TY - JOUR
AU - Stouffer, J. R.
AB - ABSTRACT Thirty-nine Holstein steer calves were assigned to one of five treatments at birth and individually fed for 200 d with milk replacer reconstituted to equal the fat and protein concentration of beef cow milk. Treatment levels were the quantities of reconstituted milk fed per day based on lactation curves, which were based on peak milk levels (PML) of 2.72, 5.44, 8.16, 10.88, and 13.6 kg/d, respectively. In addition to reconstituted milk, chopped alfalfa hay was offered ad libitum to allow for maximal voluntary forage consumption. All calves were fed a high-energy diet postweaning until they reached a similar degree of fatness in the 12th rib (4 to 5% chemical fat) as determined by ultrasound. There were differences (P < 0.05) among groups in weaning weight, preweaning ADG, age, and weight at slaughter. During the preweaning phase, there was a linear relationship (P < 0.01) for daily milk and forage DE intake; however, DE intake per unit of BW did not differ across treatments (P = 0.06). Increasing PML resulted in a linear (P < 0.01) decrease in alfalfa hay intake in the preweaning phase, and G:F increased quadratically (P < 0.01). During the postweaning phase, preweaning milk intake had no meaningful effect on postweaning ADG, but overall ADG had a linear relationship (P < 0.01) with preweaning milk level. There was no effect of PML on the 12th-rib lipid percent, marbling score, or quality grade, but protein and fat concentration in the carcass and empty BW increased linearly (P < 0.01) with PML. The group fed at 2.72 kg/d PML was 58 kg lighter (P = 0.03) and required 34 d more (P < 0.01) to reach the predetermined degree of fatness at slaughter than the group fed at 13.6 kg/d PML, suggesting that increased milk production by the dam can decrease the number of days to the slaughter weight at which a similar rib lipid concentration is reached. Introduction Forage intake by nursing calves is influenced by amount of suckled milk (Baker and Barker, 1978) and by availability and quality of forage (Wright and Russel, 1987). The range of correlation between level of milk consumption and weight gain among calves varies from 0.4 to 0.88 (Totusek and Arnett, 1965; Wyatt et al., 1977). Forage intake by nursing calves increases as lactation declines, and subsequently, applies greater pressure on the forage management program (Fox et al., 1988). It has also been shown that forage intake per unit of BW before weaning is consistently increased for calves receiving low quantities of milk (Le Du et al., 1976; Broesder et al., 1990), and that the consumption of milk decreases herbage intake (Baker et al., 1976). Few experiments have evaluated the performance by calves nursing controlled amounts of milk, while consuming forage, and the subsequent effect on the feedlot finishing phase. Therefore, the objectives of this study were to evaluate the effect of milk intake on forage intake, pre- and postweaning growth, and body composition of calves. Due to their availability at birth, Holstein bull calves were used as a model. Materials and Methods Preweaning Phase Humane animal care and use procedures were followed (Cornell University Institutional Animal Care and Use Committee Protocol 86–209). Thirty-nine Holstein bull calves from the Cornell University dairy herd were individually-fed with nurse pails one of five levels of milk based on Eq. [1] (Wood, 1967), with the adjustments proposed by George (1984) and Fox et al. (1988) for mature beef cows, assuming five peak milk levels (PML: 2.72, 5.44, 8.16, 10.88, and 13.66 kg/d):  \[\mathit{MY_{t}}\ =\ \mathit{A}\ {\times}\ \mathit{t^{b}}\ {\times}\ \mathit{e}^{{-}\mathit{c}\ {\times}\ \mathit{t}}\] [1] where MYt is milk yield at time t, kg/d; t is days after parturition; and A, b, and c are parameters of the equation proposed by Wood (1967). The coefficient A is a general scaling factor associated with the average daily milk yield at the start of lactation. Calves were fed reconstituted milk substitute (18% DM; Table 1) and ad libitum chopped alfalfa hay from birth for 200 d. This approach avoided technical problems associated with establishing and maintaining a range of known milk and forage intakes over an extended period in a group of naturally suckled beef breed calves. The composition of the milk replacer and chopped alfalfa hay is shown in Table 1. Within 24 h after parturition, as they became available from the Cornell dairy herd, the calves were weighed, fed 7.3 kg/d of colostrum from the Cornell dairy herd, and assigned randomly to one of five PML. Table 1. Composition and chemical analysis (DM basis) of milk replacer and alfalfa hay Itema  Milk replacerb  Alfalfa hayc  DM, %  98.8  89.4    ––– % of DM –––  CP  22.8  13.8  ADF  0.1  42.6  NDF  0.0  63.8  NDFP  0.0  4.21  CP solubility, % CP  95.0  26.4  Ca  0.83  0.80  P  0.66  0.31  Mg  0.11  0.24  K  1.89  1.73  Na  0.78  0.02    ––– mg/kg of DM –––  Fe  101  142  Zn  99  24  Cu  7  8  Mn  48  30  Mo  1.3  1.3  Itema  Milk replacerb  Alfalfa hayc  DM, %  98.8  89.4    ––– % of DM –––  CP  22.8  13.8  ADF  0.1  42.6  NDF  0.0  63.8  NDFP  0.0  4.21  CP solubility, % CP  95.0  26.4  Ca  0.83  0.80  P  0.66  0.31  Mg  0.11  0.24  K  1.89  1.73  Na  0.78  0.02    ––– mg/kg of DM –––  Fe  101  142  Zn  99  24  Cu  7  8  Mn  48  30  Mo  1.3  1.3  a NDFP = NDF protein. b The milk replacer was Beacon Super Nurse (Beacon Milling Co., Cayuga, NY) and contained 20% fat and the following ingredients: dried skimmed milk, dried whey product, dried whey protein concentrate, animal fat, and dried milk protein. The reconstituted milk fed comprised 18% milk replacer and 82% warm water. c Chop length was 5 to 10 cm. View Large Table 1. Composition and chemical analysis (DM basis) of milk replacer and alfalfa hay Itema  Milk replacerb  Alfalfa hayc  DM, %  98.8  89.4    ––– % of DM –––  CP  22.8  13.8  ADF  0.1  42.6  NDF  0.0  63.8  NDFP  0.0  4.21  CP solubility, % CP  95.0  26.4  Ca  0.83  0.80  P  0.66  0.31  Mg  0.11  0.24  K  1.89  1.73  Na  0.78  0.02    ––– mg/kg of DM –––  Fe  101  142  Zn  99  24  Cu  7  8  Mn  48  30  Mo  1.3  1.3  Itema  Milk replacerb  Alfalfa hayc  DM, %  98.8  89.4    ––– % of DM –––  CP  22.8  13.8  ADF  0.1  42.6  NDF  0.0  63.8  NDFP  0.0  4.21  CP solubility, % CP  95.0  26.4  Ca  0.83  0.80  P  0.66  0.31  Mg  0.11  0.24  K  1.89  1.73  Na  0.78  0.02    ––– mg/kg of DM –––  Fe  101  142  Zn  99  24  Cu  7  8  Mn  48  30  Mo  1.3  1.3  a NDFP = NDF protein. b The milk replacer was Beacon Super Nurse (Beacon Milling Co., Cayuga, NY) and contained 20% fat and the following ingredients: dried skimmed milk, dried whey product, dried whey protein concentrate, animal fat, and dried milk protein. The reconstituted milk fed comprised 18% milk replacer and 82% warm water. c Chop length was 5 to 10 cm. View Large All calves were castrated within the first 10 wk of age. Milk replacer (Table 1) was reconstituted to equal the fat (4%) and protein (4%) concentration of beef cow milk (NRC, 1984, 1996). Each calf was fed in an individual pen that measured 4.92 or 5.28 m2 in a slatted-floor confinement barn. During the preweaning period, milk was fed by nursing from a bucket through a rubber teat. To simulate the milk consumption pattern of nursing calves (Odde et al., 1985; Day et al., 1987), the daily allowance of milk computed with Eq. [1] for each PML level was offered in four feedings per day for the first month. Feeding times were 0900, 1200, 1500, and 1700, with the quantity of milk being divided into four feedings of 2/9, 2/9, 2/9, and 3/9, respectively, of the daily total. In the second month, calves were switched to