Performance and carcass characteristics of Nelore and Nelore x Brown Swiss F1 cattle, submitted to different castration managements and confined / Desempenho e caracterÃsticas de carcaÃas de bovinos Nelore e F1 Pardo suiÃo X Nelore, submetidos a diferentes manejos de castraÃÃo e confinados

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

The research was done on the Santo AntÃnio das Granjas Reunidas farm, BocaiÃva, MG and in the FrigorÃfico Mata Boi S.A., Araguari, MG, from July to November of 2004. The animals were fed with the same diet during an experimental period of 103 days, preceded by an adaptation period of 15 days. 20 Nelore and 20 F1 Brown Swiss X Nelore F1 steers were utilized in feedlot and submitted, according to sexual condition, to five management situations (uncastrated, castrated with a knife and castrated with a burdizzo 15 days before the start of the feedlot, castrated with a knife and castrated with a burdizzo at the start of the feedlot). The experimental design utilized was a completely randomized, in a (2 x 5) factorial scheme with four replicates. The objective of the research was to evaluate the effect of different managements, involving different techniques and times of castration, upon the performance and carcass characteristics of cattle of the Nelore breed, and Brown Swiss X Nelore crossbred all confined. The pre-experimental and experimental period (feedlot) lasted 118 days, with weighings performed 15 days before the start of the feedlot, at the start of the feedlot, at 35, 61 and 103 days afterwards, for evaluation of daily average weight gain (GMD). At slaughter, the animals were evaluated as to hot and cold carcass weight (PCQ, PCF), hot carcass yield (RC), carcass length (CC/100kg PCVZ estimated and P/C index), basic cut yields total hindquarter (RTT), special hindquarter (RTE), forequarter (RD) and spare ribs (RPA), pH24, weight lossat cooling (QR%). They were also evaluated as to carcass typifying, according to the ministerial decree number 612 of October/5th/1989. The results obtained were: uncastrated animals obtained greater (P<0.05) GMD and PVF than the castrated ones (1.21 vs. 1.04, 0.95, 0.95, 1.04kg and 502.00 vs. 472.50, 479.00, 470.00, 486.00kg), respectively. The F1 was superior (P<0.05) by 18% in the GMD relative to Nelore (1.12 vs. 0.95kg) and inferior (P<0.05) in the RTE (47.47% vs. 48.49%). Uncastrated animals were inferior (P<0.05) in the RTT relative to the castrated ones (58.89% vs. 60.43%, 60.31%, 60.92%, 60.64%). The RC, CC/100kgPCVZestimated, QR% and pH24 were similar (P>0,05) in all the management situations and for the two genetic groups. The castration methods did not influence any variables (P>0.05). The castration time influenced (P<0.05) the PCQ of the animals castrated at 15 days before the start of the feedlot At typifying, all the castrated animals were classified as Type B and the uncastrated ones as Type I, and the sexual condition (uncastrated) was the determining factor for the non-classification as Type B, except for the three animals in the burdizzo-castrated management at the start of the feedlot, which were taken for uncastrated ones.

ASSUNTO(S)

performance confinement carcass nelore nelore carcaÃa castration castraÃÃo zootecnia brown swiss pardo suiÃo confinamento desempenho

ACESSO AO ARTIGO

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