HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Min, B. R. Articles by Hume, M. E. Search for Related Content PubMed PubMed Citation Articles by Min, B. R. Articles by Hume, M. E.

In vitro bacterial growth and in vivo ruminal microbiota populations associated with bloat in steers grazing wheat forage¹

B. R. Min^*, W. E. Pinchak^*,2, R. C. Anderson and M. E. Hume

^* Texas Agricultural Experiment Station, P.O. Box 1658, Vernon 76385; and United States Department of Agriculture, Agricultural Research Service, Southern Plains Agricultural Research Center, Food and Feed Safety Research Unit, 2881 F & B Rd., College Station, TX 77845

² Corresponding author: bpinchak{at}ag.tamu.edu

The role of ruminal bacteria in the frothy bloat complex common to cattle grazing winter wheat has not been previously determined. Two experiments, one in vitro and another in vivo, were designed to elucidate the effects of fresh wheat forage on bacterial growth, biofilm complexes, rumen fermentation end products, rumen bacterial diversity, and bloat potential. In Exp. 1, 6 strains of ruminal bacteria (Streptococcus bovis strain 26, Prevotella ruminicola strain 23, Eubacterium ruminantium B1C23, Ruminococcus albus SY3, Fibrobacter succinogenes ssp. S85, and Ruminococcus flavefaciens C94) were used in vitro to determine the effect of soluble plant protein from winter wheat forage on specific bacterial growth rate, biofilm complexes, VFA, and ruminal H₂ and CH₄ in mono or coculture with Methanobrevibacter smithii. The specific growth rate in plant protein medium containing soluble plant protein (3.27% nitrogen) was measured during a 24-h incubation at 39 ° C in Hungate tubes under a CO₂ gas phase. A monoculture of M. smithii was grown similarly, except under H₂:CO₂ (1:1), in a basal methanogen growth medium supplemented likewise with soluble plant protein. In Exp. 2, 6 ruminally cannulated steers grazing wheat forage were used to evaluate the influence of bloat on the production of biofilm complexes, ruminal microbial biodiversity patterns, and ruminal fluid protein fractions. In Exp. 1, cultures of R. albus (P < 0.01) and R. flavefaciens (P < 0.05) produced the most H₂ among strains and resulted in greater (P < 0.01) CH₄ production when cocultured with M. smithii than other coculture combinations. Cultures of S. bovis and E. ruminantium + M. smithii produced the most biofilm mass among strains. In Exp. 2, when diets changed from bermudagrass hay to wheat forage, biofilm production increased (P < 0.01). Biofilm production, concentrations of whole ruminal content (P < 0.01), and cheesecloth filtrate protein fractions (P < 0.05) in the ruminal fluid were greater on d 50 for bloated than for nonbloated steers when grazing wheat forage. The molecular analysis of the 16S rDNA showed that 2 different ruminal microbiota populations developed between bloated and nonbloated animals grazing wheat forage. Bloat in cattle grazing wheat pastures may be caused by increased production of biofilm, resulting from a diet-influenced switch in the rumen bacterial population.

Key Words: bacterial diversity • frothy bloat • gas production • methane • rumen

This article has been cited by other articles:

				J. T. Vasconcelos and M. L. Galyean ASAS Centennial Paper: Contributions in the Journal of Animal Science to understanding cattle metabolic and digestive disorders J Anim Sci, July 1, 2008; 86(7): 1711 - 1721. [Abstract] [Full Text] [PDF]