TY - JOUR
AU - Meng, Q. X.
AB - Abstract A new apparatus, named Bang-Bang (BB), which can facilitate the in situ nylon bag measurement of ruminal degradation in beef cattle, is described. The BB is an apparatus specially designed as a replacement of the traditional steel chain or flexible plastic tubes for binding the bags used in the in situ nylon bag (ISNB) method. The BB apparatus consists of cylindrical pedestals, sealing clips, nylon string, and nylon bags. A series of in situ rumen incubations using 3 ruminally cannulated beef steers were conducted to compare the BB with the ISNB method by measuring rumen DM degradation kinetics of 12 different feedstuffs commonly offered to beef cattle in China. Greater (P < 0.01) DM disappearance and less (P < 0.01) relative SD (%) were observed with the BB than with the ISNB method. In addition, effective degradability of DM was highly correlated between the 2 methods (ISNB = (1.01 ± 0.04 × BB) − 4.03 ± 2.12; r2 = 0.99, P < 0.001, n = 12). These results indicate that the BB apparatus can be effectively used to determine the rumen degradation properties of feedstuffs with advantages over the traditional ISNB technique. INTRODUCTION Since Quin et al. (1938) used silk bags to investigate the digestion of feeds in the rumen of cannulated sheep, the in situ nylon bag (ISNB) technique has been modified and widely used to evaluate the digestion of feeds in the rumen. The nylon bag technique gives a more rapid estimate of the rate and extent of ruminal degradation of feedstuffs compared with in vivo techniques (Ørskov et al., 1980). In general, the nylon bags are sewn using nylon fabric and polyester threads and bound either to a flexible plastic tube or a steel chain. When ruminal degradation parameters of feed nutrients were measured, the bags with feed substrates were placed in the rumen for microbial digestion while bound to a flexible plastic tube or steel chain or contained within a nylon laundry bag (Figroid et al., 1972; Varel and Kreikemeier, 1995; Cruywagen, 2006). However, the standardization of the in situ procedure is hard to guarantee due to the different size and type of the steel chains or plastic tubes as well as the different binding ways used in different laboratories. Several disadvantages for the traditional ISNB method are obvious: 1) nylon bags are manually tied to and later separated from the steel chains or the plastic tubes before and after ruminal incubation, which is time consuming and inconvenient in operation and frequently results in shear leakage from the bags as well, and 2) nylon bags are pursed shut at one end, which reduces the effective surface area of the bag and its accessibility to ruminal microorganisms. Therefore, a new apparatus, herein referred to as the Bang-Bang (BB), has been developed by a research team at the China Agricultural University (CAU; Beijing, P. R. China) for facilitating rumen in situ feed degradation measurement using the nylon bag technique. The measurement of ruminal degradation using the BB apparatus method has several advantages over ISNB, including time savings, ease of attachment and removal of nylon bags, increased bag surface area for rumen microorganisms to access feed substrates, and reduction in variability of ruminal degradability estimates. The objective of this study was to provide a detailed description of the BB apparatus and to compare the BB apparatus with the existing steel chain nylon bag technique on measuring rumen DM degradation of 12 different feedstuffs in beef steers. MATERIALS AND METHODS Animal care and use were approved and conducted under established standards of the College of Animal Science and Technology, CAU, Beijing, P. R. China (permit number DK1008). Design of Bang-Bang Apparatus The BB is an apparatus specially designed as a replacement of the traditional steel chain or flexible plastic tubes used in the ISNB method. The main body of the apparatus is composed of following components. Cylindrical Pedestal. The cylindrical pedestal is made of polyethylene carbon material with a hollow structure design (100 g of weight, 105 mm long, and 40 mm in diameter). Two pieces of stainless steel block (50 g of weight, 40 mm long, and 20 mm in diameter for each) are prepared for adding weights to the cylindrical pedestal. Nine notches are uniformly distributed around the pedestal, and the size of the notch only allows for a sealing clip to be inserted. To prevent all sealing clips from detaching from the pedestal, a cap is tightly screwed on