16 November 2001

FW guide helps you pick the best silage additive

Welcome to the farmers weekly Forage Additives Guide,

published in association with UKASTAs UK Forage Additive

Approval Scheme. Using this guide to selecting a

suitable additive from those marketed can ease a difficult

task, as requirements differ between farms and even

cuts, as Richard Allison finds out

SILAGE making this year proved a greater challenge than usual with the cold, wet spring and foot-and-mouth restrictions resulting in more emphasis on selecting the appropriate additive.

This guide aims to simplify the process of choosing a silage additive by allowing rapid comparisons between products. It covers all additives listed in the UK Forage Additive Approval Scheme (FAAS), now in its ninth year.

There have been no changes to the testing scheme this year. The last thing the industry needs after the F&M crisis is to grapple with a new system, says UKASTAs Derek Ward.

For a product to gain approval in any category (see below), benefits must be proved in independent scientific trials when compared with identical untreated silage, says SACs John Weddell. "This rigorous assessment of product claims gives producers confidence when selecting their additive.

"Additive quality is also monitored by independent sampling and testing. Biological additives are tested to check whether they contain the stated bacterial, numbers and species."

With more than 65 additives listed, there is considerable choice for producers. The first stage in narrowing product choice is to identify why an additive is needed.

"Is it to improve animal performance, aerobic stability or reduce effluent production? For increasing milk production, consider products approved for enhancing milk gain and intake. To improve aerobic stability, consider acids and salts."

Silage stability at feed out is crucial because heating reduces nutritive value, says Kingshays Duncan Forbes. "There is no point investing time and cash to improve ensiling only to lose the benefits before forage is fed."

Be aware that different silage cuts may require different products, he adds. "Many producers stick to one product, but later cuts of silage are often ensiled in poorer weather with lower sugar levels than first cut. In addition, early cuts remain in the clamp for longer and stability is the main factor."

This year, more second and third cut crops received an additive, says Nicola McDougall, of Genus. "This is because producers are relying more on later silage cuts due to smaller first cuts and the push for milk output with current low quota prices."

To assist additive selection the approval scheme provides information on the effectiveness of each silage additive on animal and silo performance, together with application rates and treatment costs. This allows producers to select an additive for a particular purpose, such as improving aerobic stability or reducing effluent production.

The animal performance approval section of this guide indicates when each product has been shown to enhance performance across five categories:

&#8226 Gains: When trials found it enhanced daily liveweight gain.

&#8226 Milk: Products shown to increase milk production.

&#8226 Intake: Where trials reveal that additive treated silage results in a greater intake than untreated silage.

&#8226 Digestibility: A product which improves digestibility in trials.

&#8226 Efficiency: When animal production efficiency improvements have been reported.

Silo performance approval includes four categories:

&#8226 Fermentation: The product has show it improves fermentation.

&#8226 Stability: When aerobic stability improvements have been proven.

&#8226 Effluent: Trials show it reduced effluent production.

&#8226 Losses: When it cuts clamp losses.

When products have a G or M next to the stability category, this means they have been approved for improving aerobic stability of either grass or maize silage, respectively: When a GM appears, the product will improve aerobic stability of both grass and maize silage. &#42

FAAS OBJECTIVES

&#8226 Improving choice available by identifying effective products.

&#8226 Improving producer knowledge of which product is best suited to their needs.

&#8226 Increasing additive use in circumstances where justified.