EFFECT OF THE PROTEIN AND ENERGY SUPPLEMENTATION OF RUSTIC SACCHARINABASED RATIONS ON GROWING-FATTENING BULLS

Forty eight Zebu bulls of an average live weight of 160 kg were housed at a rate of 2 animals per pen and 8 per treatment in a random block design, to evaluate the effect of protein and energy supplementation i n Saccharina based rations. The treatments evaluated in the first peri od (140 days) were levels of 0, 300 and 600 g/animal/day of soybean me al in rations with or without ad libitum homemade protein molasses (HP M) and ad libitum or restricted final molasses instead of HPM in the s econd period (120 day). Saccharina consumption was lower (P < 0.001) i n HPM treatments, without differences between soybean meal levels whil e HPM and total dry matter consumptions and live weight gains were sig nificantly higher in these treatments when they were supplemented with soybean meal, but the protein utilization efficiency worsened in comp arison to the rations which were not supplemented with HPM and receivi ng the lowest soybean meal supplementation levels. In the second perio d, the substitution of HPM by final molasses provoked better live weig ht gains in all treatments, but were higher (P < 0.001) in those suppl emented with 300 and 600 g of soybean meal and final molasses where th ere was a better protein utilization efficiency. The supplementation o f rations based on rustic Sacrharina with 300 g of soybean meal and 4 kg of sugar cane final molasses is suggested.