after all sealing clips are inserted in the pedestal (Fig. 1, 2a, and 2b). Figure 1. View largeDownload slide Dismantling diagram for the Bang-Bang apparatus. Figure 1. View largeDownload slide Dismantling diagram for the Bang-Bang apparatus. Figure 2. View largeDownload slide Schematic diagram for operating the Bang-Bang apparatus: (a) cylindrical pedestal, (b) a sealed nylon bag fixed to a cylindrical pedestal, (c) sealing clip, and (d) a nylon bag sealed with a sealing clip. Figure 2. View largeDownload slide Schematic diagram for operating the Bang-Bang apparatus: (a) cylindrical pedestal, (b) a sealed nylon bag fixed to a cylindrical pedestal, (c) sealing clip, and (d) a nylon bag sealed with a sealing clip. Sealing Clip. The sealing clip made of polyethylene carbon material is 8.5 cm long and 0.5 cm thick (Fig. 1 and 2c). A zigzag pattern was designed along both edges of the clip to prevent the nylon bags from slipping. At one end, there is a snap fastener structure for clipping a nylon bag. Nylon Bag. The bags used in this technique are made of nylon fabric material with 48 μm pores (Vanzant et al., 1998). The size of the bags is 80 · 140 mm with one end open (Fig. 1 and 2d). The bottom corners are rounded to prevent feed samples from being trapped. To guarantee the bags are uniform, the bag is heat pressed through special sealing equipment (model HD-1501; Lihan Machinery Manufacturing Co. Ltd., Dongguan City, Guangdong Province, P. R. China). The opening side is treated with a soldering iron to prevent the edge from fraying. Nylon Bag Installation Operation Samples were weighed into labeled nylon bags, which were oven-dried at 65 °C for 48 h. The nylon bag was then placed between the 2 trim strips of a sealing clip at a distance of about 0.5 cm from the opening edge of the bag and then clipped by the snap fastener located at the end of sealing clip. The bags were attached to the cylindrical pedestal by inserting the clips into the notches of the cylindrical pedestal. Two pieces of stainless steel block were inserted into the central hole of the cylindrical pedestal to allow the bags to drop to the bottom of the rumen. After all the sealing clips were inserted into the pedestal, the cap was tightly screwed on (Fig. 3). After being labeled, the pedestal was attached to a nylon string through the central hole for attaching to the cap of the rumen cannula. A relatively long string can minimize the variation of the results because it allows bags to freely move within the rumen without becoming tangled. The free part of the string with a minimum length of 25 cm is recommended between most proximal bags and the cap of rumen cannula as suggested by Hawley (1981). The apparatus can be placed into a polyester laundry bag for ruminal incubation as well. Figure 3. View largeDownload slide Appearance of the Bang-Bang apparatus with 9 bags installed. Figure 3. View largeDownload slide Appearance of the Bang-Bang apparatus with 9 bags installed. Comparison of Bang-Bang and In Situ Nylon Bag Substrates. In this experiment, 12 different feedstuffs, including corn, sorghum, barley, wheat, Chinese wildrye grass, corn stalk, rice straw, soybean straw, soybean meal, distillers' dried grains with solubles (DDGS), brewer's grains, and sunflower meal, were used as substrates. All feed samples were obtained from Beijing City and Hebei Province, P. R. China. The collected samples were air-dried and ground to pass a 2-mm screen in a Wiley mill (Vanzant et al., 1998). Animals and Diet. Three Angus steers (380 ± 15 kg live weight) fitted with permanent rumen cannulas (CAU Beef Cattle Research Center, Beijing, P. R. China) were used. Animals were fed twice daily a total mixed ration, which consisted of 40% steam-flaked corn, 40% corn stalk silage, 4.5% cottonseed meal, and 13.5% brewer's grains (DM basis) and 0.5% salt and 0.5% premix (2.4 g/kg Mg, 7.6 g/kg K, 12.0 g/kg Fe, 1.0 g/kg Cu, 200 mg/kg Mn, 650 mg/kg Zn, 2 mg/kg Se, 22 mg/kg I, 9 mg/kg Co, 121,000 IU/kg vitamin A, 37,400 IU/kg vitamin D, and 55 IU/kg vitamin E) were additionally added. Steers were adapted to the diet for 2 wk before the start of the experiment. In Situ Procedures. The ruminal incubations were performed based on the procedure of Ørskov et al. (1980). Twelve feedstuffs were divided into 4 groups with 3 feeds for each: 1) Chinese wildrye grass, corn stalk, and rice straw; 2) soybean straw, brewer's grains, and sunflower meal; 3) corn, sorghum, and barley; and 4) wheat, soybean meal, and DDGS. Each group of