Feeding cereal grains to livestock: wholecrop silage
Understanding the differences between types of wholecrop silage
Wholecrop cereal silage is made by harvesting the whole plant and storing it anaerobically. It can be made from a wide range of cereals, clamped, baled and wrapped or conserved in a plastic tube. However, baled wholecrop, especially wheat, can attract vermin, so take steps to protect it. Ideally, store on a hardstanding or concrete pad. If baling, use six layers of wrap on bales at least, as wholecrop is drier and more susceptible to yeasts and moulds than grass silage. Chopping improves compaction, and using an additive will help ensure a good fermentation and aid the keeping quality of the crop once exposed to air.
|Maize silage||Fermented wholecrop||Drier milled wholecrop||Dry alkaline wholecrop|
|Which species can be used?||Maize||Barley, wheat, oats, triticale||Barley, wheat, oats, triticale||Barley, wheat, oats, triticale|
|Harvest timing||25–35% DM The grains are hard on the outside but still milky on the inside. Grains nearest the stem are dimpled and feel waxy||30–45% DM Crop is just starting to turn yellow with grain at the ‘soft cheddar’ stage (about 4–6 weeks before conventional harvest)||45–75% DM Two to three weeks before conventional harvest. There is still some green in the crop||70–85% DM At the conventional combinable stage|
|Harvest equipment needed||Direct cut forage harvester with maize header||Direct cut forage harvester Disc mower and forager within an hour of each other||Direct cut forage harvester fitted with a grain mill||Direct cut forage harvester fitted with a grain mill|
|Field losses||Minimal in unlodged crops||Height of stubble can be controlled in direct cut systems Losses will be moderately low in well-timed mower and forager operations||Height of stubble can be controlled in direct cut systems Separate mower and forage harvester not recommended, due to high field losses||Height of stubble can be controlled in direct cut systems. Separate mower and forage harvester not recommended, due to high field losses|
|Additive options||Sulphite and potassium salts, buffered acid blends, inoculants and enzymes||Buffered acid blends, acid salts, sulphite and potassium salts, inoculants and enzymes||Sulphite and potassium salts, buffered acid blends, inoculants. Urea can be added to make ureatreated wholecrop||Alkaline-ammonia-release system, e.g. urea and enzymes|
|Storage||Clamp or plastic tube, sealed to exclude air||Clamp or plastic tube, sealed to exclude air||Clamp or plastic tube, sealed to exclude air||Clamp or plastic tube, sealed to exclude air|
|Drier milled wholecrop||45–75||10.3–11.3||9*||50||20–28||3||0.2||0.25||0.1|
|Dry alkaline wholecrop||70–85||10.3–11.5||14–16||55||28–32||2||0.2||0.25||0.1|
*Protein levels will be higher if urea is added at ensiling
Average nutritional composition of wholecrop (% in DM or MJ/kg DM or ME)
Forage maize is a very palatable feed. It has high energy and starch content, but, if fed alone, its protein content is too low for cattle and sheep, so supplementation is required. Like all cereal wholecrops, it is low in minerals, vitamins and trace elements. When ordering mineral and vitamin supplements, tell the supplier they are to be fed with maize silage.
The ensiling of wet wholecrop cereals such as barley, wheat, oats and triticale will produce a feed of moderate energy content with low protein levels. This can be a good option if, for instance, first-cut grass silage yields were low or there is an obvious shortfall in forage for the winter.
The combination of wholecrop with other forages fed together significantly increases daily DMI and helps maximise rumen function. Cereal and legume bi-crops can make useful wholecrop silages, lifting protein content above that of the cereal alone.
Drier milled wholecrop
Drier milled wholecrop made from barley, wheat, oats or triticale has moderate energy and protein levels. Its starch content is usually higher than fermented wholecrop because it is harvested later. It can be used in place of silage for growing animals performing at moderate levels and for pregnant livestock. However, take care to ensure it is properly balanced for protein, minerals and vitamins.
Being relatively dry, an additive is advisable to control yeasts and moulds. Adding urea to this type of wholecrop can increase protein content and inhibit spoilage and fermentation losses through increasing the pH. This typically raises protein content to between 14–16% CP in DM.
Dry alkaline options for wholecrop
The use of an ammonia-releasing product increases the crude protein level to around 16%. The ammonia stabilises the crop material and makes it alkaline. The feeding value is similar to that of good-quality grass or maize silage, which it can be used to replace a proportion of in the overall diet. Care should be taken to provide adequate levels of rapidly fermentable energy in the ration, to use the ammonia in the rumen effectively. This is a useful product to feed alongside acidic silage.
With all wholecrops, it is possible to increase the energy density of the crop by raising the cutting height so the proportion of ear to stem is increased.