Intake and digestibility of crossbred goats finished on caatinga grassland receiving feed supplementation during dry season

Resumo

It was evaluated the effect of feed supplementation at 0.4; 0.8 and 1.2% of body weight (BW) on intake and digestibility of crossbred goats finished on caatinga, in relation to crossbred goats not supplemented (0.0% of BW). Thirty-two crossbred, Anglo-Nubian goats were used, eight months old and with body weight of 18 ± 2.5 kg, organised into randomised blocks, which were kept on 37 hectares of caatinga from 7 h to 16 h. Intake of dry matter, organic matter, crude protein, ether extract, neutral and acid detergent fibre, total carbohydrates and total digestible nutrients was influenced (P < 0.05) by the levels of feed supplementation, with linear increases of 202.31; 179.42; 25.05; 11.83; 35.79; 12.27; 142.63 and 166.79 g animal^-1 day^-1 respectively. There was a substitution effect (P < 0.05) on dry matter intake when using feed supplementation at 0.7% BW.  Feed supplementation resulted in positive linear effect (P < 0.05) for digestibility of dry matter, organic matter, crude protein, ether extract, total carbohydrates, total digestible-nutrient content and digestible energy, with an increase of 17.15; 16.64; 19.07; 44.74; 15.15 and 17.56% for dry matter, and 0.69 Mcal kg^-1 of dry matter respectively. Final body weight, total gain and average daily gain, showed a linear increase (P < 0.05) of 2.60, 3.09 and 0.036 kg per percentage point of each additional level of supplement. Feed supplementation increases the intake and digestibility of total dry matter and nutrients, a fact that makes greater performance possible, and recommends use up to a level of 0.7% BW to avoid any substitution effect.