three feeding times per day (0900, 1200, and 1500), with one-third of the daily milk being offered at each feeding. Chopped alfalfa hay (Table 1) was offered ad libitum (available at all times, with refusals weighed every 2 wk when the calves were weighed) from the second day in feeders in each pen until 200 d to determine voluntary forage intake in addition to milk. Postweaning Phase Calves were weaned as they reached 200 d of age and were switched to a TMR high-energy diet (Table 2) containing 33 ppm of monensin formulated for three stages of growth (136 to 227, 227 to 318, and 318 kg of BW until market) with the Cornell Net Carbohydrate and Protein System (CNCPS; Fox et al., 1992). Diet CP (DM basis) level at weaning was 16% and was decreased to 14 and 12% at 227 and 318 kg BW, respectively. Calves were fed individually in the same pens described previously and were weighed at 2-wk intervals until slaughter. Animals were slaughtered as they reached an ultrasonic lipid concentration of 4 to 5% in the 12th rib. Based on the results of Abdalla et al. (1988), a sound reflectance or attenuation reading, which is the loss of signal energy as a function of reduced tissue penetration as fat concentration increases, of 0.4 to 0.5 was taken to be indicative of the 4 to 5% chemical fat in the LM. The attenuation reading to determine degree of lipid was measured with an ultrasonic scanner (GE Co. Medical Systems Group, Milwaukee, WI). Empty body weight (EBW) was estimated from chilled carcass weight (CCW) based on Eq. [2] (Fox et al., 1976): Table 2. Postweaning diet ingredients and chemical composition (DM basis) for three stages of postweaning growth   BW range  Itema  136 to 227 kg  227 to 318 kg  >318 kg  Diet composition  ––– % of DM –––      Corn silage  20.0  20.0  20.0      High-moisture shelled corn  59.2  64.8  70.0      Soybean meal  16.4  12.5  8.4      Trace mineral saltb  0.50  0.50  0.50      Limestone  1.80  0.90  0.90      Dicalcium phosphate  2.10  1.30  —      Potassium chloride  —  —  0.20  Chemical analyses      DM, %  62.73  61.15  60.0        ––– % of DM –––      CP  16.55  14.70  14.15      ADFP  0.55  0.40  0.45      CP solubility, % CP  19.0  27.5  28.5      NDFP  1.40  1.20  1.50      NDF  21.20  20.50  21.20      ADF  9.40  10.60  8.90      TDN  77.0  76.0  77.0      Ca  1.12  0.64  0.44      P  0.75  0.57  0.29      K  0.80  0.70  0.75    BW range  Itema  136 to 227 kg  227 to 318 kg  >318 kg  Diet composition  ––– % of DM –––      Corn silage  20.0  20.0  20.0      High-moisture shelled corn  59.2  64.8  70.0      Soybean meal  16.4  12.5  8.4      Trace mineral saltb  0.50  0.50  0.50      Limestone  1.80  0.90  0.90      Dicalcium phosphate  2.10  1.30  —      Potassium chloride  —  —  0.20  Chemical analyses      DM, %  62.73  61.15  60.0        ––– % of DM –––      CP  16.55  14.70  14.15      ADFP  0.55  0.40  0.45      CP solubility, % CP  19.0  27.5  28.5      NDFP  1.40  1.20  1.50      NDF  21.20  20.50  21.20      ADF  9.40  10.60  8.90      TDN  77.0  76.0  77.0      Ca  1.12  0.64  0.44      P  0.75  0.57  0.29      K  0.80  0.70  0.75  a NDFP = NDF protein, and ADFP = ADF protein. b Trace mineral salt composition: NaCl, 0.98%; Fe, 0.5%; Mn, 0.2%; Zn, 0.2%; Cu, 0.04%; Co, 0.0007%; and I, 0.002%. View Large Table 2. Postweaning diet ingredients and chemical composition (DM basis) for three stages of postweaning growth   BW range  Itema  136 to 227 kg  227 to 318 kg  >318 kg  Diet composition  ––– % of DM –––      Corn silage  20.0  20.0  20.0      High-moisture shelled corn  59.2  64.8  70.0      Soybean meal  16.4  12.5  8.4      Trace mineral saltb  0.50  0.50  0.50      Limestone  1.80  0.90  0.90      Dicalcium phosphate  2.10  1.30  —      Potassium chloride  —  —  0.20  Chemical analyses      DM, %  62.73  61.15  60.0        ––– % of DM –––      CP  16.55  14.70  14.15      ADFP  0.55  0.40  0.45      CP solubility, % CP  19.0  27.5  28.5      NDFP  1.40  1.20  1.50      NDF  21.20  20.50  21.20      ADF  9.40  10.60  8.90      TDN  77.0  76.0  77.0      Ca  1.12  0.64  0.44      P  0.75  0.57  0.29      K  0.80  0.70  0.75    BW range  Itema  136 to 227 kg  227 to 318 kg  >318 kg  Diet composition  ––– % of DM –––      Corn silage  20.0  20.0  20.0      High-moisture shelled corn  59.2  64.8  70.0      Soybean meal  16.4  12.5  8.4      Trace mineral saltb  0.50  0.50  0.50      Limestone  1.80  0.90  0.90      Dicalcium phosphate  2.10  1.30  —      Potassium chloride  —  —  0.20  Chemical analyses      DM, %  62.73  61.15  60.0        ––– % of DM –––      CP  16.55  14.70  14.15      ADFP  0.55  0.40  0.45      CP solubility, % CP  19.0  27.5  28.5      NDFP  1.40  1.20  1.50      NDF  21.20  20.50  21.20      ADF  9.40  10.60  8.90      TDN  77.0  76.0  77.0      Ca  1.12  0.64  0.44      P  0.75  0.57  0.29      K  0.80  0.70  0.75  a NDFP = NDF protein, and ADFP = ADF protein. b Trace mineral salt composition: NaCl, 0.98%; Fe, 0.5%; Mn, 0.2%; Zn, 0.2%; Cu, 0.04%; Co, 0.0007%; and I, 0.002%. View Large  \[\mathit{EBW}\ =\ 1.4\ {\times}\ \mathit{CCW}\ +\ 40.2\] [2] where EBW and chilled carcass weight are expressed in kilograms. The 9th- to 11th-rib section was removed as described by Hankins and Howe (1946) using their skeletal reference points. The 9th- to 11th-rib section was weighed and separated into soft tissue and bone with ligaments. The soft tissue was chopped with a knife and ground in an Alexanderwerk Schneidmeister (model M-40, Horsham, PA) silent cutter and two 0.5-kg homogenized samples were frozen. The samples were then ground with dry ice to pass a 2-mm screen of Wiley mill (Thomas Scientific, Swedesboro, NJ) as described by Adballa (1986). Protein was determined using the standard macro-Kjeldahl method (AOAC, 1990), and fat was analyzed using the chloroform-refluxing Soxhlet apparatus. The percentages of protein and lipid in the rib section were used to calculate carcass protein and carcass fat as shown in Eq. [3] and [4], which were developed from Holstein calves (Nour and Thonney, 1994) similar to those used in the present study:  \[\mathit{Fat_{Carcass}}\ =\ 0.79\ {\times}\ \mathit{Fat_{Rib}}\ +\ 2.78\] [3]  \[\mathit{Protein_{Carcass}}\ =\ 0.7\ {\times}\ \mathit{Protein_{Rib}}\ +\ 5.29\] [4] where FatRib and ProteinRib are the fat and protein concentration of the 9th- to 11th-rib section. The predicted carcass fat and protein values were used to predict empty body fat (EBF, % of EBW) and empty body protein (EBP, % of EBW) using Eq. [5] and [6], respectively (Garrett and Hinman, 1969):  \[\mathit{EBF_{Body}}\ =\ 0.9246\ {\times}\ \mathit{EBF_{Carcass}}\ {-}\ 0.647\] [5]  \[\mathit{EBF_{Body}}\ =\ 0.7772\ {\times}\ \mathit{EBF_{Carcass}}\ +\ 0.713\] [6] Initial fat and protein composition at the beginning of the trial was assumed to be similar to those reported by Diaz et al. (2001). They reported fat and protein values for Holstein calves at birth of 4.7 and 20.9% of EBW, respectively. Initial EBW was assumed to be 40.4 kg (Diaz et al., 2001). Fat and protein deposition was then determined from the difference between predicted initial and final concentration of fat and protein in the EBW. Retained energy (RE, Mcal) was computed based on fat and protein deposition multiplied by the caloric value of fat and protein, respectively (Lofgreen, 1965), as indicated in Eq. [7] to [9]:  \[\mathit{FG}\ =\ \mathit{EBF_{Final}}\ {-}\ \mathit{EBF_{Initial}}\] [7]  \[\mathit{PG}\ =\ \mathit{EBP_{Final}}\ {-}\ \mathit{EBF_{Initial}}\] [8]  \[\mathit{RE}\ =\ (9.367\ {\times}\ \mathit{FG}\ +\ 55.685\ {\times}\ \mathit{PG})/\mathit{DOF}\] [9] where FG is fat gain (kg); PG is protein gain (kg); DOF is days on feed; and