  2.8  2.8    0.67      O  97.4  97.2  97.2          R  1.3  0  0      Fatness,3 %      1  6.6  4.1  5.5    0.84      2  60.5  68.1  68.1          3  32.9  27.8  26.4        Treatment1      Item  CF  CFL  SF  SEM  P-value  No.  76  72  72      Days of study, d  223.1  223.1  223.1  1.26  1.00  Slaughter age, d  322.2  322.5  321.9  6.55  0.93  Slaughter BW, kg  464.8  462.8  456.5  10.30  0.21  HCW, kg  249.7  247.9  244.1  4.70  0.15  Dressing percentage, %  53.7  53.6  53.5  0.29  0.78  Conformation,2 %      P  1.3  2.8  2.8    0.67      O  97.4  97.2  97.2          R  1.3  0  0      Fatness,3 %      1  6.6  4.1  5.5    0.84      2  60.5  68.1  68.1          3  32.9  27.8  26.4      1Treatments were different concentrate feeder design. CF = a control feeder with 4 feeding spaces; CFL = a feeder with less concentrate capacity; SF = a single-space feeder with lateral protections. 2Graded according to the European Union classification system into (S)EUROP categories (European Union regulation number 1208/81 and 1026/91). The conformation class designated by the letter “E” (excellent) describes carcasses with all profiles convex to superconvex, and with exceptional muscle development, whereas the conformation classified as “U” (very good) describes carcasses with profiles on the whole convex, and with very good muscle development. The carcasses classified as “R” (good) present profiles on the whole straight and good muscle development. Carcasses classified as “O” (fair) present profiles straight to concave, and with average muscle development, whereas carcasses classified as “P” (poor) present all profiles concave to very concave with poor muscle development. In addition, the degree of fat cover describes the amount of fat on the outside of the carcass and in the thoracic cavity. 3Graded according to the EU classification system into 1.2.3.4.5 (EU Regulation No. 1208/81).The carcass fat cover that classifies as 1 (low) describes none to low fat cover, the class of fat cover classified as 5 (very high) describes an entire carcass covered with fat and with heavy fat deposits in the thoracic cavity.. View Large Table 5. Carcass characteristics from Holstein bulls fed a high-concentrate diet with different concentrate feeder designs after a 223-d fattening period   Treatment1      Item  CF  CFL  SF  SEM  P-value  No.  76  72  72      Days of study, d  223.1  223.1  223.1  1.26  1.00  Slaughter age, d  322.2  322.5  321.9  6.55  0.93  Slaughter BW, kg  464.8  462.8  456.5  10.30  0.21  HCW, kg  249.7  247.9  244.1  4.70  0.15  Dressing percentage, %  53.7  53.6  53.5  0.29  0.78  Conformation,2 %      P  1.3  2.8  2.8    0.67      O  97.4  97.2  97.2          R  1.3  0  0      Fatness,3 %      1  6.6  4.1  5.5    0.84      2  60.5  68.1  68.1          3  32.9  27.8  26.4        Treatment1      Item  CF  CFL  SF  SEM  P-value  No.  76  72  72      Days of study, d  223.1  223.1  223.1  1.26  1.00  Slaughter age, d  322.2  322.5  321.9  6.55  0.93  Slaughter BW, kg  464.8  462.8  456.5  10.30  0.21  HCW, kg  249.7  247.9  244.1  4.70  0.15  Dressing percentage, %  53.7  53.6  53.5  0.29  0.78  Conformation,2 %      P  1.3  2.8  2.8    0.67      O  97.4  97.2  97.2          R  1.3  0  0      Fatness,3 %      1  6.6  4.1  5.5    0.84      2  60.5  68.1  68.1          3  32.9  27.8  26.4      1Treatments were different concentrate feeder design. CF = a control feeder with 4 feeding spaces; CFL = a feeder with less concentrate capacity; SF = a single-space feeder with lateral protections. 2Graded according to the European Union classification system into (S)EUROP categories (European Union regulation number 1208/81 and 1026/91). The conformation class designated by the letter “E” (excellent) describes carcasses with all profiles convex to superconvex, and with exceptional muscle development, whereas the conformation classified as “U” (very good) describes carcasses with profiles on the whole convex, and with very good muscle development. The carcasses classified as “R” (good) present profiles on the whole straight and good muscle development. Carcasses classified as “O” (fair) present profiles straight to concave, and with average muscle development, whereas carcasses classified as “P” (poor) present all profiles concave to very concave with poor muscle development. In addition, the degree of fat cover describes the amount of fat on the outside of the carcass and in the thoracic cavity. 3Graded according to the EU classification system into 1.2.3.4.5 (EU Regulation No. 1208/81).The carcass fat cover that classifies as 1 (low) describes none to low fat cover, the class of fat cover classified as 5 (very high) describes an entire carcass covered with fat and with heavy fat deposits in the thoracic cavity.. View Large Animal Behavior General Activities. During the 2.5-h observation period in the morning, the percentage of animals per pen standing (66.6 ± 0.06%), lying (33.4 ± 0.11%), drinking (1.9 ± 0.05%), and ruminating (11.3 ± 0.06) were not affected by feeder design and the interaction between day and treatment was not significant (Table 6). During this observation period in the morning, the percentage of animals eating concentrate tended (P = 0.06) to be less for SF (5.7 ± 0.05%) than for CF and CFL (10.7 ± 0.05%) throughout the study. Exceptionally, for the first 3 d of the study, this interaction was not observed because chute was widened, and more than 1 animal was often recorded at the feeder. Also, in the morning and throughout the study, a greater (P < 0.01) proportion of animals in SF pens were eating straw (12.8 ± 0.05%) compared with animals in CF and CFL pens (10.0 ± 0.05%). Table 6. Percentages of general activities (%) from bulls fed a high-concentrate diet with different concentrate feeder designs for 214 d of study recorded by scan sampling   Treatment1    P-value3  Item  CF  CFL  SF  SEM2  Trt  Per  Trt × Per  Standing  63.9  67.1  68.7  0.06  0.22  <0.01  0.14  Lying  36.1  32.9  31.3  0.11  0.29  <0.01  0.31  Eating concentrate  10.8a  10.6a  5.7b  0.05  <0.01  0.15  0.06  Eating straw  10.0b  9.9b  12.8a  0.05  <0.01  0.02  0.33  Drinking  1.8  2.2  1.6  0.05  0.89  0.68  0.37  Ruminating  11.2  10.4  12.2  0.06  0.78  <0.01  0.87    Treatment1    P-value3  Item  CF  CFL  SF  SEM2  Trt  Per  Trt × Per  Standing  63.9  67.1  68.7  0.06  0.22  <0.01  0.14  Lying  36.1  32.9  31.3  0.11  0.29  <0.01  0.31  Eating concentrate  10.8a  10.6a  5.7b  0.05  <0.01  0.15  0.06  Eating straw  10.0b  9.9b  12.8a  0.05  <0.01  0.02  0.33  Drinking  1.8  2.2  1.6  0.05  0.89  0.68  0.37  Ruminating  11.2  10.4  12.2  0.06  0.78  <0.01  0.87  a–cMeans within a row with different superscripts are differ (P < 0.05). 1Treatments were different concentrate feeder design. CF = a control feeder with 4 feeding spaces; CFL = a feeder with less concentrate capacity; SF = a single-space feeder with lateral protections. 2The values presented herein correspond to back-transformed means; however, SEM and P-values correspond to the ANOVA analyses using log-transformed data. 3Fixed effects were treatment (Trt), period (Per), and interaction between treatment and period (Trt × Per). View Large Table 6. Percentages of general activities (%) from bulls fed a high-concentrate diet with different concentrate feeder designs for 214 d of study recorded by scan sampling   Treatment1    P-value3  Item  CF  CFL  SF  SEM2  Trt  Per  Trt × Per  Standing  63.9  67.1  68.7  0.06  0.22  <0.01  0.14  Lying  36.1  32.9  31.3  0.11  0.29  <0.01  0.31  Eating concentrate  10.8a  10.6a  5.7b  0.05  <0.01  0.15  0.06  Eating straw  10.0b  9.9b  12.8a  0.05  <0.01  0.02  0.33  Drinking  1.8  2.2  1.6  0.05  0.89  0.68  0.37  Ruminating  11.2  10.4  12.2  0.06  0.78  <0.01  0.87    Treatment1    P-value3  Item  CF  CFL  SF  SEM2  Trt  Per  Trt × Per  Standing  63.9  67.1  68.7  0.06  0.22  <0.01  0.14  Lying  36.1  32.9  31.3  0.11  0.29  <0.01  0.31  Eating concentrate  10.8a  10.6a  5.7b  0.05  <0.01  0.15  0.06  Eating straw  10.0b  9.9b  12.8a  0.05  <0.01  0.02  0.33  Drinking  1.8  2.2  1.6  0.05  0.89  0.68  0.37  Ruminating  11.2  10.4  12.2  0.06  0.78  <0.01  0.87  a–cMeans within a row with different superscripts are differ (P < 0.05). 