Farmers warned of increased risk of mycotoxin in silage after drought
High levels of mycotoxins could be a key characteristic of grass silage crops made in Ireland this year, according to animal nutritionists.
This is a direct consequence of the drought conditions that developed over the summer months.
Stress is the word that best describes what many grass crops endured during June and July.
Like any crop, grass requires adequate moisture to sustain normal growth and development.
When drought conditions persist, plants become increasingly vulnerable to the ingress of moulds.
These moulds can become incorporated into silage during harvesting and ensiling, creating challenges that may only become apparent months later.
Mycotoxins
Of particular concern are mycotoxins, compounds produced by certain mould species that can have significant consequences for livestock health and performance.
The issue has been highlighted by Belfast-based United Feeds.
Company nutritionist Jenny Chestnutt explained: "Mycotoxins remain one of the most complex and rapidly evolving areas of animal nutrition.
"While several toxins have been identified and can now be tested for, we know there are many more that remain poorly understood.
"Given the level of drought stress experienced this season, we are beginning to see indications that some second-cut silages may present a higher mycotoxin risk than normal."
One of the frustrations associated with mycotoxins is that they are often difficult to detect.
The mould responsible for producing the toxin may have disappeared long before the silage is fed, leaving no obvious visual evidence of contamination.
Symptoms
As a result, farmers often need to identify the problem through changes in animal performance.
Chestnutt said: "Producers should be alert to sudden unexplained changes in their herds’ behaviour, health or performance.
“These include elevated mastitis levels, sudden changes in performance or dung consistency, fertility issues or a general increase in health-related problems.
“All of these issues can indicate that mycotoxins are playing a role.
“Mycotoxin challenges may be more apparent, but not exclusively, when a new silo is opened or forage from the back end of a pit is included in the diet."
As with many livestock health issues, prevention remains far preferable to cure.
While eliminating mycotoxin risk entirely is impossible, practical management measures can significantly reduce the threat.
Good silage-making practices remain the first line of defence.
Achieving adequate compaction at ensiling, maintaining effective sealing, and minimising air penetration at feed-out through good silo face management can all help reduce the conditions that favour mould development.