feedstuffs was measured in duplicate bags within each steer for ruminal DM degradability by both the BB technique and the traditional ISNB technique. Therefore, 4 runs were conducted and 3 feedstuffs were incubated in each run. Samples of 3 g (Chinese wildrye grass) or 5 g (other feedstuffs) were weighed into nylon bags. Six bags (2 bags for each substrate) were attached to a BB apparatus with 6 sealing clips or tightly bound to each steel chain (weighing about 250 g) by 6 pieces of nylon thread, respectively. The same bags were used for both methods (Fig. 4). To ensure free movement of the bags within the rumen in both methods, about 50 cm of the nylon threads were left between the BB apparatus or the steel chain and the cap of the rumen cannula. For group 1 and group 2, the bags for withdrawal at the last 4 time points were introduced in a reverse sequence into the rumen at 0800 h and incubated for 48, 72, 96, and 120 h. The bags for 6, 12, and 24 h of incubation were inserted into the rumen at the same time and withdrawn separately (Fig. 5a). For group 3 and group 4, feed samples were not incubated in the rumen for longer than 72 h (Fig. 5b). Therefore, no steer received more than 48 bags in total. After removal, the bags were immediately rinsed with cold water to stop fermentation, which was followed by the procedure of washing for 6 times (1 min/rinse) in a washing machine until the water was clear and then dried at 65°C for 48 h. The washing losses at 0 h were obtained by soaking 6 bags in the tap water for 10 min and washed until the water became clear and then dried at 65°C for 48 h. All the feed substrates and residues in this experiment were analyzed in duplicate for DM using the AOAC (2012) method 934.01. Kinetic parameters of DM degradation were estimated using the nonlinear regression procedure of SAS (SAS Inst. Inc., Cary, NC) using the model of McDonald (1981):  6pin which y is ruminal disappearance at time t, a is rapidly degraded fraction (%), b is the slowly degraded fraction (%), c is the degradation rate constant at which b is degraded (%/h), and t is time of incubation. Figure 4. View largeDownload slide Different sealing ways for the Bang-Bang (BB) technique and the steel chain in situ nylon bag (ISNB) technique. Figure 4. View largeDownload slide Different sealing ways for the Bang-Bang (BB) technique and the steel chain in situ nylon bag (ISNB) technique. Figure 5. View largeDownload slide In situ incubation procedures. Subscript numbers with “Bag” represent the periods of incubation; for example, Bag6h represents 6 h of incubation. (a) Incubation procedures for Chinese wildrye grass, corn stalk, rice straw, soybean straw, brewer's grains, and sunflower meal. (b) Incubation procedures for corn, sorghum, barley, wheat, soybean meal, and distillers' dried grains with solubles. Figure 5. View largeDownload slide In situ incubation procedures. Subscript numbers with “Bag” represent the periods of incubation; for example, Bag6h represents 6 h of incubation. (a) Incubation procedures for Chinese wildrye grass, corn stalk, rice straw, soybean straw, brewer's grains, and sunflower meal. (b) Incubation procedures for corn, sorghum, barley, wheat, soybean meal, and distillers' dried grains with solubles. The effective degradability (ED) of the DM was calculated from the following equation of Ørskov and McDonald (1979):  6pin which k represents the rate of feed passage from the rumen. In this experiment, k was assumed to be 5.00%/h for corn, sorghum, barley, wheat, soybean meal, and DDGS, whereas k was 3.00%/h for Chinese wildrye grass, corn stalk, soybean straw, rice straw, brewer's grains, and sunflower meal (Renecker and Hudson, 1990). Data obtained from the BB and ISNB technique were subjected to a GLM procedure of SAS (version 9.4). In situ DM degradation parameters of the 2 methods were compared with a single-factor ANOVA with 6 replicates for each feed sample (3 steers). The statistical model used was yij= μ + αi+ eij, in which yij is the observation or dependent variable, μ is the overall mean, αi is the fixed effect of method i, and eij∼ N(0, σ2e) is the random residual error. Dry matter disappearance (%) at different incubation times of the 2 methods was compared based on a 2-factor ANOVA without interaction. The statistical model used was yij= μ + αi+ βj+ eij, in which yij is the observation or dependent variable, μ is the overall mean, αi is the fixed effect of method i, βj is the fixed effect of feedstuff j, and eij ∼ N(0, σ2e) is the