The theoretical length of cut for the forage harvester should be adjusted to ensure good health of the dairy animals and minimize problems handling the silage to and from storage. If the forage is harvested too short, animal health problems, such as displaced abomasum, are more likely to occur. If the forage is too long, forage handling may be a problem.
The recommended theoretical length of cut for alfalfa silage is 3/8 inch or longer. Some of the unloading equipment for upright silos may limit the length to no greater than 3/8 inch. This is influenced not only by the type of equipment but also the condition of that equipment. Worn conveyors such as augers may perform poorly if length is 3/8 inch or longer. For horizontal storage, the length can be as large as one half inch.
From the animal standpoint, short silage can be compensated by feeding dry baled hay. Based on 1000 samples of silage and TMR rations analyzed with the forage particle separator throughout Wisconsin, nearly two-thirds of the dairy animal feed is too short. But many producers minimize the health problems by feeding long baled hay.
The length of cut on a forage harvester can be adjusted by changing the feedroll speed or the number of knives. Increasing the feedroll speed will increase the length of cut and should be the first adjustment made to increase the length. Other factors that influence length of the harvested forage are condition of the knives and shearbar, maturity of the forage, and density of the harvested windrow.
Increasing the length of cut has other benefits such as, reduced fuel requirement and increased machine capacity. Producers should check the machine length of cut, adjust it correctly and maintain the harvester to ensure top machine performance.
For more information contact Mike Rankin|
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