Also this.The Border collie is one of the breeds that has a particularly high incidence of IE. Suggested incidences of IE in dogs vary from 0.5 to 20% in some severely affected breeds (Podell 1995, Mellersh 2010). From data on estimates of total dog population in the UK and on the percentage of all micro-chip registered dogs that are Border collies (Lucy Asher, 2011, personal communication), we estimate that the UK population size of this breed may be around 400,000.