Processing wilted alfalfa with crop processing rolls on a pull-type forage harvester

Crop processors on forage harvesters have become readily available and widely used by North American livestock producers. Past research has shown that intensive mechanical processing at the time of cutting can improve the fiber digestibility of alfalfa and grasses, and questions have surfaced as to the potential effectiveness of a crop processor on a forage harvester to also improve the animal utilization of wilted forages. Processing wilted alfalfa with crop processing rolls was effective in increasing the level of plant tissue disruption, as quantified by leachate conductivity, by more than 30% in all cases and similarly reduced particle-size from the theoretical-length-of-cut. Processed material was visibly darker and more bruised than control treatments. Processor roll clearance and cutterhead theoretical-length-of-cut had a greater effect on crop physical properties than did processing roll speed difference. Processing wilted alfalfa increased harvester energy requirements by 36 to 113% depending upon crop moisture and the feeding characteristics of the processing rolls as affected by the aggressiveness of the tooth profile. Processing wilted alfalfa increased the crops in situ dry matter disappearance at 12 and 24 h by greater than six percentage units and increased the instantly soluble fraction by up to seven percentage units. However, processed alfalfa did not affect lactation performance of Holstein dairy cows