https://vital.seals.ac.za/vital/access/manager/Index ${session.getAttribute("locale")} 5 https://vital.seals.ac.za/vital/access/manager/Repository/vital:62624 Thu 16 Mar 2023 15:05:52 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10965 Thu 13 May 2021 00:16:19 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:46153 B > A; (P<0.0001). Performance parameters like Body condition score (BCS), body weight (BW), dry matter intake (DMI), and daily methane were higher (P<0.05) in Bonsmara. However, Methane per BW was higher in Nguni (P<0.05), and methane per DMI did not differ among breeds (P>0.05). Body condition, BW, and DMI were higher (P<0.05) in commercial grazing system. Contrary, daily methane production, methane production per DMI, and methane produced per BW were higher in communal grazing. In the second study, Ruminal NH3-N concentration ranged between 69.05 - 96.78 mg/L and was higher (P<0.05) in Nguni. It was also higher (P<0.05) in the commercial grazing system. Ruminal pH, temperature, total VFAs, and certain individual VFAs (iso-butyrate, valeric and iso-valeric) did not differ (P>0.05) among breeds and grazing systems. However, total VFAs were slightly lower in communal grazing (78.87 mmol/L) than commercial grazing (89.80 mmol/L). Acetate, propionate, butyrate proportions, and acetate to propionate ratio did not differ (P>0.05) among breeds but differed (P<0.05) between grazing systems. Acetate (P<0.05) and acetate to propionate ratio (P<0.05) were higher in the communal grazing system, while the reverse was true for propionate (P<0.05) and butyrate (P<0.05). Bonsmara produced more methane than Nguni under similar conditions, with Nguni uniquely producing more methane per BW, indicating host genetics influence. Communal animals and older animals produced more CH4 than commercial and younger cows regardless of the breed, indicating ruminal inefficiencies in very old cows. These results emphasize the idea that host genetics or breed, grazing system, and age influence methane output and performance. Hence, breeding strategies for hard-to-measure traits like methane production need to put all these factors into consideration.]]> Thu 03 Feb 2022 14:52:24 SAST ]]>