The Effect of Whey Protein Concentrate or Dried Skim Milk in Milk Replacer on Calf Performance and Blood Metabolites 1

The Effect of Whey Protein Concentrate or Dried Skim Milk in Milk Replacer on Calf Performance and Blood Metabolites 1 B. P. LAMMERS,* A. J. HEINRICHS,*,2 and A. AYDIN *Department of Dairy and Animal Science, The Pennsylvania State University, University Park 16802 Select Veal Feeds Inc., Hardlysville, PA 19438 ABSTRACT Whey protein concentrate and dried skim milk were each evaluated as the major protein source in milk replacer using four treatments (100% skim milk, 67% skim milk and 33% whey protein concentrate, 33% skim milk and 67% whey protein concentrate, and 100% whey protein concentrate). In the first trial, 64 calves were fed only milk replacer from birth to 6 wk of age. In the second trial, 61 calves were fed milk replacer and were allowed ad libitum intake of starter from birth to 6 wk of age. Calves were fed milk replacer at 10% of birth weight for the first 2 wk and at 12% of birth weight thereafter. In trial 1, average daily gains and feed efficiencies were significantly improved for calves that consumed the milk replacers containing 67 and 100% whey protein concentrate over those for calves that were fed the milk replacer containing 100% skim milk. No difference in growth or feed efficiency caused by treatment was detected in trial 2. Average daily gain in trial 2 was correlated with total starter intake. In trial 1, plasma glucose concentrations were correlated with growth rates and were highest for calves fed the milk replacer containing 67% whey protein concentrate. No differences were found for fecal scores or days scoured between trials. When only milk replacer was fed, higher proportions of whey protein concentrate improved calf performance, but, when starter was also provided, no effect of milk replacer was found. ( Key words: calves, milk replacer, protein, growth) Abbreviation key: ADG = average daily gain, DSM = dried skim milk, WPC = whey protein concentrate. Received October 10, 1997. Accepted March 11, 1998. 1This research was a component of NC-119, Dairy Herd Management Strategies for Improved Decision Making and Profitability. 2To whom reprint requests should be sent. INTRODUCTION In the past, the principle ingredient in most milk replacers has been dried skim milk ( DSM) (8); however, very little DSM is currently used in the formulation of milk replacers. In 1991 and 1992, the National Dairy Heifer Evaluation Project ( 9 ) conducted a survey of US dairy farms to evaluate commercial milk replacers. Results of the survey suggested that only 2.1% of the milk replacers fed formed a firm clot using the rennet coagulation test and that skim milk protein was not the major protein source in most milk replacers during this period. The primary protein source in milk replacers currently is whey (8). Ultrafiltration of whey produces a product, whey protein concentrate ( WPC), that has essentially the same chemical composition as DSM (16). In addition, WPC is roughly 40% of the price of DSM (1), which has been the major impetus for the replacement of DSM with WPC. Because of decreased supply, DSM prices have risen, thereby restricting its usage in human foods. Whey protein concentrate has a better amino acid profile for growing calves than do DSM and casein (16). Therefore, WPC typically has a higher bioavailability than does DSM or casein. However, research (15) has indicated that curd formation in calves fed diets based on casein is beneficial to digestion because of the slow release of nutrients from the abomasum, although more recent research ( 5 ) has shown no improvement of curd formation on digestibility or performance in calves. Few published studies have actually compared DSM and WPC as major protein sources, although WPC has replaced DSM as the most commonly used milk protein source in the feed industry. The objectives of these trials were to evaluate milk replacers containing WPC, DSM, or combinations of WPC and DSM as the major protein source on growth rates, feed efficiencies, fecal scores, days scoured, and blood metabolites. 1998 J Dairy Sci 81:1940 1945 1940

