Author
 |
Broderick, Glen |
|
Radloff, Wendy |
|
Submitted to: Journal of Dairy Science
Publication Type: Abstract Only Publication Acceptance Date: 7/27/2001 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: Eight primiparous and 40 multiparous (8 with rumen cannulae) Holsteins were blocked by parity and DIM, randomly assigned to 4 blocks of 12 and fed TMR containing (DM basis): 40% alfalfa silage, 20% corn silage, 8% soybean meal, 2% added fat, 1% minerals and vitamins, and 18% CP. Dietary sugar was varied by replacing rolled high moisture shelled corn (HMSC) with dried dmolasses. The 4 diets were: 0% molasses, 29% HMSC; 4% molasses, 25% HMSC; 8% molasses, 21% HMSC; or 12% molasses, 17% HMSC. Cows were fed the 0% molasses diet for a 2-wk covariate period, experimental diets for 8 wk, then the 0% molasses diet for another 2 wk covariate. Milk yield and DMI were measured daily. Yield of milk components was determined one day in both covariates and every 2-wk in the 8-wk trial. Rumen sampling was in trial wk 4 and 8. The statistical model included block and covariate average. There was a linear increase in DMI and linear decreases in milk/DMI and milk N/NI with increasing dietary sugar. There were quadrati responses in yield of FCM and fat, and rumen ammonia, with increasing sugar; FCM and fat yield maxima and rumen ammonia minimum occurred at about 6% molasses. Several cubic responses were noted that were related to similar milk and protein yields at 0 and 8% molasses. Replacing readily fermented starch with dietary sugar primarily increased fat yield. GBabs4.doc |
