Changes in nutritive quality of Setaria sphacelata var. splendida with maturity

The nutritive quality in feed is an important factor that can affect the production of milk and beef. The feed quality for livestock can be analyzed by using conventional chemical techniques or lately with the use of near infrared reflectance spectroscopy (NIRS). The study was conducted to determine the optimum harvest interval for Setaria sphacelata var. splendida (Setaria splendida) based on its nutritive quality and yield when cut at different cutting intervals. In addition, the project also looks at the differences in nutritive quality parameters when measured with NIRS against that obtained by conventional method. The objective was to determine whether the NIRS was a reliable method of measuring nutritive quality of pastures. The experiment used the Randomized Complete Block Design (RCBD) with 3 treatments and 4 replications. The treatments comprised of three cutting intervals: 3 (T1), 5(T2) and 7(T3) weeks. The measurements taken during harvest were the height of grasses and a number of tillers. Laboratory and NIRS analysis was conducted to determine the Crude Protein (CP), Neutral Detergent Fiber (NDF) and Acid Detergent Fiber (ADF) as a measure of nutritive quality of the grass. There were significant differences in nutritive quality and yield among treatments (P<0.05). The fibre content (NDF and ADF) and Dry Matter Yield (DMY) increased with advancing plant maturity while its CP, Leaf to Stem Ratio (LSR) and cumulative DMY showed a decline. The proportion of plants with vegetative parts declined at the later stage of maturity. However the nutritive quality at week 3 and week 5 was not significantly different. Therefore it is recommended that the grass is harvested at 3 or 5 weeks to get higher vegetative growth and better quality forage. Besides that, the measurement NIRS analysis in this experiment was not able to be used for estimation of forage nutritive quality as the values obtained from NIRS was not correlated with the values from the chemical analysis. The inability to use NIRS in this experiment was because of the improper calibration that was employed from a calibration which was previously done on other forage samples. Calibration with the current samples was not done because of some error of the software. This demonstrates the importance of using the correct samples for calibration if NIRS is to be effectively used.

Text FP 2015 104 - IR.pdf Download (1MB)

Actions (login required)

View Item