Dairy heifer and bermudagrass pasture responses to rotational and continuous stocking

During 1990 and 1991, pastures of 'Callie' bermudagrass [Cynodon dactylon (L.) Pers.] located near Gainesville, FL (29 degrees 60' N latitude) were used to determine the effects of three grazing methods on performance of 250-kg Holstein heifers (Bos taurus) and forage nutritive value and botanical composition. The grazing methods were rotational stocking (15 paddocks) with short grazing periods (1.5 to 2.5 d/paddock), rotational stocking (three paddocks) with long grazing periods (10 to 14 d/paddock), and continuous stocking. Average daily gain across years did not differ among methods (.50 +/- .04 kg), partially because average in vitro digestible OM concentration of herbage varied little (558 +/- 12 g/kg of OM). Across years, rotational stocking with short grazing periods had a greater average stocking rate (3520 kg of liveweight/ha per d) than did rotational stocking with long grazing periods (2980 kg/ha per d), but no differences occurred in heifer gain among the three grazing methods (697 +/- 30 kg/ha). Under the conditions of our 2-yr study, effect of grazing method on heifer performance was slight, but the potential for long-term differences exists because 'Callie' stand longevity is greater under rotational stocking.