Animal Genetic Testing and Research Lab Benefits Horse Owners

Established in 1986 as the Horse Bloodtyping Laboratory, the University of Kentucky Animal Genetic Testing and Research Lab (AGTRL) offers a number of testing services of value to practitioners, horse owners, and breed registries.

After being housed in the Dimock Animal Pathology Building for 23 years, the program relocated to the Gluck Equine Research Center in 2009.

Until the 1990s, blood typing was the identification method of choice for the cattle and equine industries. Unlike the human A, B, O blood-type system, horse red cell types are more complicated and, therefore, more informative than human blood typing. Horse blood types are not only useful for donor/recipient cross-matching, but could function as an identification system and method to confirm parentage of foals. Because reagents (substances used to detect/measure other substances by means of the reactions they cause, in this case processed serum from horses that have been immunized to develop antibodies to specific red cell factors) to detect the more than 20 red cell factors in horses are not commercially available, the lab previously maintained a large group of horses at the Department of Veterinary Science farm facilities to perform its own immunizations for reagent production. Red cell typing is only one component of generating a horse blood type, and scientists used genetic differences in red cell and serum proteins to compile a profile of 17 genetic systems per animal. Three different laboratories were required to house the equipment and personnel needed to process about 200 samples per day.

Beginning in the early 1990s, DNA-based technology became available for identification purposes in humans and animals. Microsatellites, which are segments of DNA containing simple nucleotide repeats of varying sizes, became the standard for equine identification and parentage. While only slightly more accurate than blood typing, the great advantage of DNA testing is it can be done using hair samples from the mane or tail. This eliminates the need for perishable blood samples that often had to be collected by a veterinarian. Now owners can send their horses’ hairs by mail for DNA sampling.

The lab uses a standard internationally recognized panel of 17 microsatellite markers to generate a DNA profile for each sample. The majority of samples are processed on behalf of breed registries that have contracts with the laboratory. The registries use the services of the lab to verify parentage of foals prior to registration and to resolve cases of misidentified horses.

The AGTRL is the only remaining U.S. laboratory offering horse blood typing, including antibody screening and crossmatching for neonatal isoerythrolysis (NI, acute hemolytic of the newborn caused by ingestion of antibodies in the mare’s colostrum and milk that are directed against the neonate’s red blood cells). Laboratory personnel are using stored serum from years of reagent production to continue the program without the need for a large herd of horses. Instead, they use a small group of horses with known blood types is used to verify reagent specificity and screen serum samples from potential donors and pregnant mares for anti-red cell antibodies. Local veterinary clinics purchase panels of red cells and reagents so they can perform in-house testing of NI samples.

The University of Kentucky has been at the forefront of test development for equine color gene mutations, and it offers a number of available color gene tests. Color gene mutations, which were discovered by the genetics program of Ernie Bailey, PhD, include the Tobiano spotting pattern and the Champagne dilution. In addition to these tests, the lab also offers a panel of other color genotype tests. These tests allow breeders to determine what color genes a horse might pass to its offspring or in some cases, allow the owner of an odd-colored horse to determine which color genes a horse possesses.

As researchers identify more disease-causing mutations, the lab plans to offer testing so owners can confirm whether their horse is affected, a carrier, or does not have the mutation. Current disease mutation tests offered include the overo lethal white syndrome mutation and the junctional epidermolysis bullosa (JEB) test in Saddlebreds. The latter was discovered at the AGTRL by the author, who is the director of the AGTRL, and Pamela Henny.

For more information, contact Graves at 859/257-4757, ext. 81193. For forms and submission instructions visit ca.uky.edu/gluck/ServEPVL.asp.  

Kathryn Graves, PhD, is the director of the Animal Genetic Testing and Research Lab at the Gluck Center.


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