Inbreeding and Linebreeding

The Working Kelpie came from a very small number of imported Collies. I suspect quite a few of these early dogs had been bred by the kennel master on a large estate(Rutherfords, maybe)for a number of years, maybe generations, somewhere in the Scottish border country. It would appear to be impossible for a breed type to be established here in such a short time if this wasn’t so, and for that type to be dominant when crossed over other collies in those early days. I was amazed when a photo popped up on Facebook recently which backed my theory. It was posted by a very astute sheep woman in Scotland and was taken of three of her pure Border Collies about twelve years ago.

In the 1850s when gold was discovered it became hard to get shepherds and dogs were in greater demand. There were no “stud” dogs, just a motley collection of all sorts…hunting dogs, imported collies(a collie was generally known as any kind of dog that worked stock)and very many combinations of these. The more astute stockmen were quick to see the superior working skills of some lines and were known to travel long distances to mate bitches to a special dog. The prick eared, short coated  ‘kelpies’ were quite distinctive and named after a very good bitch of the same name. There are some great reads about the origin of the breed, I’m just sketching in the background so you will realise the Working Kelpie came from very small and obscure origins and was developed into an amazing stock dog through the skills of a few clever breeders and their willingness to share genetics..

This preamble shows the breed was based on a small number of imported dogs and gradually grew in numbers through both judicious and random matings to supply the needs of the rapidly growing wool industry. Through success in field trials and also its stamina and hardiness, the Kelpie became very popular in the hot, dry conditions. Eventually a breed standard was drawn up and Kelpies were shown as ‘bench dogs’. The inevitable happened and dogs were bred for their looks to win ribbons and their working ability suffered. Eventually the Working Kelpie Council was formed to stop this loss of skills, keep records and  provide some oversight of the breed’s health and development. One of the most important decisions was to maintain Appendix registers so station bred dogs without known breeding and bred by non members could gradually work their way into the main studbook over generations. 

All went well for some years. As an approximate timeline, I’d say the breed began it’s popularity “explosion” with the introduction of yard trials, making trials more accessible compared to the arena trials which demanded more time and commitment . The format was designed so dogs doing everyday farm work were able to compete, and caught on quite quickly.  Breeders put more emphasis on yard work and the use of bikes and quads in high rainfall/stocking areas made casting dogs pretty much redundant; the need to handle stock more often for worm and foot problems also made yard dogs popular. Take a leap of a few decades and we come to the 2020s and see the majority of Working Kelpies are being bred along well known ‘yard’ lines with the same dogs appearing in many pedigrees. I’m hearing multiple reports of dogs becoming smaller, of legs getting shorter, stamina lacking, temperament a bit iffy in some, a lot more bad hips , and a lady told me of seizures in her area… 

Modern Karmala sires, above

 

And so we come to COI, or coefficient of inbreeding. Many people breeding kelpies have probably not heard of it and don’t worry anyway, except to wonder about mating known relatives. Many others don’t realise it depends on how many generations are included when calculating COI, and a popular pedigree page on Facebook uses  7 generations. The result will be higher when more generations are included. I use 8 or 12 and can also ask for more, going up to 12 can increase the reading by quite a lot. Breeders should be aware of this. 

Some studs like to breed largely within their own lines to maintain a steady type of work and can get too keen on these lines and not outcross often enough. Personally, I have always been on the lookout for likely sires that are  working in difficult country. The owners are happy for me to pay for a CA test as they are also interested in the result, but most come back as carriers(74% accurate test). The ideal is to keep some of your present lines in your ‘outcross’ and introduce some new blood. It’s almost inevitable that you’ll also get some things you don’t want, that’s why some are so reluctant to try… but the alternative is running into a dead end. Every litter we plan is designed to improve on the parents. The old mustering lines I prefer are becoming rarer and thanks to some malicious gossip many years ago, I’m not able to access some of them! These lines might prove a valuable resource for the breed very shortly as one of the few outcrosses available for the yard lines.

We also have the benefit of computer programmes to do the calculations for us, and we find the homozygosity table is of great benefit when working out the most dominant dogs in a mating…and tracking down the likely source of problems. This is where knowledge of dogs in your pedigrees is so valuable; I doubt it’s possible to breed consistently good dogs without this knowledge as Prefixes tell you only one thing. The dogs at the top of the list and those appearing multiple times will have the most influence on how the dog will breed on.

 

If you haven’t heard of CA do some research.

I’ll add some reading below. I asked the author for permission to reprint and he agreed on condition the whole article appeared.

