USING ULTRASOUND AND BODY MEASUREMENTS FOR PREDICTION OF PHYSICAL AND CHEMICAL COMPOSITION OF CARCASS IN LIVE IRANIAN SHEEP

One of the most efficient ways to reducing carcass fat in ruminants is by means of selection. For this it is necessary to evaluate the physical and chemical components of carcass in live animals. For presentation suitable indexes of selection in live Iranian sheep, the effects of breed, age and sex were studied in 991 sheep of 10 Iranian breeds; Sanjabi, Gezel, Afshari, Mehrabani, Loribakhtiari, Kordi, S ange sari, Baluchi, Lori and Chal. Body weight, height at wither, body length, heart girth hipbone distance and body diagonal length were measured. Soft tissue depth on 12ih rib was determined using ultrasound and hypodermic needle. All animals were slaughtered and dissected in to different joints. Percentages of physical components of carcass (lean meat, subcutaneous and interamuscular fat, fat-tail and bone) were measured. Carcass chemical components (crude protein, ether extract, ash and moisture) were determined. Bartlett's test showed not homogeneous (PO.05) variance among the data. Therefore, the data of each breed analyzed separately. Afshari breed had the highest amounts of lean meat and bone. Loribakhtiari showed higher total amount of fat (including subcutaneous and interamascular fat and fat-tail). Afshari and Gezel breeds had the highest carcass percentage and lean meat, respectively. The highest total fat, fat-tail and subcutaneous and interamuscular fat percentages were seen in Loribakhtiari and Baluchi breeds, respectively. Gezel breed showed lowest carcass total fat, fat-tail and subcutaneous and interamuscular fat percents. Mehrabani breed had the lowest bone percent. Gezel and Sanjabi breeds had the highest moisture and crude protein, respectively. Loribakhtiari and Baluchi breeds showed higher chemical fat percent. Ash percent in Baluchi breed was higher than other breeds. Loribakhtiari, Afshari, Chal, Kordi, Sanjabi, Mehrabani, Baluchi, Lori, Gezel and Sangesari were ranked according their live body weight, respectively. According to high correlation (PO.OOI) in most studied breeds, using different body size measurements for prediction of carcass physical composition was significant (PO.Ol). According to relatively wide standard deviation in most studied breeds; selection in direction of fat depletion is more effective than selection in lean meat direction. In all breeds studied, soft tissue size taken by needle gauge and ultrasound had very high and positive correlation (PO.OOl). As the result ultrasound measurement can substitute by using needle measurement.