1Treatments were different concentrate feeder design. CF = a control feeder with 4 feeding spaces; CFL = a feeder with less concentrate capacity; SF = a single-space feeder with lateral protections. 2The values presented herein correspond to back-transformed means; however, SEM and P-values correspond to the ANOVA analyses using log-transformed data. 3Fixed effects were treatment (Trt), period (Per), and interaction between treatment and period (Trt × Per). View Large Social Behavior. During the 2.5-h observation period in the morning, behaviors related to nonagonistic interactions are presented in Table 7. Bulls in SF and CF treatments exhibited more (P < 0.05) oral behavior (7.7 ± 0.12 and 6.9 ± 0.12 times/15 min, respectively) than bulls in the CFL treatment (6.1 ± 0.12 times/15 min). No differences in social behavior were found among treatments (10.4 ± 0.11 times/15 min). The frequency of self-grooming behavior (18.9 ± 0.08 times/15 min) differed (P < 0.05) among treatments depending on the day of sampling. Regarding agonistic behaviors, no differences in fighting (5.6 ± 0.29 times/15 min) and butting (4.1 ± 0.12 times/15 min) behaviors were found among treatments. However, the incidence of displacements was less (P < 0.01) in SF pens (2.2 ± 0.20 times/15 min) in contrast to collective feeders (4.1 ± 0.20 times/15 min). Chasing and chasing-up behaviors differed among treatments over the study (P < 0.05), but these behaviors were exhibited occasionally and their interpretation is difficult. For sexual interactions, no differences among treatments in flehmen (2.9 ± 0.08 times/15 min) were observed; however, CFL bulls exhibited (P < 0.01) more attempted mounts (7.0 ± 0.27 times/15 min) and tended (P = 0.10) to exhibit more completed mounts (3.4 ± 0.12 times/15 min) than CF bulls (4.7 ± 0.27 and 2.2 ± 0.12 times/15 min, respectively). Moreover, no stereotypies were observed throughout the experiment. Table 7. Frequency of social interactions (times of behavior in the pen/15 min) from bulls fed a high-concentrate diet with different concentrate feeder designs for 214 d of study recorded by scan sampling   Treatment1    P-value3  Item  CF  CFL  SF  SEM2  Trt  Per  Trt × Per  Nonagonistic interactions      Self-grooming  18.4  19.4  18.9  0.08  0.61  <0.01  0.04      Social  10.7  10.8  9.8  0.11  0.47  <0.01  0.92      Oral  6.9ab  6.1b  7.7a  0.12  0.03  <0.01  0.48  Agonistic interactions      Fighting  5.6  5.6  5.6  0.29  1.00  <0.01  0.88      Butting  4.2  4.7  3.5  0.12  0.13  <0.01  0.47      Displacements  4.3a  3.8a  2.2b  0.20  <0.01  <0.01  0.81      Chasing  0.7b  1.6a  1.4a  0.06  <0.01  <0.01  <0.01      Chasing-up  0.5ab  0.3b  0.5a  0.08  0.08  <0.01  0.02  Sexual interactions      Flehmen  2.9  2.7  3.0  0.08  0.84  <0.01  0.70      Attempted mounts  4.7b  7.0a  5.9ab  0.27  0.01  <0.01  0.52      Completed mounts  2.2b  3.4a  3.1ab  0.12  0.10  <0.01  0.12    Treatment1    P-value3  Item  CF  CFL  SF  SEM2  Trt  Per  Trt × Per  Nonagonistic interactions      Self-grooming  18.4  19.4  18.9  0.08  0.61  <0.01  0.04      Social  10.7  10.8  9.8  0.11  0.47  <0.01  0.92      Oral  6.9ab  6.1b  7.7a  0.12  0.03  <0.01  0.48  Agonistic interactions      Fighting  5.6  5.6  5.6  0.29  1.00  <0.01  0.88      Butting  4.2  4.7  3.5  0.12  0.13  <0.01  0.47      Displacements  4.3a  3.8a  2.2b  0.20  <0.01  <0.01  0.81      Chasing  0.7b  1.6a  1.4a  0.06  <0.01  <0.01  <0.01      Chasing-up  0.5ab  0.3b  0.5a  0.08  0.08  <0.01  0.02  Sexual interactions      Flehmen  2.9  2.7  3.0  0.08  0.84  <0.01  0.70      Attempted mounts  4.7b  7.0a  5.9ab  0.27  0.01  <0.01  0.52      Completed mounts  2.2b  3.4a  3.1ab  0.12  0.10  <0.01  0.12  a–cMeans within a row with different superscripts are differ (P < 0.05). 1Treatments were different concentrate feeder design. CF = a control feeder with 4 feeding spaces; CFL = a feeder with less concentrate capacity; SF = a single-space feeder with lateral protections. 2The values presented herein correspond to back-transformed means; however, SEM and P-values correspond to the ANOVA analyses using arcsin+1-transformed data. 3Fixed effects were treatment (Trt), period (Per), and interaction between treatment and period (Trt × Per). View Large Table 7. Frequency of social interactions (times of behavior in the pen/15 min) from bulls fed a high-concentrate diet with different concentrate feeder designs for 214 d of study recorded by scan sampling   Treatment1    P-value3  Item  CF  CFL  SF  SEM2  Trt  Per  Trt × Per  Nonagonistic interactions      Self-grooming  18.4  19.4  18.9  0.08  0.61  <0.01  0.04      Social  10.7  10.8  9.8  0.11  0.47  <0.01  0.92      Oral  6.9ab  6.1b  7.7a  0.12  0.03  <0.01  0.48  Agonistic interactions      Fighting  5.6  5.6  5.6  0.29  1.00  <0.01  0.88      Butting  4.2  4.7  3.5  0.12  0.13  <0.01  0.47      Displacements  4.3a  3.8a  2.2b  0.20  <0.01  <0.01  0.81      Chasing  0.7b  1.6a  1.4a  0.06  <0.01  <0.01  <0.01      Chasing-up  0.5ab  0.3b  0.5a  0.08  0.08  <0.01  0.02  Sexual interactions      Flehmen  2.9  2.7  3.0  0.08  0.84  <0.01  0.70      Attempted mounts  4.7b  7.0a  5.9ab  0.27  0.01  <0.01  0.52      Completed mounts  2.2b  3.4a  3.1ab  0.12  0.10  <0.01  0.12    Treatment1    P-value3  Item  CF  CFL  SF  SEM2  Trt  Per  Trt × Per  Nonagonistic interactions      Self-grooming  18.4  19.4  18.9  0.08  0.61  <0.01  0.04      Social  10.7  10.8  9.8  0.11  0.47  <0.01  0.92      Oral  6.9ab  6.1b  7.7a  0.12  0.03  <0.01  0.48  Agonistic interactions      Fighting  5.6  5.6  5.6  0.29  1.00  <0.01  0.88      Butting  4.2  4.7  3.5  0.12  0.13  <0.01  0.47      Displacements  4.3a  3.8a  2.2b  0.20  <0.01  <0.01  0.81      Chasing  0.7b  1.6a  1.4a  0.06  <0.01  <0.01  <0.01      Chasing-up  0.5ab  0.3b  0.5a  0.08  0.08  <0.01  0.02  Sexual interactions      Flehmen  2.9  2.7  3.0  0.08  0.84  <0.01  0.70      Attempted mounts  4.7b  7.0a  5.9ab  0.27  0.01  <0.01  0.52      Completed mounts  2.2b  3.4a  3.1ab  0.12  0.10  <0.01  0.12  a–cMeans within a row with different superscripts are differ (P < 0.05). 1Treatments were different concentrate feeder design. CF = a control feeder with 4 feeding spaces; CFL = a feeder with less concentrate capacity; SF = a single-space feeder with lateral protections. 2The values presented herein correspond to back-transformed means; however, SEM and P-values correspond to the ANOVA analyses using arcsin+1-transformed data. 3Fixed effects were treatment (Trt), period (Per), and interaction between treatment and period (Trt × Per). View Large Eating Behavior There was a statistically significant difference (P < 0.01) among treatments in concentrate disappearance velocity recorded at the feeder (Table 8). Also, there was an interaction between treatment and period in occupancy time of feeder (P < 0.05), number of bulls at the feeder (P < 0.01), number of visits at the feeder (P = 0.09), displacements at the feeder (P < 0.01), and waiting time to access to the feeder (P < 0.01). Animals fed with SF registered less (P < 0.01) concentrate disappearance velocity (140.4 ± 8.35 g/min) than animals fed with CFL (168.9 ± 8.35 g/min) and CF (197.4 ± 8.35 g/min) throughout the study. In the first filming period (d 12), SF bulls recorded greater (P < 0.05) occupancy time at the feeder (90.6 ± 2.58% of total time analyzed, which was 567 ± 19.95 min) compared with CF and CFL bulls (80.6 ± 2.58% of total time analyzed, which was 521 ± 19.95 min). Also, in second filming period (d 125), the occupancy time at the feeder was greater (P < 0.01) in SF (80.9 ± 2.58% of total time