Influence of high energy supplements containing fatty acids on the productivity of pasture-fed dairy cows

Abstract

Three groups of 8 cows in their second month of lactation grazed irrigated perennial pasture alone, or grazed and were supplemented with either 3.3 kg/day of a high energy supplement or 3.8 kg of a high energy supplement containing additional long-chain fatty acids. Yields of milk and milk products were generally highest for those cows fed the supplement containing fat. Yield of milk fat was 13% higher in fat supplemented cows than those in the other supplemented treatment because these cows overcame the negative effect of starch supplements on milk fat test. Inclusion of long-chain fatty acids in the diet caused only minor changes in the fatty acid composition of the milk fat and in the various rumen parameters. The immediate marginal increases in daily yields of milk and milk fat per kg of long-chain fatty acids consumed by cows were 1.8 and 0.33 kg/cow. After comparison with data from other experiments, we concluded that the type of basal diet is not an important factor influencing the response of dairy cows to dietary long-chain fatty acids