Small Population Breeds and Issues of Genetic Diversity

Tufts’ Canine and Feline Breeding and Genetics Conference, 2011

Jerold S. Bell, DVM

Dept. of Clinical Sciences, Tufts Cummings School of Veterinary Medicine, N. Grafton, MA, USA

Issues of genetic diversity are a concern to dog breeders, and this can especially be so for breeds with small populations. The concern is whether there is enough genetic variation within a breed’s gene pool to maintain health and vitality. Breeders should be concerned about genetic diversity, because there are examples where damage has been done to a breed due to breeding practices. Restriction of genetic diversity can also occur in large population breeds.

All genes come in pairs: one from the sire and one from the dam. Each gene in the pair is called an allele. If both alleles in a pair are of the same type, the gene pair is homozygous. If the two alleles are different, the gene pair is heterozygous. While each dog can have a maximum of two different alleles at a gene pair, many different alleles are potentially available to be part of the gene pair. The greater the number of alleles that are available at each gene pair (called genetic polymorphism), the greater the genetic diversity of the breed.

If there is no breed diversity in a gene pair, but the particular homozygous gene that is present is not detrimental, there is no negative effect on breed health. The characteristics that make a breed reproduce true to its standard are, in fact, based on non variable (that is, homozygous) gene pairs.

The origins of breeds have a lot to do with genetic diversity. A breed established with a working phenotype tends to have diverse founder origins, and significant diversity. Even with substantial population bottlenecks, the breed can maintain considerable amounts of genetic diversity. This was shown in a molecular genetic study of the Chinook breed, which was reduced to 11 modern founders in 1981. Breeds established by inbreeding on a limited number of related founder individuals could have reduced diversity. Many breeds have also gone through diversity reducing bottlenecks*, such as occurred during World War II. For most of these breeds, their gene pools have expanded through breeding for many generations, resulting in a stable population of healthy dogs.

There are two factors that must be considered when evaluating genetic diversity and health issues in a breed: the average level of inbreeding, and detrimental recessive genes. With a small population, there is a tendency to find higher average inbreeding coefficients due to the relatedness between dogs from common ancestors. There is, however, no specific level or percentage of inbreeding that causes impaired health or vigor. The problems that inbreeding depression cause in purebred populations stem from the effects of deleterious recessive genes. (CA in Kelpies. Jan) If the founding population of a breed produces a high frequency of a deleterious recessive gene, then the breed will have issues with that disorder. This can be seen as smaller litter size, increased neonatal death, high frequency genetic disease, or impaired immunity. If these issues are present then the breed needs to seriously consider limited genetic diversity.

The issue of high average inbreeding coefficients is one that all breeds go through during their foundation. As the population increases and the average relatedness of dogs goes down (based on a fixed number of generations), the average inbreeding coefficient for the breed will go down. The effect of initially higher inbreeding coefficients in small population breeds will depend on the presence of deleterious recessive genes that will be expressed when homozygous.

Some breeders discourage linebreeding and promote outbreeding in an attempt to protect genetic diversity in their breed. It is not the type of matings utilized (linebreeding or outbreeding) that causes the loss of genes from a breed gene pool. Rather, loss of genes occurs through selection: the use and non-use of offspring. If a breed starts narrowing their focus to breeding stock from a limited number of lines, then a loss of genetic diversity will occur.

The process of maintaining healthy lines, with many breeders crossing between lines and breeding back as they see fit, maintains diversity in the gene pool. If some breeders outbreed, and some linebreed to certain dogs that they favor while others linebreed to other dogs that they favor, then breedwide genetic diversity is maintained. It is the varied opinion of breeders as to what constitutes the ideal dog, and their selection of breeding stock based on their opinions, that maintains breed diversity.

The most important factor for diminished genetic diversity in dog breeds is the popular sire syndrome. The overuse of a popular sire beyond a reasonable contribution through frequent breedings significantly skews the gene pool in his direction, and reduces the diversity of the gene pool. Any genes that he possesses – whether positive or negative – will increase in frequency. Through this founder’s effect, breed-related genetic disease can occur. Another insidious effect of the popular sire syndrome is the loss of genetic contribution from quality, unrelated males who are not used for breeding. There is a finite number of quality bitches bred each year. If one male is used in an inordinate amount of matings, there will be fewer females left for these quality males that should be contributing to the gene pool. The popular sire syndrome is a significant factor in both populous breeds and breeds with small populations.

The best methods for ensuring the health and diversity of any breed’s gene pool are to: 1) Avoid the popular sire syndrome; 2) Utilize quality dogs from the breadth of your population to expand the gene pool; 3) Monitor genetic health issues through regular health surveys; 4) Do genetic testing for breed-related disorders; 5) Participate in open health registries, such as CHIC (www.caninehealthinfo.org) to manage genetic disorders.

This article can be reprinted with the written permission from the author: jerold.bell@tufts.edu

Jan…my italics.

* during WWII many good lines of Kelpies were lost. This is in addition to losses from Distemper, parvo, snakes and injury. Imagine the modern dog without all these setbacks.