Intake, digestibility, nitrogen balance and performance in lamb fed spineless cactus silage associated with forages adapted to the semiarid environment Spineless cactus silages in diets for lambs

Abstract

The study aimed to evaluate the intake, apparent digestibility, nitrogen balance and productive performance in lamb fed spineless cactus silage associated with forages adapted to the semiarid environment. Forty intact crossbred lambs, with an average body weight of 22.65 ± 1.01 kg, were distributed in a completely randomised design with five treatments (diets based on: spineless cactus silage (SCS), spineless cactus + buffelgrass silage (SCBS), spineless cactus + gliricidia silage (SCGS), spineless cactus + pornunça silage (SCPS) and corn silage (CS; witness) and eight animals per treatment. Intake, apparent nutrient digestibility, nitrogen balance, and performance of animals were evaluated. The SCGS diet showed higher intake of dry matter and organic matter (P<0.05). The SCGS and SCPS diets showed the highest crude protein intake (P = 0.005). Lower intake of ether extract was found in animals receiving diets containing SCS and SCBS (P = 0.001). SCBS and SCGS provided a higher intake of neutral detergent fiber (P = 0.015). SCS and SCGS diets displayed a higher intake of non-fiber carbohydrates (P = 0.003). SCGS diets displayed the highest total digestible nutrients intake (P = 0.001). SCPS diet showed lower digestibility of dry matter, organic matter, and crude protein (P<0.05). SCGS diet showed a lower digestibility coefficient for ether extract (P = 0.009). SCPS diet showed lower digestibility coefficients for neutral detergent fiber (P = 0.022). SCS and SCPS diets showed lower digestibility coefficients for non-fiber carbohydrates (P = 0.011). The CS promoted lower results for intake (P = 0.003), absorbed (P = 0.003) and balance (P = 0.012) for nitrogen. SCPS diet promoted higher excretion of nitrogen via faeces (P = 0.001) and less excretion of nitrogen via urine (P = 0.033). SCGS diet provided a higher final weight (P = 0.006). SCS and SCGS diets provided more significant body weight gain (P = 0.001). Combining spineless cactus with a roughage base allowed weight gains over 200 g/day, proving to be efficient in diets for feedlot lamb and gains similar or superior to corn-based diets.