Silage Making For 2007 – Coping With Another Dry Year

Dr. Colin Shorrock – Technical Manager, Denis Brinicombe Group

With last years dry weather there was a lot of high dry matter silage made with the subsequent knock on effect of aerobic instability with yeast and mould activity resulting in heating clamps, mouldy bales, production of mycotoxins and loss of feed value.

Aerobic instability, the activity of yeasts and moulds, is not as some people persistently call it a fermentation process (it often gets called secondary fermentation which is an even worse mistake). It is purely the activity of yeasts and moulds in the presence of air using up any available sugar and producing heat, carbon dioxide and water. Mycotoxins are also a product of their metabolic processes.

Weather predictions this year are that it could be another year of above average temperatures with the associated danger of producing drier silages, which will be prone to aerobic deterioration.

What action should be taken?

Producing quality silage in a dry year is in the operator’s hands; attention to detail is paramount. In hot dry weather wilt the grass for as short a time as possible, in some circumstances it may be possible to cut in the late morning and pick up in the late afternoon. Shorten the chop length, but maintain it long enough for good rumination characteristics, fill the clamp quickly but with lots of thin layers and lots of rolling. When you think that you have rolled the clamp enough then roll it again.

Seal the clamp effectively; the last few trailer loads should be direct cut grass to give weight to the top of the clamp. Alternatively, finish the clamp of with a layer of brewer’s grains, draff, potato slurry or anything that is wet and dense to exclude the air. Sheet the clamp well and apply as much weight as possible.

Is it worthwhile considering using an additive?

In the type of conditions we may expect to encounter this season the additive of choice MUST have specific activity against yeast and mould activity. Drier silages do not normally have problems of undergoing fermentation to produce lactic acid, as is the problem with wetter silages.

What types of additive should I use in dry conditions?

Use ones that contain heterofermentative lactic acid bacteria (LAB). These types of LAB provide activity against yeast and mould. Alternatively, use products containing sulphites, again these have the effect of inhibiting the action of yeast and moulds.

From the Denis Brinicombe range Biological additive products such as Biophage Big Bale, Biophage Wholecrop and Biophage Maize contain the required heterofermentative LAB and the sulphite based product Cropshield™ provides the appropriate anti- yeast and mould activity.