Table 5.
Methane production rate (MPR), methane yield (MY), methane produced/digested organic matter (MDOM), methane conversion factor (Ym) and rumen kinetics (mean retention time (MRT) (h) (liquid and solid phase)) of Boran steers fed a ration consisting mainly of Rhodes grass hay offered at either 0·4, 0·6, 0·8 or 1·0 times calculated maintenance energy requirements (MER) measured during a 21-d feeding period following a 14-d adaptation period
(Mean values and pooled standard errors)
| Enteric CH4 | 1·0 MER | 0·8 MER | 0·6 MER | 0·4 MER | Pooled sem | P |
|---|---|---|---|---|---|---|
| MPR (g CH4/d) | 133·3a | 114·6b | 94·4c | 65·0d | 3·55 | <0·0001 |
| MY (g CH4/kg DM intake) | 29·0a | 29·9ab | 31·2b | 31·2b | 0·81 | <0·001 |
| MDOM (g CH4/kg DOM) | 48·5a | 50·6ab | 51·8bc | 53·4c | 1·33 | <0·001 |
| Ym (CH4 (MJ)/GEI (MJ)) | 9·14a | 9·72b | 9·74b | 10·06c | 0·225 | <0·001 |
| Rumen kinetics | ||||||
| MRT liquid (h) | 19·10a | 23·28b | 25·60b | 26·19b | 1·292 | <0·005 |
| MRT solid (h) | 59·36a | 72·05b | 73·56b | 78·86b | 3·882 | <0·001 |
GEI, gross energy intake.
a,b,c,d Mean values within a row with unlike superscript letters were significantly different (P < 0·05).