Understanding Supporting Limb Laminitis in HorsesBy Kentucky Equine Research Staff · April 10, 2017
Anyone who has suffered alongside a horse with laminitis knows the emotional distress and physical duress the disease causes. Veterinary researchers* devoted to laminitis research know well the effects of the disease, which explains their interest in developing new ways to study laminitis, especially supporting limb laminitis, to ultimately improve treatment options and survival rates.
According to this team of researchers, laminitis occurs in one of three main ways:
1. Systemic sepsis, caused by bacterial toxins circulating in the bloodstream following disease or infection. Diarrhea and colitis put horses at risk for developing laminitis.
2. Hormone disorders, known also as endocrinopathies, can also contribute to laminitis. Common examples include Cushing’s disease and insulin dysregulation.
3. Supporting limb laminitis (SLL) secondary to severe lameness in one limb, causing excessive weight bearing and laminitis on the opposite supporting limb (e.g., if the right forelimb is injured, the horse shifts weight to the left front).
While many research groups focus on the underlying causes of laminitis following sepsis and hormonal disorders, little information regarding factors contributing to the development of SLL exists. According to Gardner and colleagues:
- Between 10 and 27% of horses with conditions involving nonweight-bearing lameness develop SLL;
- Despite several risk factors (e.g., weight/size of horse and the severity and duration of lameness), the development of SLL remains unpredictable;
- Once SLL hits, failure of the lamellae, the tissues that bind the hoof to the third phalanx or coffin bone, occurs rapidly;
- Distal displacement, also called sinking, of the coffin bone frequently occurs; and
- Mortality associated with SLL is high, with approximately 50–75% of affected horses succumbing to disease.
To help horses with SLL, the researchers created a V-shaped device that can be placed on a horse shoe to prevent normal weight bearing on the fitted foot, thereby increasing weight bearing on the opposite limb.
After testing the model and analyzing various genes in the lamellae, the researchers suggested that SLL results from decreased oxygen supply to the tissues. They wrote, “Further studies are required to more thoroughly assess both hypoxia-related signaling and other signaling associated with lamellar damage that could play a role in SLL. With improvements in study design, it is likely that the preferential weight-bearing model with the V-insert can be used in the future to more accurately assess lamellar events leading to failure.”
Hoof health can also be maximized by maintaining a horse on a fully fortified, balanced diet and supplementing horses with a product containing optimal amounts of biotin and other key nutrients, such as those found in Bio•Bloom PS (or Bio-Bloom in Australia), advised Kathleen Crandell, Ph.D., a nutritionist for Kentucky Equine Research (KER).
*Gardner, A.K., A.W. van Eps, M.R. Watts, et al. 2017. A novel model to assess lamellar signaling relevant to preferential weight bearing in the horse. Veterinary Journal. 221:62-67.