Allometric Growth Coefficients and Partitioning of Fat Depots in Indigenous Ethiopian Menz and Horro Sheep Breeds

A total of 146 Menz and Horro lambs of both sexes were serially slaughtered and dissected at 5 different stages of growth (i.e. at 1, 3, 6, 9 and 12 months of age) to define the pattern of growth and partitioning of fat among body depots of indigenous Ethiopian Menz and Horro sheep breeds. The GLM procedure of SAS and an allometric growth equation were used to assess the effects of various factors on the growth of body depots and to estimate rates of growth relative to Total Body Fat (TBF) and Empty Body Weight (EBW), respectively. Results obtained showed that the growth of carcass fat (CF), Non-Carcass Fat (NCF) and Tail Fat (TF) are significantly affected by the genotype (P<0.0001) and stage of growth (P<0.0001) of lambs. Except for CF growth of both NCF and TF were also significantly affected (P<0.001 and P<0.05, respectively) by the sex of the lamb and the season in which lambs were born. Menz sheep deposited more fat into CF and less in NCF depots as compared with Horro sheep. Females of both breeds tended to deposit more fat intra-abdominally than male lambs. In both breeds, the highest allometric growth coefficient obtained for TF and the lowest for NCF indicate that the former is a late developing while the later is an early maturing depot fat.