Digestibility and feeding behavior of cattle fed soybean hulls to replace corn in high concentrate diets

The objective of this study was to evaluate the replacement of 0, 25, 50, 75 and 100% of ground corn (GC) with pelleted soybean hulls (SH) in the concentrate portion of cattle diets. The evaluation was conducted using five 13-month-old Nellore steers cannulated in the rumen, with a mean body weight of 265.00 + 11.60 kg. The steers received a diet composed of 90% concentrate and 10% sugarcane bagasse as the only source of roughage. The statistical design used was a 5x5 Latin square. There was no effect (p > 0.05) of replacement levels or interaction (p > 0.05) between replacement levels and sampling time on ruminal pH, which ranged from 5.8 to 6.0. The apparent digestibility of DM, CP, EE, CHOT and CHONF were not influenced (p > 0.05) by the replacement levels, showing mean values of 67.88 + 2.02; 67.43 + 2.89; 68.29 + 4.11; 70.54 + 1.68 and 80.21 + 1.85%, respectively. The NDF digestibility increased linearly (p < 0.05) with the replacement of corn with soybean hulls. There was no effect (p > 0.05) of replacement levels on time spent feeding (F) and total idle time (TI), with mean values of 10.51 and 4.61% of the day, respectively. However there was a quadratic effect (p < 0.05) of soybean hull inclusion on the time spent ruminating. It was concluded that although the replacement of corn with soybean hull does not improve the ruminal pH of steers fed diets with a high proportion of concentrate, pelleted soybean hulls improve the digestibility of the fibrous fraction of the diet and increase the time spent ruminating, indicating that this ingredient can be included in high-concentrate diets to improve economic efficiency.