Animal Performance with and without Supplements in Mombaça Guinea Grass Pastures during Dry Season

The objectives were to: 1) evaluate the potential of the animal performance on Panicum maximum cv. Mombaça (mombaça guinea grass) pasture during dry season, and 2) determine the effects of protein or protein-energy supplementation on liveweight gain of steers grazing guinea grass pasture. A complete randomized block design was employed with three treatments and three replicates. Treatments included non-supplemented animals (NS) and animals supplemented with protein (PS) or protein-energy (PES), provided at 0.15% or 0.6% of body weight for 115 days, during dry period. We used 36 weaned calves from initial bodyweigh (LW) of 192 kg (±5 kg) on nine plots of mombaça guinea grass (1.25 ha each). Each month, animals were weighed and pastures sampled to estimate forage characteristics. The average daily gain (ADG) was greater (P = 0.0001) for cattle fed supplement than for cattle fed no supplement (250 g steer-1), and greater for protein-energy supplement (770 g steer-1) than for protein supplement (460 g steer-1). Mombaça guinea grass pastures with 45 cm height at the end of the wet season have enough forage mass for maintenance throughout the dry season about 1.4 AU ha-1 (AU = 450 kg BW), and reasonable nutritive value (average of 8,1% of crude protein and 55,3% of in vitro organic matter digestibility) to provide small gains. Considering the nutritive value of Mombaça guinea grass during the dry period, protein and energy supplementation is required for weaned calves to optimize their performance.