Late silage cuts will take on far greater importance this year as dairy farmers across the country strive to build stocks ahead of the winter.
It is vital to ensure late silage cuts make the maximum contribution possible and inoculants containing enzymes can play a major role says Roy Eastlake, Biotal Technical Support Manager.
“We look set for some excellent growing conditions now we have had some rain. With high soil temperatures and good residual nitrogen, grass is expected to move away quickly – and this accelerated growth should be seen across the entire grass platform.”
Mr Eastlake recommends working out available and projected forage stocks now and assessing how closely they match requirements.
On many farms, stocks have been hit by reduced first and second cuts combined with increased buffer feeding during the drought.
At the same time, there has been a big increase in the amount of fermented wholecrop made as farmers used the flexibility of the crop to plug the gap in grass stocks.
“Work out any potential silage shortfall and decide what you need from later cuts,” he says. “If you are facing a less sizeable shortfall you will be able to focus on a smaller, but better quality late cut.
"However, for many, the size of the shortfall will mean that quantity will take priority over maximising quality. So the skill then must be in achieving the best balance. There is no point just producing belly-fill.”
As grass matures and bulks up, so the proportion of structural fibre increases – reducing the digestibility and energy content of the grass and resultant silage.
The more grass bulks up, the poorer the quality so, while a large crop may provide bulk and rumen fill, it will come at a cost of requiring increased supplementation.
“If you need to make a larger cut, you still need to ensure the best quality in the increased quantity. Focus on silage making technique and do not cut corners. Remember, it is a very valuable feed which will have a significant impact on performance and production costs this winter.”
Mr Eastlake stresses the importance of wilting which helps concentrate sugars, reduce the risk of pH buffering and improve eventual dry matter intakes. However, the length of wilt needs to be carefully managed.
Ideally, grass should be ensiled at around 32 per cent DM which is the optimum for fermentation efficiency and subsequent dry matter intakes. All the time grass is lying in the swath it is respiring, with sugars being used up so pick it up quickly.
He says the longer it is left lying, the more sugars are lost and the poorer the silage feed quality. You cannot eliminate these respiration losses, but you can manage them and, in so doing, can preserve feed value.
He advises the use of inoculants on later cuts is essential to promote a more rapid and complete lactic fermentation. He explains that with lower sugar levels in late season grass it is important that grass ferments as quickly and efficiently as possible, making an inoculant a prudent investment.
“To further improve quality, choose an inoculant containing enzymes which break down hemicellulose in the structural fibre in grass, as this has two benefits. The first is in the clamp when the improved breakdown of fibre releases sugar to fuel a faster fermentation and improve preservation.
“The second is in the rumen when the silage is fed. As the hemicellulose degrades, the rest of the fibre is exposed to action by the microbes in the rumen, resulting in more efficient utilisation of the fibre by the cow. In essence, the enzymes unlock the feed potential of the crop
“Together these can mean better feed value despite later harvesting and research shows this translates into better performance. In independent UK trials, over the eight hours that forage typically remains in the rumen, silage treated with a bacteria and enzyme inoculant was 19 per cent more digestible than untreated silage, meaning more energy is available.”
In a trial at the Agricultural Research Institute of Northern Ireland (ARINI) at Hillsborough, the improved digestibility of forage treated with an enzyme and bacteria inoculant resulted in 1.3 litres more milk and higher milk quality.