RE is expressed in megacalories per day. The ME value of diets and alfalfa hay were assumed to be 82% of the DE values (NRC, 1996, 2000). From the energy and protein gained, the total efficiency of ME (kME) was determined by Eq. [10]:  \[\mathit{k_{ME}}\ =\ \frac{\mathit{RE}}{\mathit{MEI}}\] [10] where RE is as defined above; kME is efficiency of ME to RE; and MEI is ME intake (Mcal/d). Digestibility and Blood Measures Acid detergent insoluble ash (ADIA) was used as an internal marker (Porter, 1987) by collecting a fecal sample from each steer over 5 d near the end of the preweaning period to determine the influence of milk on forage digestibility. Samples were analyzed in duplicate for ADIA, as described by Van Soest (1994). The five fecal samples were composited and a 1- to 4-g sample of feed or feces (sample size was increased as necessary to insure a 10 mg of ash residue) was refluxed in 100 to 250 mL acid detergent solution (Goering and Van Soest, 1970) for 1 h, filtered through a 50-mL Gooch crucible (coarse porosity), and ashed at 500°C for 12 h. This was repeated during the postweaning period to establish the DM digestibility of the high-energy diets. Diet digestibility percentage was calculated as shown in Eq. [11]:  \[\mathit{Digestibility}\ =\ 100\ {-}\ \left(\frac{\%\mathit{ADIA_{Feed}}}{\%\mathit{ADIA_{Feces}}}\right)\ {\times}\ 100\] [11] The preweaning forage digestibility was determined by assuming that the ADIA concentration in milk was zero because there is no fiber in milk with which ADIA is associated. We assumed the milk digestibility was 95% (Diaz et al., 2001). Feed samples (milk powder, alfalfa hay, and postweaning dietary ingredients) were analyzed for CP using the standard macro-Kjeldahl method (AOAC, 1990). Protein solubility and degradability were determined according to Krishnamoorthy et al. (1983). The NDF and nonsequential ADF concentration were determined according to Goering and Van Soest (1970). The residual N in the NDF samples was measured by the standard Kjeldahl method (AOAC, 1990). Serum samples were obtained at 1 mo of age, weaning, 1 mo after weaning, and before slaughter and analyzed for insulin and triiodothyronine (T3). Insulin and T3 concentrations were determined by RIA insulin and T3 kits (Micromedic Systems, Inc., Horshem, PA). Statistical Analyses All statistical analyses were conducted with PROC GLM of SAS (SAS Inst., Inc., Cary, NC). A one-way analysis of variance was used to analyze the data. The experimental units were steers. Orthogonal polynomials (linear, quadratic, cubic, and quartic) were used to assess the effect of PML on response variables. Residual plots showed that the residuals were normally distributed. Results and Discussion Preweaning Phase Data for animal growth and consumption of reconstituted milk and alfalfa hay are shown in Table 3. Calves had quadratic increases in ADG and weaning BW due to milk level (P < 0.01; Table 3). The average daily milk DMI for 2.72, 5.44, and 8.16 kg/d PML (0.38, 0.79, and 1.16 kg of DM/d, respectively) were similar to the target amount based on Eq. [1] (0.39, 0.79, 1.19 kg of DM/d, respectively); however, for 10.88 and 13.66 kg/d PML (1.49 and 1.77 kg DM/d, respectively), they were lower (P < 0.01) than the target amount (1.59 and 2.01, respectively). Some calves in 10.88 and 13.66 kg/d PML rejected a portion of the milk offered daily, and some calves had diarrhea for few days, indicating those milk levels at early ages exceeded calf milk intake capacity. The target ratio of milk DMI was 1:2:3:4:5, and the observed ratio was 1:2:3:3.9:4.6 for 2.72, 5.44, 8.16, 10.88, and 13.66 kg/d PML, respectively. Table 3. Animal growth and consumption of milk replacer and alfalfa hay for each milk intake level during the preweaning phasea   Preweaning peak milk, kg/d    P-valued  Itemb  2.72  5.44  8.16  10.88  13.66  SEc  L  Qd  C  Qt  No.  8  8  8  7  8  —  —  —  —  —  Initial BW, kg  43.3  46.2  48.1  44.1  47.5  1.83  0.28  0.48  0.17  0.24  Days on feed  195  193  193  194  195  1.51  0.83  0.24  0.58  0.87  Final BW, kg  153  198  228  235  249  5.83  0.01  0.01  0.26  0.41  ADG, kg/d  0.560  0.785  0.938  0.979  1.04  0.03  0.01  0.01  0.27  0.43  DMI, kg/d      Milk  0.383  0.768  1.16  1.49  1.77  0.02  0.01  0.01  0.43  0.74      Alfalfa  1.82  1.70  1.62  1.16  1.04  0.06  0.01  0.12  0.13  0.04      Total  2.21  2.47  2.77  2.65  2.81  0.07  0.01  0.02  0.25  0.04  G:F, g/kg  254  317  338  371  371  8.11  0.01  0.01  0.71  0.14  DMD, %  73.1  71.4  71.7  71.2  69.9  1.44  0.15  0.99  0.52  0.83  DE, Mcal/kg of DMe  3.28  3.18  3.19  3.16  3.08  0.07  0.08  0.95  0.48  0.81  DEI, Mcal/d      Milk  1.86  3.74  5.63  7.24  8.60  0.10  0.01  0.01  0.43  0.74      Alfalfa  5.98  5.42  5.18  3.66  3.22  0.23  0.01  0.24  0.31  0.05      Total  7.84  9.16  10.8  10.9  11.8  0.27  0.01  0.02  0.56  0.07  DEI/BW  80.1  75.2  78.2  78.1  79.9  1.43  0.57  0.06  0.20  0.20  Predicted G:F, g/kgf  325  297  322  333  336  —  —  —  —  —  Observed/predicted G:F  0.78  1.07  1.05  1.11  1.10  —  —  —  —  —    Preweaning peak milk, kg/d    P-valued  Itemb  2.72  5.44  8.16  10.88  13.66  SEc  L  Qd  C  Qt  No.  8  8  8  7  8  —  —  —  —  —  Initial BW, kg  43.3  46.2  48.1  44.1  47.5  1.83  0.28  0.48  0.17  0.24  Days on feed  195  193  193  194  195  1.51  0.83  0.24  0.58  0.87  Final BW, kg  153  198  228  235  249  5.83  0.01  0.01  0.26  0.41  ADG, kg/d  0.560  0.785  0.938  0.979  1.04  0.03  0.01  0.01  0.27  0.43  DMI, kg/d      Milk  0.383  0.768  1.16  1.49  1.77  0.02  0.01  0.01  0.43  0.74      Alfalfa  1.82  1.70  1.62  1.16  1.04  0.06  0.01  0.12  0.13  0.04      Total  2.21  2.47  2.77  2.65  2.81  0.07  0.01  0.02  0.25  0.04  G:F, g/kg  254  317  338  371  371  8.11  0.01  0.01  0.71  0.14  DMD, %  73.1  71.4  71.7  71.2  69.9  1.44  0.15  0.99  0.52  0.83  DE, Mcal/kg of DMe  3.28  3.18  3.19  3.16  3.08  0.07  0.08  0.95  0.48  0.81  DEI, Mcal/d      Milk  1.86  3.74  5.63  7.24  8.60  0.10  0.01  0.01  0.43  0.74      Alfalfa  5.98  5.42  5.18  3.66  3.22  0.23  0.01  0.24  0.31  0.05      Total  7.84  9.16  10.8  10.9  11.8  0.27  0.01  0.02  0.56  0.07  DEI/BW  80.1  75.2  78.2  78.1  79.9  1.43  0.57  0.06  0.20  0.20  Predicted G:F, g/kgf  325  297  322  333  336  —  —  —  —  —  Observed/predicted G:F  0.78  1.07  1.05  1.11  1.10  —  —  —  —  —  a The reconstituted milk was 18% DM. b DMD = DM digestibility; DEI = DE intake; and DEI/BW is kcal/(kg•d). c SE was computed as the square root of the mean square error divided by the square root of 7.8. d P-value of linear (L), quadratic (Qd), cubic (C), and quartic (Qt) effects using orthogonal polynomial contrasts. e Alfalfa DE. Milk DE was assumed to be fixed at 4.87 Mcal/kg, which was computed as the milk GE of 5.124 multiplied by 0.95 digestibility. f Predicted with the equations of Guiroy et al. (2001). View Large Table 3. Animal growth and consumption of milk replacer and alfalfa hay for each milk intake level during the preweaning phasea   Preweaning peak milk, kg/d    P-valued  Itemb  2.72  5.44  8.16  10.88  13.66  SEc  L  Qd  C  Qt  No.  8  8  8  7  8  —  —  —  —  —  Initial BW, kg  43.3  46.2  48.1  44.1  47.5  1.83  0.28  0.48  0.17  0.24  Days on feed  195  193  193  194  195  1.51  0.83  0.24  0.58  0.87  Final BW, kg  153  198  228  235  249  5.83  0.01  0.01  0.26  0.41  ADG, kg/d  0.560  0.785  0.938  0.979  1.04  0.03  0.01  0.01  0.27  0.43  DMI, kg/d      Milk  0.383  0.768  1.16  1.49  1.77  0.02  0.01  0.01  0.43  0.74      Alfalfa  1.82  1.70  1.62  1.16  1.04  0.06  0.01  0.12  0.13  0.04      Total  2.21  2.47  2.77  2.65  2.81  0.07  0.01  0.02  0.25  0.04  G:F, g/kg  254  317  