Sheep Performance in Managed Caatinga Rangeland Under Different Herbage Allowance.

The objective was to evaluate the effect of different herbage allowance (2.0; 2.5; 3.0 and 3.5 kg of dry matter per kg of body weight) under the slaughter body weight (SBW), empty body weight (EBW) and carcass weight (CW) of lambs in managed Caatinga rangeland, Serra Talhada, Brazil The study area was mainly composed of ‘corrente’ grass [Urochloa mosambicensis (Hack.) Dandy], buffel grass (Cenchrus ciliares L.), ‘mororó’[Bauhinia cheilantha (Bong.) Steud.], ‘aroeira’ (Myracrodruon urundeuva Fr. All.), ‘capa-bode’ (Melochia tomentosa L.), and ‘feijão-bravo’ (Capparis flexuosa L.). It was used 24 male sheep with initial live weight of 23 kg under continuous stocking, during 39 days. The design was a randomized complete block. Treatments (herbage allowance) were allocated in 12 paddocks of 584 m² each.  The animals were slaughtered  and carcasses were stored in a cold room at 4º C for 24 hours and weighted. The SBW, EBW, and CW showed quadratic effect (P<0.05) on different herbage allowance, peaking at 2.61 kg of DM/kg of BW(y=–19.36+34.39x–6.58x², R²=0.64), which generated 25.56 kg of SBW. The EBW mean was of 18.97 kg with herbage allowance 2.60 kg of DM/kg of BW(y=–17.98+28.52x–5.50x², R²=0.75). With herbage allowance of 2.59 kg of DM/kg of BW(y=–9.12+15.13x–2.96x², R²=0.68) the CW mean was 10.22 kg. This indicates that not always a greater forage supply will result in greater weight gain. Undergrazing may decrease forage nutritional value and animal performance as a result. Herbage allowance of 2.60 kg of DM/kg of BW provides better results for SBW, EBW, and CW of lambs in managed Caatinga rangeland.