EFFECT OF A PROTECTED FAT PRODUCT ON PRODUCTIVITY OF LACTATING HOLSTEIN AND JERSEY COWS

Diets supplemented with Ca salts of fatty acids were fed to Holstein and Jersey cows to determine the effects on production and metabolic measures. Cows averaged 95 d in milk at the start of the study. A total mixed ration (concentrate, corn silage, and alfalfa silage) was offered. Holsteins and Jerseys consumed approximately .45 and .35 kg/d Ca salts of fatty acids, respectively. Milk production was not changed by fat supplementation, but FCM increased from 25.9 to 27.1 kg, milk fat percentage increased 5.5%, and milk protein declined 3.2% for cows receiving Ca salts of fatty acids. No breed by treatment interaction was significant. Group DM intake was similar among treatments, and calculated net energy intake exceeded net energy needs for maintenance and milk production. Body weight changes were similar among treatments. Apparent digestibility of dietary DM, fiber, and fatty acids was not altered by treatment. Serum C16:0 fatty acids increased, milk short-chain fatty acids (C4:0 to C14:0) decreased, and milk long-chain fatty acids (C16:0 to C18:3) increased when fat was added to the diet. Calcium salts of fatty acids improved FCM yield of lactating cows, primarily through increased milk fat percentages. No change occurred in apparent digestibility of the diet. In most cases, breed responses to treatment were similar. © 1990, American Dairy Science Association. All rights reserved.