RESUMEN
A study was conducted on 50 steers (183 ± 4 kg initial body weight, 3 years of age) to assess effects of days in feedlot on performance, carcass characteristics and meat quality of Tanzania shorthorn zebu (TSZ) cattle with the aim of determining appropriate finishing period. Periods were 0 day (P0), 25 days (P25), 50 days (P50), 75 days (P75) and 100 days (P100) with 10 animals per period. Steers were housed in individual pens, fed with a concentrate diet and hay on an ad libitum basis except the P0 group which was slaughtered at the beginning of trial. Long stay in feedlot, P100, increased concentrate dry matter intake by 2 kg DM/day over short stay, P25. Final weight and total gain increased (P < 0.05) from P25 (22.6 kg) to P100 steers (95.4 kg). Periods had no influence (P > 0.05) on an average daily gain (ADG) and feed conversion ratio (FCR) but affected carcass characteristics. Empty body weight (EBW) and hot carcass weight (HCW) increased by 61 and 65 %, respectively, from no feedlot, P0 to P100. Dressing percentage was high (P < 0.05) for P100 steers. Carcass measurements, internal fat, fat thickness and carcass total fat were the highest (P < 0.05) on P100 steers and the lowest on P0 steers. Rate of pH decline increased with days in feedlot, while cooking loss and shear force values decreased in advanced ageing time. Feedlot periods of 75 and 100 days resulted into high intake, carcass measurements and tenderness, but 100 days further increased carcass fatness and fat thickness levels, thus, with this particular feeding system and animal's condition, 75 days is the recommended period to finish TSZ cattle in feedlots.