analyzed, which was 528 ± 19.95 min) than CFL and CF (65.6 ± 2.58% of total time analyzed, which was 424 ± 19.95 min). However, in the last filming period (d 206), no differences were observed among treatments (62.6 ± 2.58% of total time analyzed, which was 406 ± 19.95 min). Animals in the SF treatment showed fewer (P < 0.01) visits (23.8 ± 24.27 visits/d) than other treatments (137.3 ± 24.27 visits/d) during the first filming period. In the second period, the SF group exhibited less frequent (P < 0.05) feeder visits (44.8 ± 24.27 visits/d) than CF (128.9 ± 24.27 visits/d), whereas in the third period, no differences among treatments were observed (71.7 ± 24.27 visits/d). Whereas in the SF group always 1 animal was registered at the feeder over the study, the number of bulls for CF and CFL changed throughout the study, being 2 animals per feeder in the first filming period and the remaining of fattening the number of bulls decreased to 1.5 animals per feeder. However, the number of displacements registered in CFL and CF was greater in the first filming period (7.8 ± 0.83 and 4.9 ± 0.82, respectively), whereas for the remaining of fattening, the number of displacements reduced in both treatments (1.4 ± 0.82 for second period and 0.8 ± 0.82 for third period). No displacements at the feeder were recorded in SF throughout the study. Although SF animals spent more waiting time to access the concentrate feeder over the study compared with other treatments, this waiting time progressively declined throughout the filming periods (130.2 ± 11.24, 88.4 ± 11.24, and 32.4 ± 11.24 min for first, second, and third period, respectively, which represented 21.2 ± 2.02 %, 13.6 ± 2.02 %, and 5.1 ± 2.02 % of total time analyzed). Table 8. Eating behavior at concentrate feeder on d 12, 125, and 206 of the study from bulls fed a high-concentrate diet with different concentrate feeder designs, from recording videos (0600 to 1800 h)   Treatment1  SEM  P-value2  Item  CF  CFL  SF    Trt  Per  Trt × Per  Concentrate disappearance velocity, g/min  197.4a  168.9b  140.4c  8.35  <0.01  <0.01  0.26  Total time analyzed, min/d  644.6  644.6  641.4  5.52  0.84  0.72  0.50  Occupancy time of feeder, min/d  438.3  459.2  500.1  32.71  0.02  <0.01  0.05  Occupancy rate of feeder, % of time  67.8  71.3  77.7  5.61  <0.01  <0.01  0.04  Number of bulls at the feeder  1.8  1.6  1.0  0.12  <0.01  <0.01  <0.01  Number of visits at the feeder  112.5  102.6  41.0  16.7  <0.01  0.18  0.09  Displacements at the feeder, no./h  2.3  3.4  0.0  0.48  <0.01  <0.01  0.01  Waiting time to access to the feeder, min/day  4.1  2.5  83.7  9.57  <0.01  <0.01  <0.01  Waiting time rate to access to the feeder, % of time  0.6  0.4  13.3  1.69  <0.01  <0.01  <0.01    Treatment1  SEM  P-value2  Item  CF  CFL  SF    Trt  Per  Trt × Per  Concentrate disappearance velocity, g/min  197.4a  168.9b  140.4c  8.35  <0.01  <0.01  0.26  Total time analyzed, min/d  644.6  644.6  641.4  5.52  0.84  0.72  0.50  Occupancy time of feeder, min/d  438.3  459.2  500.1  32.71  0.02  <0.01  0.05  Occupancy rate of feeder, % of time  67.8  71.3  77.7  5.61  <0.01  <0.01  0.04  Number of bulls at the feeder  1.8  1.6  1.0  0.12  <0.01  <0.01  <0.01  Number of visits at the feeder  112.5  102.6  41.0  16.7  <0.01  0.18  0.09  Displacements at the feeder, no./h  2.3  3.4  0.0  0.48  <0.01  <0.01  0.01  Waiting time to access to the feeder, min/day  4.1  2.5  83.7  9.57  <0.01  <0.01  <0.01  Waiting time rate to access to the feeder, % of time  0.6  0.4  13.3  1.69  <0.01  <0.01  <0.01  a–cMeans within a row with different superscripts are differ (P < 0.05). 1Treatments were different concentrate feeder design. CF = a control feeder with 4 feeding spaces; CFL = a feeder with less concentrate capacity; SF = a single-space feeder with lateral protections. 2Fixed effects were treatment (Trt), period (Per), and interaction between treatment and period (Trt × Per). View Large Table 8. Eating behavior at concentrate feeder on d 12, 125, and 206 of the study from bulls fed a high-concentrate diet with different concentrate feeder designs, from recording videos (0600 to 1800 h)   Treatment1  SEM  P-value2  Item  CF  CFL  SF    Trt  Per  Trt × Per  Concentrate disappearance velocity, g/min  197.4a  168.9b  140.4c  8.35  <0.01  <0.01  0.26  Total time analyzed, min/d  644.6  644.6  641.4  5.52  0.84  0.72  0.50  Occupancy time of feeder, min/d  438.3  459.2  500.1  32.71  0.02  <0.01  0.05  Occupancy rate of feeder, % of time  67.8  71.3  77.7  5.61  <0.01  <0.01  0.04  Number of bulls at the feeder  1.8  1.6  1.0  0.12  <0.01  <0.01  <0.01  Number of visits at the feeder  112.5  102.6  41.0  16.7  <0.01  0.18  0.09  Displacements at the feeder, no./h  2.3  3.4  0.0  0.48  <0.01  <0.01  0.01  Waiting time to access to the feeder, min/day  4.1  2.5  83.7  9.57  <0.01  <0.01  <0.01  Waiting time rate to access to the feeder, % of time  0.6  0.4  13.3  1.69  <0.01  <0.01  <0.01    Treatment1  SEM  P-value2  Item  CF  CFL  SF    Trt  Per  Trt × Per  Concentrate disappearance velocity, g/min  197.4a  168.9b  140.4c  8.35  <0.01  <0.01  0.26  Total time analyzed, min/d  644.6  644.6  641.4  5.52  0.84  0.72  0.50  Occupancy time of feeder, min/d  438.3  459.2  500.1  32.71  0.02  <0.01  0.05  Occupancy rate of feeder, % of time  67.8  71.3  77.7  5.61  <0.01  <0.01  0.04  Number of bulls at the feeder  1.8  1.6  1.0  0.12  <0.01  <0.01  <0.01  Number of visits at the feeder  112.5  102.6  41.0  16.7  <0.01  0.18  0.09  Displacements at the feeder, no./h  2.3  3.4  0.0  0.48  <0.01  <0.01  0.01  Waiting time to access to the feeder, min/day  4.1  2.5  83.7  9.57  <0.01  <0.01  <0.01  Waiting time rate to access to the feeder, % of time  0.6  0.4  13.3  1.69  <0.01  <0.01  <0.01  a–cMeans within a row with different superscripts are differ (P < 0.05). 1Treatments were different concentrate feeder design. CF = a control feeder with 4 feeding spaces; CFL = a feeder with less concentrate capacity; SF = a single-space feeder with lateral protections. 2Fixed effects were treatment (Trt), period (Per), and interaction between treatment and period (Trt × Per). View Large Rumen Liquid Determinations, Macroscopic Rumen Wall Evaluation, and Liver Abscesses An interaction between treatment and time (P < 0.05) was found in rumen pH and total VFA concentration (Table 9). At the beginning of the study (d 7), rumen pH of the SF (6.1 ± 0.01) was greater (P < 0.01) than CF and CFL (5.5 ± 0.01), whereas rumen VFA concentration in SF (96.3 ± 15.54 mM) was less (P < 0.01) than those found for CF and CFL (129.8 ± 15.53 mM). In the middle of the study (d 120), no statistical differences in average rumen pH (6.3 ± 0.01) and total VFA concentration (136.3 ± 15.51 mM) were observed among treatments. At the end of study (d 204), CF animals had lower (P < 0.05) rumen pH (5.8 ± 0.01) than CFL and SF (6.1 ± 0.01) animals, and opposite to rumen pH, total VFA concentration was greater (P = 0.10) in CF (138.9 ± 15.54 mM) compared with CFL and SF (113.9 ± 15.54 mM). Table 9. Rumen pH, total VFA concentration, and VFA proportions from bulls fed a high-concentrate diet with different concentrate feeder designs for 214 d of study   Treatment1    P-value3  Item  CF  CFL  SF  SEM2  Trt  Per  Trt × Per  pH  5.9  6.0  6.2  0.01  0.13  <0.01  <0.01  Total VFA, mM  134.3  126.9  115.9  14.62  0.17  0.03  0.04  VFA proportion, mol/100 mol      Acetate  49.3  49.8  50.3  0.69  0.57  0.01  0.22      Propionate  39.8  39.0  38.4  0.66  0.39  0.05  0.09      Butyrate  7.4  7.4  7.2  0.38  0.78  0.02  0.48      Isobutyrate  0.6  0.7  0.8  0.11  0.19  <0.01  <0.01      Valerate  1.9  2.0  2.1  0.34  0.54  <0.01  0.56      Isovalerate  0.9  1.1  1.1  0.11  0.41  <0.01  0.05      Acetate:propionate  1.3  1.3  1.4  0.05  0.12  0.27  0.06    Treatment1    P-value3  Item  CF  CFL  SF  SEM2  Trt  Per  Trt × Per  pH  5.9  6.0  6.2  0.01  0.13  <0.01  <0.01  Total VFA, mM  134.3  126.9  115.9  14.62  0.17  0.03  0.04  VFA proportion, mol/100 mol      Acetate  49.3  49.8  50.3  0.69  0.57  0.01  0.22      Propionate  39.8  39.0  38.4  0.66  0.39  0.05  0.09      Butyrate  7.4  7.4  7.2  0.38  0.78  0.02  0.48      Isobutyrate  0.6  0.7  0.8  0.11  0.19  <0.01  <0.01      Valerate  1.9  2.0  2.1  0.34  0.54  <0.01  0.56      Isovalerate  0.9  1.1  1.1  0.11  0.41  <0.01  0.05      Acetate:propionate  1.3  1.3  1.4  0.05  0.12  0.27  0.06  1Treatments were different concentrate feeder design. CF = a control feeder with 4 feeding spaces; CFL = a feeder with less concentrate capacity; SF = a single-space feeder with lateral protections. 