Effects of Nitrogen Source on Nutritive Value of Stockpiled TALL-Fescue Under Grazing.

Stockpiled tall fescue is used mainly due to its low cost compared with other feed sources, which can be used to maintain mature cows for less than one-fourth the cost of hay. The success of stockpiling depends on the accumulation period, choice of species, nutrient management, and nutritive value. Nitrogen fertilization has been well explored but there are still questions on the utilization of different sources of nitrogen application to appropriately stockpile tall fescue in order to achieve a higher nutritive and yield in order to improve animal performance. Poultry manure is considered to have high N content when excreted, and the ammonium N measured in this matter is a result of uric acid decomposition while in storage. The objective of this study is to determine different sources of nitrogen application in order to achieve the higher nutritive value under the most economical scenario for stockpiled tall-fescue under grazing. The research was conducted at the Middle Tennessee Research and Education Center of The University of Tennessee in Spring Hill, TN, from August to December 2013. Each individual plots (3 acres) were replicated three times in a completely randomized design. The treatments consisted of two sources of nitrogen fertilization prior stockpiling:

1)    Stockpiled tall fescue with application of 60 pounds of N per acre

2)    Stockpiled tall fescue with application of 60 units of N via the form of poultry litter per acre

Samples to characterize the morphological composition and nutritive value of the sward canopy were randomly collected on a weekly basis during the entire grazing period. The samples were then separated into its morphological components, dried in at 60^oC to constant weight and then ground for in vitro neutral detergent fiber digestibility (NDFD) and neutral detergent fiber (NDF), using the NIR.