06/10/2026
Following a recent discussion re the number of rabbits succumbing to myxomatosis and being found dead.
Firstly there is no direct risk to horses.
However,
Yes, decaying rabbit carcasses in fields present a major health risk to grazing livestock—but not from the myxomatosis virus itself.
While the myxoma virus cannot infect livestock, the rotting carcass creates a breeding ground for a deadly bacterial toxin called botulism.
The UK Government strictly warns livestock farmers that a wild myxomatosis outbreak significantly increases the risk of botulism in grazing cattle, sheep, and horses.
The Danger: Botulism (Clostridium botulinum)
• The Toxin: As a rabbit carcass decomposes, it becomes warm, wet, and anaerobic (deprived of oxygen). This is the perfect environment for Clostridium botulinum bacteria—naturally present in soil—to multiply and release a lethal neurotoxin (specifically Type C).
• The Risk of Grazing: Horses and cattle grazing near the decaying carcass can accidentally ingest the toxin.
• The Risk of Forage (Highest Danger): If fields with dead rabbits are cut for silage, haylage, or hay, the bodies get crushed into the winter feed. The toxin spreads through the bale, leading to devastating outbreaks that can kill entire herds.
• The Effect: Grazing livestock are incredibly sensitive to botulinum toxin. It causes progressive muscle weakness, inability to swallow, paralysis, and respiratory failure. It is highly fatal and has no easy cure.
Other Potential Risks
• Tularemia (Rabbit Fever): Decomposing rabbits can also harbor Francisella tularensis, a bacteria that can be transmitted to livestock (and humans) via contact or flies, causing severe systemic infections.
• Secondary Predators: Carcasses attract foxes, birds, and flies, increasing the risk of overall pasture contamination.
Whilst not wishing to be alarmist, we have seen outbreaks of myxomatosis before.
My advice would be to remove the dead rabbits from your grazing fields.
Incineration is, I imagine, the best way to dispose of them. 🔥
Or burial in a deep grave.