random residual error. A Duncan's significant difference test procedure was used to determine the differences among means. Significance was declared at P ≤ 0.05. The regression analysis between the 2 methods was determined by the CORR and REG procedures of SAS (version 9.4). RESULTS AND DISCUSSION Comparison of Bang-Bang and In Situ Nylon Bag Technique This study used 12 feed substrates to represent feeds commonly offered to beef cattle in China. Dry matter disappearance (DMD) of the feedstuffs at different time intervals was determined and degradation parameters were analyzed. The kinetic parameters of DMD data are presented in Table 1. It has been reported that a part of the weight loss from nylon bags may be due to the loss of fine particulate fractions by washing and also a result of the solubility of the substrate (Ørskov et al., 1980). Therefore, preparation of 0-h control bags is important for correction of the washing loss. In the present study, six 0-h control bags used for each method were washed individually and freely in a washing machine without rumen incubation, and the 0-h DMD value was the mean of 12 measurements of the 2 methods. The digestibility of a feed substrate is defined by the potential degradability, the degradation rate of this potentially degradable fraction (b), and its retention time in the rumen plus digestion in the hind gut (Ørskov et al., 1980). In the present study, the rapidly degraded fraction (a) determined with the BB method was not significantly different (P > 0.05) from that of the ISNB method for most feedstuffs, except for sorghum, barley, and brewer's grains. However, the slowly degraded fraction (b) was either less (P < 0.05) for barley or greater (P < 0.05) for DDGS, Chinese wildrye, soybean stalk, and sunflower meal with the BB method vs. the ISNB method or it was not different (P > 0.05) for other feed substrates between the 2 methods. Overall, greater values were observed with the BB method in the degradation rate (c) of the b fraction even though the difference was not significant for some of the feedstuffs. Considering that the variables a, b, and c were estimated by an iterative least squares method based on DMD and that the DMD values for the BB method were generally greater (P < 0.05) than those for the ISNB method (Table 2), this result is reasonable. An increase in DMD was previously observed as the bag size, for a given sample size, was increased (Mehrez and Ørskov, 1977). Because of the different sealing methods, the bags with the BB method remained outspread (Fig. 4), which may have resulted in a relatively larger effective surface area of the nylon bags. Moreover, the overall values of relative SD were lower with the BB method (averaged 4.95%) compared with the ISNB method (averaged 6.20%), which indicated that variation between bags was reduced with the BB apparatus. Table 1. In situ rumen DM degradation kinetic parameters measured using the Bang-Bang (BB) technique and the steel chain in situ nylon bag (ISNB) technique     BB  ISNB      Feed source  Item1  Mean  RSD,2 %  Mean  RSD %  SEM  P-value  Corn  a, %  27.89  0.82  26.58  4.77  0.53  0.15  b, %  66.77  3.60  70.83  5.63  1.90  0.21  c, %/h  5.81  6.99  4.20  8.32  0.22  <0.01  ED, %  63.72  0.35  58.81  1.88  0.46  <0.01  Sorghum  a, %  20.55  3.74  17.91  0.61  0.32  <0.01  b, %  69.22  0.64  75.09  12.56  3.85  0.34  c, %/h  3.46  5.85  2.40  22.43  0.23  0.03  ED, %  48.83  0.98  41.79  1.27  0.29  <0.01  Barley  a, %  29.98  0.73  30.86  1.19  0.17  0.02  b, %  55.93  0.38  57.23  1.09  0.27  0.03  c, %/h  11.82  2.79  8.51  15.51  0.56  0.01  ED, %  69.28  0.76  66.76  2.07  0.61  0.04  Wheat  a, %  29.78  0.60  30.18  2.25  0.29  0.39  b, %  62.47  0.89  62.10  2.70  0.72  0.73  c, %/h  14.59  5.93  12.05  24.54  1.26  0.23  ED, %  76.30  1.17  73.71  2.81  0.92  0.12  Soybean meal  a, %  32.68  2.59  33.32  2.05  0.44  0.37  b, %  72.03  1.19  69.07  4.96  1.44  0.22  c, %/h  3.43  9.45  3.03  11.32  0.19  0.21  ED, %  61.94  1.06  59.37  4.72  1.17  0.20  DDGS3  a, %  32.32  0.18  31.41  2.44  0.31  0.11  b, %  70.82  5.95  51.88  8.41  2.48  <0.01  c, %/h  2.35  12.79  2.71  13.12  0.19  0.25  ED, %  54.81  1.33  49.51  2.48  0.58  <0.01  Chinese wildrye  a, %  11.05  9.65  11.34  5.71  0.51  0.70  b, %  67.87  4.84  56.16  3.29  1.54  0.01  c, %/h  1.47  6.70  1.78  11.02  0.09  0.07  ED, %  33.38  3.31  32.22  1.37  0.49  0.16  Corn stalk  a, %  19.30  3.67  19.10  8.26  0.71  0.85  b, %  51.79  10.73  51.21  10.34  3.13  0.90  c, %/h  