What do fevers have to do with founder and laminitis?
Turns out, there are, unfortunately, many ways for your horse to develop laminitis. One of them is from a fever - and it doesn’t really matter what the cause of the fever is. Yet another reason to check your horse’s TPR daily. So how does this all happen? Well, I’m going to back up and take you through your horse’s body and how fevers work.
A horse can have a fever and still look and act totally normal.
Your horse’s hypothalamus in his brain is responsible for temperature regulation. It creates sweating, causes shivering, makes hairs stand on end to trap air. The hypothalamus sets the temperature of your horse’s body.
Now - let’s say there’s something - a pathogen - that infects your horse. This creates a huge inflammatory reaction in your horse’s body. His immune system sends white blood cells to attack bacteria, fungus, virus, etc. This process releases cytokines into your horse’s blood. These cytokines tell the other cells in your horse's body to start getting inflamed. One cytokine in particular, the pyrogen, tells the hypothalamus to increase the horse’s body temperature - and now your horse has a fever.
Check daily for heat and a digital pulse.
Fevers burn up invaders! Fevers increase metabolism! Fevers increase the number of chemical reaction in your horse! All good things to fight an invader. BUT BUT BUT BUT…. a fever is whole body inflammation - and that includes the hooves.
Hoof capsules and coffin bones from laminitic horses.
The exact mechanism isn’t known about how fevers cause laminitis - but we know enough. Laminitis can happen when horses get fevers. There’s inflammation which can end up in the hoof capsule causing the laminae to inflame. Inflammation can also weaken the intestinal lining, letting toxins from your horse’s natural gut population of bacteria cross into the blood stream and end up in the hooves.
My point to this story is this - it’s not just spring grass that leads to laminitis. Any fever - for any reason - can lead your horse down the road to laminitis. Diligence and preventative icing during a fever can help, as well an immediate phone call to your Vet.