By now, most forage harvest will be completed. Some additional oatlage or haylage may still be harvested this season but the vast majority of silage, haylages and dry hay crops have been "carefully" put into storage. For the next 8 to 11 months your forage supplies will need to be maximized to save feed costs or to ensure top dollar during sales. In the grain business shrink is referred to as the loss of the commodity from harvest until sale. Shrink also affects forages and can range from 5% to more than 40% and some instances losses can be higher.
The first forage that comes to mind regarding the high potential for storage losses is corn silage. When exposed to air, yeasts and molds rapidly consume carbohydrates and reduce dry matter content in silages during feedout. Frequently these losses are greatest in the upper levels and the exposed face of bunker silos. Losses can also be significant in ag bags and poorly maintained, leaky, upright silos. To properly store any silage crop all efforts need to be made to ensure that silage exposure to air is minimized and managed accordingly to reduce spoilage. Ensuring a dense silage pile pack; keeping silage coverings in place; using a silage facer to maintain a smooth feedout face; and managing removal rates based on season of the year can significantly reduce shrink. These same principals apply in ag bags, tower silos and piles. Remember the key to minimizing silage shrink is to limit exposure to air. There is only a fine line between silage and compost. Additional silage shrink comes from spills during mixing and delivery and feed refusals. One percent here and 3% there will add up quickly.
Hay crops stored as baleage or haylage can also experience significant forage shrink. Long term storage of haylage requires optimum conditions during fermentation in a silo or a wrapped bale. Optimum moistures; short wilting periods; proper stage of maturity; environmental temperatures during the fermentation period; proper use of inoculants; type and number of plastic wraps will affect the potential for shrinkage. Many baleage producers mark each harvest and feed out according to long term storage considerations. Any exposure to air from rodents and other vermin needs to be repaired to ensure optimum long term storage.
Dry hay shrinkage can also be significant. Hay put away at above optimum storage moistures will heat up and sweat in the mow. This heating is the result of microbial activity consuming carbohydrates and reducing dry matter content just like silages. The largest amount of shrinkage in hay is during feedout. Unlimited access to hay will result in over consumption and general wasting. In a study reported in Wisconsin cows fed large round bales in a rack wasted 9% of the forage. When fed without a hay rack wastage was reported to be 45%.
To minimize forage shrink producers need to consider all aspects of storage and feedout practices. Forage values are the highest immediately following harvest. Shrinkage during storage and feedout can significantly impact total feed costs. Focus on your shrinkage potential and minimize these risks to take full advantage of your forage production efforts in 2008.