The effect of a baler chopping system on fermentation and losses of wrapped big bales of alfalfa

The improvement of wrapped big bale silage quality by increasing bale densities should be an important target. The objectives of this research were to evaluate the effects of the use of a cutting system (15 knives spaced 93 turn apart) installed behind the windrow pickup of a fixed chamber round baler. Three field trials were conducted near Turin, Italy (44 degrees 50' N, 7 degrees 40' E) by ensiling wrapped round bale of first- and second-cutting alfalfa (Medicago sativa L.) at different dry matter (DM) concentrations. The DM and crude protein (CP) losses at baling, forage mean particle length, wet and dry bale weights, bale density, fermentation pattern, and the conservation losses were evaluated. The DM losses at baling ranged from 0.5 to 2.0% and from 0.7 to 4.7% of DM yield at cutting for unchopped and chopped treatments, respectively. The chopping system increased the percentage of stems shorter than 10 cm from 14 to 38% on a DM basis. Chopping increased DM bale density by about 4% in all the trials. After 140 d of conservation the final fermentation quality of silages was not consistently improved by chopping.