Breeding measures to reduce the prevalence of bone spavin in equines : (A review of literature)

Abstract

The aim of the study was to perform a review study regarding breeding measures to reduce the prevalence of bone spavin in the domestic horse. Bone spavin is one of the most common forms of hind limb lameness in the horse (GOUGH and MUNROE, 1998). The cause of bone spavin is of multifactorial origin, and both inherited poor tarsal conformation, special types of work, injuries, trauma and genetic predisposition are factors contributing to the disease. The articles on bone spavin in this thesis were mostly done on specific horse breeds. Bone spavin is described as a disease commonly occurring in all horse breeds including ponies, but may more frequent be seen in some breeds as the Icelandic horse. Osteoarthrosis in the distal tarsal joints, bone spavin, is a well known condition which is common in Icelandic horses age 6-12 (BJÖRNSDÓTTIR et al. 2004) The Icelandic horse in Iceland is considered to have been pure for 1000 years as importation of horses to Iceland is not allowed according to the Icelandic law. Even though the number of horses on Iceland is quit large inbreeding still comes to thought. Inbreeding is a system of breeding in which related animals are mated and even though it is not a system used on Icelandic horses where the breeding is regulated by the Farmers Association of Iceland and monitored by the studbook World Fengur it is known that inbreeding increase the risk of genetic disorders. The whole equine genome scan was completed in 2007 and has made it possible to investigate genomic areas holding genes for specific diseases. Several disorders of multifactorial origin has been revealed on chromosome-wide quantitative trait loci. This has not yet been the case for bone spavin, but research is continuously progressing. Björnsdóttir et al concluded in 2000 that the prevalence for bone spavin could be reduced by breeding selection based on flexion test of the tarsus and radiology of the joint. In 2003 she studied the culling rate and revealed that bone spavin affects the duration of the use of the Icelandic horse. By performing a high detailed radiography and histology on the centrodistal tarsal joint of Icelandic horses age 6 months to 6 years she concluded that poor conformation and joint architecture seemed to be the cause of bone spavin rather than trauma and overloading in 2004. Stock and Distl studied the prediction of breeding values of several important joint pathologies on the Hanoverian Warmblood horse and indicated that it is possible to simultaneously consider health and performance traits. In 2006 the same researchers studied the genetic correlations between the same joint pathologies and concluded that genetic correlation between radiological health traits deserve close attention in horse breeding. Bone spavin does not necessarily have to end your horse's performance career, but they certainly require careful attention and care. Every horse and situation is different, so you will need to work with your veterinarian (KING, M. 2003)