2.69  9.14  2.01  30.04  0.27  0.15  ED, %  43.70  4.29  39.10  2.77  0.88  0.02  Rice straw  a, %  16.95  6.90  15.35  4.31  0.55  0.11  b, %  52.10  4.64  50.17  2.97  1.16  0.30  c, %/h  2.50  13.46  2.20  10.93  0.17  0.27  ED, %  40.51  1.05  36.54  3.86  0.60  <0.01  Soybean stalk  a, %  19.18  4.78  18.44  3.38  0.45  0.31  b, %  44.74  2.48  40.32  1.88  0.55  <0.01  c, %/h  3.36  16.09  3.23  6.86  0.24  0.71  ED, %  42.71  2.37  39.33  1.17  0.45  <0.01  Brewer's grains  a, %  29.34  2.47  27.09  2.67  0.42  0.02  b, %  42.17  1.42  43.19  1.05  0.31  0.08  c, %/h  2.60  18.70  2.31  17.93  0.26  0.47  ED, %  48.79  2.24  45.76  2.34  0.62  0.03  Sunflower meal  a, %  19.39  6.50  19.73  0.74  0.52  0.67  b, %  57.48  0.69  56.22  1.09  0.30  0.04  c, %/h  7.23  26.41  5.54  3.34  0.78  0.20  ED, %  59.58  4.54  56.20  1.20  1.14  0.10      BB  ISNB      Feed source  Item1  Mean  RSD,2 %  Mean  RSD %  SEM  P-value  Corn  a, %  27.89  0.82  26.58  4.77  0.53  0.15  b, %  66.77  3.60  70.83  5.63  1.90  0.21  c, %/h  5.81  6.99  4.20  8.32  0.22  <0.01  ED, %  63.72  0.35  58.81  1.88  0.46  <0.01  Sorghum  a, %  20.55  3.74  17.91  0.61  0.32  <0.01  b, %  69.22  0.64  75.09  12.56  3.85  0.34  c, %/h  3.46  5.85  2.40  22.43  0.23  0.03  ED, %  48.83  0.98  41.79  1.27  0.29  <0.01  Barley  a, %  29.98  0.73  30.86  1.19  0.17  0.02  b, %  55.93  0.38  57.23  1.09  0.27  0.03  c, %/h  11.82  2.79  8.51  15.51  0.56  0.01  ED, %  69.28  0.76  66.76  2.07  0.61  0.04  Wheat  a, %  29.78  0.60  30.18  2.25  0.29  0.39  b, %  62.47  0.89  62.10  2.70  0.72  0.73  c, %/h  14.59  5.93  12.05  24.54  1.26  0.23  ED, %  76.30  1.17  73.71  2.81  0.92  0.12  Soybean meal  a, %  32.68  2.59  33.32  2.05  0.44  0.37  b, %  72.03  1.19  69.07  4.96  1.44  0.22  c, %/h  3.43  9.45  3.03  11.32  0.19  0.21  ED, %  61.94  1.06  59.37  4.72  1.17  0.20  DDGS3  a, %  32.32  0.18  31.41  2.44  0.31  0.11  b, %  70.82  5.95  51.88  8.41  2.48  <0.01  c, %/h  2.35  12.79  2.71  13.12  0.19  0.25  ED, %  54.81  1.33  49.51  2.48  0.58  <0.01  Chinese wildrye  a, %  11.05  9.65  11.34  5.71  0.51  0.70  b, %  67.87  4.84  56.16  3.29  1.54  0.01  c, %/h  1.47  6.70  1.78  11.02  0.09  0.07  ED, %  33.38  3.31  32.22  1.37  0.49  0.16  Corn stalk  a, %  19.30  3.67  19.10  8.26  0.71  0.85  b, %  51.79  10.73  51.21  10.34  3.13  0.90  c, %/h  2.69  9.14  2.01  30.04  0.27  0.15  ED, %  43.70  4.29  39.10  2.77  0.88  0.02  Rice straw  a, %  16.95  6.90  15.35  4.31  0.55  0.11  b, %  52.10  4.64  50.17  2.97  1.16  0.30  c, %/h  2.50  13.46  2.20  10.93  0.17  0.27  ED, %  40.51  1.05  36.54  3.86  0.60  <0.01  Soybean stalk  a, %  19.18  4.78  18.44  3.38  0.45  0.31  b, %  44.74  2.48  40.32  1.88  0.55  <0.01  c, %/h  3.36  16.09  3.23  6.86  0.24  0.71  ED, %  42.71  2.37  39.33  1.17  0.45  <0.01  Brewer's grains  a, %  29.34  2.47  27.09  2.67  0.42  0.02  b, %  42.17  1.42  43.19  1.05  0.31  0.08  c, %/h  2.60  18.70  2.31  17.93  0.26  0.47  ED, %  48.79  2.24  45.76  2.34  0.62  0.03  Sunflower meal  a, %  19.39  6.50  19.73  0.74  0.52  0.67  b, %  57.48  0.69  56.22  1.09  0.30  0.04  c, %/h  7.23  26.41  5.54  3.34  0.78  0.20  ED, %  59.58  4.54  56.20  1.20  1.14  0.10  1a = rapidly degraded fraction (%); b = the slowly degraded fraction (%); c = the degradation rate constant at which b is degraded (%/h); ED = effective degradability (%), calculated from the equation of Ørskov and McDonald (1979): ED = a + bc/(c + k), in which k represents the rate of feed passage from the rumen. 2RSD = relative SD (%). 3DDGS = distillers' dried grains with solubles. View Large Table 1. In situ rumen DM degradation kinetic parameters measured using the Bang-Bang (BB) technique and the steel chain in situ nylon bag (ISNB) technique     BB  ISNB      Feed source  Item1  Mean  RSD,2 %  Mean  RSD %  SEM  P-value  Corn  a, %  27.89  0.82  26.58  4.77  0.53  0.15  b, %  66.77  3.60  70.83  5.63  1.90  0.21  c, %/h  5.81  6.99  4.20  8.32  0.22  <0.01  ED, %  63.72  0.35  58.81  1.88  0.46  <0.01  Sorghum  a, %  20.55  3.74  17.91  0.61  0.32  <0.01  b, %  69.22  0.64  75.09  12.56  3.85  0.34  c, %/h  3.46  5.85  2.40  22.43  0.23  0.03  ED, %  48.83  0.98  41.79  1.27  0.29  <0.01  Barley  a, %  29.98  0.73  30.86  1.19  0.17  0.02  b, %  55.93  0.38  57.23  1.09  0.27  0.03  c, %/h  11.82  2.79  8.51  15.51  0.56  0.01  ED, %  69.28  0.76  66.76  2.07  0.61  0.04  Wheat  a, %  29.78  0.60  30.18  2.25  0.29  0.39  b, %  62.47  0.89  62.10  2.70  0.72  0.73  c, %/h  14.59  5.93  