ISSUE FOCUS 44 FEED & ADDITIVE MAGAZINE November 2024 the tip of the iceberg. Through advanced analytical techniques, over 800 mycotoxins have been identified, with feeds, including both cereals and forages, often contaminated by multiple fungi species and toxins. HOW TO BEST PROTECT THE FUTURE HERD Low mycotoxin contamination levels, often measured in parts per billion (ppb) do not imply no risk to animal welfare or development. European guidance levels do not account for masked or emerging toxins, yet intestinal dysfunctions such as digestion, gut permeability, liver stress and susceptibility to infectious diseases have been noted in monogastrics and young calves below these suggested limits (Valgaeren et al. 2019). As such, a precautionary mycotoxin risk management stance should be taken from an early stage, by monitoring the mycotoxin loads in starter feeds, observing calf performance including unexplained health outcomes, and use of a comprehensive mycotoxin management product. As scientific knowledge expands about the diversity of mycotoxins and their negative effects, so too does our understanding about how to best defeat the array of mycotoxins that can occur in a typical ruminant feed. Case in point: whereas the European Feed Safety Association recognized that inorganic binders, such as certain sources of bentonite, are capable of adsorbing planer or 2D molecules like aflatoxins (Figure. 1a), research has demonstrated that binders are ineffective for binding more complex molecules as found with A- and B-trichothecenes (Figure. 1b) or zearalenone. These more complex mycotoxins require their structure to be altered thereby detoxifying or biotransforming them into harmless compounds that can be excreted. IMPACT ON CALF PERFORMANCE IN PRACTICE A good example of low-level contamination inhibiting calf performance comes from a commercial trial in Germany, with eight-week-old male Fleckvieh calves (n=110) divided into two groups and monitored for 100 days. Diets were the same, with feed Figure 1a. Aflatoxins - Polarity, functional groups and planarity (Image source, ChemSpider SyntheticPages, 2001 http://cssp.chemspider.com/123) Figure 1b. DON - Polarity, functional groups but no planarity! (Image source, ChemSpider SyntheticPages, 2001 http://cssp.chemspider.com/123)
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