Implication of Feeding Isoenergetic Diets Containing Animal Fat on Milk Composition of Alpine Does During Early Lactation

Abstract

Lactation and digestion trials were conducted to test the hypothesis that supplemental animal fat in goat diets would alleviate low fat content and decrease concentrations of fatty acids responsible for flavor problems in goat milk during early lactation. In a 17-wk trial, 14 Alpine does were assigned randomly to isonitrogenous and isoenergetic diets with either 0 or 5% animal fat in a double crossover experiment. Intakes of NDF and ADF were higher in goats fed 5% dietary fat, but intakes of other nutrients were similar between treatments. Total ruminal VFA concentration was lower, and acetate and butyrate proportions were higher, in does fed 5% fat. Plasma NEFA, triglyceride, and total cholesterol were higher in does fed 5% fat. Milk fat content was higher in does fed 5% fat (3.8 vs. 3.1%). Yields of 4% FCM and SCM were similar between treatments. No differences were observed in milk cholesterol content as a result of dietary animal fat. Milk caproic, caprylic, capric, lauric, and myristic acids were lower, whereas palmitic, stearic, and oleic acids were higher, in milk from does fed 5% fat. Efficiencies of feed, energy, and protein for milk yield were not altered by supplemental animal fat in the diet. We concluded that an intake of animal fat combined with high fiber altered lipid metabolism in the rumen and peripheral circulation and contributed to changes in fat content and fatty acid composition in goat milk.