INFLUENCE OF NONENZYMATICALLY BROWNED SOYBEANS ON RUMINAL FERMENTATION AND LACTATIONAL PERFORMANCE OF DAIRY-COWS

Four ruminally fistulated Holstein cows were assigned to one of four t otal mixed rations (TMR) in a 4 x 4 Latin square with 3-wk periods to investigate the effects of added lipid from nonenzymatically browned s oybeans or soybean oil on ruminal metabolism and milk fatty acids. All rations contained 50% forage and 1) 4% added lipid from soybean oil, 2) 4 or 6% added lipid from nonenzymatically browned soybeans, or 3) n o added lipid (control). The TMR that contained nonenzymatically brown ed soybeans increased milk C-18:2 by 35% compared with the TMR that co ntained soybean oil. A lactation trial was conducted in which 60 Holst ein cows were assigned to one of five TMR from wk 3 to 18 of lactation . The TMR contained 1) 4.5% added lipid from soybean oil, 2) 1.5% adde d lipid from nonenzymatically browned soybeans and 3% from soybean oil , 3) 3% added lipid from nonenzymatically browned soybeans and 1.5% fr om soybean oil, 4) 4.5% added lipid from nonenzymatically browned soyb eans, and 5) 4.5% added lipid from Ca salts of long-chain fatty acids. Dry matter intake was reduced by 11% for cows fed the TMR containing soybean oil only compared with that for cows fed the other TMR. Milk C -18:2 and C-18:3 were increased as the inclusion of nonenzymatically b rowned soybeans in the TMR increased. All percentages of the nonenzyma tically browned soybeans fed to cows resulted in fat-corrected milk yi elds that were similar to those of cows fed the TMR that contained Ca salts of fatty acids.