Ca soaps of fatty acids (CSFA, 0·5 kg/d) were added to the diet of lactating cows for 170 d, and production, body condition score and blood lipids were examined.
Production of fat-corrected milk was increased by 1·5 kg/d owing to increase in both milk and fat production. Over 250 d lactation, production of fat-corrected milk was enhanced by 1·3 kg/d. Body condition scores were lower in cows fed CSFA in early lactation, but tended to exceed those of control cows after 80 d lactation. Reproductive performance was improved in cows fed CSFA.
Serum total lipids, phospholipids and cholesterol were increased in CSFA cows at 15 and 29 d but not at 59 d post partum. The cholesterol increase was mainly in the high density lipoprotein fraction.