Relationships of fat-tail dimensions with fat-tail weight and carcass characteristics at different slaughter weights of Torki-Ghashghaii sheep.

The purpose of this research was to investigate the relationship between fat-tail and carcass attributes in Torki-Ghashghaii sheep. Thirty ram lambs belonging to six weight groups (weighing from 25 to 50kg) were used. Fat-tail measurements were recorded on the live animals before slaughter. Hot and cold (after 24h in the cold room) carcass weights, and the weights of the tail and internal organs were recorded. The carcass was dissected into conventional cuts. Each cut was de-boned and the physically separable fat was removed from the meat. The bone, physical fat and trimmed meat were weighed separately. The weight of trimmed meat as a percentage of slaughter weight did not change significantly from 25 to 50kg live weights (23.4-25.3%). The weights of physically separated fat and the fat-tail as a percentage of live weight varied from 6.6% to 15.5% for various weight groups. The correlation coefficients between the tail weight and dimensions were large, positive, and significant. The highest correlation coefficient was found between the tail weight and upper circumference (r=0.88), and the lowest one was found between the tail weight and upper thickness (r=0.61). The upper and lower circumferences of the tail accounted for 85% of the total variation in the tail weight. The tail weight was positively correlated with the meat chemically determined fat (ether extract; r=0.43; P<0.05) and with the total body fat (r=0.70; P<0.01). Further studies are needed to see whether inclusion of fat-tail measurements in breeding programs would result in a decrease in body fat in this breed.