|Utilization and Construction of Pit Silos (Peace Corps, 1976, 41 p.)|
Frequently stockmen are confronted with making a choice between corn or sorghum silage and grass silage. Under these circumstances, the following facts are pertinent:
1. Where adapted, corn or sorghum will generally produce a greater tonnage of feed per acre than grass silage.
2. Good quality corn or sorghum silage can be made more consistently and with greater ease than good quality grass silage.
3. Corn or sorghum silage is generally more palatable than grass silage, even when the latter is carefully preserved.
4. Grass silage is generally higher in protein and carotene but lower in total digestible nutrients than corn or sorghum silage (generally, grass silage contains about 90 per cent as much T.D.N. as corn silage, but it will equal corn silage in T.D.N. where 150 pounds of grain per ton have been added as a preservative). Thus, grass silage generally requires the addition to the ration of less protein supplement but more total concentrates than corn or sorghum silage. This would indicate that corn or sorghum silage would be slightly preferable to grass silage in high roughage finishing rations for beef cattle and sheep, whereas grass silage would be preferable in high roughage rations for dairy animals and young beef cattle and sheep.
5. Grass silage is higher in carotene content but lower in vitamin D, unless made by the wilting process, than corn or sorghum silage.
6. Grass silage can be produced in those areas where the climate is too cool and the growing season too short for corn or sorghum silage.
7. The production of grass silage will result in less soil washing than the production of corn or sorghum silage on lands subject to erosion.
Effect of silage on Milk Odor and Flavor:
Silage sometimes affects the flavor and odor of milk. This effect may be somewhat more pronounced with some silages than with others The dairyman will do well, therefore, to feed all silages after, rather than before, milking.
Some losses are incurred in the ensiling process regardless of the procedures used. Field losses vary with the degree of field drying. Losses in the silo can be grouped under three main headings: (1) surface spoilage, (2) seepage, and (3) gaseous or fermentation losses.
The amount of surface spoilage is a function of the degree of exposure to air and water. Losses of 20% or more can occur in stack silos. Each 1 cm of surface spoilage represents approximately 3 cm of silage lost. The most effective way to reduce loss from surface spoilage is to reduce the surface area exposed or to provide suitable protection such as a plastic cover.
Storage losses tend to be higher with direct-cut materials, due to squeezing out water and movement of feed nutrients out of the silo with the water. In a high-moisture silage 50% or more of the dry matter losses may be due to seepage. These losses usually increase with the percent moisture of the ensiled forage and &dine height of the silo. A horizontal silo will have less seepage loss because of lower vertical pressures. In general, silages with leas than 70% moisture have little or no seepage loss.
Gaseous or fermentation loss is due to respiration by the plant in the silo and the subsequent bacterial fermentation. Both of these factors result in loss of dry matter in the silo. Some of this is unavoidable; but unnecessary loss can result because of entry of air into the silo, failure of PH to decline rapid and existence of unfavorable fermentations. Adherence to principles of good silage making will keep this loss at a minimum.
* SILAGE-MAKING PRACTICES
One of the basic problems in making high-quality silage is the variability of the product even under apparently similar conditions. Generally, the following practices have resulted in making a good grass-legume silage.
1. Use a crop of high quality.
2. Harvest forage at the proper stage of growth.
3. Fine-chop. length of cut for unwilted material should be 6-25 cm in length; for wilted material 6-12 cm in length.
4. Field-dry to 65% or less to produce either a wilted or low-moisture silage, or use an additive.
5. Use a silo which excludes air and water.
6. Fill the silo rapidly and pack thoroughly.
7. Use a suitable seal to exclude air.
8. Leave silo until ready to use the feed.