Get to grips with grain preservation and mould management.

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In Denmark we traditionally rely on grain drying as the primary solution to conserve cereals and grains, while most of our neighbouring countries choose to use acids, either as the only method, or to complement drying for grain conservation. While grain drying seems to work for the most part we still often hear about mycotoxins in the feed. Particularly at this time of year when silos are starting run low and grains have been stored for long, the risk of mycotoxins is high. Cereals harvested both in 2018 and 2019 have reportedly given problems with mycotoxins that required some intervention to maintain feed quality.

The problem with moulds of course is the development of mycotoxins that can have several negative effects on animal production, reproduction, and performance. SEGES monitors Fusarium toxin levels in winter wheat with every harvest and generally finds high levels of vomitoxin (DON) with an average of 63% of samples being positive the last 17 years. Some years the levels are low like 4% in 2014 and other years as high as 99%. While the same numbers for ZEA have a lower  average at about 28%, ranging from 0% to 63% from year to year. In maize, the problem is significantly larger and the recommendation is simply – know the levels in whole grain maize prior to using it for feed.

Given that this is an ongoing problem we asked Lars Brendstrup, our own expert in feed hygiene and grain preservation, why do our neighbouring countries rely more heavily on the use of acids for grain conservation? Lars has worked globally for Perstorp, one of Agmondo’s key partners, as business development manager for feed preservation prior to joining us. “The main reasons for this are that it is significantly safer than drying at keeping moulds under control for the entire storage period, offers a larger flexibility with regards to dry matter content at harvest and most importantly is cheaper than grain drying,” says Lars. His general recommendation is that as a bare minimum one should treat all cereals with pure propionic acid 99%, or a product like MondoGrain that does not require HACCP. Products like these are not only reserved for crimping, ensiling or TMR management, but also as a standard for making cereals suitable for long term storage storage in open or closed grain silos. “By treating the grain with propionic acid, we see that cereals can be safely stored for up to 6 months without the growth of moulds,” Lars adds and continues, “The main disadvantage is that propionic acid is quite corrosive to equipment, but there are much safer alternatives available like the more classic MondoGrain type of acid blend or the latest product designed for this purpose – ProSid MI700.”

Aerobic development of moulds during storage

Moulds and therefore mycotoxins can develop under aerobic conditions in the silo both when pockets of humidity increase the moisture and conditions for growth. Also variation in temperature between day and night, particularly in the summer can create ideal conditions for growth.

During the day the silo heats up causing evaporation of any moisture in the grains

At night the silo cools down causing the moisture to condensate along the sides of the silo

ProSid MI700 is the latest innovation with regards to grain preservation and one of the alternatives to propionic acid that is gaining significant traction, particularly in Germany. While it offers all the advantages of propionic acid, it also offers significantly less corrosiveness and can extend the storage time to up to 12 months. The technology behind ProSid MI700 is deceptively simple, but highly effective, and one you are more than likely familiar with. The product is a propionic acid glycerol ester. More common glycerol esters are plant fats or triglycerides. Where a triglyceride is made up of three fatty acids attached to a glycerol molecule, Prosid MI700 is made up of fatty acid molecules – propionic acid – attached to glycerol combined with a little pure propionic acid. This not only makes the product highly concentrated in propionic acid (83%) but acts like a fat that reduces the surface tension which means that the product binds well to the crop. Additionally, it is a lot less volatile than pure propionic acid which reduces evaporation, makes it non-corrosive and therefore easy to handle. Finally, since it is a fat it is considered a complementary feed and therefore does not requires HACCP like propionic acid. By using 3-4 kg/ton you can store your grain for up to 12 months and reduce the risk of developing moulds and thus the development of DON, ZEA mycotoxins in your cereals all the way through to the next harvest, also removing the need for mycotoxin binders.

Moisture along the inside of the silo walls led to development of moulds and germination of grains.

Mold developing in corn on a south-facing wall in winter, likely due to solar heating. 
(Iowa State University Extension)

With increasing demands to produce antibiotic and zinc free the role of maintaining a high level of feed hygiene throughout the feed supply chain is becoming paramount. Using propionic acid, MondoGrain or ProSid MI700 can help you maintain good feed by controlling pathogenic bacteria, moulds and yeast in cereals with a relatively high water percentage. The added bonus is that by controlling these pathogens that live off of the protein and starch in the grains you also maintain the nutritional value of your cereals.

Agmondo has significant in-house expertise in grain preservation so please feel contact us if you are concerned about molds, mycotoxins or feed hygiene issues in your operation. 

How to practically preserve grain with acids

The product is applied directly to the grain at harvest before storage.

Check the temperature daily for the first few weeks, then check once a week. This applies to all preservatives. A temperature rise of 4 degrees Celsius or more indicates that the dosage is too low and / or insufficiently mixed.

Peas, beans and rapeseed must be treated twice. For the first treatment, use half of the recommended dose and repeat the treatment after 3 days with the second half.

About the author

Jason Lorjé

Jason Lorjé

Jason is CEO and founder of Agmondo and a veterinarian who has worked many years in the animal pharmaceutical and feed additive industry.

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