We have seen or heard of a few cases of ergot poisoning in cattle this winter. Ergot poisoning is caused by a fungus Claviceps purpurea that grows on the seedhead of any type of grasses e.g. ryegrass or fescue. It occurs when long grass with seedhead gets wet before it is made into balage/hay.
The weather this year has been ideal for the development of the dark brown to black fungal growths on the seedheads of grasses. This, in combination with late harvesting of balage/silage or hay increases the likelihood of these growths occurring.
Ergot poisoning causes vasoconstriction of small blood vessels to the extremities such as ears, tail and feet. The blood flow is compromised and in severe cases can result in gangrene or sloughing off of hooves and distal parts of ears and tails.
Initially the animal may show a painful lameness, which may be confused with other lameness such as footrot. On closer examination, the extremities are cool to the touch and a line of demarcation may be seen between the normal and unhealthy tissue. Other initial signs are decreased feed intake, rough hair and weight loss.
Treatment involves removing the animals from the affected feed and supportive care to manage pain and secondary infections. However, once gangrene appears you can’t reverse the damage done and in severe cases, euthanasia may be the only option.
This disease could become more common and it is important to be aware of the conditions that may increase the likelihood of the disease occurring,
· If grass is left too long before it is harvested then seedhead is more likely to be present and may be a risk; the risk is increased further if weather conditions are also ideal for the fungus growth.
· Keep an eye on the grass close to cutting time. You can easily see the distinctive black seed on the seed head in the paddock. The grass needs to be cut before this appears!
· Check balage/ hay when it is being fed out. This is harder to do when it is put in a bale feeder as you can only see what its like on the outside. Do not feed any balage/hay that is affected. It will need to be disposed of as it will affect any age of stock.
If you think your stock may be affected by ergotism then please contact us at the clinic.