Choose wholecrop cereal harvest date according to farm needs
05 July 2024
Dairy farmers making wholecrop silage from winter or spring cereals should choose the crop’s harvest date and percentage dry matter (%DM) content according to the farm’s needs, says Peter Smith, silage specialist at Volac.
“A key benefit of wholecrop cereals, compared with other silage crops, is that you can decide when to harvest the cereal crop based on factors such as whether you are short of forage and which cows the wholecrop will be fed to,” says Mr Smith.
Most farmers preserve wholecrop by fermentation as this is a simple and cost-effective method. Fermented wholecrop can be made when the crop has reached anywhere from 30-60% DM. Harvesting towards the lower end of this range will provide silage with more bulk. Harvesting towards the higher end, when the crop is more mature, will provide silage with more scratch factor and starch.
“However, whenever wholecrop is made, it is important to conserve it properly to prevent losses in feed value. You have already invested in growing the crop, so you don’t want some that investment to go to waste.
“Consider a dual-acting additive, such as Ecocool to aid the fermentation process but also to keep it aerobically stable and cool. The risk of losses from wholecrop silage heating increases when it is harvested at higher %DMs,” he adds.
Elaborating on the different %DMs that cereals for fermented wholecrop can be harvested at, Mr Smith offers the following guidance:
Harvesting at 30-40% DM
Harvesting cereals at 30-40% DM for wholecrop offers the maximum amount of fresh weight, so is useful for those farms that need to make up for low grass yields or low grass silage stocks this season, says Mr Smith. However, because it is harvested early, he says it will not provide the highest yield of DM per hectare.
“Wholecrop in this %DM range has had less time to lay down starch in the grain, and is often fed to dry cows and youngstock. At these %DMs it can be harvested without specialist equipment – using a wholecrop header, or by mowing before harvest without the conditioner turned on,” he says.
Harvesting at 40-50% DM
A more common %DM range for harvesting cereals for wholecrop, this can offer a similar fresh weight yield to the lower %DM material, but has the benefit of providing more starch, making it useful for reducing starch-based concentrates and for animal performance, Mr Smith explains.
“Harvesting in this % DM range offers a sweet spot between starch content versus sugars and moisture for fermentation. However, because the crop is drier, it becomes more difficult to keep cool and stable, making a dual-acting additive particularly important. Placing 2-3ft of freshly-cut consolidated grass on top before covering the clamp can also help to seal it and keep it cool.
“To harvest in this %DM range, a wholecrop header is required. Above 45% DM a grain cracker may also be needed to prevent intact grains passing through the cow, although if the crop is undersown this can increase the moisture enough to soften the grain.”
Harvesting at 50-60% DM
Harvesting at 50-60% DM will increase starch levels further and increase “scratch factor” as the crop becomes more fibrous, says Mr Smith, making it useful for higher production animals, especially if other forages are low in fibre.
“Because the crop is now even drier, it becomes more difficult to consolidate, making an additive that protects against heating even more important. Clamps should always be filled in layers no more than 10-15cm deep, but at this %DM this is critical. Again, consolidated fresh grass over the top is good practice, and a grain cracker on the harvester is essential.”
For more details, you can reach out to Peter Smith at Volac. He can be contacted at 07920 721955 or via email at peter.smith@volac.com. Feel free to get in touch with any inquiries or questions you may have!