In many cases, mycotoxins won’t alert livestock producers to their presence. There may be no visible mould and no bad smell [1]. Yet, the infestation can be there – waiting to drag down production, decrease herd health, lower fertility and even be a food safety hazard.

Renato Schmidt, PhD, Technical Services – Silage, Lallemand Animal Nutrition explains:

"While mycotoxins are produced by specific moulds, visible signs of mould may not translate to measurable mycotoxin levels and vice versa. It’s virtually impossible to completely avoid mycotoxin exposure. The toxins can be produced both on the growing crop and during storage and feedout."

To help reduce mycotoxin production, producers can plant insect and disease-resistant varieties, avoid leaving stubble standing in the field and practice crop rotation. In addition, it helps to avoid or minimise the effects of plant stressors like inadequate fertilisation. Still, producers cannot avoid damage from pest infestation or weather events that can predispose crops to mould infestation and mycotoxin production.

When the crop has been stressed or physically damaged, the potential for mould infestation significantly increases. In these cases, Dr Schmidt advises producers to take extra care with silage management.

To help minimise mycotoxin-producing moulds – and all moulds that cause spoilage – producers should use proven silage inoculants as part of a good overall management programme. For example, silage inoculated with Lactobacillus buchneri NCIMB 40788 will be more resistant to heating and spoilage as this organism reduces the growth of yeasts, the initiators of spoilage. In fact, L. buchneri 40788 applied at 400,000 CFU per gram of silage or 600,000 CFU per gram of high-moisture corn (HMC), has been uniquely reviewed by the FDA and allowed to claim improved aerobic stability.

In the ensiling structure, moulds tend to grow in hot spots where there is air (Oxygen) present, Dr Schmidt notes. This is typically in poorly sealed surface layers, corners or shoulders of ensiled forages, or where pockets of air were trapped and packing was inadequate.

Dr Schmidt advises:

"If visibly mouldy silage is identified, discard it. Feeding even small amounts of spoiled silage into a ration has been shown to reduce dry matter intake and NDF digestibility of the whole ration [2]. While it may feel like an economic hit, you’re risking more in terms of lost production, herd health and reproduction if you choose to feed spoiled silage."

For more information about mycotoxins and mould in silage, livestock producers can download a free copy of the Silage Quick Facts Handbook.

As reported by Lallemand Animal Nutrition

[1] Rankin M and Grau C. Agronomic Considerations for Molds and Mycotoxins in Corn Silage. University of Wisconsin-Extension. Focus on Forage, 2002;(4)1.

[2] Whitlock LA, Wistuba T, Siefers MK, Pope RV, Brent BE, Bolsen KK. Effect of level of surface-spoiled silage on the nutritive value of corn silage-based rations. Cattlemen’s Day 2000.

Image: Medmyco