21 April 1995

A NEED TO STANDARDISE

GRASS silage is the main part of most winter rations for stock, especially in the north and west of the country, where it is harder to grow alternative forages.

By its nature grass silage is an unpredictable forage. Cut early and wilt rapidly to get a high dry matter crop and the chances are the ensiled material will be digestible, with high intake characteristics. But just how digestible, and how well will it be eaten by cattle or sheep? That is where silage analysis should help.

It is vital to know how much energy and protein stock will receive from the silage, how well it has been preserved, and what intakes are likely to be. This helps in planning the level and type of other feeds to include in the diet. But all too often the analysis fails to reflect how the silage actually feeds. And as farmers weeklys silage analysis survey shows, silage analysis reports cause variation and confusion.

Different labs are using different analysis systems and reporting different information. The same information is reported in different ways.

All these differences have arisen because the service is often part of a selling drive for advice, feed, and silage additives.

In our survey we sent one silage sample, albeit a tricky one, to 11 labs for analysis. That the farmer was presented with ME values for the one silage ranging from 8.8 to 11.4 MJ/kg dry matter is an illustration of the variation that exists between the different services. No wonder producers are sceptical about the value of silage analysis.

However, progress has been made in recent years with the development of M4E. But it is up to the industry to standardise silage analysis still further so farmers can have faith in the results.