A case of multiple assignments (paternity/maternity) in an equine-out breeding system.

Recently, the use of DNA markers has provided a more accurate method of identifying individuals and verifying parentage. In this report, we describe foal assignment in a farm bred jumping horses (Silla argentino). Ten mares were freely served by two stallions, resulting in nine foals. Weaning occurred without registration of the mare of each offspring, resulting in a failure to identify either the mare or the sire of each foal. Animals were typed using 12 microsatellite systems and four biochemical polymorphisms in order to determine the paternity/maternity of each foal. We used the CERVUS program to evaluate the parentage of each offspring. It was possible to determine maternity in eight cases, and paternity in all of them. We concluded that this set of codominant markers analyzed following a likelihood-based approach included in the CERVUS package, are useful tools to solve parentage assignments in domestic horses.