The multi-cut approach of cutting grass for silage younger and taking more cuts in a season is gaining ground.
A recent survey of more than 150 UK dairy farmers by forage preservation and animal nutrition experts Volac, and forage seed experts Germinal, found 60% had already brought their fi rst-cut date earlier in the past three years, and 44% had shortened cutting intervals. Among those already taking more silage cuts per year, or intending to, 71% said this was to make better quality silage, 68% said it was to make more milk from grass silage, and 65% said it was to reduce bought-in feed costs.
While the system may not suit every farm, it can provide real benefi ts, agree independent silage consultant Dr David Davies and Volac silage microbiologist Philip Jones, but it is important to follow the correct steps to produce it.
Dr Davies says: “The average dairy farm could improve income by thou- sands of pounds by making better silage. If you make better silage, you will get better nutrition from it. “You would not graze high producing cows on stemmy grass, so why make silage from it? To me, multi-cut grass silage is anything more than three cuts per season.”
Apart from the obvious benefit of younger cut grass being more digestible from being more leafy and less stemmy, and therefore having the potential to provide more metabolisable energy for milk production, Dr Davies says it also offers other advantages. For a start, protein is likely to be higher, he says, and silage which is more digestible will not spend as long in the rumen, so cows can eat more of it, allowing forage intakes to improve. Additionally, frequent cutting can give a better total grass yield over the season, he says, while a hidden benefi t for milk yield could come from grass being at a more uniform growth stage when cut earlier, resulting in less variability in the clamp and, therefore, in the daily ration.
Mr Jones agrees, saying the latest updates to Cut to Clamp are designed to help producers make the most of these types of benefits. He says: “Cut to Clamp was launched last year to help producers make consistently better silage. “Since then, it has become apparent more people are going down the multi-cut route, so we have developed some updates for those preferring this approach.”
ONE of the first points to watch if cutting more frequently is to adjust fertiliser policy accordingly, says Dr Davies, whether using bagged fertiliser or slurry. He says: “If cutting at four to fi ve- week intervals, regrowth will require less nitrogen fertiliser than if cutting every six or so weeks. Also, slurry should be injected or applied with a trailing shoe. It should not be surface spread.” Another point when it comes to earlier cutting is to ensure your contractor is available, says Mr Jones: “You may be cutting in April rather than mid-May. “Clearly, if you are taking fi rst-cut earlier, the weather can be wetter, so you need to bear this in mind, although the lower bulk should make wilting easier.”
JUST as with conventional silage, the aim with multi-cut silage should still be to wilt as quickly as possible to a target 28-32% dry matter, say Mr Jones and Dr Davies, ideally cutting in the morning and wilting rapidly so grass can be picked up in the afternoon. However, because the yield of individual cuts is likely to be lower with more frequent cutting, wilting times can be much shorter, they say. Dr Davies says: “Because you can wilt quicker, there is less loss in the fi eld from continued respiration of grass. The longer you wilt, the more sugar you lose.”
ALTHOUGH high D-value grass from earlier cutting is benefi cial, its lower fi bre content can make it more prone to slipping in the clamp, says Dr Davies. In response, he says chop length when harvesting may need lengthening compared with more fi brous grass. Dr Davies says: “If you have a 75 D-value silage at 30% DM, maybe look at a 5cm chop length. Firstly to help hold it in the clamp, but also to help it stay in the rumen a bit longer to get better value from it.”
THERE is an added argument with a multi-cut system that you need a good additive because sugar levels will be lower, says Dr Davies, since sugars accumulate during plant growth. He says: “Protein will be higher because the plant has assimilated nitrogen into protein, but it has not grown as much, so the protein has not been diluted. “Higher protein increases buffering, so you need to get the pH down quickly. If you do not have a good silage additive, protein breaks down and you need more acid to counteract this.” Mr Jones agrees, and says without an effi cient fermentation to convert sugars into benefi cial acid to ‘pickle’, and therefore preserve the silage, some of its higher nutrient content risks being lost. He says: “You need a proven additive capable of delivering highly effi cient homo-fermentative bacteria. This is what Ecosyl has been developed to do.”
DR Davies and Mr Jones agree that a useful practical benefi t of cutting grass while it is younger and con- tains less stem material is easier consolidation in the clamp. Dr Davies says: “The best equipment for moving silage into the clamp is a push-off buckrake. As you drive up the clamp, it main- tains an even layer, making it easier to consistently achieve the correct 15cm layer depth for fi lling. “With a consolidator, it can be a single-pass job because grass should contain less stem material. It can also speed up fi lling of the clamp and help you keep pace with the contractor bringing silage loads.”
ONE of the key points with multi-cut at feeding, says Dr Davies, is to be mindful of the extra protein it can deliver. Also, there is a slight risk there could be higher nitrate content in silage because it is cut sooner. Dr Davies says: “Protein may be higher than you think. If you feed excess protein, it is shipped out of the animal in urea, which takes energy, and fertility can drop. “High nitrates in silage and, therefore, in the cow, could be exacer- bated if feeding urea-treated cereal.” In response, Dr Davies advises having a wet silage analysis con- ducted, so protein levels in the ration can be accurately balanced. Also, although less stem mat- erial can help with consolidation, it can mean extra fi bre has to be added to the ration with multi-cut silage, says Mr Jones, but fi bre is relatively cheap.
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