Genetic markers in south african thoroughbred stallions

Genetically controlled markers are ideal for the identification of individual animals, and throughout the world laboratories have been established whose chief function is to provide a blood-typing service for animals including horses. In order to achieve the aim of improved recording of foals almost all South African sires at stud were tested and their blood type identification completed. The genetic markers included in this survey were 14 blood group factors, transferrin, plasma esterase, haemoglobin, carbonic anhydrase, 6-phosphogluconate dehydrogenase, phosphoglucomutase and phosphohexose isomerase. Gene frequency calculations were performed and comparisons made with similar surveys in Thoroughbreds overseas. The results indicate that the strict selection for speed in Thoroughbred racing horses has resulted in a high degree of genetic uniformity between South African and overseas racing Thoroughbreds.