This study aimed to evaluate the metabolic, productive, and carcass parameters of feedlot lambs fed high-concentrate diets with cottonseed associated with calcium lignosulfonate. Treatments consisted of diets including whole cottonseed, crushed cottonseed, whole cottonseed with lignosulfonate (100 g/kg), crushed cottonseed with lignosulfonate (100 g/kg), and a control diet without cottonseed. Thirty ½ Dorper ½ Santa Inês, non-castrated male lambs with an average live weight of 24.9 ± 3.6 kg and an average age of 3.5 months were evaluated in a completely randomized design. There was no effect (P > 0.05) on the intakes of dry matter, organic matter, crude protein, and non-fibrous carbohydrates. The crushing of cottonseed and association with lignosulfonate increased (P < 0.01) the intake and digestibility of ether extract. No effect was observed (P > 0.05) for the concentrations of urine and plasma urea N, which averaged 616.2 and 108.6 mg/dL, respectively. There was a change (P < 0.01) in nitrogen balance for digested N in g/day. There was no effect (P > 0.05) on the urinary concentration of purine derivatives, except for uric acid excretions (P < 0.05). Lignosulfonate associated with cottonseed provided an average daily gain of 0.293 kg/day, which was higher than the 0.226 kg/day obtained without lignosulfonate, but lower than control (0.302 kg/day), which also showed higher values of carcass yield. High-concentrate diets formulated without cottonseed improve lamb production performance. The use of high-concentrate diets with cottonseed associated with calcium lignosulfonate provides greater weight gains in lambs.
Keywords: Co-product; Feed additive; Feedlot; Ruminants.