Submitted to: Journal of Dairy Science
Publication Type: Abstract Only
Publication Acceptance Date: 7/24/2000
Publication Date: N/A
Technical Abstract: Two sets of 24 Holstein cows (41 ± 5 kg/d of milk) were blocked by DIM and randomly assigned in two flights to four groups of 6 cows and fed TMR containing (DM basis): 40\% alfalfa silage, 20\% corn silage, 20.5\% rolled high moisture shelled corn, 9\% soybean meal, 2\% fat, 1\% vitamin-mineral supplement, 7.5\% supplemental non-structural carbohydrate (NSC), 16.7\% CP, and 29\% NDF. The NSC fed in the four diets was: 7.5\% corn starch, 0\% sucrose; 5.0\% starch, 2.5\% sucrose; 2.5\% starch, 5.0\% sucrose; or 0\% starch, 7.5\% sucrose. The diet with 7.5\% starch was fed for a 2-wk covariate period then cows were fed their assigned diets for 8-wk. Milk yield was measured at each milking; DMI was determined daily. Yield of milk components was determined from milk samples taken at both daily milkings one day during the covariate and every 2-wk during the experimental period. The statistical model included flight (n = 2), block (n = 12), and covariate yield of each milk component; LS means are reported below. There were linear increases (P ¿ 0.04) in DMI and milk fat content and yield as sucrose increasingly replaced corn starch in the diet; there was trend (P = 0.09) for a linear decline in milk/DMI with increasing sucrose. No other yield trait was affected significantly.