Recria de fêmeas de corte para acasalamento aos 18 meses de idade

Abstract

It was evaluated the performance of beef heifers on grazing receiving different levels of supplement: 0,0; 0,3; 0,6 and 0,9% of live weight (LW), in black oats (Avena strigosa Schreb.) plus Italian ryegrass (Lolium multiflorum Lam.) pasture and exclusively in natural pasture engaged by Annoni grass (Eragrostis planna Nees) after the end of the cycle of these forages. On cultivated pasture it was evaluated the botanic composition and the diurnal ingestive behavior of beef heifers. The supplement utilized was a commercial ration (14% CP; 18,8% NDF; 78,2% TDN) daily supplied at 2 pm. The studied variables were the average daily gain (ADG), body condition (BC), stocking rate (SR), weight gain per area (WGA), total forage on offer (TFO), height, live weight:height relation at 12 and 18 month of age and efficiency of transformation of forage in animal product. On the diurnal ingestive behavior were determined: grazing time, rumination, idle, trough permanence, biting rate and bite weight, in four dates. In cultivated pasture the ADG did not differ between animals that received different levels of supplement and it was bigger to supplemented animals. At 12 month of age the BC, SR, WGA, TFO and height of the animals did not differ between the supplement levels. On supplemented animals it was necessary 8.8 kg of DM of grass to produce 1 kg of live weight. The supply of supplement for heifers in grazing of oats and ryegrass interfere in a positive way on life weight, body condition and life weight: height relation of these animals at 18 months of age. The supplement levels affected partially the diurnal ingestive behavior of animals, reducing grazing time, increasing idle time, interfering on trough permanence time, biting rate and bite weight (P<0.05). The rumination time was not affected by supplement levels (P>0.05). The botanic and structural composition of pasture is influenced by supplement levels utilized and it is related with the cycle of forages production (P>0.05).