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Title: Factors influencing methane emissions from ruminants and possible mitigation strategies with reference to dairy cattle
Author: McCourt, Anne Rose
ISNI:       0000 0001 3623 3875
Awarding Body: Queen's University Belfast
Current Institution: Queen's University Belfast
Date of Award: 2007
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A series of studies were conducted to investigate possible mitigation strategies for ruminal methanogenesis from dairy cattle. The effect of three different ensiled forages (grass silage, maize silage and fennented whole crop wheat) on methane production from dairy cows was investigated. The maize silage diet resulted in highest absolute methane production per animal per day but the grass silage diet resulted in highest methane output expressed per kilogram dry matter intake. Feeding of maize and whole crop wheat increased total dry matter intake relative to grass silage. The type of silage offered had no effect on milk yield or composition, live weight or body condition score. Gross energy intake, digestible energy intake, metabolisable energy intake, faecal energy output and heat production were significantly lower for grass silage than for maize and whole crop wheat. The sulphur hexafluoride tracer technique for measuring methane production from dairy cattle was validated against indirect open-circuit respiration calorimetry chambers. The tracer technique underestimated t?tal methane production by 25%. A prediction equation was developed to calculate total methane output from tracer estimates: Total methane output = 1.099 (tracer methane estimate) + 95. The tracer technique was used to investigate the effect ofthree levels of dietary inclusion (0, 0.7 and 1.4 kg/day) of encapsulated fumaric acid (fumaric acid within a soyabean oil capsule) on methane production from grazing dairy cattle. Encapsulated fumaric acid had no effect on methane production, live weight, body condition score, milk yield or composition, and rumen fennentation. However inclusion ofencapsulated fumaric acid at the higher le~el resulted in significantly reduced numbers of Ruminococcus flavefaciens relative to the low rate of encapsulated fumaric acid and control· treatments.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available