Introduction:
Insect bite hypersensitivity (IBH) is the most common allergic skin disease in horses, caused by bites of certain Culicoides species (tiny midges). IBH causes an intense itch, which results in self-inflicted trauma. Welfare of affected horses is seriously reduced and horse owners encounter economic losses. Currently, there is no effective treatment for or prevention against IBH available.
The aim of this PhD project is to unravel the genetic background of IBH and thus to develop tools for more efficient selection against IBH. Research activities are: estimating genetic parameters, identifying QTL and simulating response to selection of various selection strategies.
Results:
During the first research we investigated a total of 7,924 IBH scores on 6,073 Dutch Shetland breeding mares collected during foal inspections in 2003, 2005, and 2006. Mean prevalence was 8.8%. Observed prevalence in mares descending from affected dams was greater (13.4%) than the prevalence in mares descending from unaffected dams (7.7%). Observed prevalence of progeny groups per sire varied from 0 to 37%. Heritability was 0.08 (SE=0.02) on the observed binary scale and 0.24 (SE=0.06) on the underlying continuous scale. We concluded that IBH, based on clinical symptoms, is a heritable trait in the Dutch Shetland pony population.(Schurink et al., 2009).
Articles:
Schurink, A., E.M. van Grevenhof, B.J. Ducro and J.A.M. van Arendonk. 2009. Heritability and repeatability of insect bite hypersensitivity in Dutch Shetland breeding mares. J. Anim. Sci. 87: 484-490. |
