Animal production and forage quality of triticale and ryegrass pasture under nitrogen fertilization levels

The objectives of this research were to identify the nitrogen level that promotes the highest animal production per ha and to test the possible effect on the individual animal performance on triticale and ryegrass pasture. The sowing occurred on April 21 of 1997, later on subjected to the following treatments: 0, 150, 300 and 450 kg/ha of nitrogen divided in five applications. Nellore, Charolais heifers and their crosses, with initial average weight of 154 kg were used. The grazing period lasted from 06/12 to 11/17. The continuous stocking grazing method, with variable stocking rate, was used. The average forage mass was 1404, 1437, 1619 and 1599 kg of DM/ha, respectively, for the 0, 150, 300 and 450 kg N/ha. The crude protein content of the hand plucking samples showed a positive and linear effect of nitrogen levels, according to the following equation CP=23.55+. ION (P<.0001, R-2=.8015) and the IVOMD a quadratic effect, according to the following equation IVOMD=63.70+.037N-.000071 N-2 (P<.0004, R-2=3034), being the values 63.31, 68.93, 67.38 and 66.60%, respectively. The average daily gain did not present difference among treatments; the average was 750 g/animal. There was an interaction between treatment and period for stocking rate, the values were 738, 1086, 1078 and 988 kg of live weight/ha. The live weight gain/ha, also, showed a quadratic effect with the nitrogen levels (LWG=446+1.65N-.0029N(2), P<.0001, R-2=.8399). The level of 284 kg of N/ha promoted the highest animal weight gain/ha.