338  371  371  8.11  0.01  0.01  0.71  0.14  DMD, %  73.1  71.4  71.7  71.2  69.9  1.44  0.15  0.99  0.52  0.83  DE, Mcal/kg of DMe  3.28  3.18  3.19  3.16  3.08  0.07  0.08  0.95  0.48  0.81  DEI, Mcal/d      Milk  1.86  3.74  5.63  7.24  8.60  0.10  0.01  0.01  0.43  0.74      Alfalfa  5.98  5.42  5.18  3.66  3.22  0.23  0.01  0.24  0.31  0.05      Total  7.84  9.16  10.8  10.9  11.8  0.27  0.01  0.02  0.56  0.07  DEI/BW  80.1  75.2  78.2  78.1  79.9  1.43  0.57  0.06  0.20  0.20  Predicted G:F, g/kgf  325  297  322  333  336  —  —  —  —  —  Observed/predicted G:F  0.78  1.07  1.05  1.11  1.10  —  —  —  —  —    Preweaning peak milk, kg/d    P-valued  Itemb  2.72  5.44  8.16  10.88  13.66  SEc  L  Qd  C  Qt  No.  8  8  8  7  8  —  —  —  —  —  Initial BW, kg  43.3  46.2  48.1  44.1  47.5  1.83  0.28  0.48  0.17  0.24  Days on feed  195  193  193  194  195  1.51  0.83  0.24  0.58  0.87  Final BW, kg  153  198  228  235  249  5.83  0.01  0.01  0.26  0.41  ADG, kg/d  0.560  0.785  0.938  0.979  1.04  0.03  0.01  0.01  0.27  0.43  DMI, kg/d      Milk  0.383  0.768  1.16  1.49  1.77  0.02  0.01  0.01  0.43  0.74      Alfalfa  1.82  1.70  1.62  1.16  1.04  0.06  0.01  0.12  0.13  0.04      Total  2.21  2.47  2.77  2.65  2.81  0.07  0.01  0.02  0.25  0.04  G:F, g/kg  254  317  338  371  371  8.11  0.01  0.01  0.71  0.14  DMD, %  73.1  71.4  71.7  71.2  69.9  1.44  0.15  0.99  0.52  0.83  DE, Mcal/kg of DMe  3.28  3.18  3.19  3.16  3.08  0.07  0.08  0.95  0.48  0.81  DEI, Mcal/d      Milk  1.86  3.74  5.63  7.24  8.60  0.10  0.01  0.01  0.43  0.74      Alfalfa  5.98  5.42  5.18  3.66  3.22  0.23  0.01  0.24  0.31  0.05      Total  7.84  9.16  10.8  10.9  11.8  0.27  0.01  0.02  0.56  0.07  DEI/BW  80.1  75.2  78.2  78.1  79.9  1.43  0.57  0.06  0.20  0.20  Predicted G:F, g/kgf  325  297  322  333  336  —  —  —  —  —  Observed/predicted G:F  0.78  1.07  1.05  1.11  1.10  —  —  —  —  —  a The reconstituted milk was 18% DM. b DMD = DM digestibility; DEI = DE intake; and DEI/BW is kcal/(kg•d). c SE was computed as the square root of the mean square error divided by the square root of 7.8. d P-value of linear (L), quadratic (Qd), cubic (C), and quartic (Qt) effects using orthogonal polynomial contrasts. e Alfalfa DE. Milk DE was assumed to be fixed at 4.87 Mcal/kg, which was computed as the milk GE of 5.124 multiplied by 0.95 digestibility. f Predicted with the equations of Guiroy et al. (2001). View Large Increasing PML resulted in a linear (P < 0.01) decrease in alfalfa hay intake (Table 3). Church et al. (1980) also reported that calves fed low levels of milk consumed more forage earlier to compensate for the lower nutrient supply from milk consumption. Similarly, Broesder et al. (1990) indicated that a decrease in milk replacer consumption increased linearly the intake of alfalfa hay by Holstein calves. Calves fed the high levels of reconstituted milk (10.88 and 13.66 kg/d PML) consumed 36 and 43% less alfalfa hay DM, respectively, than calves fed the lowest level (2.72 kg/d PML), but milk DMI was 398 and 461% higher for 10.88 and 13.66 kg/d PML, respectively, compared with 2.72 kg/d PML. This finding is in agreement with several studies (Baker et al., 1976; Lusby et al., 1976; Wyatt et al., 1977), in which there was a preference of milk over forage if milk intake was not restricted. Overall, calves fed 13.66 kg/d PML consumed 1.39 kg more milk DM/d, grew 0.48 kg/d faster, and had 96 kg greater weaning BW (Table 3) than calves fed 2.72 kg/d PML (P < 0.01). Calves fed 8.16 kg/d PML averaged 0.78 kg more milk DM/d, and had 0.378 kg/d and 75 kg greater ADG and weaning weight, respectively, than calves fed 2.72 kg/d PML (P < 0.01). The increased growth rates of calves with increased milk intake observed in this study agree with data reported in the literature on calf growth (Baker et al., 1976; Le Du et al., 1976; Wyatt et al., 1977). Appleman and Owen (1975) reported that higher milk levels produce faster initial gains but not after 12 to 16 wk (84 to 112 d) of age. The G:F value increased quadratically as milk level increased (P < 0.01; Table 3), suggesting the average amount of energy available from milk and alfalfa was higher in the high milk level intake groups. This was expected because milk DE was greater than the average alfalfa DE concentration (4.87 vs. 3.18 Mcal/kg, respectively; Table 3) and, although milk intake increased, alfalfa intake decreased linearly (P < 0.01; Table 3). The G:F did not improve at the same rate as milk intake, however. Milk DMI as a percentage of the total DMI increased linearly through 10.88 kg/d PML; however, the rate of increase in ADG averaged five percentage units per PML increase after 8.16 kg/d PML compared with a higher rate of change from 2.72 to 5.44 kg/d PML (0.56 to 0.785 kg/d; 40%) and from 5.44 to 8.16 kg/d PML (0.785 to 0.938 kg/d; 19%). This finding suggests that when PML was increased above 8.16 kg/d, it resulted in a decreasing rate of increase in ADG. The decreased rate of improvement in ADG and G:F to 200 d at high milk intake is at least partly due to a heavier average weight for calves fed at higher levels of milk. The forage DM digestibility was 73.1% for 2.72 kg/d PML compared with 69.9% for 13.66 kg/d PML. This change with increasing PML, however, was not significant (P = 0.15). Baker et al. (1976) and Le Du et al. (1976) also found the level of milk in the diet did not affect the digestibility of the herbage consumed by calves. There were linear (P < 0.01) effects of PML on milk DE intake (DEI), alfalfa DEI, and total DEI, and quadratic effects on milk DEI (P < 0.01) and total DEI (P = 0.02). Calves fed the 13.66 kg/d PML consumed 462% more milk DEI, 150% more total DEI, and 46% less daily alfalfa DEI than the calves fed at the 2.72 kg/d PML at the same age. The quantity of daily DEI per kilogram of BW was similar among PML (Table 3), averaging 78.3 kcal/kg. This finding indicates that across PML, calves had the same intake of DE/kg of BW, but those consuming a higher proportion of DEI as milk gained faster (Table 3). Feed composition data (NRC, 1978) indicate the efficiency of DE to NEg is 35 and 23% for milk and alfalfa hay, respectively. The NRC (2001) indicated that in milk-fed calves, the efficiency for DE to ME for milk and calf starter are 96 and 88%, respectively; the efficiency for ME to NEg is 69% for milk and 57% for calf starter. This would be expected due to less methane and heat increment loss per unit of DE in milk. Treatment mean values were used for further analysis of the preweaning performance with the equations of Guiroy et al. (2001) to allow comparisons accounting for differences in DMI, diet DEI, BW, and composition of gain. The weight at 28% EBF was computed with the data in Table 4, and the diet DE values in Table 3 were used to predict diet NEm and NEg; NEm required was assumed to be 77 kcal/kg0.75 of shrunk BW for Holstein calves fed in this facility, based on Ainslie et al. (1993). Observed/expected G:F are shown in Table 3. Calves fed the lowest PML had lower than expected G:F; all other groups had 5 to 11% higher G:F than predicted. Metabolizable protein requirements for each treatment were computed with the NRC (2000) equations. Diaz et al. (2001) found that the NRC (2000) equations accurately predict net protein retained in milk-fed calves during early growth. The MP supplied by the diet was computed by assuming that digested alfalfa carbohydrate and protein fractions are degraded in the rumen and provide microbial protein at 13% of TDN, but based on the studies of Diaz et al. (2001), all the milk protein escapes ruminal degradation and is 89% MP. Metabolizable protein required