The scale of the mycotoxin challenges in Irish silages is higher than in previous years and will need to be managed in order to maintain performance.
This was the key assertion made by Alltech’s Aislínn Campbell in her presentation to a recent mycotoxins workshop.
Alltech’s European Harvest Analysis Programme for 2023 has highlighted testing results from grass silage, straw and total mixed ration (TMR) samples, taken throughout Ireland over recent weeks.
All of the work was carried out at the Alltech laboratory, based at Dunboyne in Co. Meath.
The facility provides a comprehensive overview of the mycotoxin risk in animal feeds by testing for 54 individual mycotoxins.
Mycotoxin challenge in silage
The results this year confirmed that 63% of grass silage samples, 15% of straw samples, and 76% of TMR samples were at high risk for mycotoxins.
To better understand the link between mycotoxins and animal performance, Alltech’s mycotoxin management team has developed the risk equivalent quantity (REQ).
This figure represents the overall mycotoxin risk associated with a sample and a particular species’ health and performance, based on the cumulative effect of the groups of mycotoxins present in a feed sample.
“Of the Irish grass silages assessed, 62.9% posed a high mycotoxin risk, 5.7% a moderate risk, and 31.4% a low risk,” Campbell explained.
“Penicillium compounds represented the highest mycotoxin grouping identified. The average REQ value measured across all the samples analysed was 322.8.”
“These numbers represent a worst-case scenario when considering a cumulative effect of various mycotoxins.”
Dairy cow performance
So what could all this mean for dairy cow performance?
According to Campbell, an REQ figure of 323 could impair milk production by up to 0.74L/cow/day while increasing cell count by a factor of 107.2%.
“Where 2023 straw analyses are concerned, 14.3% of samples posed a high mycotoxin risk, 14.3% a moderate risk, and 71.4% a low risk. The average straw REQ value was 286,” she said.
“Straw included within a TMR with an REQ value of 286 could have a negative on somatic cell count.
“However, when included in a TMR, it is important to consider the effects of straw in relation to mycotoxin risk, something that is often overlooked.”
Mycotoxins and animal health
The global director of Alltech’s mycotoxin management team, Nick Adams, also spoke at the workshop.
He confirmed that mycotoxins can affect any animal at any stage of production.
Problems can be ongoing or flare up suddenly, even on the same pit of silage. This may be due to hitting pockets of mycotoxins in the clamp.
Animals may exhibit one symptom or several. Mycotoxins can reduce appetite, gut integrity and rumen function, decreasing the animal’s ability to absorb nutrients from feed, resulting in performance losses.
Symptoms may include reduced or fluctuating milk yield, poor milk solids or reduced daily live weight gain (DLWG).
Fluctuating forage intakes, variable dung consistency across a batch of animals, or loose dung consistency can also be signs of gut problems.
Mycotoxins suppress the immune system, a problem which can manifest itself in multiple ways, including cell count problems such as raised somatic cell count (SCC), often leading to increased cases of mastitis or E. coli, swollen hocks, lameness and rough coats.
Fertility problems caused by mycotoxins can range from irregular heats to cysts, lower conception rates and abortions.