Effect of Forage Species on the Rumen Microbial Population to Estimate Methane Production.

EFFECT OF FORAGE SPECIES ON THE RUMEN MICROBIAL POPULATION TO ESTIMATE METHANE PRODUCTION Rondineli P. Barbero, Renata L. Nave and J. Travis Mulliniks Methane production is a concern due to its global-warming potential considered higher than carbon dioxide. Ruminants depend on the activity of a dense and diverse microbial community present in the rumen for their growth and maintenance. However, rumen microbial activity is also a major source of the greenhouse gas methane in agriculture. Forages with higher digestibility will increase dry matter intake depressing the amount of methane produced per unit of feed consumed. Overtime, utilizing stockpiled forages as a heifer development management approach may result in the development or selection of animals that are matched to the production environment, thus reducing the need for harvested feed The objective of this research was to determine the effect of stockpiled winter forage species on VFA’s gases and ammonia production, and its correlations with methane production, in yearling beef heifers. The experiment was conducted during the winter 2014 at the University of Tennessee in Spring Hill, TN. Heifers from the Middle Tennessee Research and Education Center were utilized for this study. Prior to initiation of forage treatments, heifer body weight and body corporal score was recorded. Heifers were then stratified by initial BW to 1 of 3 forage type pastures: 1) Tall fescue, 2) Big bluestem/Indian grass, or 3) Switchgrass. Pastures (n = 20) contained 2 heifers per experimental unit during the winter grazing period. Animals were ruminally sampled with an oral lavage every 28 d with approximately 20 mL of ruminal fluid collected. All samples were stored in 15-mL polypropylene conical tubes at -20°C until analysis of VFA and ammonia. Ruminal ammonia was analyzed using the phenol-hypochlorite procedure, adapted to a microtiter plate. Volatile fatty acid concentration was determined by gas chromatography. The MIXED procedure and regression analysis of SAS were used to estimate the relationship between VFA’s gases production and methane emission.