2pH data here in presented correspond to back-transformed means; however, SEM and P-values correspond to the ANOVA analyses using log-transformed data. 3Fixed effects were treatment (Trt), period (Per), and interaction between treatment and period (Trt × Per). View Large Table 9. Rumen pH, total VFA concentration, and VFA proportions from bulls fed a high-concentrate diet with different concentrate feeder designs for 214 d of study   Treatment1    P-value3  Item  CF  CFL  SF  SEM2  Trt  Per  Trt × Per  pH  5.9  6.0  6.2  0.01  0.13  <0.01  <0.01  Total VFA, mM  134.3  126.9  115.9  14.62  0.17  0.03  0.04  VFA proportion, mol/100 mol      Acetate  49.3  49.8  50.3  0.69  0.57  0.01  0.22      Propionate  39.8  39.0  38.4  0.66  0.39  0.05  0.09      Butyrate  7.4  7.4  7.2  0.38  0.78  0.02  0.48      Isobutyrate  0.6  0.7  0.8  0.11  0.19  <0.01  <0.01      Valerate  1.9  2.0  2.1  0.34  0.54  <0.01  0.56      Isovalerate  0.9  1.1  1.1  0.11  0.41  <0.01  0.05      Acetate:propionate  1.3  1.3  1.4  0.05  0.12  0.27  0.06    Treatment1    P-value3  Item  CF  CFL  SF  SEM2  Trt  Per  Trt × Per  pH  5.9  6.0  6.2  0.01  0.13  <0.01  <0.01  Total VFA, mM  134.3  126.9  115.9  14.62  0.17  0.03  0.04  VFA proportion, mol/100 mol      Acetate  49.3  49.8  50.3  0.69  0.57  0.01  0.22      Propionate  39.8  39.0  38.4  0.66  0.39  0.05  0.09      Butyrate  7.4  7.4  7.2  0.38  0.78  0.02  0.48      Isobutyrate  0.6  0.7  0.8  0.11  0.19  <0.01  <0.01      Valerate  1.9  2.0  2.1  0.34  0.54  <0.01  0.56      Isovalerate  0.9  1.1  1.1  0.11  0.41  <0.01  0.05      Acetate:propionate  1.3  1.3  1.4  0.05  0.12  0.27  0.06  1Treatments were different concentrate feeder design. CF = a control feeder with 4 feeding spaces; CFL = a feeder with less concentrate capacity; SF = a single-space feeder with lateral protections. 2pH data here in presented correspond to back-transformed means; however, SEM and P-values correspond to the ANOVA analyses using log-transformed data. 3Fixed effects were treatment (Trt), period (Per), and interaction between treatment and period (Trt × Per). View Large Treatment did not affect total rumen VFA concentration and rumen molar proportions of acetate, butyrate, and valerate (Table 9). However, for rumen proportion of propionate (P = 0.09), isobutyrate (P < 0.01), and isovalerate (P < 0.05) and acetate to propionate ratio (P = 0.06), the interaction between treatment and time tended to be or was significant. At the beginning of the study (d 7), for SF animals, rumen proportion of propionate tended (P = 0.08) to be less (38.0 ± 1.03%), isobutyrate percentage (0.9 ± 0.12%) was greater (P < 0.01), and isovalerate proportion (1.1 ± 0.13%) tended (P = 0.10) to be greater compared with other treatments (41.9 ± 1.03, 0.5 ± 0.12, and 0.7 ± 0.13%, respectively). Moreover, at the beginning of the study (d 7), acetate to propionate ratio from SF animals (1.5 ± 0.08) was greater (P < 0.05) compared with CFL and CF (1.2 ± 0.08). No differences among treatments (data not shown) in rumen color (47% classified as “3” and 47% classified as “4”), presence of clumped papillae (21.6% of clumped papillae), or presence of ulcers (0% ulcers) were found. No liver abscesses were detected at slaughterhouse. Serum Metabolites A treatment × time interaction was detected (P < 0.05) in serum NEFA and insulin concentrations (Table 10). Serum NEFA concentration was greater (P < 0.05) at the beginning of the study (d 7) in SF (0.20 ± 0.021 mmol/L) compared with CFL and CF (0.15 ± 0.021 mmol/L) animals. However, at the middle of the study (d 120), serum NEFA concentration was less (P < 0.01) for SF (0.16 ± 0.021 mmol/L) than CFL and CF (0.19 ± 0.021 mmol/L). However, at the end of the study (d 204), no differences among treatments in serum NEFA concentration were observed (0.16 ± 0.021 mmol/L). Serum insulin concentration did not differ among treatments at the beginning (d 7) and in the middle of the study (d 120); however, at the end of the study (d 204), serum insulin concentration tended (P = 0.10) to be greater for CF (1.06 ± 0.025 μg/L) compared with CFL and SF (0.82 ± 0.025 and 0.92 ± 0.025 μg/L, respectively). Plasma glucose, insulin to glucose ratio, and serum haptoglobin were not affected by feeder design. Table 10. Serum physiological parameters from bulls fed a high-concentrate diet with different concentrate feeder designs for 214 d of study   Treatment1    P-value3  Item  CF  CFL  SF  SEM2  Trt  Per  Trt × Per  NEFA, mmol/L  0.16  0.17  0.16  0.012  0.18  0.03  0.02  Haptoglobin, mg/mL  0.15  0.15  0.15  0.013  0.98  0.59  0.18  Glucose, g/L  0.87  0.87  0.86  0.006  0.66  <0.01  0.87  Insulin, μg/L  0.71  0.67  0.66  0.016  0.47  <0.01  0.02  Insulin:glucose, μg/g  0.82  0.77  0.77  0.020  0.65  0.01  0.34    Treatment1    P-value3  Item  CF  CFL  SF  SEM2  Trt  Per  Trt × Per  NEFA, mmol/L  0.16  0.17  0.16  0.012  0.18  0.03  0.02  Haptoglobin, mg/mL  0.15  0.15  0.15  0.013  0.98  0.59  0.18  Glucose, g/L  0.87  0.87  0.86  0.006  0.66  <0.01  0.87  Insulin, μg/L  0.71  0.67  0.66  0.016  0.47  <0.01  0.02  Insulin:glucose, μg/g  0.82  0.77  0.77  0.020  0.65  0.01  0.34  1Treatments were different concentrate feeder design. CF = a control feeder with 4 feeding spaces; CFL = a feeder with less concentrate capacity; SF = a single-space feeder with lateral protections. 2The values presented herein correspond to back-transformed means; however, SEM and P-values correspond to the ANOVA analyses using log-transformed data. 3Fixed effects were treatment (Trt), period (Per), and interaction between treatment and period (Trt × Per). View Large Table 10. Serum physiological parameters from bulls fed a high-concentrate diet with different concentrate feeder designs for 214 d of study   Treatment1    P-value3  Item  CF  CFL  SF  SEM2  Trt  Per  Trt × Per  NEFA, mmol/L  0.16  0.17  0.16  0.012  0.18  0.03  0.02  Haptoglobin, mg/mL  0.15  0.15  0.15  0.013  0.98  0.59  0.18  Glucose, g/L  0.87  0.87  0.86  0.006  0.66  <0.01  0.87  Insulin, μg/L  0.71  0.67  0.66  0.016  0.47  <0.01  0.02  Insulin:glucose, μg/g  0.82  0.77  0.77  0.020  0.65  0.01  0.34    Treatment1    P-value3  Item  CF  CFL  SF  SEM2  Trt  Per  Trt × Per  NEFA, mmol/L  0.16  0.17  0.16  0.012  0.18  0.03  0.02  Haptoglobin, mg/mL  0.15  0.15  0.15  0.013  0.98  0.59  0.18  Glucose, g/L  0.87  0.87  0.86  0.006  0.66  <0.01  0.87  Insulin, μg/L  0.71  0.67  0.66  0.016  0.47  <0.01  0.02  Insulin:glucose, μg/g  0.82  0.77  0.77  0.020  0.65  0.01  0.34  1Treatments were different concentrate feeder design. CF = a control feeder with 4 feeding spaces; CFL = a feeder with less concentrate capacity; SF = a single-space feeder with lateral protections. 