Dose Response of Dairy Cows to Ammonium Salts of Volatile Fatty Acids

¹ Department of Animal Science, University of Minnesota, St Paul 55108
² Department of Animal Science, Michigan State University, East Lansing 48824
³ Department of Animal Science, University of Maryland, College Park 20742
⁴ Department of Dairy Science, University of Florida, Gainesvile 32611
⁵ Animal Nutrition Supplements, Eastman Chemical Division, Po Box 1955, Kingsport, TN 37622

In previous studies ammonium salts of a mixture of isobutyrate, 2-methylbutyrate, isovalerate, and valerate were fed in a corn silage, corn, corn gluten meal, and urea diet to Holstein cows throughout lactation to define the optimum level of ammonium salts of milk production. The objective of this work was to conduct another dose response study using other forage and protein sources and to determine the effects of decreasing VFA intakes as lactation advanced. The concentrate portion of the diet contained 0, .4, .8, 1.2, or 1.6% ammonium salts of VFA. The forage to concentrate ratio was 50:50, 60:40, and 70:30 for the first, middle, and last third of lactation, respectively. The study was conducted at four university locations using 191 Holstein cows. Feeds used included corn silage, alfalfa silage or hay, corn, soybean meal, minerals, and vitamins. Treatment x location interactions were significant for milk yield during early lactation. During mid- and late lactation, supplemental VFA (3%) improved milk and protein yield. Milk composition was not greatly affected by feeding VFA. In midlactation, cows fed 3% ammonium salts of VFA ate more feed than did controls. Feed efficiencies were similar among groups throughout the experiment. Cows fed VFA tended to gain less BW during lactation than did controls. Health and reproduction were not different among groups.

Key Words: ammonium salts of volatile fatty acids • milk production • dairy cows

Submitted on October 4, 1989
Accepted on February 5, 1990