Better quality silage can be achieved with rapid wilting, silage experts in a recent Volac briefing have said.
Producers need to ‘forget the notion of a 24-hour wilt’ and switch to a target of ‘the quicker the better’, said Ecosyl silage advisor Peter Smith, who added that this had become more important in-line with the growing popularity of multi-cut systems.
Speaking in the briefing, Mr Smith said: “Once grass is cut, and until it is taken down to a stable pH, it carries on respiring sugars, burning up nutrients and protein.
“The longer grass is left in the field; the more nutrients are lost, and the more time spoilage organisms have to set in.”
Tedding the crop and cutting grass earlier in the day were major ways to achieve a faster silage wilt, according to the results of Ecosyl UK trials carried out last year.
The research, which was conducted using farm-scale silage machinery on commercial farms in Wales, compared the effects of tedding, time of day of cutting, and crop maturity on the rate of crop drying by measuring how long it took grass silage to reach an optimum dry matter (DM) of between 28 and 32 per cent.
Findings from the first trial in Pembrokeshire, which was carried out on a light, multi-cut grass crop cut on a warm, dry July day found that cutting at 10am and tedding immediately resulted in grass reaching the target DM levels in 4.5 hours.
That compared with seven hours to reach 30 per cent DM for grass that was not tedded until five hours after cutting, and 24 hours if grass was left untedded in rows.
Grass cut at 3pm and tedded immediately after cutting also reached 30 per cent DM in five hours, but the crop not tedded until the following morning took 23 hours to reach target DM levels.
Where the 3pm cut was left untedded, it failed to achieve 30 per cent DM, instead reaching 24 per cent DM after 24 hours.
The second trial, carried out in Carmarthenshire on a grass crop cut on an overcast day in September, compared a heavy mature grass crop and a lighter multi-cut crop in terms of wilting speed.
Results here also showed that tedding also increased drying speed, although some rain at this site meant neither crop reached the target DM, with the heavier crop cut at 11am and tedded immediately reaching 22 per cent DM within five hours, compared with the untedded crop which reached 21 per cent DM after 23 hours.
In both crops, tedding twice was also found to further improve wilting.
Ecosyl silage scientist Dr Mark Leggett said: “Generally speaking, cutting early and tedding the crop out is going to result in the best and fastest wilt which will maximise the nutritional value of the crop.
“This is highly relevant as farms strive to increase milk production from homegrown forage and silage, because the longer that grass is wilted for, the more nutrients it will lose.
“Wilting to 28 to 32 per cent DM gives the best balance between minimising effluent and minimising field and clamp losses.
“Coupled with good consolidation, wilting rapidly is another key step to help farmers produce consistently better silage.”