Forage quality of winter and summer anual grasses under nitrogen fertilization and pig slurry

Nutrient accumulation and forage quality were evaluated in a field experiment in Chapecó, Southern Brazil, with different grasses and nitrogen fertilization. The treatments were a combination of the nitrogen sources: ammonium
nitrate (AN) and pig slurry (PS), applied at the rates of 0, 60, 120 and 180kg/ha of N before seeding the annual grasses: pearl millet in the summer and black oat + Italian ryegrass in the winter. Nutrient accumulation, crude protein (CP),
acid detergent fiber (ADF), in vitro organic matter digestibility (IVOMD) and total nutrient digestibility (TND) were evaluated in the dry matter. Both N sources linearly increased CP content in pearl millet and oat + ryegrass forage. The variables IVOMD, ADF and TND were not affected by nitrogen. Nutrient accumulation increased by increasing N rates
from both sources. In comparison to AN, PS increased the absorption of P, K and Zn in all forage plants.