- Category: Deaf Koolies
It is a sad fact that koolies are sometimes born deaf, this is not to say it is a common occurrence in the Koolie breed, certainly not as common as some other breeds. Many breeders have only ever had one or two after several litters. Usually it is not difficult to predict which in a litter are going to suffer this defect. White around the head, particularly over the ears and around the eyes are indications that the puppy should be carefully checked for the ability to hear and see before being sent to new homes. A lack of pigment in the hair in the ears makes it impossible for sound to be transmitted along the hair into the inner ear. Sometimes though it is not so obvious and all conscientious breeders will be aware anyone can breed an affected puppy. Occasionally a puppy that is strongly coloured can be deaf. Most cases of deafness are caused by the puppy being a homozygous merle (MM) where the mating was merle to merle and the puppy has inherited the merle gene from both parents. Heterozygous merles (Mm) usually have no problem, but deafness can be from other causes although less common. Homozygous merles are also often quite pale in their merling and often have large areas of white over the body apart from what is often around the chest, collar, stomach and socks usually called Irish Trim. Some are all white with just a touch of colour or merling here and there. This isn't a guarantee of problems, sometimes these dogs can hear and see OK but they are more than likely homozygous merle anyway and should not be bred to another merled dog. Certainly dogs of this colouring that are not affected still can make very good working dogs, agility, obedience or companion dogs.