Itching & wool fall-out not always worst
DO not immediately assume a sheep is suffering from sheep scab when it is itching and wool is falling out, warned Dr Agnes Winter, vet and lecturer at Liverpool University.
She advised producers to consider other possibilities because it was dangerous to make assumptions and apply inappropriate treatments.
When diagnosing the condition, Dr Winter asked producers to consider whether just a single sheep was involved, or the whole flock. History of the animals movements should also be consulted.
"For example, recently a producer with a 3000-ewe flock bought in some replacement rams," she said. "These were put in with the resident rams and three weeks later introduced to the ewes. Sheep scab appeared in the flock – and it had never been seen before on that farm. So flock security and quarantine for bought-in sheep is of paramount importance."
But some of the symptoms of sheep scab could have their roots elsewhere. "Some sheep cast their wool naturally," said Dr Winter. Ringworm could also be confused with scab – as could the lesions associated with blowfly strike when they started to heal. The symptoms associated with scrapie can also cause confusion. "Sheep with scrapie react in the same way – by throwing their head back and in some cases experiencing a fit when touched along the back – but it is only individuals which are affected, unlike the flock with sheep scab."
Other ectoparasites, such as keds, lice and ticks also cause skin irritation and damage.
"Diagnosing sheep scab may not always be as easy as it may seem initially," she said, advising producers to consult their vet if concerned.