title: Effects of fat concentration of a high-protein milk replacer on calf performance.
abstract: The hypothesis was that calves fed high-fat milk replacers (MR) would have reduced starter intake, digestibility, and average daily gain (ADG). Forty-eight Holstein calves (initially 42.4 +/- 1.5 kg of body weight, 2 to 3 d of age; 12 calves/treatment) were fed 0.66 kg dry matter (DM) of MR per calf daily that contained 14, 17, 20, or 23% fat. This MR had crude protein (CP) to metabolizable energy (ME) ratios ranging from 51.6 to 56.7 g of CP/Mcal of ME, which were above and below a previously determined optimum. Calves were weaned at 28 d; postweaning measurements were continued to d 56. A 20% CP starter and water were fed ad libitum all 56 d of the trial. Measurements of digestion were made using chromic oxide as a marker in the MR and starter from fecal samples collected on d 19 to 23 from 4 calves/treatment. Selected serum constituents were measured on d 21. Calves were housed individually in pens bedded with straw within a naturally ventilated barn with no added heat. The average barn temperature was 2 degrees C. Data were analyzed as a completely randomized design using polynomial contrasts to separate differences in the means. Preweaning apparent digestibility of DM, organic matter, fat, nonfiber carbohydrates, Ca, and P and serum amylase concentration were linearly reduced as fat increased from 14 to 23%. Preweaning starter intake responded quadratically to fat, being lowest at 14 and 23% fat. A reduction in digestibility and starter intake contributed to less ADG at the higher fat concentrations in the MR. A 27% CP, 17% fat MR with 55 g of CP/Mcal of ME maximized preweaning ADG when fat concentration was varied to obtain various CP to ME ratios in the MR. Additionally, a 27% CP, 20% fat MR with 53 g of CP/Mcal of ME supported overall ADG similar to calves fed the 17% fat MR but preweaning digestion measurements and serum amylase concentrations were less than in calves fed the 17% fat MR.
authors.affiliation: Akey Nutrition and Research Center, Lewisburg, OH 45338, USA.
authors.forename: T M
authors.initials: TM
authors.lastname: Hill
authors.forename: H G
authors.initials: HG
authors.lastname: Bateman
authors.forename: J M
authors.initials: JM
authors.lastname: Aldrich
authors.forename: R L
authors.initials: RL
authors.lastname: Schlotterbeck
mesh_terms: D000681:Amylases / Q000097:blood; D000818:Animals; D002118:Calcium / Q000097:blood; D002417:Cattle / Q000254:growth & development / Q000502:physiology*; D004040:Dietary Carbohydrates / Q000378:metabolism; D004041:Dietary Fats / Q000008:administration & dosage / Q000032:analysis* / Q000378:metabolism; D004044:Dietary Proteins / Q000008:administration & dosage / Q000032:analysis*; D004063:Digestion; D004435:Eating / Q000502:physiology; D006799:Housing, Animal; D041941:Milk Substitutes / Q000008:administration & dosage* / Q000737:chemistry*; D010758:Phosphorus / Q000097:blood; D014886:Weaning; D015430:Weight Gain
chemical_list: D004040:Dietary Carbohydrates; D004041:Dietary Fats; D004044:Dietary Proteins; D010758:Phosphorus; D000681:Amylases; D002118:Calcium