Influence of Harvesting Age and Season on Digestibility and Chemical Composition of Pelleted Coastal Bermudagrass

Open Access
Publisher Website
Google Scholar
Abstract
Coastal Bermuda grass was harvested at either 3-, 5-, or 7-wk frequencies throughout the season, dehydrated and pelleted. It was fertilized with 400 lb of N per acre in split applications. Total collection digestion trials were conducted with Holstein bull calves. Digestibility of all components decreased as the age of the grass at harvest increased. In excess of 95% of the variation associated with forage age was attributed to the linear effect for dry matter, energy, organic matter, crude fiber, crude protein, ash, and NFE. Average digestibilities for forages harvested at 3-, 5-, and 7- wk frequencies were organic matter, 66.0, 60.7, and 56.8; dry matter, 65.9, 60.7, and 56.6, protein, 67.0, 58.8, and 51.7; crude fiber, 66.2, 59.1, and 54.2; and NFE, 65.3, 61.7, and 59.2. Correspondingly, calculated estimated net energy values were: 59.2, 51.2, and 45.0 therms per 100 lb. As forage age at harvest increased, the protein content declined substantially, but there was only a moderate increase in crude fiber. On a within-harvesting frequency basis, nylon bag dry matter disappearance determined in fistulated steers tended to be lowest in the middle of the season. The 3-, 5-, and 7-wk forages contained the following percentages on a dry basis: protein, 15.3, 11.8, and 10.8, and crude fiber, 28.0, 30.9.