MILK REPLACER WITH WHEY OR SKIM MILK PROTEIN 1941 MATERIALS AND METHODS Milk Replacers and Diet Formulation Four milk replacers were formulated to contain 100% DSM, 67% DSM and 33% WPC, 33% DSM and 67% WPC, or 100% WPC as the major protein source. To meet these criteria, concentrations of DSM and WPC were altered in the milk replacer (Table 1). Diets were formulated to be isonitrogenous and isocaloric and were balanced using current data for the amount and ingredient availability of essential amino acids, vitamins, and minerals with 22% protein and 18% fat. Dried whey was added to provide approximately 47% dietary lactose. Therefore, DSM and WPC were the major protein sources in the milk replacers. Feed samples were taken weekly for analysis. Soluble (12) and degradable (13) protein concentrations were determined for the starter. Both the starter and milk replacer were assessed for CP (2), but the milk replacer was also analyzed for lactose content (6). Gross energy values of the milk replacer were determined with a bomb calorimeter (Parr Instrument Co., Moline, IL). Calves and Feeding All calves were removed from their dams and given colostrum within 2 h after birth. Calves were housed in individual pens (1.9 1.17 m) in an indoor, mechanically ventilated barn. In the first trial, 64 Holstein calves were fed only milk replacer from birth through 6 wk of age. In the second trial, 64 Holstein calves were fed a commercial calf starter for ad libitum intake beginning on the 3rd d along with the treatment milk replacer from birth through 6 wk of age. Three calves were removed from the second trial because of clinical pneumonia; therefore, data from 61 calves are presented. All calves were fed milk replacer at 10% of BW during the first 2 wk of life; this rate was increased to 12% of BW during wk 3 through 6. Water was offered for ad libitum intake beginning at 3 d of age. During the 3rd wk of life, amprolium (5 mg/kg of BW; Corid ; MSD AGVET, Rahsay, NJ) was added to the milk replacer of all calves to prevent coccidiosis. Measurements and Analytical Procedures Body weight, height at withers, heart girth, and blood samples were taken at 2 d and 2, 4, and 6 wk of age. Blood was taken from the left jugular vein via venipuncture at 4 to 5 h after the morning feeding. TABLE 1. Ingredient and chemical composition of milk replacers. Composition 100% DSM 67% DSM 33% WPC 33% DSM 67% WPC 1DSM = Dried skim milk; WPC = whey protein concentrate. 2Contained 45.3% edible lard, 36% whey, 13.5% edible tallow, 4% sodium caseinate, 0.6% lecithin, and 0.6% emulsifier. 3Contained 39.6% edible lard, 29.8% edible tallow, 21% refined coconut oil, 8% lecithin, and 1.6% emulsifier. 4Denkavit Co. (Voorthuizen, The Netherlands). 5Contained 0.066% neomycin and 0.033% terramycin. 100% WPC Ingredient Dried whey 20.5 19.4 17.8 16.6 DSM 47.7 32.2 16.2 0.0 WPC 0.0 17.0 34.4 51.8 Dry fat blend 2 19.9 19.1 18.9 18.3 Liquid fat 3 6.0 6.0 6.0 6.0 L-Lysine 0.0 0.09 0.18 0.27 Vitamin and mineral premix 4 1.13 1.13 1.13 1.13 Neo-terra premix 5 4.5 4.5 4.5 4.5 Calcium chloride 0.26 0.26 0.26 0.0 Calcium carbonate 0.00 0.07 0.09 0.31 Dicalcium phosphate 0.0 0.3 0.7 1.1 Ferrous sulfate 0.05 0.05 0.05 0.05 Chemical DM, % 96.1 96.7 95.9 96.6 CP, % of DM 20.6 21.1 21.1 20.7 Lactose, % of DM 47.5 49.5 48.0 48.0 Gross energy, cal/g 4745 4726 4719 4761 Plasma and serum were aspirated after centrifugation (3000 g) and frozen ( 20 C) for later analysis. Plasma samples were analyzed for glucose by the glucose oxidase method (catalog no. 510; Sigma Diagnostics, St. Louis, MO). Serum samples were analyzed for NEFA (10), urea nitrogen (procedure no. 0580; Stanbio Laboratory Inc., San Antonio, TX), and total protein with a refractometer. Fecal scores, as outlined by Larson et al. (14), were taken three times weekly from birth through 6 wk of age. Statistical Analysis Average daily gain ( ADG), height at withers, heart girth, and blood parameters were analyzed over time; measurements were taken from 2 d and 2, 4, and 6 wk of age by the MIXED procedure of SAS (20) using a split-plot design. The whole model tested for differences that were due to treatment; calf was used as the error term. Interactions of treatment and time were not significant. Initial BW was used as a covariate for the analysis of ADG and the rate of growth in stature and heart girth. An adjusted Tukey s test was used to determine differences among treatment means.

