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ARS Home » Pacific West Area » Logan, Utah » Forage and Range Research » Research » Publications at this Location » Publication #292555
Title: Effects of energy supplementation in pasture forages on in vitro ruminal fermentation characteristics in continuous cultures

Author
item NOVIANDI, C - Utah State University
item EUN, J - Utah State University
item Peel, Michael
item Waldron, Blair
item MIN, B - Tuskegee University
item ZOBELL, D - Utah State University
item MILLER, R - Utah State University

Submitted to: Professional Animal Scientist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/2/2013
Publication Date: 2/1/2014
Citation: Noviandi, C.T., Eun, J.S., Peel, M., Waldron, B.L., Min, B.R., Zobell, D.R., Miller, R.L. 2014. Effects of energy supplementation in pasture forages on in vitro ruminal fermentation characteristics in continuous cultures. Professional Animal Scientist. 30:13-22.

Interpretive Summary: A dual-flow continuous culture system was used to determine the effects of energy supplementation with 4 pasture forages on in vitro ruminal fermentation characteristics. The dietary treatments tested were: energy supplementation (no concentrate, 30% ground corn, or 30% dried distilled grains) with pasture forages [tall fescue (TF) without N fertilizer (TF-NF), TF with N fertilizer (TF+NF), TF-alfalfa mixture (TF+ALF), and TF-birdsfoot trefoil mixture (TF+BFT)]. Average daily culture pH was affected by energy supplementation, but not by pasture forage, ranging from 5.94 to 6.44. The greatest total volatile fatty acid and propionate concentrations were detected when corn was supplemented in pasture forages. In addition, supplementing corn in the TF+BFT sizably increased total volatile fatty acid and propionate concentration compared with the TF+ALF. Higher concentrations of acetate and propionate were found when the TF+NF was offered, but no noticeable effects were detected among the other pasture forages. Energy supplementation decreased acetate-to-propionate ratio across pasture forages, and corn supplementation in the TF+NF resulted in the lowest ratio. Lower ammonia-N (NH3-N) and methane (CH4) concentrations were achieved due to energy supplementation, in particular when corn grain was the supplement. Feeding the TF+NF or the TF+BFT elicited similar NH3-N: volatile fatty acid ratios with no energy or corn supplementation, which indicates that the TF+BFT was effectively fermented in cultures, resulting in similar efficiency of ruminal fermentation compared as the TF+NF. Overall data in the current study imply that BFT grown with TF may substitute N fertilizer for the grass, and would improve ruminal fermentation and nutrient utilization efficiency.

Technical Abstract: A dual-flow continuous culture system was used to assess the effects of energy supplementation with 4 pasture forages on in vitro ruminal fermentation characteristics. Twelve dietary treatments were tested in a split-plot design energy supplementation [no concentrate, 30% ground corn, or 30% dried distilled grains with soluble (DDGS)] as a whole plot and pasture forages [tall fescue (TF) without N fertilizer (TF-NF), TF with N fertilizer (TF+NF), TF-alfalfa mixture (TF+ALF), and TF-birdsfoot tremoil mixture (TF+BFT)] as a subplot. A total of 15 g DM/d was offered to each culture fermentor at 4 equal portions of pasture forages (fed at 0600, 1200, 1800, and 2400 h) and 2 equal portions of energy supplement (fed at 1200 and 2400 h). Three replicated runs lasted 9 d each, with the first 7 d allowed for microbial adaptation to the diets, and lasted 2 d for data collection and sampling. The TF-legume mixtures (TF+ALF and TF+BFT) contained similar CP concentration as the TF+NF. Average daily culture pH was affected by energy supplementation (P < 0.01), but not by pasture forage, ranging from 5.94 to 6.44. The greatest total VFA and propionate concentrations (P < 0.01) were detected when corn was supplemented in pasture forages. In addition, supplementing corn in the TF+BFT sizably increased total VFA and propionate concentration compared with the TF+ALF. Higher concentrations of acetate and propionate were found when the TF+NF was offered (P < 0.01), but no noticeable effects were detected among the other pasture forages. Energy supplementation decreased acetate-to-propionate ratio across pasture forages, and corn supplementation in the TF+NF resulted in the lowest ratio (P < 0.01). Lower ammonia-N (NH3-N) and methane (CH4) concentrations (P < 0.01) were achieved due to energy supplementation, in particular when corn grain was supplemented. Feeding the TF+NF or the TF+BFT elicited similar NH3-N:VFA ratios with no energy or corn supplementation, which indicates that the TF+BFT was efffectively fermented in cultures, resulting in similar efficiency of ruminal fermentation compared with the TF+NF. Overall data in the current study imply that interseeding BFT with TF may substitute N fertilizer on grass pasture, and would be a sustainable component in cattle grazing systems to improve ruminal fermentation and nutrient utilization efficiency.