Mycotoxin
A Mycotoxin is a toxic compound produced by certain moulds (fungi) growing on crops, animal feeds, and stored grains. Mycotoxins are produced as a defence mechanism by the mould; for cattle, buffalo, and other livestock that eat the contaminated feed, they cause a range of health and production problems.
Mycotoxins are a major silent threat in Indian cattle feed. They are invisible without testing, stable to heat and acid (cooking and digestion don't destroy them), and can pass into milk where they reach human consumers.
Common mycotoxins in Indian cattle feed
| Mycotoxin | Produced by | Found on | Main effect |
|---|---|---|---|
| Aflatoxin (B1, B2, G1, G2) | Aspergillus flavus, A. parasiticus | Maize, groundnut cake, DORB | Liver damage, milk M1 contamination, immunosuppression |
| Zearalenone (ZEN) | Fusarium | Maize, wheat | Reproductive failure, false heat signs |
| Deoxynivalenol (DON) / Vomitoxin | Fusarium | Maize, wheat | Reduced feed intake, vomiting |
| Fumonisins (FB1, FB2, FB3) | Fusarium | Maize especially | Liver and kidney damage |
| Ochratoxin A | Aspergillus, Penicillium | Wheat, barley, coffee | Kidney damage |
| T-2 toxin | Fusarium | Cereals | Immune suppression, hemorrhage |
| Ergot alkaloids | Claviceps | Bajra, rye | Lameness, abortion, low milk |
In Indian conditions, aflatoxin is by far the most common and economically damaging mycotoxin. The full mycotoxin profile of any given feed lot can include several toxins together, with combined (synergistic) effects.
Effects on cattle
Mycotoxins typically cause chronic, sub-acute problems that are easy to misdiagnose:
| System | Mycotoxin effect |
|---|---|
| Milk production | 10–25% drop in yield |
| Reproduction | Reduced fertility, repeat breeding, abortion (in severe cases) |
| Immune function | More respiratory infections, mastitis, scouring |
| Liver and kidney | Damage with chronic exposure |
| Hooves | Laminitis and lameness (some mycotoxins) |
| Feed intake | Reduced; selective rejection of contaminated feed |
| Milk safety | Aflatoxin M1 appears in milk, regulated to under 0.5 µg/kg by FSSAI |
Many of these symptoms look like other diseases (poor nutrition, hormonal problems, infectious diseases). This is why mycotoxin damage is often missed.
When mycotoxins develop
Mycotoxin contamination develops in two stages:
Pre-harvest
Some moulds (especially Fusarium species) infect crops while they are still growing in the field. This is more common when:
- Weather is humid + warm during grain filling
- Crops are stressed by drought or insects
- Some plant varieties are more susceptible
Post-harvest (during storage)
Most aflatoxin in Indian feed develops in storage, when:
- Moisture content of stored grain is above 12% (see maize and groundnut cake articles)
- Storage humidity is above 70%
- Storage temperature is warm (28–35°C is ideal for Aspergillus)
- Insect damage breaks the seed coat
- Stored too long (over 6 months)
Indian monsoon humidity (June–September) is the highest-risk window for mycotoxin development.
Regulatory limits in India
| Standard | Aflatoxin B1 limit |
|---|---|
| BIS IS:2052 (compound cattle feed) | 20 ppb max |
| FSSAI (milk M1) | 0.5 µg/kg max |
| FSSAI (animal feed, total aflatoxins) | 30 ppb max |
For mycotoxins other than aflatoxin (zearalenone, fumonisins, DON, etc.), Indian regulatory limits are less specific. International limits (used by export-oriented Indian dairies):
- Zearalenone: 250 ppb in feed for adult dairy
- DON: 1 ppm in feed for adult dairy
- Fumonisin B1: 20 ppm in feed for adult dairy
Detection and testing
| Test | Detection | Cost (per sample) | Used by |
|---|---|---|---|
| Rapid lateral-flow strip (e.g., Charm, Romer, Neogen) | Aflatoxin B1, individual mycotoxins | ₹100–500 | Feed mills, large dairies |
| ELISA | Quantitative B1, ZEN, DON, FB1 | ₹500–2,000 | Certified labs |
| HPLC / LC-MS | Reference method, multi-mycotoxin | ₹2,000–8,000 | Research, export, regulatory |
| Visual inspection | Severe contamination only | Free | Daily farm-gate check |
Visual inspection cannot reliably detect mycotoxin contamination — many contaminated lots look normal. Routine testing of high-risk raw materials (maize, groundnut cake, DORB) is the only reliable defence.
Prevention and control
The standard defence program against mycotoxins in Indian cattle feed:
- Source quality raw materials — buy from established mills, demand certificates of analysis
- Test high-risk inputs — rapid tests on every truck of maize, groundnut cake, and DORB
- Store dry — keep stored ingredients below 12% moisture and 70% humidity
- FIFO rotation — first in, first out; don't hold stocks long
- Limit summer / monsoon stocks — buy smaller quantities more frequently in high-risk months
- Use mycotoxin binders — add 1–2 kg per ton of feed (see aflatoxin article)
- Reject obvious contamination — visible mould, off-smell, dark patches = reject
Mycotoxin binders
When contamination has already occurred and the feed can't be replaced, mycotoxin binders are added to the ration. Common binder types:
| Binder | Target mycotoxins | Inclusion |
|---|---|---|
| Clay (bentonite, HSCAS) | Aflatoxin B1 (primary) | 1–2 kg per ton of feed |
| Yeast cell wall (Saccharomyces cerevisiae) | Aflatoxin, zearalenone, fumonisin | 0.5–1 kg per ton |
| Activated charcoal | Multiple, less selective | 0.5–1 kg per ton |
| Combination products | Broad spectrum | 1–2 kg per ton |
See the aflatoxin article for detailed binder protocols.
Practical use
For an Indian dairy operator, the practical mycotoxin strategy is:
- Buy compound cattle feed when possible — BIS-licensed manufacturers test and reject contaminated raw materials at the mill gate
- For farm-mixed concentrate users: rapid-test maize, groundnut cake, and DORB; reject lots above limits
- Use a year-round mycotoxin binder at 1 kg/ton of feed during high-risk months (April–October in most of India)
- Watch milk yield and reproduction — sustained unexplained drops are often mycotoxin-related
The cost of prevention is small compared to the cost of contaminated feed causing milk rejection at the processor.