1942 LAMMERS ET AL. Dry matter intake, feed conversion efficiency, and measurements at the beginning of the trials for BW, stature, and heart girth were analyzed in a block design by the GLM procedure of SAS (19). Calves were assigned to block by age and sex. Initial weight was used as a covariate for DMI and feed efficiency. Differences among means were determined using Tukey s test. Calf Performance RESULTS AND DISCUSSION Chemical composition of the milk replacers is shown in Table 1. The starter had a chemical composition of 20.8% CP, 67.0% degradable CP (percentage of CP), and 17.5% soluble CP (percentage of CP). The milk replacer was fed as a percentage of initial BW throughout the trials and was not different among treatments for both trials (Table 2). When grain was offered for ad libitum intake to calves in trial 2, calves consumed a mean 408 g/d of starter from birth through 6 wk of age. No differences in the DMI of starter were detected among treatments. Also, when calves received starter (trial 2), total DMI was 70% greater than when calves received only milk replacer (trial 1). At birth, calves were randomly assigned to a treatment in blocks of 4 calves. Therefore, the significant difference between initial BW in both trials was merely due to the random assignment of calves to a treatment. These differences were removed statistically using a covariate for initial BW. For calves fed the milk replacers containing 67 and 100% WPC, ADG was 31 and 30% higher, respectively, than the ADG of calves fed the milk replacer containing 100% DSM. Calves fed the milk replacer containing 67% WPC had higher ( P < 0.10) feed efficiencies than did calves fed the milk replacer con- TABLE 2. Intake, growth, and feed efficiency of calves fed different milk replacers from birth through 6 wk of age with or without ad libitum intake of starter. a,bmeans in row with different superscripts differ ( P < 0.05). x,ymeans in row with different superscripts differ ( P < 0.10). 1DSM = Dry skim milk; WPC = whey protein concentrate. 2During trial 1, calves were not offered starter. During trial 2, calves were offered starter for ad libitum intake. 3Average daily gain. 67% DSM 33% DSM Variable 100% DSM 33% WPC 67% WPC 100% WPC SE Trial 1 2 Milk DMI, g/d 588 584 587 589 4 Initial BW, kg 42.5 ab 42.0 b 45.2 ab 47.1 a 1.4 ADG, 3 g/d 199 b 231 ab 260 a 258 ab 17 Feed efficiency, g of DM/g of gain 3.00 a 2.52 ab 2.29 b 2.40 ab 0.15 Stature Initial, cm 75.5 75.4 77.7 76.6 0.7 Growth, cm/d 0.11 0.13 0.13 0.14 0.01 Heart girth Initial, cm 79.76 79.76 81.28 82.30 0.84 Growth, cm/d 0.18 0.18 0.20 0.21 0.01 Trial 2 Milk DMI, g/d 590 587 583 580 4 Starter DMI, g/d 399 437 406 390 29 Initial BW, kg 46.4 x 44.2 xy 45.3 xy 41.1 y 1.5 ADG, g/d 452 505 470 447 27 Feed efficiency, g of DM/g of gain 2.21 2.01 2.43 2.16 0.20 Stature Initial, cm 77.9 77.3 77.8 76.0 0.8 Growth, cm/d 0.13 0.16 0.16 0.14 0.02 Heart girth Initial, cm 82.55 82.30 82.04 80.01 1.02 Growth, cm/d 0.22 0.24 0.24 0.23 0.02

