Resumen

HERNANDEZ-BAUTISTA, J et al. Yield of carcass and non-meat components of brown swiss x zebu bullocks in the three feeding systems in a humid tropical climate. Universidad y ciencia [online]. 2009, vol.25, n.2, pp.173-180. ISSN 0186-2979.

A high production of crossbreed Brown Swiss x Zebu bullocks exists in the damp tropical regions of Mexico, and in spite of its economic importance, there is little information on the characteristics and yield of the carcasses obtained. The purpose of this study was to evaluate the yield of the carcass and non meat components of the bullocks reared in three feeding systems in a damp tropical climate. Thirty one bovines were used: 11 under extensive grazing (PE), 10 under grazing + a complement (PS) and 10 in a dry feed-lot (EC). Measured variables were live weight (PV), empty body weight (PVC), carcass yield (RC), consumable and non consumable body components yield, gastrointestinal tract content (CGI), dorsal fat thickness (EGD) and marbling. PV was similar in all rearing systems (419.4, 423.6, 414.4 kg for PE, PS and EC, respectively). The bullocks reared in EC were younger (P < 0.05), had more EGD (4.2 mm; P < 0.05), a greater PVC (90.9%; P < 0.05) and a lower CGI (9.04%; P < 0.05). Carcasses did not present marbling (P < 0.05) in the three feeding systems (P > 0.05). The bullocks reared in EC presented the greatest percentages of skin, feet and respiratory tract (9.5, 2.4 and 1.4 %, respectively). It can be concluded that producing bullocks in EC improves their carcass characteristics and increases the thickness of dorsal fat. The feeding system affected the gastrointestinal tract weight and the carcass yield, but not the non meat components yield.

Palabras llave : Tropical climate; yield of components; feeding system.