For farriers, one of the scariest parts about Halloween might be an increase in fall laminitis cases.
The days get shorter, and the nights get colder, which makes me want to hunker down and ride out the winter months as quickly as possible. I sleep earlier and wake later. These natural seasonal rhythms happen across nature. The trees turn. The bears hibernate. And ACTH (adrenocorticotropic hormone) rises in horses. Starting in late summer, ACTH levels increase for horses in the northern hemisphere. This controls the production of cortisol and epinephrine and is responsible for horses developing their winter coats.
“Both are needed to release glucose, for energy, out of glycogen stores in the liver and muscle,” says Dr. Juliet Getty, an independent equine nutritionist from Texas. “Glucose from liver glycogen stimulates the pancreas to secrete insulin. The healthy body has a homeostatic mechanism to maintain these hormones within a normal range. This seasonal rise of ACTH can negatively impact the already insulin-resistant horse by further increasing inflammatory insulin, potentially leading to a laminitis attack.”
For horses with existing metabolic issues, such as PPID and EMS, this seasonal rise in ACTH offers a higher risk of laminitis. In addition, cooler nighttime temperatures raise the NSC (non-structural carbohydrates) in grass, which is composed of WSC (water-soluble carbohydrates and includes ethanol-soluble carbohydrates and fructan) and starch — digested down to glucose. Too much glucose in the bloodstream and it raises insulin.
“Elevated insulin stimulates the production of insulin-like growth factors within the hoof’s laminae, resulting in the proliferation of the epidermal layer,” Getty says, noting that this uncontrolled growth can lead to structural failure in the laminae.
For both healthy horses and ones with metabolic issues, feeding them forages with less than 12% NSC on a dry-matter basis can help avoid laminitis.
“If the nighttime temperature remains above 41 degrees Fahrenheit, the NSC will be lowest in early morning until approximately 10 a.m. and then again at night, starting a few hours after the sun sets,” Getty says.
However, when the nighttime temperature remains below 41 degrees F for 2-3 weeks, cool-season grasses are high in NSC 24 hours per day. Getty’s tip is to wait for the stems of the grass to turn brown for a better chance at avoiding high-NSC forage.
The risk of laminitis is highest when owners, farriers and others who care for horses don’t know what to look for and how to prevent it. Those who have horses with metabolic issues should take extra care in avoiding forage high in sugars and starches.
Be on the lookout for:
- Stretching in the white line
- New flat or thin soles
- Hesitant on hard ground
- Tension or stiffness in body
- Reluctance or trot or make sharp turns
As we roll into November and then December in what will surely feel like the blink of an eye, monitor foot, behavior and movement changes for any signs of laminitis. And as you prepare for the struggles of winter hoof care, look through our Winter eGuide for tips and tricks on how to manage seasonal changes.
