Effect of shading strategies on intake, digestibility, respiratory rate, feeding behaviour, and performance of feedlot-finished Nellore bulls in the semi-arid region of Brazil

Abstract

The objective of this study was to evaluate the effects of different shading strategies on the intake and digestibility of nutrients, nutrient use efficiency, feeding behaviour, respiratory rate, and performance of feedlot-finished Nellore bulls in the semi-arid region of Brazil. Two hundred and twenty-five intact Nellore cattle with average body weight (BW) of 294 ± 19 kg and 24 months of age were allotted to a completely randomised design with three shading strategies (full sun, artificial shade, and natural shade). There was a significant effect of shading strategies on air temperature (p = .02), black globe temperature (p < .01), and radiant heat load (p < .01), which were 3.63%, 44.07%, and 4.10% higher in the full sun pen than in natural shade pen, respectively. The dry matter intake of animals kept in the natural shade pen was 14.76% higher than that of animals in the full sun pen (mean of 7.39 kg DM/day). The longest feeding time (p = .02) was observed in animals kept in the artificial shade pen. Bulls kept in the natural shade pen had the highest (p = .05) final body weight and average daily gain (p = .02). There was no effect of treatments on feed efficiency, averaging 0.184 kg/kg of DM. There was a trend (p = .09) towards higher hot carcase weight for animals kept in the natural shade pen. Natural shade is recommended for feedlot-finished Nellore cattle in the semi-arid region of Brazil.Highlights Natural shade in feedlot pens improves the thermal comfort of animals in the semi-arid region The dry matter intake was higher in bulls kept in the pen with natural shade than in animals kept in the full sun pen Animal performance was improved in shaded pens

Keywords

• animal welfare
• dry matter intake
• intensive system
• respiration rate
• weight gain