Length of Feeding Periods on Mutton pH and Color of Highland (Arsi-Bale) and Lowland (Black Head Ogaden) Male Sheep of Ethiopia

Abstract

Yearling sheep from highland (Arsi-Bale) and lowland (Black Head Ogaden) areas of Ethiopia were used to determine effects and interactions of breed and length of feeding period on mutton pH and color. Rams were purchased, transported, and handled in accordance with normal practices of abattoirs in Modjo Modern Export Abattoir. 18-20 sheep of each origin were subjected to feeding periods 2, 4, and 6 weeks in length, during which time grass hay was consumed ad libitum and concentrate supplement was provided at approximately 200 g/day per animal (DM basis). Mutton pH and color measurements were made at 45 min (day 0) and 1, 2, and 3 days post-slaughter, with storage at 4°C. The data were analyzed using the GLM of SAS. Average mutton pH of Arsi-Bale rams was similar to Black head Ogaden rams on the same day of post slaughters. Both linear and quadratic length of feeding period had significant influence in mutton pH on day 0, 1, 2, and 3 post slaughters (P < 0.05). Length of feeding periods had greater effect to reduce mutton pH. For both sheep breeds, mutton pH values were lowest among feeding period lengths for 6 weeks. Mutton pH decreased as post slaughter days increased, but considerably decreased between day 0 and 1 post slaughters and then after slightly decreased as post slaughter days increased. The average mutton lightness (L*) was greater (P < 0.05) for Black head Ogaden rams (L*=29.50, 39.68, 40.91 and 42.73) than Arsi-Bale rams (L*=27.89, 35.81, 36.67 and 38.04) on the same day of 0, 1, 2, and 3 day post slaughters, respectively. Mutton a* (as an index of redness) changed with increasing day post-slaughter. The results of this study revealed that mutton darkening of both sheep origins was not detected/ apparent from comparisons of mutton pH and color measures with values reported in different literatures.