Cactus Pear Silage to Mitigate the Effects of an Intermittent Water Supply for Feedlot Lambs: Intake, Digestibility, Water Balance and Growth Performance

The aim of this study was to evaluate the intake, digestibility, water balance and growth performance of lambs receiving diets containing cactus silage under an intermittent water supply. Thirty-six male, uncastrated Santa Inês lambs with an initial weight of 19.8 ± 2.1 kg and age of 6 months were distributed in a 3 × 3 factorial arrangement, with three proportions of cactus pear in the diets (0 (control diet containing Tifton hay), 21% and 42% of dry matter) and three periods of intermittent water supply (0, 24 and 48 h), with four repetitions. Lambs that received diets non-isonitrogenous with cactus silage showed higher intakes of dry matter (p < 0.001), total digestible nutrients (p < 0.001), water excretion via faeces (p < 0.001) and water balance (p < 0.001). Lambs that received diets with cactus silage showed higher digestibility of total carbohydrates, non-fibre carbohydrates (p = 0.005), water intake via food (p < 0.001), total water intake (p < 0.001), water excretion via urine (p < 0.001) and water balance (p < 0.05), when compared to the control diet. Lambs that received diets with cactus silage promoted growth performance (p = 0.001). When using 42% forage cactus silage in place of Tifton hay and water offered at 48 h intervals, intake, digestibility, and performance of feedlot lambs were improved.