Why do horses get laminitis in the spring?
Firstly what is laminitis?
Laminate are structures which hold the pedal bone in place within the hoof capsule. They attached the pedal bone like velcro and are very strong. Laminitis is the inflammation that occurs within these structures which is very painful, and it causes the laminate to be weaker. This can lead to the pedal bone moving inside the hoof capsule which is commonly known as ‘Founder’.
It is common knowledge that horses and ponies are more likely to present with laminitis in the spring. This is because the grass starts to grow rapidly which becomes higher in sugar. Many horses often eat short grass which means they intake a high sugar content. Horses grazing longer grass means that for parts of the day when the sugars are lower down in the grass, less sugars are consumed as they can eat away at the top half.
Another problem is ‘Fructan’ content of grass. This sugar is undigested in the stomach and small intestine of the horse and is a sugar that can trigger laminitis likely due to hind gut disturbances. Fructans are high in any grass that is stressed: Stressed grass includes flooded and drought prone grass, grass grazed very short, and frosted grass.
Another very common trigger is horses and ponies coming out of the winter being over weight. Horses in the wild lose body condition during the winter, but often this is not the case in our horses due to newer feeding abilities. An overweight horse can have metabolic disturbances that result in a high circulating Insulin level. This is called Insulin Resistance. This insulin resistance is a cause in itself for laminitis.
This year in the Spring I have blood tested many overweight ponies who had no known history of laminitis, but I was concerned they were at high risk of developing it due to their post winter obesity. 50% of these ponies tested had a very high circulating Insulin level. I do not believe they had a true metabolic disorders such as Cushings or Equine Metabolic Syndrome. Unfortunately, the high circulating Insulin was just associated with being overweight. This is a very important thing to know as an owners so that we can change their dietary management and help to prevent what would have been the inevitable onset of ‘spring laminitis’.
In summary how can we help to prevent laminitis this spring?
Graze grass that is longer from last autumn. Leave the spring flush to grow and only graze it when it is 10cm long. Do be careful your horse doesn’t eat too much and put on weight though.
Avoid grazing stressed grass, most commonly because it has been over grazed too short previously.
Avoid having your horse carry too much weight. Let’s remember they are athletes and additional weight puts more strain on their joints. If you need help body condition scoring your horse they just ask.
Lastly, if you think you might have over fed your horse this spring and you want to see how at risk they are from the spring sugars, ask for a blood test and I can help you with a safe nutritional programme