12.05  24.54  1.26  0.23  ED, %  76.30  1.17  73.71  2.81  0.92  0.12  Soybean meal  a, %  32.68  2.59  33.32  2.05  0.44  0.37  b, %  72.03  1.19  69.07  4.96  1.44  0.22  c, %/h  3.43  9.45  3.03  11.32  0.19  0.21  ED, %  61.94  1.06  59.37  4.72  1.17  0.20  DDGS3  a, %  32.32  0.18  31.41  2.44  0.31  0.11  b, %  70.82  5.95  51.88  8.41  2.48  <0.01  c, %/h  2.35  12.79  2.71  13.12  0.19  0.25  ED, %  54.81  1.33  49.51  2.48  0.58  <0.01  Chinese wildrye  a, %  11.05  9.65  11.34  5.71  0.51  0.70  b, %  67.87  4.84  56.16  3.29  1.54  0.01  c, %/h  1.47  6.70  1.78  11.02  0.09  0.07  ED, %  33.38  3.31  32.22  1.37  0.49  0.16  Corn stalk  a, %  19.30  3.67  19.10  8.26  0.71  0.85  b, %  51.79  10.73  51.21  10.34  3.13  0.90  c, %/h  2.69  9.14  2.01  30.04  0.27  0.15  ED, %  43.70  4.29  39.10  2.77  0.88  0.02  Rice straw  a, %  16.95  6.90  15.35  4.31  0.55  0.11  b, %  52.10  4.64  50.17  2.97  1.16  0.30  c, %/h  2.50  13.46  2.20  10.93  0.17  0.27  ED, %  40.51  1.05  36.54  3.86  0.60  <0.01  Soybean stalk  a, %  19.18  4.78  18.44  3.38  0.45  0.31  b, %  44.74  2.48  40.32  1.88  0.55  <0.01  c, %/h  3.36  16.09  3.23  6.86  0.24  0.71  ED, %  42.71  2.37  39.33  1.17  0.45  <0.01  Brewer's grains  a, %  29.34  2.47  27.09  2.67  0.42  0.02  b, %  42.17  1.42  43.19  1.05  0.31  0.08  c, %/h  2.60  18.70  2.31  17.93  0.26  0.47  ED, %  48.79  2.24  45.76  2.34  0.62  0.03  Sunflower meal  a, %  19.39  6.50  19.73  0.74  0.52  0.67  b, %  57.48  0.69  56.22  1.09  0.30  0.04  c, %/h  7.23  26.41  5.54  3.34  0.78  0.20  ED, %  59.58  4.54  56.20  1.20  1.14  0.10      BB  ISNB      Feed source  Item1  Mean  RSD,2 %  Mean  RSD %  SEM  P-value  Corn  a, %  27.89  0.82  26.58  4.77  0.53  0.15  b, %  66.77  3.60  70.83  5.63  1.90  0.21  c, %/h  5.81  6.99  4.20  8.32  0.22  <0.01  ED, %  63.72  0.35  58.81  1.88  0.46  <0.01  Sorghum  a, %  20.55  3.74  17.91  0.61  0.32  <0.01  b, %  69.22  0.64  75.09  12.56  3.85  0.34  c, %/h  3.46  5.85  2.40  22.43  0.23  0.03  ED, %  48.83  0.98  41.79  1.27  0.29  <0.01  Barley  a, %  29.98  0.73  30.86  1.19  0.17  0.02  b, %  55.93  0.38  57.23  1.09  0.27  0.03  c, %/h  11.82  2.79  8.51  15.51  0.56  0.01  ED, %  69.28  0.76  66.76  2.07  0.61  0.04  Wheat  a, %  29.78  0.60  30.18  2.25  0.29  0.39  b, %  62.47  0.89  62.10  2.70  0.72  0.73  c, %/h  14.59  5.93  12.05  24.54  1.26  0.23  ED, %  76.30  1.17  73.71  2.81  0.92  0.12  Soybean meal  a, %  32.68  2.59  33.32  2.05  0.44  0.37  b, %  72.03  1.19  69.07  4.96  1.44  0.22  c, %/h  3.43  9.45  3.03  11.32  0.19  0.21  ED, %  61.94  1.06  59.37  4.72  1.17  0.20  DDGS3  a, %  32.32  0.18  31.41  2.44  0.31  0.11  b, %  70.82  5.95  51.88  8.41  2.48  <0.01  c, %/h  2.35  12.79  2.71  13.12  0.19  0.25  ED, %  54.81  1.33  49.51  2.48  0.58  <0.01  Chinese wildrye  a, %  11.05  9.65  11.34  5.71  0.51  0.70  b, %  67.87  4.84  56.16  3.29  1.54  0.01  c, %/h  1.47  6.70  1.78  11.02  0.09  0.07  ED, %  33.38  3.31  32.22  1.37  0.49  0.16  Corn stalk  a, %  19.30  3.67  19.10  8.26  0.71  0.85  b, %  51.79  10.73  51.21  10.34  3.13  0.90  c, %/h  2.69  9.14  2.01  30.04  0.27  0.15  ED, %  43.70  4.29  39.10  2.77  0.88  0.02  Rice straw  a, %  16.95  6.90  15.35  4.31  0.55  0.11  b, %  52.10  4.64  50.17  2.97  1.16  0.30  c, %/h  2.50  13.46  2.20  10.93  0.17  0.27  ED, %  40.51  1.05  36.54  3.86  0.60  <0.01  Soybean stalk  a, %  19.18  4.78  18.44  3.38  0.45  0.31  b, %  44.74  2.48  40.32  1.88  0.55  <0.01  c, %/h  3.36  16.09  3.23  6.86  0.24  0.71  ED, %  42.71  2.37  39.33  1.17  0.45  <0.01  Brewer's grains  a, %  29.34  2.47  27.09  2.67  0.42  0.02  b, %  42.17  1.42  43.19  1.05  0.31  0.08  c, %/h  2.60  18.70  2.31  17.93  0.26  0.47  ED, %  48.79  2.24  45.76  2.34  0.62  0.03  Sunflower meal  a, %  19.39  6.50  19.73  0.74  0.52  0.67  b, %  57.48  0.69  56.22  1.09  0.30  0.04  c, %/h  7.23  26.41  5.54  3.34  0.78  0.20  ED, %  59.58  4.54  56.20  1.20  1.14  0.10  1a = rapidly degraded fraction (%); b = the slowly degraded fraction (%); c = the degradation rate constant at which b is degraded (%/h); ED = effective degradability (%), calculated from the equation of Ørskov and McDonald (1979): ED = a + bc/(c + k), in which k represents the rate of feed passage from the rumen. 2RSD = relative SD (%). 3DDGS = distillers' dried grains with solubles. View Large Table 2. Dry matter disappearance (%) at different incubation times determined by the Bang-Bang (BB) technique and the steel chain in situ nylon bag (ISNB) technique Incubation time  Feeds,1 no.  