Digestibility of Rations and Nitrogen Balance by Lambs as Influenced by Animal Fat, Urea, Soybean Meal and Linseed Meal

Abstract

Feed processing and handling of livestock feeds have benefited from the use of fats in many ways. Nutritionally speaking, several reasons in favor of the use of stabilized animal fats in feeds have been reported. However, the optimum level and value of added fats in the rations for ruminants are not well established and further work is needed. It is known that fat is absorbed more slowly from the intestine than either carbohydrates or protein, and this may be an important factor in the utilization of added fat in the diet. Research with urea as a protein sparer has been widespread, and its potential is more closely defined than is that of added fat in the ration. Both urea and fat are being used in some commercial feeds. It has been shown that urea is more efficiently utilized in protein synthesis with starch than with sugar. The effects of high levels of fat on urea utilization need to be determined if they are to be used together in ruminant feeds. The work reported herein is a part of a project designed to determine the effect of lard, urea, soybean meal, and linseed meal upon the digestibility of rations and nitrogen balance by lambs. Rations testing these factors singularly and in combination were employed in an attempt to gain a more concise picture of the action of these factors upon the digestibility of the other nutrients in these rations