Submitted to: Journal of Dairy Science
Publication Type: Abstract Only
Publication Acceptance Date: July 23, 2003
Publication Date: July 23, 2003
Citation: BRODERICK, G.A., RADLOFF, W.J. EFFECTS OF FEEDING GRADED AMOUNTS OF LIQUID MOLASSES TO HIGH PRODUCING DAIRY COWS. JOURNAL OF DAIRY SCIENCE. 2003. v. 86 (Suppl. 1). Abstract p. 217 Technical Abstract: Previously, we observed that replacing dietary starch sources with sucrose or dried molasses significantly increased DMI and fat yield in lactating cows. In the present trial, we tested the effect of replacing dietary high moisture shelled corn (HMSC) with liquid molasses. Forty-eight multiparous Holstein cows were assigned by DIM to 12 blocks; cows were fed a covariate diet formulated to 17% CP and 26% NDF that contained (DM basis): 30\% alfalfa silage, 20\% corn silage, 37.4\% HMSC, 7.0\% soybean meal, 4.4\% roasted soybeans, plus 1.2\% minerals and vitamins. After a 2-wk covariate period, cows within blocks were randomly assigned to one of four TMR that contained (DM basis): 0\% molasses, 37.4\% HMSC (covariate diet); 3\% molasses, 34.4\% HMSC; 6\% molasses, 31.4\% HMSC; or 9\% molasses, 28.4\% HMSC. Cows were fed experimental diets for 8 wk. Milk yield and DMI were measured daily. Yield of milk components was determined one day during the covariate period and every 2-wk during the 8-wk trial. The statistical model included block and covariate average for each production trait. Least square means are reported below. There were significant linear trends for reduced yield with increasing molasses; this was driven by a dramatic reduction in all production traits at 9\% dietary molasses. Although there was a trend for a quadratic effect on FCM, unlike the previous trials, there was no quadratic effect on fat yield of feeding sugar as molasses. However, there were significant quadratic responses for DMI and yield of milk, protein, lactose, and SNF with increasing dietary molasses; maximal intake and yield occurred at 3\% molasses. One cubic response was noted for DMI. Replacing HMSC with liquid molasses optimized yield and DMI when fed at about 3\% of dietary DM.