Minimise foot issues in sheep, webinar tips

Professor Allworth, speaking in a recent webinar hosted by Meat &Livestock Australia, said producers needed to be aware of issues such as ovine interdigital dermatitis, footrot and foot abscess.

"Normally the sheep's foot has hair covering between the claws of the two digits and that intact skin and hair is a very good barrier to any infections but long term exposure to wet conditions... that breaks down that natural barrier and allows bacteria to get in.

"The most common one that gets in under wet conditions is fusobacterium necrophorum and it lives in the gut of sheep so it is on every property in Australia.

"You only get interdigital dermatitis when you get wet conditions and sheep are then walking in manure which happens regularly but happens even more frequently if you yard sheep and not only are the yards usually muddy but they're also faecally contaminated.

"The relevance of OID is it leads to the two major problems that we have in Australian sheep's feet and that is both footrot and foot abscess."

Professor Allworth said it meant that it was important to avoid wet, muddy yards, especially for late pregnant ewes.

"If you're having foot abscess problems I would really be recommending you give the pre-lamb vaccination earlier," he said.

While foot bathing can treat OID, if the sheep are being brought into wet yards, producers can actually risk increasing the problem, Professor Allworth said.

When it comes to footrot, Professor Allworth said there are several strains of bacterium that cause the problem, with benign strains causing mild inflammation while virulent strains cause complete separation of the foot.

"In terms of diagnosis or working out what sort, you really need to get professional help," he said.

"It's got to have come from somewhere, so the history is always very important."

Professor Allworth said producers can do a progression test on their own farms to tell if footrot was benign or virulent.

"From a sheep gets infected til when it starts underrunning takes four to seven days and with virulent footrot it's completely underrun in around 10 days," he said.

"People used to say just wait a week and that's very good advice, in a week's time if they haven't progressed it's not going to be as severe if you've got the right environmental conditions."

Producers can tag 10 to 20 sheep with score two lesions and then look at them again in 10 to 14 days time to see what kind of strain they are dealing with.

Professor Allworth said the recommended minimum length for a foot bath is eight metres.

"What you want is you want the sheep to have at least three or four quiet steps in the foot bath before they're going out so the disinfectant, presumably zinc sulphate, or whatever you've got in there, has a chance to get in the interdigital space," he said.

"I guarantee you if they just jump in and jump out a lot of them can be not treated effectively."

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