Laminitis in the making!
Imagine, winter is just around the corner, or you maybe you are already in the midst of it. For many horse owners that triggers a sigh of relief – the grass growth is slowing down or is non existent, and the risk of their horse suffering from laminitis is going down for the next few months. Until spring arrives, that is, when the grass starts growing again. Then the laminitis monster will keep those horse owners living in fear, once again.
Unfortunately, the reality is that it is how the horse is kept from now until spring, that significantly influences the odds whether or not the horse will suffer from laminitis this spring.
Let me explain.
For laminar corium to remain healthy, it needs to be regularly and sufficiently stimulated. This occurs when the horse loads and unloads the hoof, on ground that is sufficiently firm to provide the Ground Reaction Force (GRF) to expand the hoof-capsule on loading. In New Zealand, over the summer months, the ground is generally firmer than in winter, and the horses tend to get ridden more. Come winter, the ground gets softer and less riding occurs.
The GRF from the softer ground reduces, and in some instances it maybe insufficient to expand the hoof-capsule properly, thus the laminar corium becomes under-stimulated. This has a negative impact on the laminar horn production, as well as the tissue health itself.
Less riding tends to lead to less movement, aka fewer steps, which in conjunction with the previous point amplifies the problem.
Horses often get trimmed at longer intervals in winter, commonly this is due to the hoof not growing as much as in summer. Ironically this is a very clear indicator that the hoof is under-stimulated, the side-effect of under-stimulation is reduced horn production. Hooves with good stimulation in winter, grow horn at the same rate as in summer, often with less abrasion, leading to a greater build up of horn.
Longer trimming intervals can lead to hooves that become too long, which in turn further reduces the hoof’s ability to function properly.
Soft ground allows the hoof to sink in lower in the toe, especially seen frequently in the front hooves. This rotation of the hoof allows for weight transfer towards the laminar connection in the toe region. The result, chronic stress on this connection. Over time, the various living tissues in the hoof, including laminar corium, can become unhealthy tissue.
Other common signs that suggest under-stimulated hooves are, hooves that are cold to touch, frogs that “shrivel up”, thrush, seedy toe or white-line disease, and mudfever just above the hoof region.
Typically, the horse enters winter with a better hoof than they leave it. This means, the symptoms of under-stimulation are not visible for a while, while the better horn grows out. Only at a later state, when the damaging factors have been present for weeks and months, will we see their impact.
Then spring comes around. It gets warmer, the sunshine hours go up, the ground becomes firmer again creating to a higher GRF. As a result, the hooves and their internal living tissues receive more stimulation again, leading to better hoof expansion and blood flow. When unhealthy tissue becomes recognised by the immune system, a healing response kicks in. The response we see when tissue heals, we call inflammation, and the inflammation of laminar corium we call laminitis.
You can see, this mechanism leading to laminitis is independent of grass growth, even though that also occurs at spring time, it is a correlation, not a causation.
Therefore, now is the time to take action. Ensure your horse’s hooves are sufficiently stimulated, functioning, and comfortable, and avoid laminitis this spring.