MILK REPLACER WITH WHEY OR SKIM MILK PROTEIN 1943 taining 100% DSM. Furthermore, the milk replacer containing 100% WPC also improved ( P < 0.10) feed efficiency over that of calves fed the milk replacer containing 100% DSM. Calves that are fed milk replacer without casein proteins have decreased chymosin secretion (7), decreased clotting of milk in the abomasum (18), and faster rates of nutrient flow from the abomasum (3, 21). The presence of casein in DSM promotes clotting in the abomasum, which slows the flow of nutrients from the abomasum. This process may alter the digestibility of the milk replacer, resulting in improved feed conversion efficiencies and improved growth rates. Terosky et al. (23) conducted a digestibility trial using the same milk replacers that were utilized in these trials. Those researchers (23) were unable to detect differences ( P > 0.05) in apparent digestibilities among the four milk replacers; however, that study was done with a limited number of calves. The current trials showed that calves fed the milk replacer containing 100% DSM performed more poorly than did calves fed milk replacers with higher proportions of WPC, and the clotting effect of casein was not required for optimal performance. In the second trial, the overall ADG was 469 g/d; no significant differences were observed among treatments. However, the ADG was highly correlated with total starter intake ( r 2 = 0.73). Therefore, with this amount of milk replacer intake, which is typical in the dairy industry, the amount of starter consumption has a large impact on performance from birth through 6 wk of age. When starter was offered for ad libitum intake, growth rates were increased 84% over those of calves in trial 1 fed milk replacer only. The increased ADG for calves in the second trial were due to the increased DMI of the starter because consumption of milk replacer was similar between the two trials. Feed efficiencies (DMI/gain) averaged 2.6 and 2.2 for calves in the first and second trials, respectively, which suggests that starter offered for ad libitum intake can be effectively and efficiently utilized by young calves. In trial 1, the rate of growth in stature (wither height) tended ( P < 0.15) to be higher for calves fed the milk replacer containing 100% WPC than for calves fed the milk replacer containing 100% DSM. This result supports the results of the ADG data, which indicated that higher proportions of WPC improved growth rates. No differences were detected for heart girth in either trial or for stature in trial 2. The error associated with these measurements, along with the small degree of skeletal growth during this period, makes it difficult to detect possible differences. Blood Profiles In trial 1, plasma glucose concentrations were higher ( P < 0.05) for calves fed the milk replacer containing 67% WPC vs. 0% WPC, but no differences were detected for the second trial (Table 3). The plasma glucose concentrations appeared to be positively correlated with ADG. Chandler et al. ( 4 ) and TABLE 3. Blood profiles of calves fed different milk replacers from birth through 6 wk of age with or without ad libitum intake of starter. 67% DSM 33% DSM Variable 100% DSM 33% WPC 67% WPC 100% WPC SE Trial 1 2 Hematocrit, % 39.4 37.3 37.0 37.4 1.3 Plasma glucose, mg/dl 98 b 103 b 107 a 106 ab 3 Serum NEFA, g/dl 194 182 185 203 8 Serum total protein, g/dl 5.22 5.02 5.23 5.39 0.15 Serum urea N, mg/dl 8.88 8.40 9.63 8.67 0.42 Trial 2 Hematocrit, % 36.5 34.9 36.1 33.6 1.2 Plasma glucose, mg/dl 96 99 103 104 3 Serum NEFA, mg/dl 220 194 202 180 14 Serum total protein, g/dl 5.22 4.99 5.29 5.08 0.13 Serum urea N, mg/dl 9.96 8.81 9.48 8.52 0.50 a,bmeans in rows with different superscripts differ ( P < 0.05). 1DSM = Dry skim milk; WPC = whey protein concentrate. 2During trial 1, calves were not offered starter. During trial 2, calves were offered starter for ad libitum intake.

