UTILIZATION OF Arachis pintoi BANK AS A PROTEIN SOURCE IN A PARTIAL FEEDLOT SYSTEM OF FINISHING STEERS. 1. PARTIAL SUBSTITUTION OF THE PROTREIN FROM THE FISH MEAL BY THE PROTEIN FROM Arachis pintoi.

Abstract

In order to reduce feeding cost in a partial feedlot system of finishing steers, crude protein (CP) from fish meal was substituted for CP from Arachis pintoi, offered as a protein bank. A restricted grazing was used over the grass (Bracharia decumbens/Dactylon mlenfuensis) and a complete feedlot supplementation during the rest of the day. Two treatments were evaluated fish meal in the feed supplement (THP) and substitution of 75% of the meal from the suplement for A. pintoi (TAP). The grass was grazed during the morning (10.2 AU/ha, 3-4 hours/day, 3/21 grazing-resting days, and fertilization) as well as the A. Pintoi bank (24-80 Au/ha, one hour/day and an alternate grazing and fertilization. The supplementary feed consisted of molasses, urea, fish meal, corn grain, mineral mixture and sodic lasalosid. Thirty-two Zebu and Zebu crossbreeds bulls were used and implanted with zeranol. Treatment had not effect (P>0.290) on average dry matter (Dm) and metabolizable energy (ME) intake was greater (P<0.001) for THP than for TAP (0.195 vs 0.160 kg/100 kg of live weight/day). In the pastures, the numerical value of the grazing pressure (PP) was different (P<0.004) between treatments and averaged 1.82 and 2.09 kg DM/100 kg of live weight/day for THP and TAP, respectively. For the legume, PP decreased over time from 0.40 to 0.14 kg/100 kg of live weight/day. The body weight gain was not different between treatments. Treatment had not effect on the body weight gain (P>0.262), with a mean of 1.091 and 1.112 kg/animal/day for THP and TAP, respectively. Substitution of the protein from fish meal for CP from A. pintoi did not affect live weight gain, but reduced daily feeding cost in 13.5%.