for the observed ADG appeared to be deficient in all diets; however, the ideal AA pattern in milk protein may have allowed for more efficient growth as milk intake increased. Infusion of casein increased N retention 22% in Holstein steer calves (Houseknecht et al., 1992). Table 4. Effects of preweaning milk intake on carcass, empty body, and empty gain fat and protein compositions, and metabolizable and retained energya   Preweaning peak milk, kg/d    P-valued  Itemb  2.72  5.44  8.16  10.88  13.66  SEc  L  Qd  C  Qt  12th-rib lipid, %  5.04  4.65  3.99  4.32  4.33  0.37  0.14  0.21  0.96  0.42  Marbling scoree  6.08  6.03  5.74  5.66  5.59  0.24  0.08  0.85  0.75  0.75  Quality gradef  12.75  12.75  12.25  12.29  12.13  0.28  0.06  0.84  0.74  0.46  LM area, cm2  63.7  64.4  68.5  62.7  63.2  2.24  0.70  0.22  0.68  0.13  KPH, %  1.90  1.65  1.47  2.22  1.63  0.17  0.95  0.70  0.01  0.03  Carcass      Chilled weight, kg  267  276  292  286  291  8.42  0.04  0.33  0.83  0.38      Fat thickness, mm  4.26  5.34  5.97  5.50  6.80  0.72  0.03  0.80  0.35  0.57      Yield grade  2.77  2.82  2.74  3.22  3.14  0.16  0.03  0.59  0.41  0.19      Protein, %  15.8  15.5  15.3  15.0  15.0  0.28  0.03  0.63  0.95  0.71      Fat, %  32.4  33.4  34.3  35.0  35.9  1.05  0.01  0.92  0.92  0.99  Empty body      Weight, kg  414  427  450  440  448  11.8  0.04  0.33  0.83  0.38      Protein, %  12.9  12.6  12.6  12.3  12.3  0.22  0.03  0.63  0.95  0.71      Fat, %  29.3  30.3  31.0  31.8  32.6  0.97  0.01  0.92  0.92  0.99      Predicted BW at 28% fatg  396  394  407  386  381  —  —  —  —  —  Empty body gain      Protein, kg  45.1  45.6  48.0  45.8  46.6  1.56  0.53  0.49  0.80  0.28      Protein, %  12.0  11.8  11.7  11.4  11.5  0.23  0.05  0.69  0.92  0.63      Fat, kg  119  127  138  138  144  5.93  0.01  0.53  0.86  0.60      Fat, %  32.0  33.0  33.6  34.5  35.4  1.06  0.02  0.98  0.92  0.95  RE, Mcal/d  3.08  3.42  3.84  3.74  3.95  0.13  0.01  0.11  0.61  0.21  ME intake, Mcal/d  13.4  14.6  17.3  15.9  17.0  0.63  0.01  0.08  0.61  0.03  RE:ME intake, %  23.8  24.1  22.3  23.6  23.3  1.13  0.67  0.67  0.91  0.28    Preweaning peak milk, kg/d    P-valued  Itemb  2.72  5.44  8.16  10.88  13.66  SEc  L  Qd  C  Qt  12th-rib lipid, %  5.04  4.65  3.99  4.32  4.33  0.37  0.14  0.21  0.96  0.42  Marbling scoree  6.08  6.03  5.74  5.66  5.59  0.24  0.08  0.85  0.75  0.75  Quality gradef  12.75  12.75  12.25  12.29  12.13  0.28  0.06  0.84  0.74  0.46  LM area, cm2  63.7  64.4  68.5  62.7  63.2  2.24  0.70  0.22  0.68  0.13  KPH, %  1.90  1.65  1.47  2.22  1.63  0.17  0.95  0.70  0.01  0.03  Carcass      Chilled weight, kg  267  276  292  286  291  8.42  0.04  0.33  0.83  0.38      Fat thickness, mm  4.26  5.34  5.97  5.50  6.80  0.72  0.03  0.80  0.35  0.57      Yield grade  2.77  2.82  2.74  3.22  3.14  0.16  0.03  0.59  0.41  0.19      Protein, %  15.8  15.5  15.3  15.0  15.0  0.28  0.03  0.63  0.95  0.71      Fat, %  32.4  33.4  34.3  35.0  35.9  1.05  0.01  0.92  0.92  0.99  Empty body      Weight, kg  414  427  450  440  448  11.8  0.04  0.33  0.83  0.38      Protein, %  12.9  12.6  12.6  12.3  12.3  0.22  0.03  0.63  0.95  0.71      Fat, %  29.3  30.3  31.0  31.8  32.6  0.97  0.01  0.92  0.92  0.99      Predicted BW at 28% fatg  396  394  407  386  381  —  —  —  —  —  Empty body gain      Protein, kg  45.1  45.6  48.0  45.8  46.6  1.56  0.53  0.49  0.80  0.28      Protein, %  12.0  11.8  11.7  11.4  11.5  0.23  0.05  0.69  0.92  0.63      Fat, kg  119  127  138  138  144  5.93  0.01  0.53  0.86  0.60      Fat, %  32.0  33.0  33.6  34.5  35.4  1.06  0.02  0.98  0.92  0.95  RE, Mcal/d  3.08  3.42  3.84  3.74  3.95  0.13  0.01  0.11  0.61  0.21  ME intake, Mcal/d  13.4  14.6  17.3  15.9  17.0  0.63  0.01  0.08  0.61  0.03  RE:ME intake, %  23.8  24.1  22.3  23.6  23.3  1.13  0.67  0.67  0.91  0.28  a The reconstituted milk was 18% DM. b RE = retained energy, Mcal/d, and KPH is given as a percentage of chilled carcass weight. c SE was computed as the square root of the mean square error divided by the square root of 7.8, except MEI and RE:MEI that had 36 animals, and therefore were divided by the square root of 7.2. d P-value of linear (L), quadratic (Qd), cubic (C), and quartic (Qt) effects using orthogonal polynomial contrasts. e Marbling scores: Slight = 4; Small = 5; Modest = 6; and Moderate = 7. f Quality grade: low Choice = 10; Choice = 11; high Choice = 12; low Prime = 13. g Predicted with the equations of Guiroy et al. (2001). View Large Table 4. Effects of preweaning milk intake on carcass, empty body, and empty gain fat and protein compositions, and metabolizable and retained energya   Preweaning peak milk, kg/d    P-valued  Itemb  2.72  5.44  8.16  10.88  13.66  SEc  L  Qd  C  Qt  12th-rib lipid, %  5.04  4.65  3.99  4.32  4.33  0.37  0.14  0.21  0.96  0.42  Marbling scoree  6.08  6.03  5.74  5.66  5.59  0.24  0.08  0.85  0.75  0.75  Quality gradef  12.75  12.75  12.25  12.29  12.13  0.28  0.06  0.84  0.74  0.46  LM area, cm2  63.7  64.4  68.5  62.7  63.2  2.24  0.70  0.22  0.68  0.13  KPH, %  1.90  1.65  1.47  2.22  1.63  0.17  0.95  0.70  0.01  0.03  Carcass      Chilled weight, kg  267  276  292  286  291  8.42  0.04  0.33  0.83  0.38      Fat thickness, mm  4.26  5.34  5.97  5.50  6.80  0.72  0.03  0.80  0.35  0.57      Yield grade  2.77  2.82  2.74  3.22  3.14  0.16  0.03  0.59  0.41  0.19      Protein, %  15.8  15.5  15.3  15.0  15.0  0.28  0.03  0.63  0.95  0.71      Fat, %  32.4  33.4  34.3  35.0  35.9  1.05  0.01  0.92  0.92  0.99  Empty body      Weight, kg  414  427  450  440  448  11.8  0.04  0.33  0.83  0.38      Protein, %  12.9  12.6  12.6  12.3  12.3  0.22  0.03  0.63  0.95  0.71      Fat, %  29.3  30.3  31.0  31.8  32.6  0.97  0.01  0.92  0.92  0.99      Predicted BW at 28% fatg  396  394  407  386  381  —  —  —  —  —  Empty body gain      Protein, kg  45.1  45.6  48.0  45.8  46.6  1.56  0.53  0.49  0.80  0.28      Protein, %  12.0  11.8  11.7  11.4  11.5  0.23  0.05  0.69  0.92  0.63      Fat, kg  119  127  138  138  144  5.93  0.01  0.53  0.86  0.60      Fat, %  32.0  33.0  33.6  34.5  35.4  1.06  0.02  0.98  0.92  0.95  RE, Mcal/d  3.08  3.42  3.84  3.74  3.95  0.13  0.01  0.11  0.61  0.21  ME intake, Mcal/d  13.4  14.6  17.3  15.9  17.0  0.63  0.01  0.08  0.61  0.03  RE:ME intake, %  23.8  24.1  22.3  23.6  23.3  1.13  0.67  0.67  0.91  0.28    Preweaning peak milk, kg/d    P-valued  Itemb  2.72  5.44  8.16  10.88  13.66  SEc  L  Qd  C  Qt  12th-rib lipid, %  5.04  4.65  3.99  4.32  4.33  0.37  0.14  0.21  0.96  0.42  Marbling scoree  6.08  6.03  5.74  5.66  5.59  0.24  0.08  0.85  0.75  0.75  Quality gradef  12.75  12.75  12.25  12.29  12.13  0.28  0.06  0.84  0.74  0.46  LM area, cm2  63.7  64.4  68.5  62.7  63.2  2.24  0.70  0.22  0.68  0.13  KPH, %  1.90  1.65  1.47  2.22  1.63  0.17  0.95  0.70  0.01  0.03  Carcass      Chilled weight, kg  267  276  292  286  291  8.42  0.04  0.33  0.83  0.38      Fat thickness, mm  4.26  5.34  5.97  5.50  6.80  0.72  0.03  0.80  0.35  0.57      Yield grade  2.77  2.82  2.74  3.22  3.14  0.16  0.03  0.59  0.41  0.19      Protein, %  15.8  15.5  15.3  15.0  15.0  0.28  0.03  0.63  0.95  0.71      Fat, %  32.4  33.4  34.3  35.0  35.9  1.05  0.01  0.92  0.92  0.99  Empty body      Weight, kg  414  427  450  440  448  11.8  0.04  0.33  0.83  0.38      Protein, %  12.9  12.6  12.6  12.3  12.3  0.22  0.03  0.63  0.95  0.71      Fat, %  29.3  30.3  31.0  31.8  32.6  0.97  0.01  0.92  0.92  0.99      Predicted BW at 28% fatg  396  394  407  386  381  —  —  —  —  —  Empty body gain      Protein, kg  45.1  45.6  48.0  45.8  46.6  1.56  0.53  0.49  0.80  0.28      Protein, %  12.0  11.8  11.7  11.4  11.5  0.23  