Surgical castration and immunocastration improve cuts yield of high market value from animals crossbred Aberdeen Angus x Nellore
This trial aimed to evaluate the effect of castration methods (surgical or immunological) on percentage of main cuts from hindquarter of beef cattle raised in pasture. Thirty animals ½ Angus x ½ Nellore with 233.0 ± 38.2 kg of initial BW and 8 mo of age were fed in pasture of Brachiaria brizantha cv Marandu receiving 3 g/kg BW/day of proteic-energetic supplement (25% crude protein and 60% of total digestible nutrients). Animals were supplemented for 356 days (20 days for adaptation and 336 days of experimental period (07/21/2011 - 07/11/2012). The treatments comprised 10 replicates: non-castrated animals (NC); surgical castrated (SC) and immunocastrated (IC). The surgical castration was realized on last day of adaptation period and the immunocastration was realized with Bopriva® (anti-GnRH) being applied on the first day, 84 and 237 days after beginning of the experiment. The animals were slaughtered and all carcasses were chilled at 0°C for 24 h. After slaughter were recorded the carcass weight (CW; hot and cold) and carcass shrink loss (CSL). Cuts from left carcass (Rib Eye, Striploin Back Chain, Rump Heart, RumpCap e Tenrderloin Chain) were removed and weighed. These cuts are considered of high market value in Brazil. Data were analyzed (randomly design) by the MIXED procedure of SAS and the Fisher test used considering 10% probability. Animals NC had greater final hot CW (281.8 kg; P < 0.001) and cold CW (278.3 kg; P < 0.001) than those animals SC and IC. However, the castration methods did not affect the hot and cold DP (P > 0.10). Animals NC had higher CSL (1.26%; P = 0.024) than those animals SC (0.76%) and IC (0.87%). Animals castrated showed greater hindquarter yield (47.8%; P = 0.003) than animals NC (46.3%). The total weight (sum of all cuts evaluated) in relation the total weight of hindquarter was not affect by castration methods (P > 0.10). However, when these sum of all cuts were realized in relation to cold CW had greater percentage these cuts of hindquarter from both animals castrated than animals NC (P= 0.049). A greater commercial cuts yield from hindquarter in the carcass is profitable in a beef cattle market. The castration methods evaluated in the animals produces carcass with greater commercial cuts yield from hindquarter in relation to cold carcass weight.
Keywords: anti-GnRH, commercial cuts, yield carcass