Processing methods of flint corn and protein supplement in forage-free diets for feedlot lambs

Diets without forage increase the productivity in less time and favor greater practicality and better quality carcass. The corn grain is mostly used associated with pellets but processing these ingredients can bring benefits. The present study evaluated the effect of diets without forage based on whole or coarse ground corn associated with pelleted or ground protein supplement on performance, eating behavior, carcass characteristics, and ruminal morphology of feedlot lambs. Thirty-five Dorper × Santa Inês lambs were used, with 23.85 ± 3.88 kg of initial body weight and 88 ± 9 days old. The experimental design was in a randomized complete block, defined by body weight and age. The experimental diets were control (CONT), containing 90% of concentrate and 10% of forage (coastcross hay), and 4 diets without forage: WC+P, 70% whole flint corn and 30% pelleted protein supplement; WC+G, 70% whole flint corn and 30% ground protein supplement; GC+P, 70% ground flint corn and 30% pelleted protein supplement; and GC+G, 70% ground flint corn and 30% ground protein supplement. There was an interaction between treatments and experimental periods for DMI in kg/day (P = 0.01) and g/kg of BW^0.75 (P < 0.01; Table 3). For the DMI in kg/day, no significant differences were observed between the treatments in any of the experimental periods. However, for DMI expressed in g/kg of BW^0.75, the animals fed WC+P had lower DMI than the animals on the CONT (P < 0.01) only in the first period. The ADG, FBW, and FE were not affected by the treatments. Compared to CONT, forage-free diets decreased ingestion time (min/day) and rumination and chewing (min/day and min/g of dry matter). There was no effect of treatments for any of the carcass traits evaluated. The diets did not cause lesions suggestive of ruminitis. Forage-free diets containing whole or ground corn associated with pelleted or ground protein supplement can be used successfully for feedlot lambs; they provide proper performance and carcass characteristics, without harming the animal's health.