Effects of Feeding Protected Tallow to Dairy Cows in Early Lactation

Abstract

Mixed diets containing 0 (control), 15 (medium fat), and 30% (high fat) of a protected tallow supplement (60% formylated soybean meal and 40% tallow) were fed to Holstein cows during the first 15 wk of lactation. Calculated energy densities of the diets were 1.85, 1.85, and 2.15 Mcal net energy lactation/kg dry matter. Dry matter intakes were higher on control and medium fat than on the high fat diet, but energy intakes were similar for all three diets. Treatments did not affect milk yield, but both diets containing protected tallow increased yields of fat and fat-corrected milk and energy efficiency, and decreased yields of solids-not-fat. Synthesis of fatty acid in the mammary gland was depressed 40 to 50% by protected tallow feeding. Transfers of dietary fatty acids to milk fat were about 35 and 25% from the medium fat and high fat diets. Concentrations of glucose in plasma were not affected by treatment. Non-esterified fatty acids, triglyceride, and cholesterol were elevated by protected tallow feeding. © 1978, American Dairy Science Association. All rights reserved.