Faced with increasing purchased feed costs and fluctuating milk prices, now more than ever, organic dairy producers need to maximise the volume and quality of their grass silages. ForFarmers Forage Product Manager, Mel Digger, shares her advice.
With grass silage representing one of the most cost-effective feeds available on organic farms, producing high yields of consistent, good quality silage, with high dry matter, will be key to maintaining farm profitability.
“No matter how many silage making seasons a farmer has under their belt, now is the time to review silage production setup, from cutting length to clamp management. For the best results, all aspects of cutting, harvesting and ensiling must becarried out with clear attention to accuracy and consistency.”
For organic producers, it’s especially important to produce adequate stores of high-quality grass silage. Any shortfalls in silage production must be met by increased expenditure on premium organic concentrates or sourcing forages from other organic producers, which often proves challenging and costly.
“When it comes to silage making, organic producers should break the different stages of production down into two, overarching areas of focus,” says Mel. “The first is about gaining as much feed value from grass as possible and achieving the optimum condition for ensiling.
“The second is all about preserving as much of the grasses’ feed value as possible. This includes how clamps are filled, compaction levels and sealing of the clamp, but the importance of inoculants shouldn’t be overlooked either. There is a range of organic-approved inoculants available, and I would encourage every producer to treat their silage with one, to help maximise quality.”
To achieve the right balance between good grass yields and grass quality, it’s important that grass is cut at the optimum time. For some producers, there’s often the temptation to delay harvesting in the hope of giving grass more time to grow and therefore achieving higher yields. However, this approach can lead to a loss in grass quality.
“It’s vital that quality isn’t sacrificed,” says Mel. “Cutting too late will result in a protein loss and lower digestibility value, which can fall by as much as 0.5 units per day after grass heading.
“Energy loss is also an important consideration. Based on a 1,000-tonne grass yield, there can be an energy difference of up to 300,000 MJ by cutting younger grass at 11.5 ME compared to 10.5 ME.” That 30,000MJ is equivalent to 60,000 litres of milk which at 40ppl is around £24,000.
Getting cutting height right is vital too, with slightly longer chop lengths improving digestibility of grass silage. Conversely, cutting too low reduces digestibility and increases the risk of soil contamination.
“This contamination can lead to a poor fermentation in the clamp and result in silage with a lower feed value, so it’s something that needs to be avoided,” continues Mel. “Once grass is cut it then needs to be wilted as quickly as possible to reduce sugar losses, which can be as high as 6% over a 24 to 36 hour period.
“After this wilt, it’s time to harvest and farmers need to remember the influence that chop length will have on consolidation when it comes to ensiling. For grass above 30% DM, aim for a chop length between 15 and 25mm and at DMs between 20 and 30%, a good length is 25 to 50mm. The longer the chop length, the longer it takes to remove air from the clamp, but too short and it can cause problems with slippage.”
With producers having gone to the time and effort to produce high-quality grass, it’s essential that productive potential isn’t wasted by poor ensiling protocols. Reviewing which inoculants are used to treat silage and how this silage will be ensiled should also be on a producer’s pre-silage season ‘to do’ list.
“Using a silage inoculant improves fermentation and quality by increasing the number of beneficial bacteria present during the ensiling process,” explains Mel. “I would recommend that all farmers use a grass silage inoculant. While they don’t help make poor quality silages good, they do help make good quality silages even better. And with the potential to help increase milk production by up to 1.5 litres per cow, per day, their positive impact shouldn’t be overlooked.”
“There are lots of silage inoculants available, so it’s important to choose ones that suit their predicted feed requirements, and also that they are organic compliant. It’s a good idea to get inoculant orders in early, well before the silaging season starts. That way farmers can ensure that they have their ‘number one’ pick of inoculant to hand, ready for prompt use during the ensiling process.”
Inoculants help with fermentation in a silage clamp and aids a rapid drop in pH, down to a target of 3.7 to 4.2 pH when grass is ensiled. This helps inhibit the growth of undesirable bacteria and moulds, such as clostridia and bacilli, as well as preventing protein and DM losses.
When clamping grass Mel reiterates the importance of good consolidation and clamp sealing and encourages producers to look back at their approach over previous years and consider improvements that could be made.
“Achieving good consolidation is incredibly important,” says Mel. “When clamps are being loaded, aim to do it in layers no more than 15cm deep, with each layer thoroughly consolidated before the next goes on top.
“By getting as much air out of the clamp as possible, including clamp edges, producers ensure that the quality of silage fermentation will be maximised, and it also helps increase the aerobic stability of silage when it is fed out.”
Clamps should then then be sealed effectively to prevent air getting in and the top of the clamp weighted to help maximise silage density.
“It’s all too easy to approach silage making in the same way as previous years,” concludes Mel. “But taking the time to review your approach, and doing this review process early, can often help highlight areas for improvement.
“With increasing feed and input costs, now more than ever, organic producers need to following these steps to produce the best homegrown forages possible which will help sustain their businesses for the year ahead.”
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