Utilization Of Different Body Measurment Of Two Iranian Sheep Breeds (Moghanie and Makuie) For Predicting Physical And Chemical Composition Of Carcass

Use of selecnon in breeding flocks id possibly one of the most efficient way to reduce the carcass fat content of ruminants. For this purpose,firstly it is necessary to assess the physical and chemical constituents of live animal and their interaction with breed and sex, an experiment was carried out in may 1994 ,at Animal Husbandry Research Institute, Karaj,lran. Two different sheep breeds of northwest of the country Moghani and Makoui,were studied. The depth of soft tissues over 12th rib,13 cm from the dorsal midline of the live animals (including 200 male and female lambs 12( +1) months) were measured by two different methods. 1- Using the ultrasonic instrument(pie Medical scanner - 480 - VET). 2- Using the hypodennic Needle (22 - gauge). The height at wither ,body length,heal1 gil1h,linear measurement ,hip - bones distance ,and body diagonal lenght ,were measured. Then all the animals were killed, carcasses cut into joints and dissected. The percentage o/physical constituents of carcass (ie, Lean meat, subcutaneous fat, intramascular fat, fat-tail) and chemical composition of tissues (ie, percentage of protein, fat, ash and humidity) were measures. In conclusion, the breed and sex of the animals have a significant effect on physical constituents (PO.Ol) but they have no significant effect on the percentage of chemical composition of carcass (P0.05). Empty body weightlive »reight, heart gil1h, height at wither were significantly associated with lean meat and total fat content of carcass (PO.Ol). A highly significant association exist between the depth of soft tissues over 12 th rib on the dorsal midline of live animal measured by both of the methods shouled it is possible to replace the ultrasonic by the needle method (r 0.05) For prediction of the physical constituents of carcass, the linear equations were establis ed by using the soft tissues depth over 12 th rib, empty baby weigth, height at wither and distance between the pin - bones. The coefficient of determination here of were considerable and significant (P0.C1). According to the calculated phenotypic, a 3 percent of genetic progress for reduced fat content of carcass is predicted in each generation.