Abstract

The association between residual feed intake (RFI) and growth, carcass and meat quality traits were investigated using 233 Hereford steers. Individual feed intake, body liveweight, average daily gain and ultrasound measurements were recorded during 70-d post-weaning period to calculate RFI. Steers were categorized into high efficient (<0.5 SD below the RFI mean; 72), medium (mid ± 0.5 SD; 85), and low efficient steers (>0.5 SD above the RFI mean; 76). After the feed intake test, steers grazed on sorghum pasture and oat with corn supplementation during summer and autumn and winter, respectively, until achieving the slaughter weight (with back fat thickness 6.35 mm). During the finishing phase, the efficient steers had some lighter weights (P<0.05) at the start of finishing but achieved the same slaughter weight (P<0.001). Average daily gains during finishing were similar among efficiency groups. No differences were found among groups on ultrasound measures except a slight difference on UBFAT at pre-slaughter between medium and lower efficient (P=0.009). No differences were found among RFI groups for any carcass or meat quality traits. Phenotypic correlations with RFI were close to zero for all traits. These results suggest that increasing feed efficiency by RFI does not lead to unfavorable effect on finishing performance, carcass and meat quality. Larger dataset will allow the estimation of genetic correlation among these traits and the prediction of genetic correlated responses. Keywords: Residual feed intake, beef cattle, growth, tenderness

Maria Isabel Pravia, Elly Ana Navajas, Fernando Macedo, Juan Clariget, Santiago Luzardo

Proceedings of the World Congress on Genetics Applied to Livestock Production, Volume Electronic Poster Session - Biology - Feed Intake and Efficiency 1, , 604, 2018
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