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The effect of canola oil on in vitro ruminal gas production kinetics, in vivo production, and intrinsic methane production and performance in feedlot lambs
Thesis (MScAgric)--Stellenbosch University, 2026.
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| Format: | Thesis |
| Language: | English |
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Stellenbosch : Stellenbosch University
2026
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| _version_ | 1867613982140923904 |
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| access_status_str | Open Access |
| author | Van Blerk, Katelin |
| author2 | Van Zyl, J. H. C. |
| author_browse | Van Blerk, Katelin Van Zyl, J. H. C. |
| author_facet | Van Zyl, J. H. C. Van Blerk, Katelin |
| author_sort | Van Blerk, Katelin |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MScAgric)--Stellenbosch University, 2026. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/135703 |
| institution | Stellenbosch University (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:44:46.833Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2026 |
| publishDateRange | 2026 |
| publishDateSort | 2026 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/135703 The effect of canola oil on in vitro ruminal gas production kinetics, in vivo production, and intrinsic methane production and performance in feedlot lambs Van Blerk, Katelin Van Zyl, J. H. C. Cruywagen, C. W. C. Stellenbosch University. Faculty of AgriSciences. Dept. of Animal Science. Thesis (MScAgric)--Stellenbosch University, 2026. Van Blerk, K. 2026. The effect of canola oil on in vitro ruminal gas production kinetics, in vivo production, and intrinsic methane production and performance in feedlot lambs. Unpublished masters thesis. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/a1147c76-307d-4aaa-855e-cd5917c14bb0 Crude canola oil represents a compelling strategy for mitigating methane emissions from ruminant livestock, which constitute growing environmental concern. This potential is attributed to bioactive compounds and its capacity to induce fiber coating within the rumen. While the oil has shown to reduce methane emissions from ruminants, the use of a practical approach in a feedlot system has yet to be studied. The present study investigated whether crude canola oil sourced from canola seeds, abundantly available in Southern Africa, can reduce in vitro methane production while maintaining total gas production when replacing maize in a lamb feedlot diet. Furthermore, the production performance and methane emissions from feedlot lambs were investigated to determine whether the substitution of maize with crude canola oil may result in reduced methane emissions while maintaining animal performance. Four treatment diets were incubated using bovine rumen fluid as inoculum: 0 (T1; control), 20 (T2), 40 (T3), and 60 (T4) g/kg dry matter (DM) in a lamb feedlot diet. Total gas and CO2 production was determined with the aid of a methane potential test system (AMPTS III) and methane production was estimated by difference. Cumulative gas production data were fitted to modified Gompertz and Ørskov-McDonald models to derive kinetic parameters. Maximum total gas production (b) decreased significantly (P < 0.05) with increasing canola oil inclusion, with T4 producing 18-19% less total gas than T1. The maximum rate of total gas production (kmax) decreased (P < 0.001) progressively from T1 (0.300 Nml/g DM per minute) to T4 (0.187 Nml/g DM per minute). Similarly, the maximum rate of methane production declined (P = 0.011) from T1 (0.181 Nml/g DM per minute) to T2 - T4 (0.131-0.149 Nml/g DM per minute), but canola oil treatment did not decrease absolute methane volumes. The ratio of methane to total gas also did not differ significantly across treatments. The parallel reductions in total gas production and methane production rate (kmax), combined with the constant methane:total gas ratio, indicate that the primary effect of canola oil was a general inhibition of ruminal fermentation rather than specific anti-methanogenic activity. The observed reductions in fermentation rate and total gas production, particularly at 60 g/kg DM inclusion, likely result from inhibitory effects of unsaturated fatty acids on ruminal microorganisms and potential coating of feed particles, reducing substrate accessibility. In a second trial, 38 Merino ewe lambs with an average initial body weight of 26 kg were randomly allocated to four dietary treatment groups: (1) 0 g canola oil per kg DM (T1; control), (2) 20 g canola oil per kg DM (T2), (3) 40 g canola oil per kg DM (T3), and (4) 60 g canola oil per kg DM (T4). The trial was conducted over seven weeks, with weekly measurements of dry matter intake (DMI) and body weight, and daily methane emissions measured using laser methane detection (LMD) technology. Canola oil inclusion significantly affected animal performance parameters. Final body weight was highest (P = 0.002) for T3 (43.7 kg) and lowest for T4 (38.9 kg), while T3 did not differ from T1 and T2. Average daily gain (ADG) followed a similar pattern (P = 0.019), with T3 recording the highest (0.26 kg/d) and T4 the lowest (0.20 kg/d). A higher (P = 0.006) feed intake was observed for T3 (1.53 kg/d) compared to 1.38 kg/d, and 1.29 kg/d for treatments T1, T2 and T4, respectively. No differences among treatments were observed for feed conversion ratio (FCR). Regarding methane emissions, no differences were observed among treatments, in either grams per day, grams per kilogram bodyweight per day or grams per kilogram DM per day. This could be related to the type of methane measurement that was used and that the laser instrument might not have been sensitive enough. This study concluded that canola oil can successfully be included in lamb feedlot diets at rates up to 40 g/kg DM without compromising growth performance. Suggesting that it could possibly be used to substitute maize in the diet but would result in a more expensive feed than the control feed. Under the conditions of this study, canola oil supplementation was unsuccessful in reducing methane emissions when included at levels of up to 60 g/kg DM in feedlot lamb diets. Further research into the use of crude canola oil in a feedlot system is needed to investigate the potential of the oil in reducing methane emissions from ruminants. Masters 2026-04-08T09:02:24Z 2026-04-08T09:02:24Z 2026-03 Thesis https://scholar.sun.ac.za/handle/10019.1/135703 en Stellenbosch University 112 pages application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Van Blerk, Katelin The effect of canola oil on in vitro ruminal gas production kinetics, in vivo production, and intrinsic methane production and performance in feedlot lambs |
| title | The effect of canola oil on in vitro ruminal gas production kinetics, in vivo production, and intrinsic methane production and performance in feedlot lambs |
| title_full | The effect of canola oil on in vitro ruminal gas production kinetics, in vivo production, and intrinsic methane production and performance in feedlot lambs |
| title_fullStr | The effect of canola oil on in vitro ruminal gas production kinetics, in vivo production, and intrinsic methane production and performance in feedlot lambs |
| title_full_unstemmed | The effect of canola oil on in vitro ruminal gas production kinetics, in vivo production, and intrinsic methane production and performance in feedlot lambs |
| title_short | The effect of canola oil on in vitro ruminal gas production kinetics, in vivo production, and intrinsic methane production and performance in feedlot lambs |
| title_sort | effect of canola oil on in vitro ruminal gas production kinetics in vivo production and intrinsic methane production and performance in feedlot lambs |
| url | https://scholar.sun.ac.za/handle/10019.1/135703 |
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