Resumo

JIMENEZ, A; MANRIQUE, C  e  MARTINEZ, C. A. GENETIC PARAMETERS AND VALUES FOR BODY COMPOSITION TRAITS, RIB EYE AREA AND BACK FAT MEASURED BY ULTRASOUND IN BRAHMAN CATTLE. Rev. Med. Vet. Zoot. [online]. 2010, vol.57, n.3, pp.178-190. ISSN 0120-2952.

The Brahman cattle in Colombia is the beef cattle of greater participation as a pure breed and has greater influence over the commercial cattle. Until now Asocebu has done Genetic Evaluations for growth traits, but has not done yet for carcass traits. The objective of this work was to determinate genetic parameters (Heritabilities and correlations) and genetic values (DEP’S) to rib eye area (REA), back fat (BF), gluteus medius muscle depth of gluteus medius muscle (GMMD) and rump fat (RF). Measurements of 934 progenies that were between 15 to 18 months of age of 164 Brahman sires were taken by ultrasound. To perform the analysis was create contemporary groups taking into account (animals of the same sex, same season and same feed managemen). Univariate analysis was performed using a Sire Model taking into account contemporary group (animals of the same sex, same season and same feed management), age as a covariable and the farm effect was included in the model. The estimates of heritabilities were 0.37 ±0.11, 0.29 ±0.10, 0.26 ±0.10 y 0.11 ±0.09 to REA, BF,GMMD and RF respectively. The EPD’S to REA oscillated of -2.84 to 3.43 cm², for BF of -0.372 to 0.235 mm, for GMMD of -0.187 a 0.235 cm and RF of -0.176 a 0.298 mm. The genetic correlations were positives and highs indicating that the genetic selection by musculature does not affect the fat endpoint. This work showed that in Pure Brahman cattle exist genetic variation for the carcass characteristics measures by ultrasound and this will allow include them into Genetic Improvement Program from Asocebú Colombia.

Palavras-chave : Ultrasound; genetic parameters; back fat; loin eye area; beef.

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