Shirima E.J.M., Mtenga L.A., Kimambo A.E., Laswai G.E., Mgheni D.M., Mkwanda A.T., Lemoringata T.S.
Ministry of Livestock and Fisheries Development, P.O. Box 9152, Dar-es-Salaam, Tanzania; Department of Animal Science and Production, Sokoine University of Agriculture, P.O. Box 3004, Morogoro, Tanzania; Ministry of Home Affairs, P.O. Box 534, Mtwara, Tanzania; Community Research and Development Services, P.O. Box 50 Kibaya-Kiteto, Tanzania
Shirima, E.J.M., Ministry of Livestock and Fisheries Development, P.O. Box 9152, Dar-es-Salaam, Tanzania; Mtenga, L.A., Department of Animal Science and Production, Sokoine University of Agriculture, P.O. Box 3004, Morogoro, Tanzania; Kimambo, A.E., Department of Animal Science and Production, Sokoine University of Agriculture, P.O. Box 3004, Morogoro, Tanzania; Laswai, G.E., Department of Animal Science and Production, Sokoine University of Agriculture, P.O. Box 3004, Morogoro, Tanzania; Mgheni, D.M., Department of Animal Science and Production, Sokoine University of Agriculture, P.O. Box 3004, Morogoro, Tanzania; Mkwanda, A.T., Ministry of Home Affairs, P.O. Box 534, Mtwara, Tanzania; Lemoringata, T.S., Community Research and Development Services, P.O. Box 50 Kibaya-Kiteto, Tanzania
Seventy castrated sheep (wethers) of Tanzanian long fat-tailed strain (21.1 ± 0.6 kg initial body weight, aged 12 months) were used to evaluate growth performance and carcass characteristics under different fattening period in feedlot. The experiment lasted for 84 days and the animals were randomly allocated to seven treatments as 0 (D0), 14 (D14), 28 (D28), 42 (D42), 56 (D56), 70 (D70) and 84 (D84) days to stay in feedlot each with 10 animals per treatment in a completely randomized block design. Animals in D0 (control) were slaughtered immediately after being purchased from livestock keepers. The experimental units (D14, D28, D42, D56, D70 and D84) were provided with ad libitum iso-caloric and iso-nitrogenous diets containing molasses based diet (MBD) and forage hay of Cenchrus ciliaris spp. Data were collected on feed intake, growth rates, slaughter and carcass weights and carcass composition. The total dry matter intake (DMI) increased by almost 31% more for 84 days (D84) treatment as compared to intake observed in the 14 (D14) days treatment. The highest average daily gains and lowest feed conversion ratio were observed at 42 (D42) days treatment. Hot carcass weight (HCW) increased from 6.5 kg to 13.5 kg in control (D0) to 84 days treatment (D84), respectively which was almost 108% weight increment which was also corresponding with an increase in energy intake from 4.6 MJ ME/day to 6.2MJ ME/day. Also, dressing percentage (DP) was highest at 56 (D56) days treatment (47.7%) followed by 42 (D42) days treatment (45.2%). The proportion of carcass joints (as % HCW) of neck, ribs, breast, loin, and chump increased while that of hind leg and shoulder decreased proportionally with increasing days to stay in the feedlot. Similarly, the pooled proportion of lean tissue in the joints showed that hind leg and shoulder were much leaner (64.4% and 60.6% respectively) and less fat deposits (12.9% and 12.5% respectively). The present study revealed that the most appropriate fattening treatment for 12 months old Tanzanian long fat-tailed with MBD was 42 days (D42) for highest daily gain and dressing percentage. Also, it can be concluded that yield of non-carcass components and wholesale cuts respond differently to fattening periods however, 42 days period was almost optimal to most of the parameters used.