Cashew processing product as alternative energy feedstuff for grazing beef cattle under tropical conditions

Abstract

The aim of this study was to examine the effect of replacing corn with dried cashew processing product (CPP) in dietary supplements on the intake, digestibility and nitrogen (N) metabolism of grazing beef cattle. Five Nellore bulls with an average initial weight of 359 ± 34.8 kg were used in a 5 × 5 Latin square design. The animals were kept in five 0.32-ha paddocks of marandu grass (Urochloa brizantha cv. Marandu). Five isonitrogenous protein-energy supplements (310 g crude protein [CP]/kg of supplement) were formulated with CPP replacing corn at different levels (0, 0.25, 0.50, 0.75 or 1.00 g/g). The diets were supplied daily in the amount of 1.0 kg/animal. The replacement of corn with CPP caused a linear decrease in the intakes of supplement DM, total DM, CP and digestible organic matter, but did not influence forage DM intake. On the other hand, the substitution resulted in a linear increase in the intakes of indigestible neutral detergent fiber and total tannins. The replacement of corn with CPP caused a linear decrease in the digestibility coefficients of total DM, organic matter, CP and neutral detergent fiber and in the dietary concentration of OM. A linear decrease was also noted for N retention, microbial N synthesis, rumen ammonia N and blood urea N, while no changes were detected in fecal or urinary N excretion or microbial efficiency. Replacing corn with cashew processing product reduces intake, apparent diet digestibility, microbial nitrogen synthesis and nitrogen retention in grazing cattle.