What are the characteristics of a good corn hybrid for silage?
A corn hybrid must be capable of producing a high whole-plant dry matter (DM) yield and high grain to forage ratio in the silage. It also should have a whole-plant DM content of 30% to 36% when the kernel is in the 50% to 75% milk-line stage of maturity.

How do sorghums compare to corn as silage crops?
Grain sorghum compares very favorable to corn as a whole-plant silage. Grain sorghum should be harvested at the mid- to late-dough stage of kernel maturity. It usually has a higher crude protein (CP) content than corn silage, but slightly lower net energy values for beef and dairy cattle.

   The agronomic and nutritional quality traits of forage sorghum silages are far more variable than those of whole-plant corn or grain sorghum silages. Therefore, hybrid or variety selection is critical for forage sorghum, and a good rule of thumb is to avoid the phenotypic extremes.

Is it better to harvest (ensile) the silage crop too early or too late?
For corn, sorghum, and small grain cereals, it is probably better to harvest too early rather than too late, but excessive effluent must be avoided (i.e., do not harvest above 70% to 72% moisture). The earlier-harvested silage will have a lower pH, a higher acid content, and the chance of a greater DM loss in the silo than later-harvested silage. The later-harvested crop will be more difficult to chop and pack, and the drier silage will be more aerobically unstable during the feedout phase than earlier-harvested silage.

   For field-wilted forages that are more difficult to ensile, it is probably better to harvest too late (i.e., at a lower moisture) rather than too early (i.e., at a higher moisture). When these forages are ensiled too wet, chances are greater for a clostridial fermentation and high butyric acid and ammonia-nitrogen levels in the silage. When pre-wilted forages are ensiled at a lower moisture, they are more difficult to pack and present risks of heat damage (i.e., a decrease in nutrient availability) and a high mold content. Regardless of the length of the field-wilting period, these forages must be cut at the correct stage of maturity.

How can very wet grasses or legumes be ensiled?
These forages should be field-wilted, whenever possible. If weather conditions do not allow field-wilting to at least 25% DM prior to chopping, then one of several strategies should be followed. These forages must be ensiled with an effective bacterial inoculant. Add 30 lb to 50 lb of either dry or wet molasses or 100 lb to 200 lb of a dry feedstuff or by-product per ton of chopped forage. Ground grain, wheat bran, wheat midds, rice bran, or citrus or beet pulps have been used to ensile wet forages. Finally, the material added should be mixed as uniformly as possible with the wet forage.

What is the proper size for a bunker, trench, or pile silo?
The tons of crop to be ensiled and the projected tons of silage to be fed daily determine the proper size for a bunker, trench, or pile silo. The height, width, and depth dimensions should be small enough to allow a rapid progression through the silage mass during the feedout phase. Most silos are too large--they take too long to fill, and the feedout rate is too slow.

How soon after filling can the silo be opened for feeding?
The fermentation phase should be completed before the silo is opened for feeding. This normally takes two to three weeks after filling is completed. If silage is taken out and fed after only a few days in the silo, both DM intake and milk production are likely to be adversely affected. Inoculants should reduce the time required for the fermentation phase to be completed. Because grasses and legumes usually ferment slower than corn (or sorghum), grass or legume silages should not be fed until at least three weeks after filling.

What are the losses in very well-managed silage?
The losses in very good silage will range from 5% to 15%, whereas the losses in very poorly-managed silage range from 25% to 50%. Loss is defined as the amount of forage DM that is put in a silo minus the amount of silage DM that is removed from the silo and fed. These losses are the result of effluent, respiration, primary and secondary fermentation, and aerobic activity during the storage and feedout phases.

How does the type of silo affect "losses" and "silage quality?"
The type of silo does affect "losses" and "silage quality;" however, minimum losses and high-quality silage can be achieved in any type of silo--if it is well managed. In general, vertical silos (towers) are more efficient than horizontal silos (bunkers, trenches, piles, and bags), and smaller-capacity silos are less efficient than larger- capacity silos (provided filling is not delayed and the silage removal rate is not too slow). "Forage in" versus "silage out" losses range from as low as 5% to more than 40%.

How should the silage "face" be managed during the feedout phase?
The silage "face" should be maintained as a smooth surface that is perpendicular to the floor and side walls (in bunker and trench silos). This will minimize the square meters of surface that are exposed to air. The rate of progression through the silage mass must be sufficient to prevent the exposed silage from heating and spoiling. An average removal rate of six to twelve inches from the face per day is a common recommendation.

What are the benefits of having a roof over the silo?
When a roof is placed over the silo, it protects the exposed face from rain and snow during the feedout phase. The result is a more consistent DM content of the silage from day to day and week to week. This allows an accurate feeding rate of the silage on a DM basis, particularly in total mixed rations.

What problems are associated with silage effluent?
Silage effluent has a very high biological oxygen demand, and thus, is an environmental hazard, particularly if it is allowed to enter a watercourse. Most forages that are ensiled below 26% to 28% DM can produce effluent during the first few days postfilling. Effluent is very nutrient-rich and contains soluble sugars, nitrogen, and minerals.

What is the real cost of silage?
A common method of calculating the real cost of silage is to divide the actual cost per ton of forage after the silo is filled by the percent of the silage that is actually removed and fed when the silo is empty. For example, if 1,000 tons of whole-plant corn are ensiled in a bunker silo at a cost of $25 per ton and 900 tons of corn silage are removed and fed, the real cost is $25 divided by 90% (.9), which equals $27.78. If only 750 tons of corn silage are removed and fed, the real cost is $33.33 ($25 divided by 75% or .75).