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Thursday, February 12, 2009

Australian Fire Survivor Horses Now in Danger of Heat-Induced Laminitis

This has to be the animal-lover's photo of the year; a firefighter in the Australian state of Victoria shares his bottle of spring water with a burned koala. (photo links to Horse Deals Australia blog)

The numbers are staggering. Wildlife and public health officials in Australia estimate that as many as one million animals may have been killed in the wildfires that ripped through the state of Victoria last weekend. As if that news isn't bad enough, there may be a double whammy coming for horses who had to stand on the scorched earth: the fire in the bush is over, but the fire in the feet may be only beginning.

We know that rapid and continual cooling by the icing of the horse's lower limb and digit ("cryotherapy") can clinically prevent laminitis, as proven in studies by the Australian Equine Laminitis Research Unit at the University of Queensland, directed by Dr. Chris Pollitt.

But can the inverse be true? Can heat cause laminitis?

Dr. Pollitt is flying south to Victoria to help with rescue efforts and provide veterinary services for the hundreds of horses displaced or injured by the wild bushfires that ripped through the countryside in Victoria.

The University of Melbourne’s Faculty of Veterinary Science in Victoria is providing free care to pets and horses injured in the recent fires. Professor Ken Hinchcliff, Dean of the Faculty there, says that veterinary clinic staff at the university are deeply concerned.

Dean Lewis of the Victoria Farriers Association has spoken up about the danger of horses "losing their hoof capsules" and has offered the services of his member farriers to help with rescue operations.

One of the things that touched me was that the rescue center are having trouble feeding the horses, and put out a call for soft lucerne (alfalfa) hay. So many horses have burned muzzles that it is painful for them to eat regular hay with its stiff stalks poking their burnt flesh.

The burns on this cat's paws are typical of what pets and livestock have experienced. This cat is receiving veterinary care at the Victoria Animal Aid fire assistance center.

Triple R Equine Welfare Inc. (TREW) warns horse owners and anyone wishing to help, "The immediate threat to horses left stranded in burnt properties is damage to hooves. Prolonged exposure to hot ground will cause a low grade overheating, that develops into heat induced laminitis. The prognosis for horses suffering this condition will be extremely poor. It is imperative the we move swiftly to relocate horses off burnt properties."

The textbook Technical Large Animal Emergency Rescue by Gimenez, Gimenez, and May (Wiley-Blackwell 2008) offers some insight into what body conditions of a burn victim horse may contribute to laminitis and hoof capsule detachment:

"Thermal injury produces local and systemic responses. In the local (skin, which would include the hoof) response, inflammation is the primary reaction, caused by damaged, leaking tissues and blood vessels. Tissue fluid and electrolyte shifts cause inflammation and fluid loss...

"Tissue injury continues for 24-48 hours after the initial thermal injury, therefore the burn will increase in severity over that period of time. Necrosis (death) of the dermis and epidermis in full-thickness burns creates a hard, leathery charred appearance to the skin; this is called eschar (Pascoe 1999). As the eschar sloughs, it creates an increase in open wounds."

It's pretty straightforward to think that burned hooves are a danger in themselves, even though farriers routinely hot-fit hooves and prolonged hot fitting has not been shown to be a danger to hooves. Burned coronets would affect the blood supply to the lamina within the hoof, which would probably already be decreased by the inflammation, edema, and compromised circulation.

Let's keep all the Australians--two-legged and four-legged in our thoughts, and hope that we can learn something about laminitis and how to prevent and treat it in future forest fire emergencies.

Sam the Water Guzzling Koala is recovering at a shelter; she too has extensive burns on her feet. It looks like she's been to the hairdresser, too.

© Fran Jurga and Hoofcare Publishing. No use without permission. You only need to ask. Fran Jurga's Hoof Blog is a between-issues news service for subscribers to Hoofcare and Lameness Journal. This blog may be read online at the blog page, checked via RSS feed, or received via a digest-type email (requires signup in box at top right of blog page). To subscribe to Hoofcare and Lameness (the journal), please visit the main site, www.hoofcare.com, where many educational products and media related to equine lameness and hoof science can be found. Questions or problems with this blog? Send email to blog@hoofcare.com.

2 comments:

Anonymous said...

Reading this reminds me once again that I need to get a large tub that my horses can stand in in the event that we are ever faced with a potential laminitis event.

Fortunately those Australian horses do have Chris Pollitt.

Fran, I love your blog!

Lisa Grimm said...

Thanks for the update - I'd been having difficulty finding out what was happening post-fire.