Carcass characteristics and meat quality of cull cows from different genetic groups

Abstract

We aimed to evaluate the quality of the carcass and meat of cull cows from different genetic groups. It was considered 48 cows being 16 of the Nellore breed (NEL), 16 ½Angus ½Nellore (ANGNEL), and 16 ½Caracu ½Nellore (CARNEL), slaughtered at the end of eight pregnancy seasons, with approximately 11 years of age. For carcass analysis, body weight at slaughter (SW), hot carcass weight (HCW), carcass yield (CY), carcass finishing (CF), fat distribution (FDIST), cold storage conformation (CSC), marbling (MAR), subcutaneous fat thickness (SFT), ribeye area (REA), internal depth (INTD), external depth (EXTD), carcass length (CL), physiological maturity (FMAT), muscle color (COLOR) and texture (TEXT). For meat analysis, samples taken from the Longissimus muscle were analyzed after zero and 14 days of maturation for exudation losses (ExuL at 0 and 14 days), cooking losses (CookL), pH (pH at 0 and 14 days), color components of meat (L*, a* and b* 0 and 14 days) and shear force (SF at 0 and 14 days), the ether extract (EE) of the samples was also evaluated according to the genetic group of the cull cows. The Means were compared according to the adjusted Tukey-Kramer test (α = 0.05). The data were evaluated for the presence of outliers, homogeneity of variance, and normality of residuals. The effects of genetic groups on the described characteristics were evaluated by restricted maximum likelihood (REML) analysis, adjusting a mixed model containing the effects of cow age, genetic group, and slaughter date. NEL and ANGNEL cows presented higher SFT results when compared to CARNEL cows. The REA, INTD, and EXTD, ANGNEL and CARNEL cows obtained greater results when compared to NEL cows group. There was no significant effect on the genetic group of cull cows for the variables CY, CF, FDIST, CSC, MARM, FMAT, COLOR and TEXT. A significant difference was observed only for the L* characteristic (0 and 14 days of maturation), in which NEL cows presented darker meat than ANGNEL, with CARNEL cows having intermediate results. The ANGNEL cull cows have higher slaughter weights, and carcass weights, and AOL and EGS with better carcass finish. Cull cows slaughtered at an advanced age, between 10 and 11 years old, have similar meat quality. We recommend the meat maturation process for 14 days to improve the tenderness of the meat from cull cows, since in this 14-day meat maturation process, calpains degrade the myofibrillar proteins at certain internal points of the molecules and improve the tenderness of the meat, regardless of the genetic group.