Alfalfa Treated with a Chemical Drying Agent: Effect on Digestibility In Situ

¹ Department of Dairy and Animal Science, The Pennsylvania State University, University Park 16802

The effects of a chemical drying agent on in situ rate and extent of disappearance of DM, NDF, and ADF of alfalfa were investigated. Two field replicates of first- and second-cutting alfalfa (early bloom) were treated at harvest with a potassium carbonate-sodium carbonate based chemical drying agent (7.9 kg/ha). Samples were separated into leaf, stem, and whole plant fractions and artificially dried. Treatments were arranged as a 2 x 2 x 3 factorial and analyzed as a completely randomized block design. Treatment had a greater effect on initial nutrient composition, compared with untreated, for all fractions in second cutting alfalfa. In situ DM disappearance was not affected by treatment in the first cutting for any fraction. In first-cutting leaves, NDF and ADF in situ disappearance was increased by treatment. Rate of DM and ADF disappearance for treated second cutting leaves and stems decreased compared with untreated samples. Lag time associated with NDF disappearance increased in second-cutting leaves and stems treated with drying agent. Potentially digestible ADF and lag time increased in second-cutting stem, and lag time for the whole plant decreased. Drying agent application had different effects on nutrient composition and digestibility of first and second cuttings and on leaf and stem fractions of alfalfa.

Key Words: drying agent • in situ digestibility • alfalfa

Submitted on December 11, 1989
Accepted on March 23, 1990