Estimates of genetic parameters for visual scores and their correlation with production and reproductive traits in Brahman cattle

Abstract

-The objective of this study was to evaluate the association of visual scores of body structure, precocity and muscularity with production (body weight at 18 months and average daily gain) and reproductive (scrotal circumference) traits in Brahman cattle in order to determine the possible use of these scores as selection criteria to improve carcass quality.Covariance components were estimated by the restricted maximum likelihood method using an animal model that included contemporary group as fixed effect. A total of 1,116 observations of body structure, precocity and muscularity were used.Heritability was 0.39, 043 and 0.40 for body structure, precocity and muscularity, respectively. The genetic correlations were 0.79 between body structure and precocity, 0.87 between body structure and muscularity, and 0.91 between precocity and muscularity. The genetic correlations between visual scores and body weight at 18 months were positive (0.77, 0.57 and 0.59 for body structure, precocity and muscularity, respectively). Similar genetic correlations were observed between average daily gain and visual scores (0.60, 0.57 and 0.48, respectively), whereas the genetic correlations between scrotal circumference and these scores were low (0.13, 0.02, and 0.13). The results indicate that visual scores can be used as selection criteria in Brahman breeding programs. Favorable correlated responses should be seen in average daily gain and body weight at 18 months. However, no correlated response is expected for scrotal circumference.

Inclusion of genomic information in estimation of genetic parameters for body weights and visual scores in Nelore cattle

“…Direct selection for yearling visual score traits may promote indirect selection for BW, such that visual scores would be an indicator of the animal's biotype. These results are consistent with the results reported in the literature (Bertipaglia et al (2012), with genetic correlation results of 0.77, 0.75, and 0.58 for BS, FP, and MS, with BW at 18 months of age, respectively; and Paterno et al (2017)).…”

Modelos De Regressão Aleatória Para Característica De Crescimento Em Bovinos Da Raça Guzerá

“…Essas características são de fácil mensuração e apresentam herdabilidade de moderada a alta magnitude e, portanto, são amplamente utilizadas como critérios de seleção, resultando em maior progresso genético (1,2) . No entanto, algumas características como tamanho corporal ou de crescimento, quando avaliadas no mesmo indivíduo em várias idades, comumente apresentam medidas chamadas de longitudinais (3,4) .…”

Estimates of genetic parameters for growth traits in Brahman cattle using random regression and multitrait models1

“…These results are lower when compared with studies for weights with Nellore with RRM (0.12 to 0.22) and MTM (0.11 to 0.25; Nobre et al, 2003). However, similar estimates (from 0.32 to 0.43) were found with MTM in Brazilian Brahmans (Faria et al, 2011), and in a study of the same population in a bivariate analysis (Bertipaglia et al, 2012), lower estimates for BW at 550 d of age (0.48) were obtained.…”

“…Beef cattle breeding programs have generally selected for growth traits such as weight or weight gain at certain ages. These traits are easy to measure, have medium to high heritability, and respond well to selection, thereby resulting in genetic progress (Bertipaglia et al, 2012;Boligon et al, 2009). For genetic analyses, weights at different ages are widely used, particularly in traditional multitrait models (MTM).…”