Bromatological composition and dry matter digestibility of millet cultivars subjected to nitrogen doses

Abstract

The bromatological composition and in vitro dry matter digestibility of millet cultivars were assessed for different nitrogen doses and two sowing seasons in the Ceres municipality of Goiás state, Brazil. The treatments consisted of three millet cultivars (ADR-7010, ADR-500 and BRS-1501), four nitrogen (N) doses (0, 50, 100 and 200kg ha-1 of N) and two sowing seasons. Three replicates and a randomised block design with a 3 x 4 x 2 factorial scheme were used. Two cuttings were performed in each season when plants reached an average height of 0.70 cm. No significant interactions were observed between or among cultivars for N doses and dry matter (DM), crude protein (CP), neutral detergent fibre (NDF) and acid detergent fibre (ADF) contents. The DM, CP, NDF and ADF contents were significantly different between N doses. The DM and CP contents increased as the N dose increased to 100kg ha-1. The maximum DM and CP contents were 11.14 and 22.53%, respectively. The NDF and ADF contents were higher in the control treatment (60.11 and 30.01%, respectively). In addition, the lowest ADF and NDF concentrations occurred at an N dose of 50kg ha-1(56.33 and 30.23%, respectively). The DM contents were higher for the February sowing, with an average of 10.59%. The highest CP and ADF contents were found for the December sowing (22.46 and 31.58%, respectively). No significant differences were found for millet cultivars, N doses or sowing seasons. A significant interaction was found between sowing season and millet cultivar. The BRS-1501 cultivar had a higher in vitro dry matter digestibility in the December/2010 sowing (73.88%).