EFFECTS OF DIETARY PALMITIC AND STEARIC ACIDS ON MILK YIELD AND COMPOSITION IN COW

The effects of the isocaloric replacement of starch in the concentrate by either 5 or 10% ‘stearic acid’ (85% pure) or by 10% ‘palmitic acid’ (85% pure) on the yield and composition of milk were investigated in a feeding experiment with 12 cows in mid-lactation. The concentrate mixtures were given with a high-roughage diet that supplied 4.4 kg of hay and 2.7kg of sugar-beet pulp/day. The inclusion of 5% ‘stearic acid’ in the concentrate mixture resulted in increases in the yields of milk, milk fat, solids-not-fat (SNF) and lactose and a reduction in the content of protein in the milk, whereas, when the level of ‘stearic acid’ in the concentrate was increased to 10%, there was an increase in only the yield of milk and a reduction in the contents but not in the yields of SNF and protein in the milk. The inclusion of 10% ‘palmitic acid’ in the concentrate mixture also reduced the contents of SNF and protein in the milk but produced increases in the yields of milk, milk fat and lactose and also in the content of fat in the milk. None of the dietary treatments resulted in any changes in the concentration of blood glucose. © 1969, Proprietors of Journal of Dairy Research. All rights reserved.