Genetic analysis of Spondylosis Deformans and effect of inbreeding on the degree of osteophytes development in Italian Boxer dogs

Spondylosis deformans is a degenerative disease of the spine exhibiting the presence of one or more osteophytes, showing different degrees of development at the level of vertebral bodies (Morgan, 1967). A recent study (Carnier et al., 2004), although conducted on a relatively small sample of Italian Boxer dogs, showed that additive genetic variation for the degree of osteophytes development (DOD) is large enough to be exploited in specific breeding programs. The high prevalence of diseases and defects in pure dog breeds might be due to high selection intensities in genetically closed populations (Ubbink, 1998). Inbreeding affects mostly fitness traits and traits which are of qualitative inheritance but also quantitative traits (Klemetsdal, 1998). Mäki et al. (2001) reported estimates of inbreeding depression on hip and elbow dysplasia in six dog breeds in Finland, but no previous studies dealing with inbreeding depression on DOD in Boxer dogs are available. The aims of this study were to infer (co)variance component for DOD and to asses the effect of inbreeding depression on DOD in the Italian Boxer dog population. In conclusion The degree of osteophytes development shows exploitable additive genetic variation. Its extent in the area between the 11th and 13th thoracic vertebrae is of particular importance because it is strictly correlated to the degree of osteophytes development of all the other sites, and has a moderate heritability. A slightly detrimental effect have been noticed for the inbreeding, especially for group of dogs with F greater than 10%.