Making the most of grass silage

Grass silage
Grass silage
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Grass silage has been the predominant forage for livestock farmers for many years.

It provides a source of forage for maintaining milk production whenever grazing is limited or during the winter months. Grass silage has the potential to produce a relatively high energy, high protein feed that requires minimal supplementation under the correct conditions.

Grass silage requires a high level of management input to achieve high yields and good quality. The use of additives over the years has helped the fermentation process and the preservation of important nutrients. Additives must be specific to the conditions experienced by the crop.

If silage quality is below target, then predicted animal performance for the whole of the feeding period may be compromised; additional supplementation will be required to reach milk yield targets and there can be knock–on effects on milk quality. In reality, the outcome of two or three days’ work will determine success or otherwise for the whole winter.

This is why so much effort has been put into developing grass silage-making systems over the years - to try and improve quality and to minimise the risk from bad weather. Microbial technology should be used to improve the fermentation quality and the feeding value, by using the correct combination of bacteria and enzymes.

The use of a crop (dry matter) specific additive to ensure consistent fermentation throughout the whole clamp is essential for producing high quality grass silage.

Nutrient quality and intake characteristics deteriorate throughout the fermentation period, hence the faster the fermentation, the better. To achieve a good fermentation, the pH level of the crop has to drop from around 6.5 to 4.0 as quickly as possible.

The most effective inoculants will achieve this target within a day. Inoculants aid the natural fermentation process by adding selected lactic acid producing bacteria to the forage crop. These convert sugars in the forage to lactic acid and help reduce the pH quickly with the minimum loss of nutrients.

Even in the best ensiling conditions, this will happen more slowly without an additive, leading to a loss of nutrients and reduced animal performance. Lactic bacterial counts vary with time from ensiling, reaching more than one billion per gram at peak and declining to a background level (100 – 1000/g) with prolonged storage.

Some specific bacteria also prevent spoilage by yeasts and moulds, which are the main spoilage organisms in higher, dry matter silages and forages.

Biotal AxpHast Gold is the premium grass additive from Biotal for use on lower dry matter grass silage. It gives the producer more flexibility by increasing the dry matter range in which the product can be used. AxpHast Gold contains Biotal’s proprietary lactic acid producing bacteria as well as a specific strain of bacteria called L. buchneri. This enables AxpHast Gold to be used from 20 to 30% dry matter.

Enzymes are used to break down specific fractions of the fibrous material in the forage to release extra fermentable sugars for conversion by the bacteria to lactic acid.

The accessibility of the cellulose in the plant can be improved by breaking down specific hemicellulose fractions with the patented enzymes in Axphast Gold. This helps effluent retention and improves the rate of digestibility.

Using AxpHast Gold on lower dry matter grass silage has been shown to have significant effects on milk production and animal performance in independent trials at ARINI (Hillsborough).

Grass silage faces very different fermentation challenges in wet and dry weather/harvest conditions. Preservation and feedout characteristics can be dramatically affected if specific silage additives aren’t applied to suit different conditions.

Many companies claim to have ‘one’ product for all conditions but producers must be aware of the need for specific products to overcome the problems associated with ensiling grass in wet and dry weather.