Effect of docking and energy of diet on carcass fat characteristics in fat-tailed Badghisian sheep

Abstract

Effects of docking on carcass fat characteristics were studied in fat-tailed sheep. Male lambs were randomly divided into two groups. One group docked 3–4 h after birth, using rubber rings and the tails of other left intact (control). After weaning, 20 lambs from each group were divided into two subgroups, one subgroup was fed with a normal-energy diet (2.45 Mcal/kg ME) and the other one with a high-energy diet (2.73 Mcal/kg ME) for 84 days. Lambs were fed individually. At the end of the fattening period, 28 lambs were slaughtered for determination of carcass characteristics. Warm carcass weight (WCW) and fat depth at 12th rib was recorded. At 24 h postmortem samples of meat, omental fat and caudal fat were taken from chilled (4 °C) carcasses for the assessment of fatty acid (FA) composition. No significant difference was observed for WCW and omental fat between carcasses of docking and control lambs or lambs on two types of energy diets ( P > 0.05). Under these circumstances, docked lambs produced leaner carcass than intact lambs ( P < 0.05). Carcass fragments and fat depth at 12th rib, showed significant difference between carcasses of docking and control lambs ( P < 0.05). Energy of diets can effect on vertebral column plus longissmus dorsi muscle weight significantly ( P < 0.05). Results showed that the predominant FA in body fat of lambs was oleic acid but no significant difference was observed for percentage of FA composition between treatments ( P > 0.05). The correlation coefficients among the FA showed strong negative correlation (−0.929) between stearic and oleic acids ( P < 0.001).