0.05  0.69  0.92  0.63      Fat, kg  119  127  138  138  144  5.93  0.01  0.53  0.86  0.60      Fat, %  32.0  33.0  33.6  34.5  35.4  1.06  0.02  0.98  0.92  0.95  RE, Mcal/d  3.08  3.42  3.84  3.74  3.95  0.13  0.01  0.11  0.61  0.21  ME intake, Mcal/d  13.4  14.6  17.3  15.9  17.0  0.63  0.01  0.08  0.61  0.03  RE:ME intake, %  23.8  24.1  22.3  23.6  23.3  1.13  0.67  0.67  0.91  0.28  a The reconstituted milk was 18% DM. b RE = retained energy, Mcal/d, and KPH is given as a percentage of chilled carcass weight. c SE was computed as the square root of the mean square error divided by the square root of 7.8, except MEI and RE:MEI that had 36 animals, and therefore were divided by the square root of 7.2. d P-value of linear (L), quadratic (Qd), cubic (C), and quartic (Qt) effects using orthogonal polynomial contrasts. e Marbling scores: Slight = 4; Small = 5; Modest = 6; and Moderate = 7. f Quality grade: low Choice = 10; Choice = 11; high Choice = 12; low Prime = 13. g Predicted with the equations of Guiroy et al. (2001). View Large Postweaning Growth Growth and feed intake data for the postweaning period and over the entire experiment are summarized in Table 5. Although the quartic effect was significant, milk intake had no consistent effect on postweaning ADG. Nonetheless, as PML increased, calves started the postweaning period at increasing weights so that days required to reach 4 to 5% lipid concentration in the LM decreased (P < 0.01), even though final BW increased (P = 0.03). Postweaning DMI increased quadratically (P = 0.03) and DEI increased linearly (P = 0.01) with increasing PML due to higher mean BW, but there was no effect on DEI/BW. Table 5. Animal performance and diet DM consumption for each preweaning milk level during the postweaning and overall growth phasesa   Preweaning peak milk, kg/d    P-valued  Itemb  2.72  5.44  8.16  10.88  13.66  SEc  L  Qd  C  Qt  No.  8  8  8  7  8  —  —  —  —  —  Initial BW, kg  153  198  228  235  249  5.83  0.01  0.01  0.26  0.41  Days on feed  250  232  214  221  216  8.06  0.01  0.11  0.63  0.39  Final BW, kg  487  498  537  508  545  17.1  0.03  0.78  0.48  0.12  ADG, kg/d  1.34  1.30  1.45  1.24  1.37  0.06  0.92  0.95  0.43  0.02  DMI, kg/d  6.85  7.77  8.82  8.32  8.81  0.29  0.01  0.03  0.36  0.09  G:F, g/kg  195  167  164  149  156  5.40  0.01  0.01  0.88  0.14  DE, Mcal/kg DM  3.23  3.11  3.34  3.17  3.14  0.17  0.83  0.72  0.69  0.35  DEI, Mcal/d  22.6  24.5  29.5  26.0  27.6  1.37  0.01  0.09  0.66  0.03  DEI/BW  68.6  68.6  77.2  70.2  69.8  3.50  0.72  0.22  0.86  0.12  Predicted G:F, g/kge  174  167  163  157  150  —  —  —  —  —  Observed/predicted G:F  1.12  1.00  1.01  0.95  1.04  —  —  —  —  —  Overallf      Days  445  425  407  415  410  8.46  0.01  0.08  0.58  0.39      ADG, kg/d  0.96  1.03  1.16  1.09  1.17  0.03  0.01  0.17  0.40  0.03      DMI, kg/d  4.62  5.13  5.64  5.36  5.70  0.16  0.01  0.07  0.24  0.11      G:F, g/kg  207  201  206  204  207  5.76  0.92  0.62  0.68  0.55    Preweaning peak milk, kg/d    P-valued  Itemb  2.72  5.44  8.16  10.88  13.66  SEc  L  Qd  C  Qt  No.  8  8  8  7  8  —  —  —  —  —  Initial BW, kg  153  198  228  235  249  5.83  0.01  0.01  0.26  0.41  Days on feed  250  232  214  221  216  8.06  0.01  0.11  0.63  0.39  Final BW, kg  487  498  537  508  545  17.1  0.03  0.78  0.48  0.12  ADG, kg/d  1.34  1.30  1.45  1.24  1.37  0.06  0.92  0.95  0.43  0.02  DMI, kg/d  6.85  7.77  8.82  8.32  8.81  0.29  0.01  0.03  0.36  0.09  G:F, g/kg  195  167  164  149  156  5.40  0.01  0.01  0.88  0.14  DE, Mcal/kg DM  3.23  3.11  3.34  3.17  3.14  0.17  0.83  0.72  0.69  0.35  DEI, Mcal/d  22.6  24.5  29.5  26.0  27.6  1.37  0.01  0.09  0.66  0.03  DEI/BW  68.6  68.6  77.2  70.2  69.8  3.50  0.72  0.22  0.86  0.12  Predicted G:F, g/kge  174  167  163  157  150  —  —  —  —  —  Observed/predicted G:F  1.12  1.00  1.01  0.95  1.04  —  —  —  —  —  Overallf      Days  445  425  407  415  410  8.46  0.01  0.08  0.58  0.39      ADG, kg/d  0.96  1.03  1.16  1.09  1.17  0.03  0.01  0.17  0.40  0.03      DMI, kg/d  4.62  5.13  5.64  5.36  5.70  0.16  0.01  0.07  0.24  0.11      G:F, g/kg  207  201  206  204  207  5.76  0.92  0.62  0.68  0.55  a The reconstituted milk was 18% DM. b DEI = DE intake, and DEI/BW is kcal/(kg.d). c SE was computed as the square root of the mean square error divided by the square root of 7.8, except for DE analysis that had 36 animals and therefore was divided by the square root of 7.2. d P-value of linear (L), quadratic (Qd), cubic (C), and quartic (Qt) effects using orthogonal polynomial contrasts. e Predicted with the Cornell Net Carbohydrate and Protein System (Fox et al., 2004). f Overall includes pre- and postweaning phases. View Large Table 5. Animal performance and diet DM consumption for each preweaning milk level during the postweaning and overall growth phasesa   Preweaning peak milk, kg/d    P-valued  Itemb  2.72  5.44  8.16  10.88  13.66  SEc  L  Qd  C  Qt  No.  8  8  8  7  8  —  —  —  —  —  Initial BW, kg  153  198  228  235  249  5.83  0.01  0.01  0.26  0.41  Days on feed  250  232  214  221  216  8.06  0.01  0.11  0.63  0.39  Final BW, kg  487  498  537  508  545  17.1  0.03  0.78  0.48  0.12  ADG, kg/d  1.34  1.30  1.45  1.24  1.37  0.06  0.92  0.95  0.43  0.02  DMI, kg/d  6.85  7.77  8.82  8.32  8.81  0.29  0.01  0.03  0.36  0.09  G:F, g/kg  195  167  164  149  156  5.40  0.01  0.01  0.88  0.14  DE, Mcal/kg DM  3.23  3.11  3.34  3.17  3.14  0.17  0.83  0.72  0.69  0.35  DEI, Mcal/d  22.6  24.5  29.5  26.0  27.6  1.37  0.01  0.09  0.66  0.03  DEI/BW  68.6  68.6  77.2  70.2  69.8  3.50  0.72  0.22  0.86  0.12  Predicted G:F, g/kge  174  167  163  157  150  —  —  —  —  —  Observed/predicted G:F  1.12  1.00  1.01  0.95  1.04  —  —  —  —  —  Overallf      Days  445  425  407  415  410  8.46  0.01  0.08  0.58  0.39      ADG, kg/d  0.96  1.03  1.16  1.09  1.17  0.03  0.01  0.17  0.40  0.03      DMI, kg/d  4.62  5.13  5.64  5.36  5.70  0.16  0.01  0.07  0.24  0.11      G:F, g/kg  207  201  206  204  207  5.76  0.92  0.62  0.68  0.55    Preweaning peak milk, kg/d    P-valued  Itemb  2.72  5.44  8.16  10.88  13.66  SEc  L  Qd  C  Qt  No.  8  8  8  7  8  —  —  —  —  —  Initial BW, kg  153  198  228  235  249  5.83  0.01  0.01  0.26  0.41  Days on feed  250  232  214  221  216  8.06  0.01  0.11  0.63  0.39  Final BW, kg  487  498  537  508  545  17.1  0.03  0.78  0.48  0.12  ADG, kg/d  1.34  1.30  1.45  1.24  1.37  0.06  0.92  0.95  0.43  0.02  DMI, kg/d  6.85  7.77  8.82  8.32  8.81  0.29  0.01  0.03  0.36  0.09  G:F, g/kg  195  167  164  149  156  5.40  0.01  0.01  0.88  0.14  DE, Mcal/kg DM  3.23  3.11  3.34  3.17  3.14  0.17  0.83  0.72  0.69  0.35  DEI, Mcal/d  22.6  24.5  29.5  26.0  27.6  1.37  0.01  0.09  0.66  0.03  DEI/BW  68.6  68.6  77.2  70.2  69.8  3.50  0.72  0.22  0.86  0.12  Predicted G:F, g/kge  174  167  163  157  150  —  —  —  —  —  Observed/predicted G:F  1.12  1.00  1.01  0.95  1.04  —  —  —  —  —  Overallf      Days  445  425  407  415  410  8.46  0.01  0.08  0.58  0.39      ADG, kg/d  0.96  1.03  1.16  1.09  1.17  0.03  0.01  0.17  0.40  0.03      DMI, kg/d  4.62  5.13  5.64  5.36  5.70  0.16  0.01  0.07  0.24  0.11      G:F, g/kg  207  201  206  204  207  5.76  0.92  0.62  0.68  0.55  a The reconstituted milk was 18% DM. b DEI = DE intake, and DEI/BW is kcal/(kg.d). c SE was computed as the square root of the mean square error divided by the square root of 7.8, except for DE analysis that had 36 animals and therefore was divided by the square root of 7.2. d P-value of linear (L), quadratic (Qd), cubic (C), and quartic (Qt) effects using orthogonal polynomial contrasts. e Predicted with the Cornell Net Carbohydrate and Protein