Tensile strength of warm and cool season forage grasses in Florida

The tensile strength (TS) of four warm-season and three cool-season forage grasses was measured with an Instron Universal machine, along with cell-wall analysis and determination of in vitro organic matter digestibility. The mean TS of the warm-season grasses was significantly higher than that of the cool season grasses (22 vs. 9 kg, respectively, p < .05). The concentrations of neutral detergent fiber (NDF), acid detergent fiber (ADF), and acid detergent lignin (ADL) were significantly greater in the warm- than in the cool-season grasses (p < .05), whereas ash concentration was greater in the cool-season grasses. Among the warm-season grasses that were studied, elephant grass had the highest and bermuda grass had the lowest TS (34.4 and 14.9 kg, respectively, p < .05); Among the cool-season grasses triticale had greater TS than wheat and oats (12.6 vs. 6.8 and 7.5 kg, respectively, p < .05). TS was significantly correlated with NDF, ADF, and ADL, and negatively correlated with in vitro organic matter digestibility (correlation coefficients were 0.64, 0.73. 0.41, and -0.64, respectively).

Practical applications: Grass tensile strength may have implications on animal preference and on the energy that animals must spend during grazing, and consequently on animal performance (feed intake, daily weight gain and milk, and meat production). Information on grass TS would help to select and screen improved forage cultivars and enable to improve grassland management with better animal performance.