2The values presented herein correspond to back-transformed means; however, SEM and P-values correspond to the ANOVA analyses using log-transformed data. 3Fixed effects were treatment (Trt), period (Per), and interaction between treatment and period (Trt × Per). View Large DISCUSSION A Control Feeder with 4 Feeding Spaces vs. a Feeder with Less Concentrate Capacity Reducing concentrate capacity due to less feeder depth tended to reduce cumulative concentrate consumption by 58 kg after 214 d, which corresponds to a 4.4% reduction. It could be expected that the reduced concentrate level at the feeder may have limited the concentrate availability and concentrate consumption and, in consequence, may have reduced animal growth. However, in the present study, no differences in G:F and ADG among treatments were observed. Furthermore, in the present study, no differences among CF and CFL in serum glucose and NEFA concentration were observed; only at the end of the study serum was insulin concentration less for CFL compared with CF. This decrease in serum insulin concentration could indicate that CFL bulls could be limited at the end of the study. Murphy et al. (1994) did not observe differences in serum glucose and insulin concentration when comparing steers fed high-concentrate diets ad libitum with steers submitted to an intake restriction of 30% during 14 d. However, Schoonmaker et al. (2003) reported a decrease in serum glucose and insulin concentration when steers were restricted to a 30% of total intake during 100 d. Moreover, at the end of our study, average daily concentrate DM consumption during this period was similar for both treatments (8.0 ± 0.24 kg/d). This concentrate consumption data, in addition to the serum NEFA concentration and ADG data, would refute the hypothesis that the reduction of the concentrate level restricted concentrate consumption. Therefore, the reduction in concentrate consumption for CFL compared with CF animals may be explained by greater concentrate wastage of the CF animals due to feeder design (Myers et al., 2012). It could be expected that by decreasing the level of concentrate in the feeder, animal competition for eating could increase; in the present study, 2 indicators of the competition at the feeder were measured, concentrate disappearance velocity and displacements at the feeder. The concentrate disappearance velocity, as an indicator of eating rate, is often considered an indirect indicator of competition in the feeder (González et al., 2008). In the present study, in contrast to expectations, eating rate was decreased by 14.4% when concentrate level was reduced at the feeder. One explanation could be that eating rate or velocity of concentrate disappearance at the feeder in the present study was more related to feed spillage than to “real” eating rate; however, as no direct measurement of feed wastage was recorded, this hypothesis cannot be confirmed. Another indication that the disappearance velocity (or eating rate) of CF could be overestimated would be that mean eating rate of CF was around 200 g/min and with this eating rate animals should suffer subclinical acidosis (Sauvant et al., 1999). Sauvant et al. (1999) summarized different studies and observed that when the eating rate was above 200 g/min, rumen pH was below 5.6, the threshold pH value for rumen subclinical acidosis (Britton and Stock, 1989; Owens et al., 1998; DeVries et al., 2007) and, in consequence, animal growth could be impaired (Schwartzkopf-Genswein et al., 2003). However, no differences in ADG and rumen pH among CF and CFL animals were observed; therefore, the present study results do not support this argument. It is important to consider the rumen pH data of the present study with caution because rumen samples were collected at different times. However, other rumen acidosis indicators such as laminitis, bloat, erratic concentrate consumption, rumen wall lesions, liver abscesses, and ruminating data do not support that CF suffered more rumen acidosis than CFL animals. In summary, eating rate data of CF animals seem to be overestimated, probably because of feed wastage, explaining why it is not a good indicator of the competition at the feeder and why it was not related with rumen pH data. As mentioned before, it was expected that by decreasing the level of concentrate in the feeder, animal competition for eating would increase; in contrast to eating rate data, the increase in number of displacements at the feeder when comparing CF with CFL could support this hypothesis. Also, CFL animals exhibited more sexual activity than CF. These behaviors, displacements and sexual activity, increased when the depth of feeder was decreased, which would, in theory, induce stress and impair growth. The increase of frequency in sexual behavior that was recorded by CFL bulls could lead to increased energy requirements impairing growth and G:F; but no differences in ADG were observed and the frequency of these behaviors was low. Therefore, in the present study, the impact of sexual behaviors on energy requirements was probably insignificant. Moreover, serum haptoglobin concentration did not differ between CF and CFL animals. Haptoglobin is an acute phase protein that increases in blood as a consequence of inflammation, tissue damage or injury, infection, and stress, so haptoglobin has been proposed to be a possible marker of stress in cattle (Alsemgeest et al., 1995; Arthington et al., 2003; Hickey et al., 2003). Hence, according to most of the stress indicators measured in the present study (haptoglobin, concentrate consumption, grow, etc.), the reduction of feed level at the feeder was not stressful to the animals in spite of the increase of competition at the feeder or greater sexual activity recorded. Moreover, greater frequency of oral behavior was recorded in the CF group than the CFL group. The reasons for these behavior differences among treatments are unknown, and it is difficult to find explanations related to feeder design. In summary, behavior as well as rumen and serum metabolite data may indicate that when the feed level at the feeder was decreased, total feed consumption was reduced by 4%, probably because of the reduction in feed spillage. This reduction of the feed level at the feeder had no negative impact on performance, rumen health, or stress despite the increase of displacements at the feeder and sexual activity. Therefore, reducing concentrate level at the feeder could be a good strategy to reduce concentrate consumption and associated feed costs without negative effects on performance, stress, and rumen health. A Control Feeder with 4 Feeding Spaces vs. a Single-Space Feeder with Lateral Protections A reduction in accumulative concentrate consumption (6.7%) was achieved when animals were in SF compared with CF without impairing ADG. Andersen et al. (1997) reported that the reduction of eating space did not affect ADG and G:F, whereas other reports (Keys et al., 1978) observe a negative effect of this concentrate consumption reduction in growth rate and feed efficiency. It could be expected that reducing the feeder space to a single feeder with lateral barriers compared with a multiple-space feeder could limit the animal access to the feeder and/or the concentrate consumption impairing animal growth. The greater serum NEFA concentration in SF during the first 2 wk of the study compared with CF may indicate that animals had adaptation problems and consumption was limited. In addition, waiting time at the feeder in the first period was greater compared to the CF indicate that animals had adaptation problems to SF. Moreover, 2 animals were removed due to inability to adapt to the SF design, as they were not able to go into chute. In addition, in spite of there not being statistically significant differences between treatments in proportion of standing animals, for the first 2 wk there were numerical differences among treatments: the SF pen had greater (64.8 ± 0.05%) percentage than the CF and CFL pens (53.6 ± 0.05%). The greater proportion of standing animals during the adaptation period to single feeder design might suggest that animals need time to establish their hierarchy or internal order to feeder attendance, because after the adaptation period, these differences among treatments disappeared. This behavioral change has been also reported by other authors in similar circumstances as a