Influence of Dietary Protein on Blood Cholesterol and Related Metabolites of Growing Calves

Abstract

Forty male, Holstein calves were utilized to evaluate effects of either low (12%) or high (25%) dietary protein on growth and serum metabolites, with a particular concern for serum cholesterol. All diets contained 19% acid detergent fiber and consisted of corn silage, alfalfa hay and grain mixtures. Average concentration of total serum cholesterol was depressed (P=.001) for calves on the high-protein diets (58.8 mg/dl) as compared with their low-protein counterparts (67,9 mg/dl). Calves fed the high-protein diet had lower (P=.002) free serum cholesterol but elevated high-density lipoprotein cholesterol as a percentage of total cholesterol. Calves receiving the high-protein diets showed increases (P=.206) in lecithin cholesterol acyltransferase activity compared with low-protein counterparts. Serum urea nitrogen was increased (P=.001) for calves fed high-protein diets, while serum protein and glucose remained unchanged. Calves fed the high-protein diets consumed less dry matter with improved (P=.09) growth efficiency (gain/feed).

© American Society of Animal Science 1985