Effect of varying carbohydrate and fat levels on body composition of milk-fed calves

摘要

Recommendations in the United States for optimal nutrition for young dairy calves were designed without an adequate quantification of the requirements at this stage of development. Furthermore, nutrient requirements for optimum growth of preruminantdairy replacement calves, as they are discussed in the 1989 Dairy NRC (23) and 1996 Beef NRC (24), are greatly underestimated. Jacobsen (13) discussed the concept that nutrient requirements might vary with the goal of calf growth, and diet, and rate of gain may manipulate fat and protein deposition in the young calf. Liebenberg and van der Merwe (18) concluded that it is possible to alter the body composition of growing animals by nutrition, and this was partially elucidated by Donnelly and Hutton. Further, Owens et al. (25) discussed the potential for an animal's mature mass to be decreased by protein deficiency, and in the alternative, that retarding the deposition of fat could increase mature protein mass.