Abstract
Carcass characteristics and carcass class were compared in 24 entire male (ram) and 14 female (ewe) Suffolk lambs. Lambs were fed concentrate and hay in confinement, and slaughtered at 18 weeks of age. The means (±s. d.) for body weight at slaughter of ram and ewe were 57.2±3.5 and 48.6±3.1 kg, respectively. Carcass class were assessed by the lamb carcass classification of Japan Sheep Breeders Association.
Although cold-carcass weight of ewe were lower than that of ram (24.2±2.5 v. 27.0±2.1 kg; P<0.01), dressing percentage of ram was lower than that of ewe (52.0±1.7 v. 53.6±2.1%; P<0.05). Kidney fat percentage of ewe was higher than that of ram (2.9±0.8 v. 2.0±0.7%; P<0.01), but no significant difference was seen in back fat depth between sexes. Longissimus dorsi area of ram was higher than that of ewe (17.1±1.7 v. 15.5±1.4 cm2; P<0.01).
In the ewe carcasses, 8 out of 14 (57%) were classified into M2, the most desired class in Japan, ranged in carcass weight from 20 to 25 kg and in backfact depth from 4 to 7 mm. Five out of 14 ewe carcasses (36%) were classified into thicker backfat depth class. In contrast with ewe, 4 out of 24 ram carcasses (17%) were classified into M2. Although 13 out of 24 ram carcasses (54%) were classified into desired backfat depth class, 19 out of 24 (79%) were classified into heavier carcass weight class.
