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 3 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 40-50% 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.