Silages of thirteen cultivars of sunflower (Helianthus annuus L.) were evaluated for chemical characteristics and in vitro dry matter digestibility (IVDMD). The silages were produced when the plants presented above 90% of ripe grains. The experimental procedure followed a entirely randomized design and the mean values were compared by SNK test (P<.05). The smallest content of dry matter, 19.8%, was obtained for the hybrid M737, and the highest were observed for Contiflor 7, with 31.2%, and Cargill 11, with 32.2%. The pH values varied from 4.1 up to 5.5, and the contents of ammonia-nitrogen as percentage of total nitrogen varied from 5.9% up to 14.6%. The general averages obtained for lactic, acetic and butyric acids were of 7.1%, 1.9% and 0.06%, respectively. The hybrid Rumbosol 91 presented the smallest percentage of crude protein, with 7.2%, while contents above 9.0% were observed for five cultivars. The general average of ether extract (EE), 14.7%, was quite high when compared to others contents usually obtained for roughage. The contents of neutral detergent fiber, acid detergent fiber (ADF) and lignin presented general averages of 45.8%, 35.7% and 6.4%, and were negatively correlated to IVDMD (general average of 49.8%). The silages presented low concentrations of residual soluble carbohydrates. The high contents of ADF and lignin, and the average of IVDMD (49.8%) can restrict the application of the silages of those cultivars of sunflower for more the exigent categories of animals, and the high medium content of EE can limit the level of inclusion of those silages in bovine rations.
experimental silos; fermentation; nutritional value; roughage
