Efeitos de ambientes sombreados e a pleno sol na terminação de novilhos nelore em regime de confinamento na região semiárida

Abstract

The objective was to evaluate the effect of different shading strategies on consumption, digestibility of nutrients, nutritional efficiency, ingestive behavior, respiratory frequency and performance of Nellore cattle confined in the finishing phase. Two hundred and twenty-five Nelore post-weaning, non-castrated cattle, with average body weight (BW) of 293.58 ± 19 kg and age of 24 ± months were used to evaluate two corral shading strategies, artificial shade and natural shade, besides the control that was without shading, following a completely randomized design. There was a difference between shading strategies on air temperature (P= 0.02), black globe temperature (P <0.01) and radiant thermal load (P <0.01) in the management corrals, with the averages being in the corral without shading (Sun) 3.63%, 44.07% and 4.10% higher than the corral with natural shade, respectively. The dry matter consumption of animals kept in a corral with natural shading was 14.76% higher compared to animals without shading (7.39 kg DM / day). The longest feeding time (P = 0.02) was observed in animals with artificial shading (2.25 h / day). There was higher (P = 0.05) final body weight (451, 30 kg) and average daily gain (1.55 kg / day) (P = 0.02) in the animals kept in a corral with natural shading. There was no difference in feed efficiency and hot carcass weight, with an average of 0.184 kg / kg DM and 250.36 kg. Natural shading is recommended for Nellore cattle finished in feedlots in the semiarid region of Brazil.