BB  ISNB  SEM  P-value  0 h  12  22.93  22.93  –  –  6 h  12  41.31  36.82  0.72  <0.01  12 h  12  49.19  44.17  0.63  <0.01  24 h  12  57.38  54.20  0.51  <0.01  48 h  12  71.66  67.68  0.92  <0.01  72 h  12  78.13  74.05  0.80  <0.01  96 h  6  65.92  62.66  0.48  <0.01  120 h  6  69.00  64.10  0.60  <0.01  Incubation time  Feeds,1 no.  BB  ISNB  SEM  P-value  0 h  12  22.93  22.93  –  –  6 h  12  41.31  36.82  0.72  <0.01  12 h  12  49.19  44.17  0.63  <0.01  24 h  12  57.38  54.20  0.51  <0.01  48 h  12  71.66  67.68  0.92  <0.01  72 h  12  78.13  74.05  0.80  <0.01  96 h  6  65.92  62.66  0.48  <0.01  120 h  6  69.00  64.10  0.60  <0.01  1Number of feedstuffs used. Each observation of 1 feed is the mean of 6 measurements. Feedstuffs used for 0-, 6-, 12-, 24-, 48-, and 72-h incubation times include Chinese wildrye grass, corn stalk, rice straw, soybean straw, brewer's grains, sunflower meal, corn, sorghum, barley, wheat, soybean meal, and distillers' dried grains with solubles; n = 12. Feedstuffs used for 96- and 120-h incubation times include Chinese wildrye grass, corn stalk, rice straw, soybean straw, brewer's grains; and sunflower meal; n = 6. View Large Table 2. Dry matter disappearance (%) at different incubation times determined by the Bang-Bang (BB) technique and the steel chain in situ nylon bag (ISNB) technique Incubation time  Feeds,1 no.  BB  ISNB  SEM  P-value  0 h  12  22.93  22.93  –  –  6 h  12  41.31  36.82  0.72  <0.01  12 h  12  49.19  44.17  0.63  <0.01  24 h  12  57.38  54.20  0.51  <0.01  48 h  12  71.66  67.68  0.92  <0.01  72 h  12  78.13  74.05  0.80  <0.01  96 h  6  65.92  62.66  0.48  <0.01  120 h  6  69.00  64.10  0.60  <0.01  Incubation time  Feeds,1 no.  BB  ISNB  SEM  P-value  0 h  12  22.93  22.93  –  –  6 h  12  41.31  36.82  0.72  <0.01  12 h  12  49.19  44.17  0.63  <0.01  24 h  12  57.38  54.20  0.51  <0.01  48 h  12  71.66  67.68  0.92  <0.01  72 h  12  78.13  74.05  0.80  <0.01  96 h  6  65.92  62.66  0.48  <0.01  120 h  6  69.00  64.10  0.60  <0.01  1Number of feedstuffs used. Each observation of 1 feed is the mean of 6 measurements. Feedstuffs used for 0-, 6-, 12-, 24-, 48-, and 72-h incubation times include Chinese wildrye grass, corn stalk, rice straw, soybean straw, brewer's grains, sunflower meal, corn, sorghum, barley, wheat, soybean meal, and distillers' dried grains with solubles; n = 12. Feedstuffs used for 96- and 120-h incubation times include Chinese wildrye grass, corn stalk, rice straw, soybean straw, brewer's grains; and sunflower meal; n = 6. View Large The average estimate of ED calculated using the BB method (53.63%) was slightly greater than that calculated using the ISNB method (49.92%). Nevertheless, the values determined were highly correlated [ISNB = (1.01 ± 0.04 × BB) − 4.03 ± 2.12; r2 = 0.99, P < 0.001, n = 12], with the intercept not being significantly different from 0 whereas the slope was significantly different from 1 (Fig. 6). This relationship indicated that the BB apparatus can be used to evaluate the degradability of feeds in the rumen. Figure 6. View largeDownload slide Regression showing the relationship between the rumen effective degradability (ED; %) of 12 feedstuffs determined by the Bang-Bang (BB) technique and the steel chain in situ nylon bag (ISNB) technique: ISNB = (1.01 ± 0.04 × BB) − 4.03 ± 2.12; r2 = 0.99, P < 0.001, n = 12. Figure 6. View largeDownload slide Regression showing the relationship between the rumen effective degradability (ED; %) of 12 feedstuffs determined by the Bang-Bang (BB) technique and the steel chain in situ nylon bag (ISNB) technique: ISNB = (1.01 ± 0.04 × BB) − 4.03 ± 2.12; r2 = 0.99, P < 0.001, n = 12. Advantages of the Bang-Bang Apparatus The cylindrical structure of the pedestal makes it possible for the nylon bags remain outspread in the rumen, which would facilitate feed substrates within the bags to be easily accessible by ruminal microorganisms. Additionally, bags would not be tangled or bunched during the incubation. Shear leakage is one of the frequent problems for the traditional in situ methods because the nylon bag is sewn using threads, whereas using sealing clips helps prevent this from happening. Moreover, the BB method saves time. According to our experience, normally at least 30 s is needed to bind a nylon bag and fasten it to a steel chain, but it only takes about 3 to 5 s to seal a bag and fix it to the pedestal using the BB apparatus. In addition, as mentioned above, the values of relative SD