Nitrogen Fertilization in Coastcross Pastures Associated with Forage Peanut on Nutritional Composition of Forage and Animal Performance

The experiment was carried out at IAPAR, in Paranavaí-PR, from July 2002 to June 2007. A completely randomized design was used, with two replications and such treatments- Coastcross (Cynodon dactylon [L] Pers Cv Coastcross) + forage Peanut (Arachis pintoi Krapovickas and Gregori. Cv. Amarillo) + 200 kg ha-1 of N; Coastcross + forage Peanut + 100 kg ha-1 of N; Coastcross + 200 kg ha-1 of N and Coastcross + forage Peanut. Cross heifers were used (Red angus × Nelore × Limousin), three of them as testers plus the regulator animals, with medium initial weight of 170 kg, and management in continuous stocking and variable stocking rate. The pasture was maintained to a medium height of, approximately, 17 cm. For the nutritional value evaluations (crude protein,CP, neutral detergent fibber, NDF, and in vitro dry matter digestibility, IVDMD) forage samples were collected, each 28 days, and separated in leaf blade, sheath+stem, dead material and plants of forage Peanut. The animal production was evaluated through the average daily gain (ADG, kg ha-1 day-1), weighted in fast each 28 days, stocking rate (AU, animal unit ha-1; being that the animal unit corresponds to 450 kg of live weight) and body weight gain (BWG, kg ha-1). Pastures of grasses and legumes with no N fertilization have a lower nutritional composition than fertilized pastures. Forage nutritional composition and animal performance vary according to the conditions each year, thereby affecting stocking rate and live weight gain.