Further studies on the effect of fat supplementation of concentrates fed to lactating dairy cows. II. Total digestion and energy utilization.

Abstract

For wether sheep given 300 g hay and 800 g concentrates the addition of fat (beef tallow:palm kernel oil 9:1) to concentrates at 7 or 12% tended to decrease crude fibre digestibility and increased crude fat digestibility. For 2 rumen-fistulated cows given concentrates containing 7% fat, or 12% fat free or adsorbed on carrier, and 2 cows with fistulae and reentrant duodenal cannulae given concentrates with 12% fat in rations with hay:concentrate 1:2, there were no significant differences between diets in the digestibility of any nutrient; fat digestibility was decreased at feed intakes above maintenance, particularly with the 12% fat concentrates. The use of a carrier in the 12% fat concentrates did not affect nutrient digestibilities for sheep or cows. Inclusion of fat in concentrates increased the metabolizability of sheep diets but there were no significant differences among cattle diets, although methane losses tended to decrease as fat content increased. Additional energy from fat tended to be retained rather than used for milk yield. ME utilization for milk, storage and maintenance was 61-62.5%, tending to be highest with the 12% adsorbed fat. [See DSA 45, 5398 for part I.] (Abstract retrieved from CAB Abstracts by CABI’s permission)