System (Fox et al., 2004). f Overall includes pre- and postweaning phases. View Large From birth to slaughter, ADG was faster (P = 0.01) and therefore fewer (P = 0.01) total days of growth were required as PML increased. The DMI increased (P = 0.01) from birth to slaughter with increasing PML; however, there was no overall effect of PML on G:F. The CNCPS (Fox et al., 2004) was used to evaluate the postweaning performance to account for differences in initial and final BW, composition of ADG, and final EBF. The G:F was 12% higher than expected for those fed the low PML, whereas the other groups were within 1 to 5% of expected G:F, suggesting the low PML group had some compensatory growth during the finishing period. These results agree with those of Abdalla et al. (1988), who found that Holstein calves fed a low-protein diet during early growth exhibited compensatory growth during the finishing period. Composition Predicted carcass and empty body composition data based on actual 9th- to 11th-rib section composition are summarized in Table 4, along with predicted efficiencies of protein and energy utilization. There was no significant effect of PML on 12th-rib lipid percent, marbling score, or quality grade, indicating that the use of ultrasound resulted in harvesting the steers at the same rib lipid and quality grade endpoint; however, carcass weight and EBW increased linearly (P = 0.04) as PML increased. In addition, fat thickness and numerical yield grade increased linearly (P = 0.03), whereas carcass and EBP concentrations decreased and fat concentration increased (P = 0.01) as PML increased. In the empty body gain, concentration of protein decreased (P < 0.05), whereas the concentration of fat increased (P < 0.05) linearly as PML increased. Guiroy et al. (2001) indicated that EBF increases 1% for each 14.26-kg increase in EBW as growing cattle approach or exceed 28% EBF. When their adjustment is applied to the current data, those on the highest PML had lighter weights at 28% EBF (Table 3), indicating the higher concentrations of fat in the empty body gain resulted in lighter EBW at 28% EBF. Thus, the higher EBF at the target quality grade for the three highest PML was a result of increased BW, as well as a higher concentration of fat in the gain. It is possible that the calves fed higher PML had higher EBF at the same quality grade due to a younger age at slaughter. Although there was a linear increase (P < 0.01) in RE and MEI with increasing preweaning milk intake, the total efficiency of RE to ME was similar among PML at approximately 23%. These results are consistent with those of Abdalla et al. (1988), who reported overall efficiency of energy use was not affected by previous plane of nutrition in Holstein calves. Serum insulin concentrations increased linearly (P = 0.01) with PML at the weaning sampling time, but there was no significant effect due to preweaning milk level during postweaning growth (Table 6). Serum T3 concentration increased with PML during the first month (P = 0.01; Table 4) and the first month postweaning (P = 0.02; Table 6). The increasing serum insulin and T3 concentrations with increased milk intake during the first month of life suggest increased release of those hormones in response to increased daily nutrient intake and levels of absorbed propionate and glucose. Table 6. Serum insulin (UI/mL) and triiodothyronine (T3, ng/mL) of calves fed five levels of milk during preweaninga   Preweaning peak milk, kg/d    P-valuec  Item  2.72  5.44  8.16  10.88  13.66  SEb  L  Qd  C  Qt  Insulin      At 1st month  0.45  2.19  1.91  2.34  1.31  0.73  0.43  0.09  0.81  0.42      At weaning  0.44  0.89  1.12  1.84  3.02  0.38  0.01  0.19  0.59  0.81      1st month after weaning  0.73  0.83  0.81  0.72  0.87  0.24  0.84  0.95  0.64  0.91      At slaughter  2.41  1.78  1.17  1.65  1.02  0.49  0.07  0.56  0.47  0.43  T3      At 1st month  1.55  1.88  2.07  2.07  2.66  0.24  0.01  0.71  0.36  0.70      At weaning  1.33  1.31  1.31  1.37  1.60  0.16  0.25  0.34  0.80  0.97      1st month after weaning  1.91  1.72  1.70  1.83  1.30  0.15  0.02  0.34  0.09  0.54      At slaughter  1.81  2.23  2.04  1.72  2.00  0.13  0.75  0.39  >0.01  0.82    Preweaning peak milk, kg/d    P-valuec  Item  2.72  5.44  8.16  10.88  13.66  SEb  L  Qd  C  Qt  Insulin      At 1st month  0.45  2.19  1.91  2.34  1.31  0.73  0.43  0.09  0.81  0.42      At weaning  0.44  0.89  1.12  1.84  3.02  0.38  0.01  0.19  0.59  0.81      1st month after weaning  0.73  0.83  0.81  0.72  0.87  0.24  0.84  0.95  0.64  0.91      At slaughter  2.41  1.78  1.17  1.65  1.02  0.49  0.07  0.56  0.47  0.43  T3      At 1st month  1.55  1.88  2.07  2.07  2.66  0.24  0.01  0.71  0.36  0.70      At weaning  1.33  1.31  1.31  1.37  1.60  0.16  0.25  0.34  0.80  0.97      1st month after weaning  1.91  1.72  1.70  1.83  1.30  0.15  0.02  0.34  0.09  0.54      At slaughter  1.81  2.23  2.04  1.72  2.00  0.13  0.75  0.39  >0.01  0.82  a The reconstituted milk was 18% DM. b SE was computed as the square root of the mean square error divided by the square root of 7.8, except insulin at 1st month and weaning that had 37 and 38 animals, and therefore were divided by the square root of 7.4 and 7.6, respectively. c P-value of linear (L), quadratic (Qd), cubic (C), and quartic (Qt) effects using orthogonal polynomial contrasts. View Large Table 6. Serum insulin (UI/mL) and triiodothyronine (T3, ng/mL) of calves fed five levels of milk during preweaninga   Preweaning peak milk, kg/d    P-valuec  Item  2.72  5.44  8.16  10.88  13.66  SEb  L  Qd  C  Qt  Insulin      At 1st month  0.45  2.19  1.91  2.34  1.31  0.73  0.43  0.09  0.81  0.42      At weaning  0.44  0.89  1.12  1.84  3.02  0.38  0.01  0.19  0.59  0.81      1st month after weaning  0.73  0.83  0.81  0.72  0.87  0.24  0.84  0.95  0.64  0.91      At slaughter  2.41  1.78  1.17  1.65  1.02  0.49  0.07  0.56  0.47  0.43  T3      At 1st month  1.55  1.88  2.07  2.07  2.66  0.24  0.01  0.71  0.36  0.70      At weaning  1.33  1.31  1.31  1.37  1.60  0.16  0.25  0.34  0.80  0.97      1st month after weaning  1.91  1.72  1.70  1.83  1.30  0.15  0.02  0.34  0.09  0.54      At slaughter  1.81  2.23  2.04  1.72  2.00  0.13  0.75  0.39  >0.01  0.82    Preweaning peak milk, kg/d    P-valuec  Item  2.72  5.44  8.16  10.88  13.66  SEb  L  Qd  C  Qt  Insulin      At 1st month  0.45  2.19  1.91  2.34  1.31  0.73  0.43  0.09  0.81  0.42      At weaning  0.44  0.89  1.12  1.84  3.02  0.38  0.01  0.19  0.59  0.81      1st month after weaning  0.73  0.83  0.81  0.72  0.87  0.24  0.84  0.95  0.64  0.91      At slaughter  2.41  1.78  1.17  1.65  1.02  0.49  0.07  0.56  0.47  0.43  T3      At 1st month  1.55  1.88  2.07  2.07  2.66  0.24  0.01  0.71  0.36  0.70      At weaning  1.33  1.31  1.31  1.37  1.60  0.16  0.25  0.34  0.80  0.97      1st month after weaning  1.91  1.72  1.70  1.83  1.30  0.15  0.02  0.34  0.09  0.54      At slaughter  1.81  2.23  2.04  1.72  2.00  0.13  0.75  0.39  >0.01  0.82  a The reconstituted milk was 18% DM. b SE was computed as the square root of the mean square error divided by the square root of 7.8, except insulin at 1st month and weaning that had 37 and 38 animals, and therefore were divided by the square root of 7.4 and 7.6, respectively. c P-value of linear (L), quadratic (Qd), cubic (C), and quartic (Qt) effects using orthogonal polynomial contrasts. View Large Implications The results of this experiment suggest the overall advantages of a high level of milk intake during the preweaning phase were heavier weaning weights and fewer days to reach a heavier final weight at the Choice grade. Calves fed milk at the low lactation curve levels were as efficient from birth to slaughter as those fed higher levels of milk; however, they were as much as 58 kg lighter and 34 d older at a similar degree of fatness. The lowest level of milk was below that needed for calves to reach the full potential for weight at a small degree of marbling. Literature Cited Abdalla, H. O. 1986. Compensatory gain in calves following protein restriction.  