Residual Feed Intake and Rumen Metabolism in Growing Pelibuey Sheep

SIMPLE SUMMARY: This study determined residual feed intake (RFI), volatile fatty acid (VFA) production and enteric methane (CH(4)) from growing Pelibuey sheep. In this case, 12 non-castrated Pelibuey were classified as low, medium, and high RFI. Efficient lambs (low-RFI) had lower intakes of dry matter, organic matter, crude protein and neutral detergent fiber. Those lambs produced less CH(4). Feed intake of low RFI lambs was approximately 16% lower (p < 0.05) while growth rate was not significantly different. Their average energy loss, expressed as CH(4) production per kilogram of metabolic weight, was 17% lower (p < 0.05). ABSTRACT: This study was carried out to evaluate the residual feed intake (RFI), volatile fatty acid (VFA) production and enteric methane (CH(4)) from growing Pelibuey sheep. In this case, 12 non-castrated Pelibuey with an initial average live weight (LW) of 21.17 ± 3.87 kg and an age of 3 months, were housed in individual pens and fed a basal diet with 16% of crude protein and 11 MJ ME for 45 days. Dry matter intake (DMI) was measured and the daily weight gain (DWG) was calculated using a linear regression between the LW and experimental period. Mean metabolic live weight (LW(0.75)) was calculated. RFI was determined by linear regression with DWG and LW(0.75) as independent variables. Lambs were classified as low, medium, and high RFI. Feed efficiency was determined as DWG/DMI. For determining rumen pH, ammonia nitrogen concentration NH(3)-N)(,) and VFA, ruminal fluid was obtained using an esophageal probe on day 40. Feed intake of low RFI lambs was approximately 16% lower (p < 0.05) while growth rate was not significantly different. Their average energy loss, expressed as CH(4) production per kilogram of metabolic weight, was 17% lower (p < 0.05).