Achondroplasia in British Friesians
Jones, T.H.; McClintock, A.E.; Smith, G.F.; Williams, G.
Veterinary Record 102(18): 404
1978
ISSN/ISBN: 0042-4900 PMID: 664194 Document Number: 130101
A British Friesian bull (A) had six achondroplastic calves in about 47 000 calvings (1 per 7800) by 1970 and was slaughtered. The gestation lengths of the affected calves were between 200 and 300 days; they had foreshortened legs and face, and either hydrocephalus and cleft palate or an oedematous body. Of the 12 sons which were progeny tested, two (B and C) each produced one achondroplastic calf among their 200 recorded calvings. In further half-brother/half-sister matings, with bulls B and C the frequency of abnormal calves was 1 in 7.4 calvings, indicating that this condition behaves as a simple recessive in British Friesians.