ISSN: 0041-3216 (Online), 0041-3216 (Print)
Volume 53 Number 4
Effects of stage of growth and season on the nutritive value of four digit grasses in Trinidad
Four digit grasses from South Africa, Digitaria decumbens (two cultivars), D. milajiana subsp. eylesiana and D. umfolozi (USDA P.I. Nos. 299601, 299602, 299730 and 299892) were harvested after one to eight weeks regrowth in the late wet and early dry seasons in Trinidad. As they aged, per cent crude fibre (CF) and total extractives (TE) linearly increased, ash and organic matter digestibility (OMD) linearly decreased, and crude protein (CP) decreased sigmoidly. In the last wet season the grasses contained less CP and DOM and more ash than in the early dry season, and the same levels of CF and TE. In both seasons grasses 601 and 602 contained similar level of ash and DOM at any one age except after one week. In the dry season per cent CP and TE were similar. Grass 601 contained less CF than 602 in both seasons, and more GP and TE in the wet season. Linear regression coefficients differed with respect to CF and TE but not in the case of CP ash or OMD. D. umfolozi 892 contained less CF and more CP, ash and DOM than grasses 601 and 602, and more TE than 602 in both seasons. Regression coefficients were similar to those of 601 and 602 with respect to GP CF, ash and TE, but smaller for DOM. D. milajiana subsp. eylesiana 730 contained the same levels of CF, TE and DOM as 601 in both seasons and of CP and ash in the dry season. In the wet season it contained more ash and less CP than 601. Regression coefficients for this grass were the smallest of all the grasses with respect to CF and OMD, and the largest of all with respect to ash and TE.