Equine cytogenetics: role in equine veterinary practice

The prognostic use of karyotyping in equine breeding has been recommended since 1976. Specimens used and laboratory methods are described. The system of karyotype evaluation is explained together with a glossary of terms. The principal aberrations in horses are defined. The present state of knowledge in cytogenetics in horses is reviewed dealing with infertility in the mare, where sex chromosomes give clear indication of problems; the situation with respect to anomalies found in stallions and hermaphroditism is explained coupled with recent concepts of chromosomal roles in reproduction. The future potential for the application of cytogenetics in equine practice is explained in regard to the advanced techniques and knowledge in the human parallel field. It is concluded that karyotyping is an essential tool in the evaluation of reproductive problems in practice and should be used more frequently in future.