Forage Characteristics and Animal Performance of Beef Heifers Grazing ‘Mulato' (Brachiaria sp.) in North-Central Florida.

‘Mulato’ (Brachiaria sp.; ML) is the first hybrid of the Brachiaria genus and may have potential for use as an annual warm-season grass in north-central Florida.  This study determined forage production, nutritive value, and animal performance of beef heifers grazing ML, pearl millet (Pennisetum glaucum cv. ‘Tifleaf 3’; PM), or sorghum-sudangrass (Sorghum bicolor cv. ‘Hay Day’; SS) pastures.  The study was conducted in Marianna, FL, (30.7°N) from June to August 2008 in a completely randomized design with three replicates.  Pastures (0.6 ha) were sampled to determine herbage mass (HM), crude protein, and in vitro organic matter digestion (IVOMD) every 14 d.  Exclusion cages were used to measure herbage accumulation. Pastures were continuously stocked using a variable stocking rate with two testers per pasture [heifers; 450 ± 20 kg initial body weight (BW)].  Additional animals were added to maintain herbage allowance of approximately 1 kg DM kg^-1 BW.  Average HM was greater (P = 0.05) for PM (1940 ± 130 kg ha^-1) than SS or ML (1600 and 1450 ± 130 kg ha^-1, respectively). Herbage accumulation was greater (P = 0.03) for PM (170 ± 20 kg DM ha^-1 d^-1) than for SS (110 ± 20 kg DM ha^-1 d^-1), whereas that of ML was intermediate (130 ± 20 kg DM ha^-1 d^-1).  Crude protein concentration (162 ± 11 g kg^-1) and IVOMD (621 ± 16 g kg^-1) were not different (P = 0.10) among forages.  Average daily gain and gain ha^-1 were greater (P < 0.01) for heifers grazing SS pastures (0.7 kg d^-1; 240 kg ha^-1) than those on PM pastures (0.4 kg d^-1; 124 kg ha^-1).  Mulato pastures had intermediate ADG and gain ha^-1 (0.5 kg d^-1; 154 kg ha^-1).  Mulato may be an alternative forage for grazing replacement heifers in north-central Florida.