NONENZYMATICALLY BROWNED SOYBEAN-MEAL FOR LACTATING DAIRY-COWS

Fifty-four high producing Holstein cows were used to determine the value of nonenzymatic browning of soybean meal to support milk production. Soybean meal was heated with 5% sulfite liquor (containing 20% xylose) as the source of sugar for the browning reaction. Cows were assigned randomly to one of three treatments according to calving date. Milk production during wk 2 of lactation was used as a covariate for milk production from wk 3 through 14. Total mixed rations consisted of 53% forage mix (corn silage, alfalfa haylage, and smooth bromegrass hay) and 47% concentrate (DM basis). Diet for treatment 1 contained untreated soybean meal and was balanced to 16% CP (DM basis). Treatment 2 used the treated soybean meal at 50% of the amount of soybean meal used in treatment 1 and contained 13% CP. Treatment 3 was the same as treatment 2 but had urea added to a final dietary CP of 16%. No differences in 3.5% FCM were apparent. Intakes among diets were similar but somewhat lower for cows on the diet containing urea. Percentages of milk fat, protein, and SNF were unaffected by dietary treatment. These data demonstrated that the protein from the nonenzymatically browned soybean meal supports the same production at half the amount of supplemental soybean meal.