1944 LAMMERS ET AL. TABLE 4. Effect of milk replacer on mean fecal scores and days scoured. 67% DSM 33% DSM Variable 100% DSM 33% WPC 67% WPC 100% WPC SE Trial 1 2 Color 3 5.5 5.6 5.6 5.4 0.1 Consistency 4 1.1 1.1 1.0 1.1 0.1 Days scoured 5 0.7 0.3 0.1 0.3 0.2 Fluidity 6 1.1 1.1 1.1 1.2 0.1 Trial 2 Color 4.4 4.6 4.7 4.6 0.2 Consistency 1.1 1.1 1.1 1.1 0.1 Days scoured 0.2 0.1 0.1 0.2 0.1 Fluidity 1.1 1.0 1.1 1.0 0.1 1DSM = Dry skim milk; WPC = whey protein concentrate. 2During trial 1, calves were not offered starter. During trial 2, calves were offered starter for ad libitum intake. 3Color: 1 = white, 2 = grey, 3 = yellow, 4 = brown, 5 = red or pink, 6 = green or dark green, and 7 = black. 4Consistency: 1 = normal, 2 = foamy, 3 = mucus, 4 = sticky, and 5 = constipated. 5Total days scoured. 6Fluidity: 1 = normal, 2 = soft, 3 = runny, and 4 = watery. Kitchenham et al. (11) also found a positive correlation between growth rates and plasma glucose concentrations. Because amino acids can be used for gluconeogenesis and ATP synthesis, higher plasma amino acid concentrations may lead to increased deamination of plasma amino acids, resulting in higher blood urea nitrogen concentrations. Therefore, the milk replacer containing 67% WPC could be directly responsible for the elevation of plasma glucose concentrations, although no differences were detected for serum urea nitrogen in either trial. Total protein concentrations in serum were not statistically different among treatments at any time in either trial, which indicates that colostrum intake was not a factor in these trials because total protein concentrations in serum during the first 3 wk of life are often correlated with colostrum intake (17). Fecal Scores and Days Scoured Fecal scores for color, consistency, and fluidity and days scoured are shown in Table 4. No differences were found among treatments in either trial, which agreed with the results of Stewart et al. (22), who found no difference in the fecal index for calves consuming whey or skim milk proteins. Fecal scores (except for color) and days scoured were similar between calves that were not offered starter and those that received starter for ad libitum intake. Blood hematocrit concentrations were not affected by treatment (Table 3), which indicated that milk protein source did not affect degree of dehydration. Calves that consumed no starter compared with calves that were given ad libitum access to starter had numerically higher values for fecal color. CONCLUSIONS When fed milk replacer only for 6 wk, calves receiving the milk replacers containing 67 and 100% WPC had a higher ADG and a better feed conversion ratio than did calves fed the milk replacer containing 100% DSM. However, when starter was offered for ad libitum intake, BW gain was highly correlated with total starter intake; no apparent effects were due to milk protein source. In these trials, the use of WPC as the major protein source was better than or equal to the use of DSM, which supports previous work in which the clotting effect of DSM did not improve the performance of calves fed a nonclotting source of milk protein. REFERENCES 1 Agricultural Marketing Service. 1993. Dairy Market Statistics. USDA, Washington, DC. 2 Association of Official Analytical Chemists. 1990. Official Methods of Analysis. Vol. 1. 1st ed. AOAC, Arlington, VA. 3 Caugant, I., H. V. Petit, R. Charbonneau, L. Savoie, R. Toullec, S. Thirouin, and M. Yvon. 1992. In vivo and in vitro gastric emptying of protein fractions and milk replacers containing whey proteins. J. Dairy Sci. 75:847 856. 4 Chandler, P. T., R. D. McCarthy, and E. M. Kesler. 1968. Effect of dietary lipid and protein on serum proteins, lipids and glucose in the blood of dairy calves. J. Nutr. 95:461 468.

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