EFFECTS OF NICOTINAMIDE ON MILK-COMPOSITION AND PRODUCTION IN DAIRY-COWS FED SUPPLEMENTAL FAT

Thirty-two cows, averaging 112 DIM, were assigned to four dietary trea tments: 1) control, 2) Ca salts of fatty acids, 3) nicotinamide, and 4 ) Ca salts of fatty acids blended with nicotinamide during manufacture . Preliminary studies showed that nicotinamide survives blending with Ca salts of fatty acids during manufacture and that a blended mixture of nicotinamide and Ca salts of fatty acids gave results similar to th ose from nicotinamide plus Ca salts of fatty acids supplemented separa tely. Calcium salts of fatty acids increased milk fat percentage, decr eased milk protein percentage, but had no effect on production of milk , FCM, fat, or protein. Nicotinamide increased production of milk and protein, decreased fat percentage, but had no effect on either product ion of FCM and protein or percentage of protein. Calcium salts of fatt y acids increased NEFA in blood, and dietary nicotinamide increased co ncentrations of nicotinamide in blood, but glucose and BHBA in blood w ere unaffected by either dietary ingredient. Therefore, in these midla ctation cows, the decreased milk protein percentage caused by suppleme ntal dietary fat was prevented by nicotinamide. Supplementation with o nly nicotinamide increased total production of milk protein.