The second in a two-part series from Volac suggests farmers should prioritise quality over quantity at the cutting stage to get the best from their silage.
Silage-making season is upon us, and to achieve optimum benefits from this valuable home-grown forage farmers should prioritise quality over quantity at the cutting stage.
That is the advice from independent silage consultant Dr David Davies, who says the most common mistake made at this time is waiting for yield rather than concentrating on quality.
“Farmers need to be thinking about quality in the field – you should not be making silage from grass of a quality you wouldn’t graze cattle on. To stand a chance of achieving an ME of 11.5, you need to be cutting before there are any signs of seed stems coming up,” he explains.
“Cutting at that stage actually allows the opportunity for greater yield in the field because the regrowth will be quicker – ensuring the possibility of an extra cut. So, although cutting earlier rather than later may appear to result in lower yields, it should in fact achieve the opposite in the long run.”
Furthermore, Dr Davies says cutting younger will also speed up the wilting process, therefore increasing the chance of hitting a DM target of 30%.
“A longer wilt time allows more time for the wrong type of bacteria, yeasts and moulds to set in which, in turn, results in higher ‘invisible’ losses in the clamp as a result of the production of carbon dioxide and water.
“Reaching a 30% DM gives you a better chance of having more silage because the losses are likely to be less. There’s also more chance of maintaining that quality – around 0.7 of ME can be lost between cutting and feeding,” he adds.
Dr Davies also points out the protein content will be higher in younger grass, which is beneficial when feeding to milking cows.
“The more energy and protein they can get from silage, the less they will rely on bought-in concentrates, which is helpful from a cost saving point of view, but it will also assist in improving the fertility and health of the cows as a greater proportion of the ration will be forage.”
To best conserve the nutrients in the silage, Dr Davies says using an effective homo-fermentative additive is a must – and, in fact, the higher the quality of the grass in the first place, the more important it is to use an additive.
“A good quality inoculant is extremely important, and if the grass is very high quality to start with you have more to lose by not using one. Leaving fermentation to the natural population is an inefficient process which will lower the nutritional value of the silage.
“But when choosing an additive I strongly advise asking for independent trial results which show consistent animal performance benefits, then you can be confident you will see an improvement too.
Dr Davies also reiterates the importance of good compaction in the clamp, from the first load – aiming for thin and even layers for optimum consolidation.
“The next priority is sealing in the carbon dioxide to help reduce the undesirable bacteria, yeast and moulds which lead to spoilage. Effective sealing can result in 4% more silage.”
Dr Davies suggests the use of an oxygen barrier film below the black sheet can make a huge difference, and if using green mesh on top he advises it should be clamped into a dome in the centre to enable it to be pulled as tight as possible down the sides, and it should be pulled tight every day for the first week.
“Whichever sealing materials are used, gravel bags should be touching each other all the way round the edge of the clamp – particularly on the ramp – to prevent CO2 from escaping. The sign of a well-sealed pit is one that blows up like a bouncy castle.
“You can make a huge difference to the quality of your silage without spending anything other than time. The one thing dairy farmers don’t want to be cutting back on at this time is the quality of their silage,” adds Dr Davies.
Producing top quality silage is a key factor in the success of the forage-based system at gelli Aur college Farm, which has been managed by John owen for the past 22 years.
During this time he has developed a system which he has found to be the most profitable option for the 550- strong cross-bred milking herd. The cows are split into 300 spring calvers, with a grazing grass-based diet, and 250 autumn calvers, which rely on conserved grass.
“Our main aim is to produce as much milk from forage as possible, with the amount of concentrates we buy in varying, depending on the milk price. This year, because of the poor returns, we have cut concentrates by half. The cows are parlour fed and the system is now very much the same for both herds,” says Mr owen.
Constantly looking at ways to improve the quality of the silage, Mr owen has recently become involved in a Farming connect project, beginning this year, to investigate whether reducing the time between cuts could help increase the quality. With the possibility of taking up to five cuts, instead of their usual three, he hopes any extra costs will be outweighed by improved performance of the cows.
“Because silage is so vital to our system, attention to detail is important and we put a lot of emphasis on clamp management. We make sure the grass is well spread and well rolled between loads, and ensure a good, level surface for the sheet to stick to.
“We used cling wrap last year before the top sheet and that definitely helped reduce wastage on the top. using a block cutter leaves a nice, undisturbed face too,” says Mr owen.
“And an additive is important to help with the fermentation process and to best conserve the nutrients. We have used Ecosyl for a number of years now and it certainly does the job for us.
“Silage is by far the cheapest feed you can give to cows in the winter time and the more milk you can produce from forage, the better the profit – particularly at the moment,” he adds.
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