Initiation Date and Cutting Strategy Effects on Bermudagrass Herbage Mass and Nutritive Value.

Bermudagrass is an important forage species for cow-calf production systems, especially in the Southeast United States. Harvesting and grazing schedules are often established to ease the livestock production system, using fixed measurement tools. However, these practices can result in variable herbage mass and forage quality as the season progresses. Measuring herbage mass can help producers to ensure that pastures are being managed accordingly, avoiding under- and overuse by grazing animals and to provide sufficient nutrients and energy required by the animal. It is important to maintain herbage mass within an appropriate range to avoid both a reduction in the forage accumulation rate and forage availability to the animal. The objective of this experiment was to quantify herbage mass and nutritive value of bermudagrass throughout the summer in Tennessee under different management strategies. The experiment was conducted during the 2013 growing seasons at the University of Tennessee Plateau AgResearch and Education Center in Crossville, TN. Four initiation dates for herbage accumulation were imposed which occurred during the first week of each month from June to September. On each initiation date, swards were cut to designated a stubble height of 8-cm. Each treatment was replicated four times, in 13.9 m² plots, arranged in a completely randomized design with sub-sampling. Forage samples were collected weekly from June to July and biweekly from August to September to characterize morphological composition and forage nutritive value. Samples were taken randomly per experimental unit within a 0.1 m² area. A sub-sample was then separated by morphological components and dried to constant weight to determine the proportion of each component. Samples were ground in preparation for forage nutritive value analysis. Regression analysis in SAS will be used to track and estimate weekly changes in nutritive value.