Mississippi State researches genetic defect

STARKVILLE, MISS.-Breeding closely related horses might contribute to Hyperelastosis cutis (HC), which causes Quarter Horses' skin to weaken, wound easily and heal poorly with disfiguring scars.

Pinpointing the genetic defect responsible for a skin disease suffered by American Quarter Horses is at the top of the list for Mississippi State University (MSU) veterinarians and researchers.

HC is a genetic connective tissue defect that causes a horse's skin to be unusually loose. The disease generally is able to be detected shortly after birth, but the disease can also go unnoticed until age 2, when the animal goes into training.

The back can have open sores on it from the saddle, causing hematomas and severe pain.

Dr. Ann Rashmir-Raven, an associate professor in MSU's veterinary college, says her research has shown that years of breeding closely related horses to achieve desired traits has caused the disease.

An owner donated twin colts to the research Rashmir-Raven is conducting. The animals were getting injuries constantly that would not heal for long periods of time. After an examining veterinarian sent a skin biopsy for testing, the disease was confirmed.

The goal of the research is to create a DNA test that can identify carriers of the disease before the animal is bred. The disease is suspected to have an autosomal recessive mode of inheritance, which means that both parent horses must carry the recessive gene for the offspring to be affected.

The research includes evaluating foals for early signs of HC. Documenting changes in skin biochemistry, thermography and ultrasonography in addition to other forms of screening.

Rashmir-Raven will screen pedigree horses for the disease before matings for a $25 fee that will benefit the HC Research Fund at the university.