Supplementation strategies effects on performance of beef heifers grazing stockpiled pastures
The increased cost of inputs has led livestock producers in the southeastern United States to use alternative management practices to supplement beef cattle (Bos spp.) on pastures. The objective of this study was to evaluate the performance of beef heifers grazing stockpiled limpograss [Hemarthria altissima (Poir.) Stapf & C.E. Hubb.] pastures supplemented with cottonseed meal (CSM, Gossypium spp.) or grazing part-time annual ryegrass (Lolium multiflorum Lam.). The experiment was conducted in Ona, FL, from February to April 2007 and 2008. Twelve 0.5-ha limpograss pastures were stockpiled from October to February. Three heifers were assigned to each pasture. Treatments were three supplementation rates, 0, 1.1, and 2.2 kg head–1 d–1 of CSM, or part-time grazing (PTG; 3 d wk–1) ryegrass. Limpograss herbage mass (HM) was greater in pastures where the heifers part-time grazed ryegrass than in other treatments (2.1 vs.1.8 ± 0.1 Mg ha–1). Limpograss herbage accumulation rate (HAR; 24 ± 3 kg ha–1 d–1), crude protein (CP; 120 ± 10 g kg–1), and in vitro digestible organic matter (IVDOM; 500 ± 10 g kg–1) were similar among treatments. There was no difference in average daily gain (ADG) of heifers PTG ryegrass and supplemented with 2.2 kg CSM d–1 head–1 (0.67 vs. 0.64 kg d–1); however, 2.2 kg of CSM d–1 head–1 provided greater liveweight gain ha–1 (LWG; 291 vs. 188 kg ha–1). The PTG of ryegrass may be a viable supplementation option for beef cattle grazing stockpiled warm-season grasses when concentrate is costly and the annual ryegrass grazing period extended.