Ph.D. Diss., Cornell Univ., Ithaca, NY. Abdalla, H. O., D. G. Fox, and M. L. Thonney 1988. Compensatory gain by Holstein calves after underfeeding protein. J. Anim. Sci.  66: 2687– 2695. Google Scholar CrossRef Search ADS   Ainslie, S. J., D. G. Fox, T. C. Perry, D. J. Ketchen, and M. C. Barry 1993. Predicting amino acid adequacy of diets fed to Holstein steers. J. Anim. Sci.  71: 1312– 1319. Google Scholar CrossRef Search ADS PubMed  AOAC 1990. Official Methods of Analysis.  15th ed. Assoc. Off. Anal. Chem., Washington, DC. Appleman, F. D., and F. G. Owen 1975. Breeding, housing and feeding management. J. Dairy Sci.  58: 447– 464. Google Scholar CrossRef Search ADS   Baker, R. D., and J. M. Barker 1978. Milk-fed calves. 4. The effect of herbage allowance and milk intake upon herbage intake and performance of grazing calves. J. Agric. Sci. (Camb.)  90: 31– 38. Google Scholar CrossRef Search ADS   Baker, R. D., Y. L. P. Le Du, and J. M. Barker 1976. Milk-fed calves. 1. The effect of milk intake upon the herbage intake and performance and grazing calves. J. Agric. Sci. (Camb.)  87: 187– 196. Google Scholar CrossRef Search ADS   Broesder, J. T., J. B. Judkins, L. J. Krysl, S. A. Gunter, and R. K. Barton 1990. Thirty or sixty percent milk replacer reduction for calves: Effects on alfalfa hay intake and digestibility, digestive kinetics and ruminal fermentation. J. Anim. Sci.  68: 2974– 2985. Google Scholar CrossRef Search ADS PubMed  Church, D. C., D. L. Gorrill, and R. G. Warner 1980. Feeding and nutrition of young calves. Pages 164–183 in Digestive Physiology and Nutrition of Ruminants.  D. C. Church ed. O&B Books, Corvallis, OR. Day, M. L., A. C. Imakawa, A. C. Clutter, P. L. Wolfe, D. D. Zalesky, M. K. Nielsen, and J. E. Kinder 1987. Suckling behavior of calves with dams varying production. J. Anim. Sci.  65: 1207– 1212. Google Scholar CrossRef Search ADS PubMed  Diaz, M. C., M. E. Van Amburgh, J. M. Smith, J. M. Kelsey, and E. L. Hutten 2001. Composition of growth of Holstein calves fed milk replacer from birth to 105-kilogram body weight. J. Dairy Sci.  84: 830– 842. Google Scholar CrossRef Search ADS PubMed  Fox, D. G., T. R. Dockerty, R. R. Johnson, and R. L. Preston 1976. Relationship of empty body weight to carcass weight in beef cattle. J. Anim. Sci.  43: 566– 568. Google Scholar CrossRef Search ADS   Fox, D. G., C. J. Sniffen, and J. D. O'Connor 1988. Adjusting nutrient requirements of beef cattle for animal and environmental variations. J. Anim. Sci.  66: 1475– 1495. Google Scholar CrossRef Search ADS   Fox, D. G., C. J. Sniffen, J. D. O'Connor, J. B. Russell, and P. J. Van Soest 1992. A net carbohydrate and protein system for evaluating cattle diets: III. Cattle requirements and diet adequacy. J. Anim. Sci.  70: 3578– 3596. Google Scholar CrossRef Search ADS PubMed  Fox, D. G., L. O. Tedeschi, T. P. Tylutki, J. B. Russell, M. E. Van Amburgh, L. E. Chase, A. N. Pell, and T. R. Overton 2004. The Cornell Net Carbohydrate and Protein System model for evaluating herd nutrition and nutrient excretion. Anim. Feed Sci. Technol.  112: 29– 78. Google Scholar CrossRef Search ADS   Garrett, R. P., and H. Hinman 1969. Re-evaluation of the relationship between carcass density and body composition of beef steers. J. Anim. Sci.  28: 1– 5. Google Scholar CrossRef Search ADS   George, P. D. 1984. A Deterministic Model of Net Nutrient Requirements for the Beef Cow.  Ph.D. Diss., Cornell Univ., Ithaca, NY. Goering, H. K., and P. J. Van Soest 1970. Forage fiber analyses: Apparatus, reagents, procedures, and some applications.  Agric. Handbook No. 379. ARS, USDA, Washington, DC. Guiroy, P. J., D. G. Fox, L. O. Tedeschi, M. J. Baker, and M. D. Cravey 2001. Predicting individual feed requirements of cattle fed in groups. J. Anim. Sci.  79: 1983– 1995. Google Scholar CrossRef Search ADS PubMed  Hankins, O. G., and P. E. Howe 1946. Estimation of the composition of beef carcasses and cuts.  Tech. Bull. No. 926. USDA, Washington, DC. Houseknecht, K. L., D. E. Bauman, D. G. Fox, and D. F. Smith 1992. Abomasal infusion of casein enhances nitrogen retention in somatotropin-treated steers. J. Nutr.  122: 1717– 1725. Google Scholar PubMed  Krishnamoorthy, U., C. J. Sniffen, M. D. Stern, and P. J. Van Soest 1983. Evaluation of a mathematical model of rumen digestion and an in vitro simulation of rumen proteolysis to estimate the rumen-undegraded nitrogen content of feedstuffs. Br. J. Nutr.  50: 555– 568. Google Scholar CrossRef Search ADS PubMed  Le Du, Y. L. P., R. D. Baker, and J. M. Barker 1976. Milk-fed calves. 2. The effect of length of milk intake upon herbage intake and performance of grazing calves. J. Agric. Sci. (Camb.)  87: 197– 204. Google Scholar CrossRef Search ADS   Lofgreen, G. P. 1965. A comparative slaughter technique for determining net energy values with beef cattle.  Pages 309–317 in Proceedings of Energy Metabolism, 3. Academic Press, London, U.K. Lusby, K. S., D. F. Stephens, and R. Totusek 1976. Effects of milk intake by nursing calves on forage intake on range and creep intake and digestibility in drylot. J. Anim. Sci.  43: 1066– 1071. Google Scholar CrossRef Search ADS   Nour, A. Y. M., and M. L. Thonney 1994. Technical Note: Chemical composition of Angus and Holstein carcasses predicted from rib section composition. J. Anim. Sci.  72: 1239– 1241. Google Scholar CrossRef Search ADS PubMed  NRC 1978. Nutrient Requirements of Dairy Cattle.  5th ed. Natl. Acad. Press, Washington, DC. NRC 1984. Nutrient Requirements of Beef Cattle.  6th ed. Natl. Acad. Press, Washington, DC. NRC 1996. Nutrient Requirements of Beef Cattle.  7th ed. Natl. Acad. Press, Washington, DC. NRC 2000. Nutrient Requirements of Beef Cattle (updated 7th ed.).  Natl. Acad. Press, Washington, DC. NRC 2001. Nutrient Requirements of Dairy Cattle.  7th ed. Natl. Acad. Press, Washington, DC. Odde, K. G., G. H. Kiracofe, and R. R. Schalles 1985. Suckling behavior in range beef calves. J. Anim. Sci.  61: 307– 309. Google Scholar CrossRef Search ADS PubMed  Porter, P. A. 1987. The Acid Detergent Insoluble Ash Marker and its Use in Lactating Dairy Cows.  Ph.D. Diss., Cornell Univ., Ithaca, NY. Totusek, R., and D. Arnett 1965. Estimates of milk production in beef cows. J. Anim. Sci.  24: 906. (Abstr.) Van Soest, P. J. 1994. Nutritional Ecology of the Ruminant (2nd ed.).  Comstock Publishing Associates, Ithaca, NY. Wood, P. D. P. 1967. Algebraic model of the lactation curve in cattle. Nature.  216: 164– 165. Google Scholar CrossRef Search ADS   Wright, I. A., and A. J. F. Russel 1987. The effect of sward height on beef cow performance and on the relationship between calf milk and herbage intakes. Anim. Prod.  44: 363– 370. Google Scholar CrossRef Search ADS   Wyatt, R. D., M. B. Gould, and R. Totusek 1977. Effects of single vs simulated twin rearing on cow and calf performance. J. Anim. Sci.  45: 1409– 1414. Google Scholar CrossRef Search ADS   Copyright 2005 Journal of Animal Science
TI - The effect of milk intake on forage intake and growth of nursing calves
JF - Journal of Animal Science
DO - 10.2527/2005.834940x
DA - 2005-04-01
UR - https://www.deepdyve.com/lp/oxford-university-press/the-effect-of-milk-intake-on-forage-intake-and-growth-of-nursing-I963VcYOra
SP - 940
EP - 947
VL - 83
IS - 4
DP - DeepDyve
ER -