Effect of age on feed efficiency and carcass yield characteristics of indigenous bull

The study was conducted with the objectives to understand the effect of age of native Pabna bulls on feed conversion ratio (FCR), digestibility and carcass yield characteristics. Fifteen Pabna bulls having five in each age groups of 6 to12, 13 to 24 and 25 to 36 months were fed ad libitum mix silages of Splendida (Setaria splendida) and Andrpogan (Andropogon gyunus) grasses (1:1 fresh) and supplemented with a concentrate mixture at 1% of live weight (LW) for a period of 72 days. With the increase of age, and subsequently LW (initial LW: 98.2, 182.6 and 288 kg, respectively), there was significant decrease in dry matter (DM) intake as % LW (<0.05; 2.94, 2.61 and 2.36, respectively) and increased daily gain (<0.01; 294, 519 and 597 g/d, respectively). However, the feed conversion ratio (FCR) (>0.05; 10.88, 10.10 and 12.24, respectively) and DM digestibility (>0.05; 51.0, 48.1 and 49.1 %, respectively) of bulls were remained unchanged. In case of carcass yield characteristics, significantly lower yield grade (<0.01; 1.79, 1.27 and 0.20, respectively) of bulls of 25 to 36 years produced higher closely trimmed boneless retail cuts (CTBRC) (<0.01; 50.47, 51.64 and 54.14 %, respectively), retail cut (<0.01; 76.14, 78.55 and 83.48 %, respectively) and meat quality index (MQI) (<0.01; 67.28, 67.89 and 69.07, respectively) compared to younger bulls. It may, therefore, be recommended that beef cattle farming with native Pabna bulls of 24 to 36 months will give more daily LW gain and produce more CTBRC at a similar FCR compared to younger ones. Bang. J. Anim. Sci. 2017. 46 (1): 17-23