Feeding Protected and Unprotected Tallow to Lactating Cows

Abstract

Lactating Holstein cows were fed a control concentrate diet or concentrate diets supplemented with protected or unprotected soybean oil meal mixed with tallow 60:40 as 25% of the concentrate ration for 18 wk. The supplement provided 10% added tallow and 15% added soybean meal and was substituted for an equal part of basic concentrate diet. Changes in milk yield and milk fat of cows and growth rate of calves fed the three types of milk were of particular interest. Milk yields were increased 8 and 10% above those of controls by feeding the protected and unprotected supplements. Milk fat yields were elevated in protected but not in unprotected tallowfed cows. Elevations were marked in concentration of oleic acid in milk fat of tallow-fed cows. Plasma cholesterol and lipids increased with tallow feeding, about 1.7 times for protected material and 1.5 times for the unprotected. Calves fed milk from the three groups of cows as their only feed for 16 wk showed no differences in gains in body weight or in cholesterol of plasma. Change in the fatty acid composition of fat tissue of calves was marked, with elevations in concentration of oleic acid in calves fed milk of tallow-fed cows. The high dietary fat caused no diminution of intake or other undesired effects.