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Effects of live yeast, monensin and concentrate level in dairy cattle diets on gas and volatile fatty acids production

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dc.contributor.advisor Muya, M. C.
dc.contributor.advisor Acheampong-Boateng, O.
dc.contributor.author Mokatse, Brenda
dc.date.accessioned 2015-09-14T10:20:08Z
dc.date.available 2015-09-14T10:20:08Z
dc.date.issued 2015-06
dc.date.submitted 2015-09-14
dc.identifier.citation Mokatse, Brenda (2015) Effects of live yeast, monensin and concentrate level in dairy cattle diets on gas and volatile fatty acids production, University of South Africa, Pretoria, <http://hdl.handle.net/10500/19067> en
dc.identifier.uri http://hdl.handle.net/10500/19067
dc.description.abstract Two meta-analysis of effects of yeast culture and monensin in lactating dairy cows were first performed. Secondly, two experiments were performed to evaluate the effects of live yeast (LY) or monensin (M) or both (LY+M) on gas production and fermentation by rumen micro-organisms in vitro in low (40 %) and high (60 %) concentrate diets of dairy cows. Rumen contents were collected from one cannulated lactating Holstein cow. Gas production was measured from 0 to 48 h of incubation. Volatile fatty acids and ammonia nitrogen concentrations were measured after 48 h. Meta-analysis of monensin indicated decrease dry matter intake (DMI) and increasing milk yield, consequently improving feed efficiency. Meta-analysis of yeast culture did not show improved performance. These results highlighted the importance of the meta-analysis as a useful tool that can be employed to both summarize effects across studies and to investigate factors explaining potential heterogeneity of response. The batch fermentation showed that in high concentrate diet, M significantly increased ammonia nitrogen, decreased acetate, but tended to increase propionate concentration (7.9, 63.2, 18.6 vs. 6.3, 66.8, 14.2 mmol/l; respectively). Addition of LY increased acetate concentration (64.2 vs 66.8 mmol/l). Supplementation with M, LY and LY+M reduced total gas production by 37.1, 22.5 and 26.9 %, respectively, compared to control at 48 h. In low concentrate diet, M and LY+M decreased and increased acetate (60.1 and 69.7 vs. 7.1 mmol/l; respectively). Adding LY and LY+M produced 8.6 % less gas, and M treatment 3.4 % more gas than the control. Overall, at 48 h, high concentrate resulted in less gas than low concentrate diets. High concentrate diets showed increased ammonia (7.9 and 6.4 vs. 5.21 and 4.7 mmol/l) decreased acetate (63.0 and 63.2 vs. 67.0 and 69.7 mmol/l) with a tendency to increased propionate (18.6 and 18.9 vs. 14.6 and 14.1 mmol/l) compared to low concentrate in M and LY+M treated diets. These results indicate that the effects of M and LY on rumen fermentation are substrate dependent, the high-concentrate diet showing the greatest response en
dc.format.extent 1 online resource (xi, 68 leaves) : tables, graphs en
dc.language.iso en en
dc.subject.ddc 636.2142
dc.subject.lcsh Dairy cattle -- Nutrition en
dc.subject.lcsh Dairy cattle -- Feeding and feeds en
dc.subject.lcsh Milk yield en
dc.subject.lcsh Volatile organic compounds en
dc.subject.lcsh Fatty acids en
dc.subject.lcsh Yeast as feed en
dc.title Effects of live yeast, monensin and concentrate level in dairy cattle diets on gas and volatile fatty acids production en
dc.type Dissertation en
dc.description.department Agriculture en
dc.description.degree M. Sc. (Agriculture) en


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