waiting time for less competition at the feeder (Gonyou and Stricklin, 1981; Olofsson, 1999; Huzzey et al., 2006; González et al., 2008). Perhaps, in the present study, the strategy used to adapt animals (widen the chute for 4 first days) should be improved; a possible adaptation strategy could be to use a supplementary feeder or having more days the chute elevated to achieve easier and better adaptation. Despite serum NEFA concentrations and some behavior traits indicating that animals did not adapt well to the SF, overall performance was not impaired. The greater CV in concentrate consumption exhibited for SF may indicate that animals may have suffered rumen acidosis, and this could affect negatively ADG (Galyean et al., 1992). One possible explanation of these great fluctuations in day-to-day concentrate consumption may be that rumen acidosis can lead a reduction of feed consumption (Britton and Stock, 1987) and, thereby, can cause erratic consumption patterns (Stock et al., 1995). In feedlot cattle, Brown et al. (2000) observed a high correlation coefficient (r = 0.84) between the lowest daily ruminal pH and feed intake on the subsequent day. When ruminal pH is low, the animal's feed intake drops; this limits further production of fermentation acids and restores pH to more optimum conditions. Once the pH is restored, then the animal consumes feed and again this may lead to excessive production of acids and this cycle can be repeated. However, in the present study, rumen pH of SF animals was above 6.0. Also, records related with ruminal acidosis such as rumen wall lesions and/or liver abscesses support the hypothesis that these animals fed with the SF did not suffer rumen acidosis. In addition, as discussed previously, the eating rate average observed in SF animals (140.4 g/min) is within the range of eating rates values that would not be related with rumen acidosis (Sauvant et al., 1999; González et al., 2008). Moreover, previous research has yielded contradictory results in regards to the effects that the CV concentrate daily consumption have on performance and efficiency. Several studies have concluded that large variation in feed intake by cattle fed high-concentrate diets may cause digestive disturbances (Fulton et al., 1979; Britton and Stock, 1987) and decrease growth performance in feedlot cattle (Galyean et al., 1992; Stock et al., 1995; Devant et al., 2010) with this effect being greatest early in the feeding period (Krehbiel et al., 1995; Soto-Navarro et al., 2000). Golden et al. (2008) also reported a greater within-day variation in intake of inefficient steers than efficient steers regardless of the amount of roughage in the diet. In contrast, Cooper et al. (1999) reported that variation in intake did not increase acidosis or decrease performance in finishing steers fed ad libitum. Schwartzkopf-Genswein et al. (2004) also reported similar findings when they observed that ADG and G:F were not different between steers fed either a constant or a fluctuating amount of feed, and they concluded that daily intake fluctuations of 10% DMI or less do not alter overall intake by feedlot cattle and are unlikely to have any negative consequences on growth performance. Additionally, a study with steers fed barley-based diets indicated that the steers classified as having a high ADG and G:F showed the greatest CV of DMI (Schwartzkopf-Genswein et al., 2011). Therefore, even though concentrate CV was greater in SF animals than CF animals, it was not related to rumen acidosis and had no negative impact on performance. In addition, it could be expected that when the animals were fed in a single feeder with lateral barriers, competition at the feeder would be greater compared with a CF, causing stress and impairing growth. González et al. (2008) reported that by increasing the animal to feeding spaces ratio, the number of displacements increased, leading to a potential increase in stress and risk to suffer rumen acidosis. In the present study, no displacements at the feeder and fewer agonistic interactions were recorded in the SF compared with the collective feeders, mainly due to lateral barriers of feeder design, which reduce significantly the aggressions and displacements at the feeder (Bouissou, 1970; Grant and Albright, 1995). Although some animal behaviors were affected by feeder design, such as number of animals eating straw or frequency of oral behaviors, no evidence of an associated negative effect were found on performance, welfare, or health. Moreover, SF had a greater proportion of animals eating straw compared with collective feeders throughout the study. The sustained hypothesis could be that SF bulls attended the straw feeder more often because the concentrate feeder was occupied and that animals redirected their concentrate appetite to spend more time at straw feeder (227.9 ± 7.00 min for SF vs. 185.9 ± 7.00 min for CF) while they waited to access the concentrate feeder (data not shown). However, this greater proportion of animals eating straw did not translate to an increase of straw consumption. In addition, the single feeder design did not compromise natural cattle behavior such as feeding, resting, or rumination patterns (Friend, 1991). In the present study, resting and rumination behaviors were not affected by the feeder design. Furthermore, SF animals did not exhibit more oral behavior than CF animals. Although some authors associate oral behaviors with stereotypies (Redbo and Nordblad, 1997), others regard that is an intrinsic behavior of intensive production systems (Ishiwata et al., 2008) related with the lack of occurrence of feeding behavior. Moreover, no stereotypies were detected over the experiment. Some authors associated stereotypies as indicators of poor welfare related to restriction of movements (Redbo, 1992) and low roughage intake (Redbo and Nordblad, 1997) such as it was reported by Rotger et al. (2006). No differences in social behavior were found among treatments. Val-Laillet et al. (2009) reported that increasing competition does not disrupt the social behavior known as allogrooming behavior. The frequency of self-grooming behavior expressed was different depending on the period of fattening and treatment but without any clear pattern. Ishiwata et al. (2008) suggest that self-grooming is another behavior to spend the spare time, instead of engaging in walking; however, other authors (Phillips, 2004) associate self-grooming as a well-being or satisfaction behavior. Related to agonistic interactions, behaviors associated with hierarchy establishment (Mounier et al., 2005), no differences were found among treatments. Most behavioral data (ruminating, resting, displacements, etc.) studied did not indicate that SF provoked welfare problems; however, the interpretation of other behaviors (oral behavior and time devoted to eat straw) could be ambiguous. As other welfare indicators such as performance, serum haptoglobin, and health did not differ among treatments, it can be concluded that SF did not seem to impair animal welfare. In summary, both alternatives of feeder design, reduction of concentrate level at the feeder and a single-space feeder with lateral barriers, are good strategies to reduce total concentrate consumption without impairing performance, rumen health, and animal welfare in Holstein bulls fed high-concentrate diets and therefore may effectively contribute to the reduction of nutrition costs associated with beef production. However, at the beginning, there are evidences (NEFA and some behavior traits) that animals fed SF have adaptation problems without impairing overall performance, so further research focus on adaptation strategies is necessary. Footnotes 1 This research was made possible by the collaboration of Agropecuaria Montgai S.L., Voltec Electro Sistemes S.L., BMM, and the support from Anna Solé and Bruna Quintana. LITERATURE CITED Alsemgeest S. P. M. Lambooy I. E. Wierenga H. K. Dieleman S. J. Meerkerk B. Van Ederen A. M. Niewold T. A. 1995. Influence of physical stress on the plasma concentration of serum amyloid-a (SAA) and haptoglobin (HP) in calves. Vet. Q.  17: 9– 12. doi: https://doi.org/10.1080/01652176.1995.9694521. Google Scholar CrossRef Search ADS PubMed  Andersen H. R. Jensen L. R. Munksgaard L. Ingvartsen K. L. 1997. Influence of floor space allowance and access sites to feed trough on the production of calves and young bulls and on the carcass and meat quality of young bulls. Acta Agric. Scand. Sect. Anim. Sci.  47: 48– 56. AOAC 1995. Official methods of analysis. 