Polymorphisms of RDH16 and VEGFR1 influence M. trapezius steatosis in Japanese Black carcass

The exact cause of steatosis, one of defects in Japanese beef carcasses, has not been elucidated to date, because it is very difficult to diagnose cyclopedically with certain reproducibility due to the bias in the outbreak. Therefore, the objective of this study was to assess the influence of polymorphisms in retinol dehydrogenase 16 (RDH16), myoferlin (MYOF) and vascular endothelial growth factor receptors 1 and 2 (VEGFR1, VEGFR2) on carcass-graded Musculus trapezius steatosis. For logistic regression analysis, 646 carcasses shipped from 29 farms in Miyazaki, Japan, were used. The GG genotype in RDH16 showed significant odds ratios against AA and AG. In VEGFR1, CT had a significant odds ratio against CC. After evaluating for interaction, highly significant odds ratios were observed in the combinations that included the GG risk genotype in RDH16. It is noteworthy that there was no steatosis in the combination GG (RDH16) and CC (VEGFR1). It may be concluded that there is a possibility that steatosis can be suppressed by the CC genotype in VEGFR1. The current study revealed the influence of genetic polymorphisms on M. trapezius steatosis that had not been reported until now, and may help elucidate the cause of steatosis.

Estimation of genetic parameters for carcass defects of Japanese Black cattle in Kagoshima

Cattle exhibit a range of carcass defects, including blood splash (BLS), intramuscular edema (INE), muscle steatosis (MUS), bruising (BR), trim loss (TRL) and others (OTH). These defects lower the carcass value and can result in significant economic loss to producers. We estimated the incidence, relationship with inbreeding coefficients and genetic parameters of carcass defects in Japanese Black cattle using 561 619 carcass records from Kagoshima, Japan during April 1988 through March 2011. The defect incidence ranged from 0.22% for TRL to 5.73% for BR. The incidence of MUS and BR increased from 1.21% to 6.57% and from 1.06% to 9.31%, respectively. The incidence of INE peaked at 7.44% in 1999 and decreased thereafter. We observed a positive linear relationship between the defect incidence and the inbreeding coefficients in MUS, BR and TRL (P < 0.01). The heritabilities estimated by univariate animal model with Gibbs sampling for BLS, INE, MUS, BR and TRL were 0.24, 0.06, 0.18, 0.05 and 0.02, respectively. The contribution of farm variance to phenotypic variance was negligible (0.01 to 0.04). Significant genetic correlations of TRL were estimated with MUS (0.63) and BR (0.63). Our results suggest that genetic factors contribute to the incidence of BLS and MUS.