Abstract

Yearling goats (G) and sheep (S) from highland (H) and lowland (L) areas of Ethiopia were used to determine effects of species and origin and lengths of rest and feeding on harvest measures, particularly carcass surface lightness. The H goat used was Arsi-Bale, and the L goat was Somali. The fat-tail indigenous H sheep is thought to be an Arsi-Bale genotype, and the fat-rump indigenous L sheep genotype was the Black Head Ogaden. There were two experiments (each a 2 × 2 × 3 factorial), one with rest for 0, 1 and 2 days before slaughter (R0, R1 and R2, respectively) and the second with feeding 0, 2, and 4 weeks (0 week= 2 days rest; 0F, 2F, and 4F, respectively). There were 10 animals per treatment. In the rest experiment, the instrumental color measure L* (indicating lightness) for the hind leg surface 3 day post-slaughter was lower (P<0.05) for H than for L (34.8, 36.3, 37.4 and 38.9 for G-H, G-L, S-H and S-L, respectively). Surface L* on day 3 was increased (P < 0.05) by 1 and 2 days of rest compared with 0 day for goats regardless of origin, but was not affected for sheep (33.2, 36.3, 37.2, 38.5, 37.8, and 38.2 for G-R0, G-R1, G-R2, S-R0, S-R1 and S-R2, respectively). In the feeding experiment, surface L* on day 3 was lower (P < 0.05) for H than for L (36.5, 39.0, 36.2 and 39.8 for G-H, G-L, S-H and S-L, respectively). Feeding for 4 weeks increased (P<0.05) surface L* on day 3 regardless of species and origin (37.7, 36.8 and 39.2 for F0, F2 and F4, respectively). In summary, goat and sheep carcasses from highland areas of Ethiopia may darken more quickly compared with lowland areas, and 1 or 2 days of rest before slaughter can increase lightness of the surface of goat carcasses.

Key words: Goats, sheep, carcass, slaughter, shelf-life, meat darkening, management.