16th ed. AOAC Int., Arlington, VA. Arthington J. D. Eicher S. D. Kunkle W. E. Martin F. G. 2003. Effect of transportation and commingling on the acute-phase protein response, growth, and feed intake of newly weaned beef calves. J. Anim. Sci.  81: 1120– 1125. Google Scholar CrossRef Search ADS PubMed  Bergstrom J. R. Nelssen J. L. Tokach M. D. Dritz S. S. Goodband R. D. DeRouchey J. M. 2012. Effects of two feeder designs and adjustment strategies on the growth performance and carcass characteristics of growing-finishing pigs. J. Anim. Sci.  90: 4555– 4566. doi: https://doi.org/10.2527/jas.2011-4485. Google Scholar CrossRef Search ADS PubMed  Bouissou M. F. 1970. Role du contact physique dans la manifestation des relations hierarchiques chez les bovins. Consequences pratiques. (In French.) Ann. Zootech.  19: 279– 285. doi: https://doi.org/10.1051/animres:19700304. Google Scholar CrossRef Search ADS   Britton R. A. Stock R. A. 1987. Acidosis, rate of starch digestion and intake. Agricultural Experiment Station Research Report. Oklahoma State University, Stillwater, OK. 121: 125– 137. Britton R. A. Stock R. A. 1989. Acidosis: A continual problem in cattle fed high grain diets. In: Proc. Cornell Nutr. Conf. Feed Manufacturers.  Cornell University, Ithaca, NY. p. 8– 15. Brown H. Bing R. F. Grueter H. P. McAskill J. W. Cooley C. O. Rathmacher R. P. 1975. Tylosin and chlortetracycline for the prevention of liver abscesses, improved weight gains and feed efficiency in feedlot cattle. J. Anim. Sci.  40: 207– 213. Google Scholar CrossRef Search ADS PubMed  Brown M. S. Krehbiel C. R. Galyean M. L. Remmenga M. D. Peters J. P. Hibbard B. Robinson J. Moseley W. M. 2000. Evaluation of models of acute and subacute acidosis on dry matter intake, ruminal fermentation, blood chemistry, and endocrine profiles of beef steers. J. Anim. Sci.  78: 3155– 3168. Google Scholar CrossRef Search ADS PubMed  Colgan P. W. 1978. Quantitative ethology. John Wiley and Sons, New York, NY. Copper R. J. Klopfenstein T. J. Stock R. A. Milton C. T. Herold D. W. Parrott J. C. 1999. Effects of imposed feed consumption variation on acidosis and performance of finishing steers. J. Anim. Sci.  77: 1093– 1099. Google Scholar CrossRef Search ADS PubMed  Devant M. Ferret A. Gasa J. Calsamiglia S. Casals R. 2000. Effects of protein concentration and degradability on performance, ruminal fermentation and nitrogen metabolism in rapidly growing heifers fed high-concentrate diets, from 100 to 230 kg body weight. J. Anim. Sci.  78: 1667– 1676. Google Scholar CrossRef Search ADS PubMed  Devant M. Marti S. Bach A. 2010. Relationship between eating pattern and performance of Holstein bulls and steers fed high-concentrate rations using a computerized concentrate feeder. J. Anim. Sci.  88( E-Suppl. 2): 572– 573. Google Scholar PubMed  Devant M. Marti S. Bach A. 2012. Effects of castration on eating pattern and physical activity of Holstein bulls fed high concentrate rations under commercial conditions. J. Anim. Sci.  90: 4505– 4513. doi: https://doi.org/10.2527/jas.2011-4929. Google Scholar CrossRef Search ADS PubMed  DeVries T. J. Beauchemin K. A. von Keyserlingk M. A. G. 2007. Dietary forage concentration affects the feed sorting behavior of lactating dairy cows. J. Dairy Sci.  90: 5572– 5579. doi: https://doi.org/10.3168/jds.2007-0370. Google Scholar CrossRef Search ADS PubMed  Friend T. H. 1991. Behavioral aspects of stress. J. Dairy Sci.  74: 292– 303. doi: https://doi.org/10.3168/jds.S0022-0302(91)78173-3. Google Scholar CrossRef Search ADS PubMed  Fulton W. R. Klopfenstein T. J. Britton R. A. 1979. Adaptation to high concentrate diets by beef cattle. II. Effect of ruminal pH alteration on rumen fermentation and voluntary consumption of wheat diets. J. Anim. Sci.  49: 785– 789. Google Scholar CrossRef Search ADS   Galyean M. L. Malcom K. J. Garcia D. R. Polsipher G. D. 1992. Effects of varying the pattern of feed consumption on performance by programmed-fed steers. Clayton Livestock Research Center Progress Report. New Mexico Agricultural Experiment Station, Las Cruces. No. 78. Golden J. W. Kerley M. S. Kolath W. H. 2008. The relation-ship of feeding behavior to residual feed intake in crossbred Angus steers fed traditional and no-roughage diets. J. Anim. Sci.  86: 180– 186. doi: https://doi.org/10.2527/jas.2005-569. Google Scholar CrossRef Search ADS PubMed  Gonyou W. H. 1999. Feeder and pen design to increase efficiency. Adv. Pork Prod.  10: 103– 113. Gonyou W. H. Stricklin W. R. 1981. Eating behavior of beef cattle groups fed from a single stall or trough. Appl. Anim. Ethol.  7: 123– 133. doi: https://doi.org/10.1016/0304-3762(81)90090-0. Google Scholar CrossRef Search ADS   González J. M. Garcia de Jalón J. A. Askar A. R. Guada J. A. Ferrer L. M. de las Heras M. 2001. Efecto de la dieta con cebada y nucleo proteico sobre la patología ruminal en corderos. In: XXVI Jornadas de la SEOC, Sevilla, Spain. p. 733– 739. González L. A. Ferret A. Manteca X. Ruíz-de-la-Torre J. L. Calsamiglia S. Devant M. Bach A. 2008. Performance, behavior, and welfare of Friesian heifers housed in pens with two, four, and eight individuals per concentrate feeding place. J. Anim. Sci.  86: 1446– 1458. doi: https://doi.org/10.2527/jas.2007-0675. Google Scholar CrossRef Search ADS PubMed  Grant R. J. Albright J. L. 1995. Feeding behavior and management factors during the transition period in dairy cattle. J. Anim. Sci.  73: 2791– 2803. Google Scholar CrossRef Search ADS PubMed  Hickey M. C. Drennan M. Earley B. 2003. The effect of abrupt weaning of suckler calves on the plasma concentrations of cortisol, catecholamines, leukocytes, acute-phase proteins and in vitro interferon-gamma production. J. Anim. Sci.  81: 2847– 2855. Google Scholar CrossRef Search ADS PubMed  Huzzey J. M. DeVries T. J. Valois P. von Keyserlingk M. A. G. 2006. Stocking density and feed barrier design affect the feeding and social behavior of dairy cattle. J. Dairy Sci.  89: 126– 133. doi: https://doi.org/10.3168/jds.S0022-0302(06)72075-6. Google Scholar CrossRef Search ADS PubMed  Ishiwata T. Uetake K. Kilgour R. J. Eguchi Y. Tanaka T. 2008. Comparison of time budget of behaviors between penned and ranged young cattle focused on general and oral behaviors. Anim. Sci. J.  79: 518– 525. doi: https://doi.org/10.1111/j.1740-0929.2008.00558.x. Google Scholar CrossRef Search ADS   Jounay J. P. 1982. Volatile fatty acids and alcohol determination in digestive contents, silage juice, bacterial cultures and anaerobic fermenter contents. Sci. Aliments  2: 131– 144. Keys J. E. Pearson R. E. Thompson P. D. 1978. Effect of feedbunk stocking density on weight gains and feeding behavior of yearling Holstein heifers. J. Dairy Sci.  61: 448– 454. doi: https://doi.org/10.3168/jds.S0022-0302(78)83619-4. Google Scholar CrossRef Search ADS   Krehbiel C. R. Britton R. A. Harmon D. L. Wester T. J. Stock R. A. 1995. The effects of ruminal acidosis on volatile fatty acid absorption and plasma activities of pancreatic enzymes in lambs. J. Anim. Sci.  73: 3111– 3121. Google Scholar CrossRef Search ADS PubMed  Lesmeister K. E. Tozer P. R. Heinrichs A. J. 2004. Development and analysis of a rumen tissue sampling procedure. J. Dairy Sci.  87: 1336– 1344. doi: https://doi.org/10.3168/jds.S0022-0302(04)73283-X. Google