1233

FINDING THE RIGHT GENES
By David Hancock

When I judged a Plummer show some years ago, I was very impressed by the quality of the entry. I was therefore interested to see a recent article in Countrymans’ Weekly, that listed quite a number of health problems in this breed. Every breed of dog has flaws, some of which are worsened by a closed gene pool. It is my understanding that the Plummer Terrier breed elders have already instigated a DNA programme to evaluate the popular lines in their breed. The creator of the breed, Brian Plummer appears to have used a flawed ingredient in his mix of creation stock. In regular telephone chats with him, many years ago now, I urged him – if he was going to utilize Beagle blood to look hard at the Dummer pack for material. I strongly recommended the use of Roger Bigland’s Parson Russell-type terriers for the ‘hunt terrier’ input. I do not know of a breed of dog without genetic defects and it takes dedicated work to remedy these. I regularly see Jack Russells with a ‘hop’, the usual manifestation of a luxating patella. Finding the right genes takes time!

Physically, the Fox Terrier looks to have had the biggest influence and a reintroduction of its blood, from DNA-tested stock could be one way out of this quandary. Hybrids tend to be very healthy in the first cross but less so subsequently, unless in skilled hands. In his valuable and informative book "Dog Breeding: The Theory and the Practice" of 1994, Frank Jackson wrote that: "The vigour of recently recognised breeds provides evidence of the value of the wise use of cross-breeding. These crosses will make it easier for the breeds to retain genetic health after recognition, which places a severe restriction on the size of the available breeding population and will call for a very different system of breeding management if the breeds are henceforth to survive in a healthy state." The very different system of breed management into which all recognised breeds fall under the Kennel Club aegis means that in time racial fatigue is guaranteed. We are guilty of perpetuating breeds which, because the pedigree has been allowed to wag the dog, lack robustness, vigour and a healthy genotype. Worship of the phenotype, or what the dog looks like, ahead of all ethical factors, has led to breeds becoming prettier but no longer, to use an old-fashioned phrase, hale and hearty. Short-lived dogs may make dog-traders richer, when replacement pets are needed more regularly, but their premature deaths do not exactly enrich the precious man-dog relationship. Pet cemeteries should be full of old dogs not young ones.

Fifty years ago, US veterinary surgeon Leon Whitney found better disease resistance in his crosses between two pedigree breeds. A study by Scott and Fuller in 1964 indicated that the high puppy mortality characteristic of matings within a breed was greatly reduced when two different breeds were crossed. A study by Rehfeld in 1970 showed that the frequency of neonatal death in pure-bred Beagles increased with the degree of inbreeding. Ten years ago, a study by four distinguished Ontario Veterinary College scientists concluded that "The advantages of hybrid vigour in a pure-bred line could be realised in a carefully controlled breeding programme making use of out-crosses." Who listens when experts like this speak?

Heterosis, or hybrid vigour, in livestock breeding, is usually demonstrated by increase in size, enhanced live-weight gains, earlier attainment of maturity and increased disease resistance in the first generation of crosses. Their offspring however do not automatically demonstrate this vigour to the same extent. This means that after an outcross, the gene pool needs to be stabilised again, especially in the protection of breed type. Is not the pursuit of a more robust breed worth a temporary risk to breed type? The really skilful breeders can obtain health, vigour and essential type. But breed clubs usually ban outcrosses and KC support couldn't be guaranteed.

Far too many pedigree dog breeders merely perpetuate the past, rather than improving on it. Their dogmatic stance on colour exemplifies their intransigence. The great setter man Laverack believed that a change of colour was as good as a change of blood. For any breed to favour one colour to the detriment of others can limit the genetic base of the breed. In a number of breeds of course the coat colour is the breed. But where a breed starts off with a variety of colours and then ends up favouring only one or two is an enormous loss. Plummers are expected to have fiery-red coats.

No working shepherd, professional terrier-man, huntsman, cattle rancher or shooting man of the 19th century would have tolerated weedy dogs. That is how the splendid breeds we enjoy today came down to us. We insult the memory and betray the work of all those pioneer-breeders who bequeathed such dogs to us when we put breed purity ahead of breed vigour and breed robustness. Out-crossing, or cross-breeding, is no magic answer but it was the resort of many extremely knowledgeable, truly experienced breeders in times past. It should not be unthinkable today. The Plummer Terrier was developed as a working dog by an ambitious breeder using, he assured me, tried working stock but not, I believe, after any DNA-testing. Before this breed was emerging, I came across a number of look-a-like terriers in the working Fox Terrier fraternity – some abroad. The Plummer Terrier breed elders are working hard to remove flawed blood from their stock and need our understanding and patience.