Methane emissions and productivity of defaunated and refaunated sheep while grazing

Author(s)
Nguyen, Son Hong
Nguyen, Huyen Duong Thi
Bremner, Graeme
Hegarty, Roger Stephen
Publication Date
2018-04
Abstract
<p>Rumen protozoa produce hydrogen, which can be utilised by methanogens to produce enteric methane (CH<sub>4</sub>) that is a loss of digested energy and has an adverse environmental impact as a greenhouse gas. The aim of this study was to examine the effect of the absence of rumen protozoa on pasture intake, ruminal fermentation and enteric CH<sub>4</sub> production and performance of grazing sheep. An incomplete crossover experiment was conducted with eleven crossbred ewes (6 without [defaunated] and 5 with protozoa [refaunated]) on 2 × 2 ha pastures with daily CH<sub>4</sub> production (DMP) being measured by GreenFeed Emission Monitoring (GEM) units. Grazing defaunated sheep exhibited a lower concentration of rumen ammonia (<i>P </i>= 0.01), but similar concentrations of total rumen volatile fatty acids compared to refaunated sheep (<i>P </i>> 0.05). The molar proportion of acetate was decreased and butyrate proportion was increased by defaunation, while the proportion of propionate was unchanged. Estimated pasture intake was not different between defaunated and refaunated sheep (<i>P </i>> 0.05). Defaunated sheep tended to have a higher total dry matter intake (tDMI; <i>P </i>= 0.06), being the sum of pasture intake and pellet supplement intake. There was a tendency towards a lower CH<sub>4</sub> yield (g CH<sub>4</sub>/kg tDMI; <i>P </i>= 0.07) in defaunated sheep, but no differences in average daily gain or wool growth occurred due to defaunation.</p>
Citation
Small Ruminant Research, v.161, p. 28-33
ISSN
0921-4488
Link
Publisher
Elsevier BV
Title
Methane emissions and productivity of defaunated and refaunated sheep while grazing
Type of document
Journal Article
Entity Type
Publication

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