were less with the BB method compared with the ISNB method, suggesting that repeatability was improved using the BB apparatus. The consistently greater DMD after each incubation time or the greater ED of DM with the BB than with ISNB suggested that the ISNB method may underestimate the digestibility of feeds in the rumen. In fact, compared with the ISNB method, the effective surface area of the bag is larger for the BB method; therefore, the ratio of bag surface area to sample size increased. Udén and Van Soest (1984) found that 48-h extent of digestion increased and variability in measures of cell wall digestion decreased as the ratio of bag surface area to sample size increased. The BB apparatus described in the present study can be used for measurement of ruminal degradability of feedstuffs for dairy cattle, beef cattle, and other large ruminants; further studies oriented to small ruminants are in progress. Implications The BB technique can be used to determine feed degradability in the rumen of cattle and the repeatability of the BB technique is improved over the traditional steel chain technique. The BB apparatus has been successfully used in different laboratories in a series of trials and the procedure is standardized. It is cost effective, portable, reusable, and easy to operate. Footnotes 1 This study was financially supported by the Earmarked Fund of Modern Agro-Industry Technology Research System (Beef Cattle and Yaks, CARS-38). LITERATURE CITED AOAC 2012. Official methods of analysis,  19th ed. AOAC Int., Gaithersburg, Maryland. Cruywagen C. W. 2006. Technical note: A method to facilitate retrieval of polyester bags used in in sacco trials in ruminants. J. Dairy Sci.  89: 1028– 1030. doi: https://doi.org/10.3168/jds.S0022-0302(06)72169-5 Google Scholar CrossRef Search ADS PubMed  Figroid W. Hale W. H. Theurer B. 1972. An evaluation of the nylon bag technique for estimating rumen utilization of grains. J. Anim. Sci.  35: 113– 120. Google Scholar CrossRef Search ADS PubMed  Hawley A. W. L. 1981. Effect of bag location along a suspension line on nylon bag digestibility estimates in bison and cattle. J. Range Manage.  34: 265– 266. doi: https://doi.org/10.2307/3897847 Google Scholar CrossRef Search ADS   McDonald I. 1981. A revised model for the estimation of protein degradability in the rumen. J. Agric. Sci.  96: 251– 252. Google Scholar CrossRef Search ADS   Mehrez A. Z. Ørskov E. R. 1977. A study of the artificial fibre bag technique for determining the digestibility of feeds in the rumen. J. Agric. Sci.  88: 645– 650. doi: https://doi.org/10.1017/S0021859600037321 Google Scholar CrossRef Search ADS   Ørskov E. R. McDonald I. 1979. The estimation of protein degradability in the rumen from incubation measurements weighted according to rate of passage. J. Agric. Sci.  92: 499– 503. doi: https://doi.org/10.1017/S0021859600063048 Google Scholar CrossRef Search ADS   Ørskov E. R. DeB Hovell F. D. Mould F. 1980. The use of the nylon bag technique for the evaluation of feedstuffs. Trop. Anim. Prod.  5: 195– 213. Quin J. I. Van der Wath J. C. Myburgh S. 1938. Studies on the alimentary tract of Merido sheep in South Africa. 4. Description of experimental technique. Onderstepoort J. Vet. Sci. Anim. Ind.  11: 341– 360. Renecker L. A. Hudson R. J. 1990. Digestive kinetics of moose (Alces alces), wapiti (Cervus elaphus) and cattle. Anim. Prod.  50: 51– 61. doi: https://doi.org/10.1017/S0003356100004463 Google Scholar CrossRef Search ADS   Udén P. Van Soest P. J. 1984. Investigations of the in situ bag technique and a comparison of the fermentation in heifers, sheep, ponies and rabbits. J. Anim. Sci.  58: 213– 221. Google Scholar CrossRef Search ADS PubMed  Vanzant E. S. Cochran R. C. Titgemeyer E. C. 1998. Standardization of in situ techniques for ruminant feedstuff evaluation. J. Anim. Sci.  76: 2717– 2729. Google Scholar CrossRef Search ADS PubMed  Varel V. H. Kreikemeier K. K. 1995. Technical note: Comparison of in vitro and in situ digestibility methods. J. Anim. Sci.  73: 578– 582. Google Scholar CrossRef Search ADS PubMed  American Society of Animal Science
TI - Technical note: A special apparatus for facilitating the in situ nylon bag measurement of the ruminal degradation of feedstuffs in cattle
JF - Journal of Animal Science
DO - 10.2527/jas.2016-0574
DA - 2016-08-01
UR - https://www.deepdyve.com/lp/oxford-university-press/technical-note-a-special-apparatus-for-facilitating-the-in-situ-nylon-t9HWJxpkwq
SP - 3457
EP - 3463
VL - 94
IS - 8
DP - DeepDyve
ER -