PERFORMANCE AND CARCASS TRAITS OF DOCKED AND INTACT FAT-TAILED NAJDI LAMBS

Twelve intact and 12 docked Najdi lambs of equal numbers of males and females were utilized in the experiment. All lambs were raised under similar conditions until they attained 40 kg shorn and shrunk body weight. Thereafter, lambs were individually fed ad libitum on a diet formulated to contain 11.20 MJ ME/kg and slaughtered after 60 days feeding period. The results showed that Najdi rams averaged 6.14 kg more total gain (p < .05), required 6.80 kg less feed (p < .05) per kg of gain and produced 3.2 and 3.07 kg more (p < .05) carcass and salable cuts weights over the feeding period than comparable ewes. Body wall thickness and kidney and pelvic fat weight were greater (p < .05) for ewes than for rams; dressing percent, longissimus area and fat thickness were not significantly influenced by sex of lambs. Docked lambs kept for 60 days on feed required 1.80 kg less feed (p < .05) per kg of gain and produced 2.21 kg more (p < .05) salable wholesale cuts weight than intact lambs. Docking was not a significant source of variation for total gain, carcass weight, dressing percent, longissimus dorsi area, body wall thickness and fat thickness.