Growth Performance, Carcass Composition and Meat Quality of Jiulong-yak (Bos grunniens)

Abstract

Estimated liveweights, carcass characteristics, the proximate composition and amino-acid composition of the whole rib cut of the 10th/12th thoracic vertebrae have been determined for Jiulong-yak. The animal grows rapidly up to puberty at 2-3 years of age. At those ages, females reached 143.034.7 kg and 184.030.8 kg (SD) respectively, which was 60 to 80% of their mature weight at 6 to 7 yr old, then the rate of growth significantly slowed down. Males continued to rapidly increase body weight until an older age possibly due to the selection procedures. Animals included 20 males aged from 2.5 to 6.5 yr, seven females aged of 4.5 yr and 11 steers aged of 4.5-5.5 yr were slaughtered for carcass determination and chemical analysis of meat samples. Dressing-out percentage and ribeye area ranged from 48.53-55.04% and 48.02-68.56 cm 2 respectively, both of which differed by age and sex. Yak meat is scarlet in color and intramuscular marbling is poor. The 10th/12th rib-cut contained 24.99-31.93% dry matter; 19.98-22.58% protein; 2.52-10.86% fat and 0.93-1.00% ash. Meat from females and steers contained a higher percentage of fat than those from bulls. The pH of M. Longissimus dorsi measured at 24 h post-mortem ranged from 5.84-6.11. Amino acid composition was similar to that for other red meat, except for a lower content of methionine (1.26 g/100 g meat). The results indicated that yak meat can make a valuable contribution to the diets for the highlanders. (