|
|
||||||||
1 Hebrew University, Faculty of Agriculture, Rehovot 76100, Israel
2 Institute of Animal Science, Agriculture Research Organization, The Volcani Center, Bet Dagan and Neve-Yaar, Israel
The potential of the dacron bag technique to assess fluctuations in ruminal metabolites was studied using 40 Israeli-Friesian dairy cows assigned to an experiment with a 2 x 2 factorial design. Diets contained a low (62%) or high (65%) percentage of ruminally degradable CP and a low (55%) or high (59%) percentage of ruminally degradable OM. Metabolites were monitored before feeding and at 3 and 6 h postfeeding. Before feeding, total VFA and propionate were higher, and acetate and pH were lower, in diets containing a high percentage of ruminally degradable OM than in diets containing a low percentage of degradable OM. By 3 h postfeeding, acetate, butyrate and pH were lower, and propionate was higher, in the diets containing a high percentage of ruminally degradable OM than in the diets containing a low percentage of ruminally degradable OM. By 6 h postfeeding, propionate was higher, and acetate was lower, in diets containing a high percentage of ruminally degradable OM than in diets containing a low percentage of ruminally degradable OM. In the diets with a high percentage of ruminally degradable OM, before feeding and by 3 h postfeeding, ammonia concentrations were higher and lower, respectively, relative to the diets containing a low percentage of degradable OM. Milk yield and composition and DMI were similar among treatments. The correlation was good between the degradability data obtained by the dacron bag technique and the meal-induced variations in ruminal metabolites. The lack of a positive yield response to controlled fluctuations in ruminal metabolites may be related to surplus CP intake.
Key Words: ruminal degradation ruminal fermentation metabolite fluctuations
Submitted on May 5, 1995
Accepted on March 22, 1996
This article has been cited by other articles:
![]() |
P. Rezamand, S. M. Andrew, and T. A. Hoagland The Feeding Value of Extruded Corn Grain in a Corn Silage-Based Ration for High-Producing Holstein Cows and Heifers During Mid Lactation J Dairy Sci, July 1, 2007; 90(7): 3475 - 3481. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |