HOW TO IMPROVE RIDGES, DECREASE RIDGELESS PUPPIES, AND AVOID DERMOID SINUS
Rhodesian Ridgebacks are a beautiful breed of dog from southern Africa. Their ancestry can be traced to Khoikhoi’s ridged hunting dogs and European dogs that were brought over with early colonists. They take their name from the area that is now known as Zimbabwe but was once Southern Rhodesia. F.R. Barnes drafted the original breed standard with this name in 1922 in Bulawayo. It was approved by the South African Kennel Union five years later.
Breeding for Ridges
Recent genetic testing and collaboration with breeders have revealed that a ridge gene in both parents does not always guarantee a ridge in all puppies. Heterozygotes, puppies with two different alleles of a gene, can develop with or without a ridge. The ridge gene is typically dominant, being masked in less than 4% of heterozygote offspring according to a study of over 200 dogs. All dominant homozygotes will have a ridge.
Your first instinct might be to choose a dominant homozygous dam and sire, but there are other factors to consider besides the percentage of ridged puppies. Dermoid sinus (DS) is a congenital abnormality that causes deep, tubular depressions in the skin of the dorsal midline that penetrate to deeper tissues and are highly prone to infection. There is not enough data for an accurate estimate, but it is believed roughly 10% of ridgebacks have DS. Dominant homozygous puppies are at a higher risk compared to dominant heterozygous puppies. Recessive heterozygous and recessive homozygous puppies are at a decreased risk.
Ridge abnormalities include short or partial ridges, multiple crowns, and offset crowns. All dogs tested by JOuStore with ridge abnormalities were dominant homozygous. This suggests that while two dominant homozygous parents will increase the chance of ridges by 4%, they will also increase the occurrence of ridge abnormalities and DS.
You can accurately predict the likelihood of ridges in your puppies with genetic testing that reveals whether your dams and sires are homozygous or heterozygous and whether the homozygous specimens are dominant or recessive. This valuable information will allow you to improve your litter outcomes by avoiding the breeding of two heterozygous parents, which is much more likely to result in ridgeless puppies than one or two dominant homozygous parents. Our test is over 99% accurate and was developed by Miroslav Hornak, Ph.D., a molecular geneticist at the Veterinary Research Institute in Brno.