The use of urea dilution technique for estimating in vivo body composition of two breeds of fat tailed sheep

Abstract

Two breeds (Kordi and Balouchi) male lambs were used to evaluate urea space (US), an estimator of carcass composition, in a separate experiment. Urea space was measured 12 min after the infusion of 20% urea (130 mg urea/kg live weight (LW)). Lambs were slaughtered after urea dilution and carcass weight taken. After chilling overnight, the left side of each carcass was physically dissected into bone, tail fat and total meat. US was related to the percentage of carcass fat through the equations, 52.91- 0.52US (P<0.0001) and 57.99 - 0.41US (P< 0.001) for Kordian and Balouchian breeds, respectively. A negative correlation was obtained between US and tail fat, total fat (percentage or kg), live weight and omental fat in both breeds (P<0.05). A positive correlation (P<0.01) was estimated between fat thickness over the 12th rib and total fat in Kordian sheep but not in Balouchian sheep (P>0.05). It is concluded that urea space measurement may be used as a practical estimator of body composition assessed in vivo in fat tailed sheep.