Seasonal Liveweight Gain Of Beef Cattle On Guineagrass Pastures In The Brazilian Cerrados

The development of forage cultivars suitable for the Brazilian Cerrados should incorporate long-term cattle performance results, ensuring released material be persistent and of high quality. The objective of the study was to evaluate the effect of three guineagrass [Megathyrsus maximus (Jacq.) B. K. Simon & S. W. L. Jacobs] cultivars (Massai, Tamani, and Zuri) on live-weight gain of young Nellore (Bos indicus) bulls under grazing. The trial was performed in Planaltina (Federal District, Brazil) from 2011 to 2013 encompassing dry and rainy seasons. Cattle average daily gain (ADG) in the rainy season differed among cultivars, averaging 0.716, 0.791, and 0.883 kg head(-1) d(-1) for Massai, Tamani, and Zuri, respectively. The ADG was lesser (0.284 kg head(-1) d(-1)) in the dry season with no effects of cultivar. Massai had a similar stocking rate (SR) as Tamani but a greater SR than Zuri in the rainy season (490, 445, and 417 animal unit day ha(-1)), which was influenced by its greater herbage accumulation rate (HAR; 66.8, 41.4 and 42.3 kg DM ha(-1) d(-1), respectively). However, there were no differences among cultivars in liveweight (LW) gain per area (GA 2.28 kg ha(-1) d(-1)). In vitro dry matter digestibility (IVDMD) was lesser for Massai (530 g kg(-1)) compared to Tamani and Zuri (561 and 550 g kg(-1), respectively). Due to above-average nutritive value, Tamani and Zuri provided greater individual cattle performance than Massai, although the GA was similar among all cultivars.