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United States Department of Agriculture

Agricultural Research Service

Research Project: IMPROVING NUTRIENT DIGESTIBILITY TO ENHANCE FORAGE UTILIZATION IN LACTATING DAIRY COW FEEDING SYSTEMS Title: Changes in rumen bacterial communities and rumen chemistry in primiparous Holstein cows during the periparturient period

Authors
item Mohammed, Riazuddin -
item Stevenson, David
item Weimer, Paul
item Penner, Gregory -
item Beauchemin, Karen -

Submitted to: Journal of Dairy Science
Publication Type: Abstract Only
Publication Acceptance Date: April 10, 2012
Publication Date: July 15, 2012
Citation: Mohammed, R., Stevenson, D.M., Weimer, P.J., Penner, G.B., Beauchemin, K.B. 2012. Changes in rumen bacterial communities and rumen chemistry in primiparous Holstein cows during the periparturient period [abstract]. Journal of Dairy Science. 95(suppl 2):615.

Technical Abstract: The objectives of this study were to study the changes in: 1) rumen bacterial community composition (BCC) and fermentation as influenced by feeding regimen and period; and 2) pH and VFA profiles among selected cows with minimum (stable) and maximum variation (unstable) between pre- and post-parturient periods. Fourteen Holstein heifers paired by expected calving date and BCS were allotted to one of two prepartum feeding regimens: low-concentrate regimen (2 diets ranging from forage:concentrate, F:C = 80:20 to 54:46); or a high-concentrate regimen (4 diets ranging from F:C = 68:32 to 46:54). All cows received the same lactation diet postpartum. Microbial DNA extracted from 58 rumen digesta samples collected prepartum (d -50, -31, -14) and postpartum (d +14, +52) and amplified by PCR were subjected to automated ribosomal intergenic spacer analysis. Changes in rumen chemistry data (pH, VFA, and acidosis indicators at d -54, -35, -14, -3, +3, +17, +37, +58) were analyzed using principal component analysis (PCA). The ARISA profiles did not show a diet effect; however, 4 out of 14 cows showed a shift in BCC from the prepartum to the postpartum period. The PCA profiles did not show a diet effect on rumen fermentation. However, 4 cows (stable) showed minimal changes while 4 other cows (unstable) had greater changes in rumen fermentation when PCA profiles of individual cows were examined. The remaining cows had a PCA profile intermediate between the stable and the unstable form. Cows with a stable profile had greater minimum rumen pH, mean pH, less bouts under pH 5.5 and 5.2, and less duration and area of moderate (pH < 5.5) and acute ruminal acidosis (pH < 5.2) compared to cows with an unstable profile. Milk fat content tended to be greater for cows with a stable profile than those with an unstable profile, with no difference in milk yield or FCM. A lack of diet effect with greater changes in rumen chemistry and small changes in BCC before and after calving reflect physiological adaptations of the cows during the periparturient period.

Last Modified: 12/25/2014