Molds and their resultant mycotoxin residues are a global problem. However, I've never seen the likely costs of doing the preventive tasks set against the possible cost of various diseases and disorders caused by pigs eating very small amounts of these highly toxic substances.

The textbooks rightly advise us:

  • Do not buy moldy grain, store soybean meal in damp conditions, or use heat-damaged bedding.

  • Dry grain immediately to less than 16% moisture, preferably under 15%, especially in a wet season.

  • Keep storage bins clean.

  • Farm storage bins should be well ventilated, kept at less than 75% relative humidity and not completely filled.

  • If mold growth is visible or can be smelled in the feed, do not feed to pigs.

  • Add a mycostat to the grain during a wet season.

  • All farm bulk bins should be steam-cleaned twice yearly. This is largely difficult, if not impossible, unless a bulkhead door and swing-away boot are fitted to all future bulk bins. Manufacturers, please take note.

  • If steam cleaning is impossible, it is advisable to add a mycostat to the feed (even though it may have been added to the grain); it is essential to do this after a wet harvest.

  • Some mycotoxins are lethal (especially to young pigs and gilts) at very low feed concentrations (<10 parts per billion).

  • It is advisable (and essential after a wet harvest) to routinely add a mycotoxin absorbent, especially to feed for young pigs, to the end of the nursery period and to all breeding stock, especially replacement gilts.

  • Most feed hoppers and feed troughs, especially in the farrowing pen, are not kept clean enough. As well as routine daily inspection, it is important to pressure-wash these with hot water when the all-in, all-out process is done.

Recognizing the Cost

I have largely used production costs as my base figures, because they are the easiest and most widely understood.

Estimated costs of mycotoxin prevention include:

  • The cost of all precautions outlined above has increased total costs of production by 6% to 13%, in my experience.

  • The cost of judicious (intermittent) mycostat use and routine (continual) mycoabsorbent use increased production costs 2-2.5%.

  • In Europe, buying better grain and improved storage costs add 5-7% to production costs.

  • Cleaning bulk bins costs 1-1.5% more.

So what is the typical cost of mycotoxin contamination?

Based on client experience and performance loss cited in the literature, consider these figures:

Small pigs — Relatively mild mycotoxicosis in several forms, in pigs from 7 to 77 lb., lasted 4-8 weeks and raised production costs 18%.

Severe outbreaks, such as vomitoxin, lasted 4-5 weeks, but raised production costs 24%.

Gilts — From clients' records, mycotoxin effects delayed entry into the herd, sometimes causing whole-herd empty days to rise by 19 days/litter. This raised production costs by about 25% over a one-month breeding cycle.

Sows — Mycotoxicosis of varying severity has caused production costs to rise between 30% and 74% over periods from six weeks to six months, due to impaired fertility caused by anestrus, returns-to-service, abortions, mummies, prolapses, splay-legs and veterinary-diagnosed secondary infections.

Bin Management Payback

Reducing immunosuppressive costs from cleaning bulk bins and better trough hygiene are worthwhile. The improvement in performance from 10 cases studied across a one- to two-year period lowered production costs to slaughter between 11% and 19% (slaughtered at 231 lb.).

Cost:benefit analysis (1993-2004) from better bulk bin and trough management, where costs were either available or calculated involving various mycotoxins, suggested that before bin cleaning and improved trough hygiene, increases in production costs were between 18% and as much as 74% over a period from four weeks to six months or more.

There may have been other factors at work, but most farmers thought bin cleaning was mainly responsible for the recovery in performance.

Return to extra outlay (REO) for the complete protocol outlined above, with the production cost penalties during the outbreak compared to normal productivity, were between 1.9:1 (18% ÷ 9.5%) and 7.8:1 (74% ÷ 9.5%).


Even with milder outbreaks, the costs of a comprehensive annual protective protocol are likely to break even, at least.

But in larger or longer outbreaks, especially in sows, the payback in prevention, or even tolerance, can be over seven times the investment in time, trouble and protective products in the feed.