Effect of type of dietary fat on plasma and tissue cholesterol of calves.

Two experiments were conducted to examine the effects of liquid milk diets with varying proportions of beef tallow (T) and soybean oil (SBO), with and without dry feed, on cholesterol concentrations in blood and other tissues of nonruminating calves. In experiment 1, 4--10-day-old male Holstein calves were fed for 15 weeks a reconstituted milk containing 9% ot 12% dried skim milk and 2% SBO, 2% T or 3.5% T. Plasma cholesterol and cholesterol content (% of dry matter) of muscle, liver, omental fat and perirenal fat were greater (P less than 0.05) for calves fed the 2% SBO diet. No significant differences were observed in cholesterol concentrations of the aorta, coronary arteries, brain or spleen. Experiment 2 used 4--10-day-old male Holstein calves to study the effect of 2% fat diets formulated in ratios of SBO 2/3:T 1/3 and SBO 1/3:T 2/3 and to observe the effect of dry feed added to 2% T and 2% SBO diets. Tallow and SBO fed in weighted combinations affected plasma and tissue cholesterol concentrations like the predominant fat fed alone. The greatest increases in plasma and tissue cholesterol concentrations occurred in calves fed SBO diets. Dry feed supplementation decreased body cholesterol concentrations of calves fed either fat. Body weight gain of calves fed SBO was less in both experiments.