Equine genetics has come a long way since I studied Equine Reproduction at Colorado State University 30+ years ago! In previous years, you would send a hair sample to a university at the recommendation of your veterinarian for a specific test to check for a certain medical condition that your horse might be manifesting. Fast-forward to today, and the company Etalon Diagnostics has now taken the lead in equine genetic testing. As you can imagine, there are many uses for genetic testing when breeding. Now there are also many insights you can learn from your horse’s genetics to understand potential medical conditions to be aware of, knowing their personality types better, and predicting stamina. Etalon Diagnostics continues to add tests as they refine the science of matching gene associations to different traits. It follows that genetic testing would be a wise addition to pre-purchase exams, especially for breeding animals.
As we all know and have learned, there are medical conditions that often only come up with age, climate, exercise-related stressors or even insects. You will be surprised at some of the conditions that you may not have connected to genetics. A sampling of the genetic conditions that can be tested for that you may be familiar with include: Laminitis risk, Squamous Cell Carcinoma risk, Roaring, Polysaccharide Storage Myopathy, West Nile Virus risk, Hoof Wall Separation Disease, Equine Metabolic Syndrome, Equine Anhidrosis, HYPP (a muscular disease caused by a known genetic mutation with an autosomal dominant mode of inheritance in horses related to the AQHA stallion Impressive) and HERDA (genetic disease in Quarter Horses and Appaloosas, especially cutting horses).
“You will be surprised at some of the conditions that you may not have connected to genetics.”
Two interesting tests that Etalon Diagnostics has narrowed down in genetics are personality type and Myostatin genotype. They have named the personality gene types Curiosity and Vigilance. A horse can have one of each or both curiosity or both vigilance. Curiosity in the horse has been defined as an interest in novel objects and a willingness to approach them. Vigilance refers to the tendency of a horse to examine its surroundings. Horses homozygous for the G allele (G/G) displayed both higher curiosity and lower vigilance scores, whereas horses with one or two A alleles (A/A and G/A) had lower curiosity and higher vigilance scores. Myostatin Insertion has been found to predict skeletal muscle types, and whether those horses are short distance types like racehorse sprinters, ropers and barrel racers, or have the endurance for long distance like endurance horses, longer distance racehorses and eventers.
When it comes to breeding, the more genetic information we have, the more responsible breeders we can be and the more successful results our breeding ventures will have. Not only can we prevent lethal genetic conditions, such as Lethal White and Fragile Foal Syndrome (WFFS), when we have genetic information on both the sire and dam, we can be proactive to prevent all the medical conditions mentioned above. Stallion owners can put forth their stallion’s genetic information and mare owners can select stallions based not only on their performance records, conformation and physical traits, but also on recessive genetic conditions that could arise when bred to certain mares with the same recessive traits.
Thoughtful breeding results in horses that are healthier and therefore less costly, and are better suited for successful careers, whether that be for Olympic sport, roping, endurance, dressage, pony club or 4-H. At the same time, some genetic conditions, such as WFFS, have been found to be tied to desirable traits such as more expressive movement in dressage horses. Therefore, eliminating all genetic conditions is not always the answer. It is important to just not breed a carrier to another carrier. The hope is full genetic testing disclosure will become more commonplace and even seen as a necessity when breeding horses. At the present, breed registries are only requiring certain breed-related genetic information such as FFS, HERDA, Lethal White and HYPP.
Color genetics are fascinating and varied in different breeds. For example, in Thoroughbreds, there are some white marking characteristics and even some recessive markings that resemble the Paint Horse, but coat color is mostly limited to black, bay, dark bay/brown, chestnut and gray. Friesians are black. Quarter Horses and Mustangs can vary greatly as well as the coat patterns and colors of the Paint Horse. Etalon Diagnostics has 30 different gene combinations identified for color markings and can help you predict the offspring of two tested parents.
The Etalon Mini-Panel, which runs $149, gives information on color and personality traits, and Myostatin also includes the “Gait” gene. This is associated with horse breeds that display different types of locomotion as well as recessive gaited genes that have interestingly expressed themselves in some jumping bloodlines that trace back to the French Trotter. This was revolutionary to me and explained why some jumpers look like they are pacing at times—they are pacing!
Similar to the human and dog ancestry tests, Etalon has an equine ancestry profile as well. Out of curiosity, someone I know had their pony purchase of unknown origin from central Wyoming who has become quite the athlete tested. Turns out, he has the Percheron and Iberian breeds in his background.
What might a Mini-Panel teach you about your horse medically or otherwise? What could you do to change your horse’s diet or environment to help avoid medical conditions they are genetically susceptible to? Would it be helpful to understand your horse better knowing that their reactive personality is really genetic? Could this information be helpful when purchasing a horse? Before you breed your mare, wouldn’t you like to know her genetic traits as well as the stallion’s?
Heather McWilliams © 2023
