The objective of this work was to determine the chemical composition of irrigated Tanzaniagrass (Panicum maximum Jacq.). and to validate the Cornell system. Simulated-grazed samples were collected on three periods of the year (spring, summer and fall, totaling 10 grazing cycles) on irrigated paddocks, rotationally grazed to three post grazed stubbles (low, medium and high). Although there were no statistical differences imposed by the treatments during the year, the neutral detergent fiber (NDF) and acid detergent fiber (ADF) showed higher values in the spring/summer, and lignin in the winter grazing cycles. Along the year the carbohydrate C fraction, TDN and CP varied from 14.14 to 23.21%, 55.26 to 59.31% and 11.29 to 14.61%, respectively. The Nsol, non protein nitrogen (NNP) and nitrogen on ADF (nADF) (as CP%) varied from 18.23 to 28.77%, 24.97 to 35.97% and 6.48% to 11.94%, respectively. The average nitrogen on NDF (nFDN) (as CP%) was 49.1%. From July to September forage quality was the lowest, probably due to the slowest tissue replenishment and flowering tillers accumulation. The N largest proportion (average of 40% of the CP fraction) was recovered in the cell wall, specifically in the B3 fraction, which should be the most important fraction on ruminal fermentation kinetics studies.
carbohydrate; Cornell; Panicum maximum; protein; TND