Scholar CrossRef Search ADS PubMed  Mach N. Bach A. Realini C. E. Font iFurnols M. Velarde A. Devant M. 2009. Burdizzo pre-pubertal castration effects on performance, behavior, carcass characteristics, and meat quality of Holstein bulls fed high-concentrate diets. Meat Sci.  81: 329– 334. doi: https://doi.org/10.1016/j.meatsci.2008.08.007. Google Scholar CrossRef Search ADS PubMed  Mach N. Bach A. Velarde A. Devant M. 2008. Association between animal, transportation, slaughterhouse practices, and meat pH in beef. Meat Sci.  78: 232– 238. doi: https://doi.org/10.1016/j.meatsci.2007.06.021. Google Scholar CrossRef Search ADS PubMed  Mach N. Devant M. Bach A. Diaz I. Font M. Oliver M. A. Garcia J. A. 2006. Increasing the amount of n-3 fatty acid in meat from young Holstein bulls through nutrition. J. Anim. Sci.  84: 3039– 3048. doi: https://doi.org/10.2527/jas.2005-632. Google Scholar CrossRef Search ADS PubMed  Marti S. Realini C. E. Bach A. Pérez-Juan M. Devant M. 2013. Effect of castration and slaughter age on performance, carcass, and meat quality traits of Holstein calves fed a high-concentrate diet. J. Anim. Sci.  91: 1129– 1140. doi: https://doi.org/10.2527/jas.2012-5717. Google Scholar CrossRef Search ADS PubMed  Marti S. Velarde A. de la Torre J. L. Bach A. Aris A. Serrano A. Manteca X. Devant M. 2010. Effects of ring castration with local anesthesia and analgesia in Holstein bulls at three months of age on welfare indicators. J. Anim. Sci.  88: 2789– 2796. doi: https://doi.org/10.2527/jas.2009-2408. Google Scholar CrossRef Search ADS PubMed  Mounier L. Veissier I. Boissy A. 2005. Behavior, physiology, and performance of bulls mixed at the onset of finishing to form uniform body weight groups. J. Anim. Sci.  83: 1696– 1704. Google Scholar CrossRef Search ADS PubMed  Murphy T. A. Fluharty F. L. Loerch S. C. 1994. The influence of intake level and corn processing on digestibility and ruminal metabolism in steers fed all-concentrate diets. J. Anim. Sci.  72: 1608– 1615. Google Scholar CrossRef Search ADS PubMed  Myers A. J. Goodband R. D. Tokach M. D. Dritz S. S. DeRouchey J. M. Nelssen J. L. 2012. The effects of feeder adjustment and trough space on growth performance of finishing pigs. J. Anim. Sci.  90: 4576– 4582. doi: https://doi.org/10.2527/jas.2012-5389. Google Scholar CrossRef Search ADS PubMed  Nocek J. E. Heald C. W. Polan C. E. 1984. Influence of ration physical form and nitrogen availability on ruminal morphology of growing bull calves. J. Dairy Sci.  67: 334– 343. doi: https://doi.org/10.3168/jds.S0022-0302(84)81306-5. Google Scholar CrossRef Search ADS PubMed  NRC 1996. Nutrients requirements of beef cattle. 7th ed. Natl. Acad. Press, Washington, DC. Olofsson J. 1999. Competition for total mixed diets fed for ad libitum intake using one or four cows per feeding station. J. Dairy Sci.  82: 69– 79. doi: https://doi.org/10.3168/jds.S0022-0302(99)75210-0. Google Scholar CrossRef Search ADS PubMed  Owens F. N. Secrist D. S. Hill W. J. Gill D. R. 1998. Acidosis in cattle: A review. J. Anim. Sci.  76: 275– 286. Google Scholar CrossRef Search ADS PubMed  Phillips C. J. C. 2004. The effects of forage provision and group size on the behavior of calves. J. Dairy Sci.  87: 1380– 1388. doi: https://doi.org/10.3168/jds.S0022-0302(04)73287-7. Google Scholar CrossRef Search ADS PubMed  Redbo I. 1992. The influence of restraint on the occurrence of oral stereotypies in dairy cows. Appl. Anim. Behav. Sci.  35: 115– 123. doi: https://doi.org/10.1016/0168-1591(92)90002-S. Google Scholar CrossRef Search ADS   Redbo I. Nordblad A. 1997. Stereotypies in heifers are affected by feeding regime. Appl. Anim. Behav. Sci.  53: 193– 202. doi: https://doi.org/10.1016/S0168-1591(96)01145-8. Google Scholar CrossRef Search ADS   Robles V. González L. A. Ferret A. Manteca X. Calsamiglia S. 2007. Effects of feeding frequency on intake, ruminal fermentation, and feeding behavior in heifers fed high-concentrate diets. J. Anim. Sci.  85: 2538– 2547. doi: https://doi.org/10.2527/jas.2006-739. Google Scholar CrossRef Search ADS PubMed  Rotger A. Ferret A. Manteca X. Ruiz de la Torre J. L. Calsamiglia S. 2006. Effects of dietary nonstructural carbohydrates and protein sources on feeding behavior of tethered heifers fed high-concentrate diets. J. Anim. Sci.  84: 1197– 1204. Google Scholar CrossRef Search ADS PubMed  Sauvant D. Meschy F. Mertens D. R. 1999. Les composantes de l'acidoseruminale et les effetsacidogenes des rations. (In French.) INRA Prod. Anim.  12: 49– 60. Schoonmaker J. P. Cecava M. J. Faulkner D. B. Fluharty F. L. Zerby H. N. Loerch S. C. 2003. Effect of source of energy and rate of growth on performance, carcass characteristics, ruminal fermentation, and serum glucose and insulin of early-weaned steers. J. Anim. Sci.  81: 843– 855. Google Scholar CrossRef Search ADS PubMed  Schwartzkopf-Genswein K. S. Beauchemin K. A. Gibb D. J. Crews D. H. Kickman D. D. Streeter M. McAllister T. A. 2003. Effect of bunk management on feeding behavior, ruminal acidosis and performance of feedlot cattle: A review. J. Anim. Sci.  81( E. Suppl.): E149– E158. Schwartzkopf-Genswein K. S. Beauchemin K. A. McAllister T. A. Gibb D. J. Streeter M. Kennedy A. D. 2004. Effect of feed delivery fluctuations and feeding time on ruminal acidosis, growth performance, and feeding behavior of feedlot cattle. J. Anim. Sci.  82: 3357– 3365. Google Scholar CrossRef Search ADS PubMed  Schwartzkopf-Genswein K. S. Hickman D. D. Shah M. A. Krehbiel C. R. Genswein B. M. A. Silasi R. Gibb D. G. Crews D. H. McAllister T. A. 2011. Relationship between feeding behavior and performance of feedlot steers fed barley-based diets. J. Anim. Sci.  89: 1180– 1192. doi: https://doi.org/10.2527/jas.2010-3007. Google Scholar CrossRef Search ADS PubMed  Soto-Navarro S. A. Krehbiel C. R. Duff G. C. Galyean M. L. Brown M. S. Steiner R. L. 2000. Influence of feed consumption fluctuation and frequency of feeding on nutrient digestion, digesta kinetics, and ruminal fermentation profiles in limit-fed steers. J. Anim. Sci.  78: 2215– 2222. Google Scholar CrossRef Search ADS PubMed  Stock R. A. Brink D. R. Brandt R. T. Merrill J. K. Smith K. K. 1987. Feeding combinations of high moisture corn and dry corn to finishing cattle. J. Anim. Sci.  65: 282– 289. Google Scholar CrossRef Search ADS   Stock R. Klopfenstein T. Shain D. 1995. Feed intake variation. In: Proc. Symp.  Feed Intake by Feedlot Cattle, Okla. State Univ., Stillwater, OK. p. 56– 59. Stock R. A. Sindt M. H. Parrott J. C. Goedeken F. K. 1990. Effects of grain type, roughage level and monensin level on finishing cattle performance. J. Anim. Sci.  68: 3441– 3455. Google Scholar CrossRef Search ADS PubMed  Tietz N. W. editor. 1995. Clinical guide to laboratory tests.  3rd ed. WB Saunders Company, Philadelphia, PA. Val-Laillet D. Guesdon V. vonKeyserlingk M. A. G. de Passillé A. M. Rushen J. 2009. Allogrooming in cattle: Relationships between social preferences, feeding displacements and social dominance. Appl. Anim. Behav. Sci.  116: 141– 149. doi: https://doi.org/10.1016/j.applanim.2008.08.005. Google Scholar CrossRef Search ADS   Van Soest P. J. Robertson J. B. Lewis B. A. 1991. Methods for dietary fiber, neutral detergent fiber, and nonstarch polysaccharides in relation to animal nutrition. J. Dairy Sci.  74: 3583– 3597. doi: https://doi.org/10.3168/jds.S0022-0302(91)78551-2. Google Scholar CrossRef Search ADS PubMed  American Society of Animal Science
TI - Effect of concentrate feeder design on performance, eating and animal behavior, welfare, ruminal health, and carcass quality in Holstein bulls fed high-concentrate diets
JF - Journal of Animal Science
DO - 10.2527/jas.2014-8540
DA - 2015-06-01
UR - https://www.deepdyve.com/lp/oxford-university-press/effect-of-concentrate-feeder-design-on-performance-eating-and-animal-9kXY0Ut9t1
SP - 3018
EP - 3033
VL - 93
IS - 6
DP - DeepDyve
ER -