SHORT, LONG OR DOCKED......... (continued)

 

As I wrote earlier, it is possible to breed and select for short tails, as the relevant genes are still present in the gene pool. However, the question arises, whether it’s not a risky business.....

 

Old wives tales or scientific truth?

Traditionally, the bobtail gene(s) was supposed to have definite lethal or semi-lethal effects. Early reports claimed that homozygous foetuses die in the mother’s womb. Live specimens show degeneration of spinal cord vertebrae and Hip Dysplasia. Lethal effect was first suggested in the sixties by Raber in Switzerland . He observed in Entlebucher (a swiss cattle dog breed) that litters by short-tailed parents were distinctly smaller than average. This observation led him to the conclusion that some puppies must die during the early stages of their development.

 

Strong semi-lethal effects of bobtail gene(s) in PLS was suggested by Haufschild in Germany . He reported a case of one litter born from short-tailed parents. The litter was very small and the surviving bobtail puppy was later diagnosed with a vertebral defect and Hip Dysplasia. Having published his observation, Mr Haufschild (at that time a well known German breeder) eventually established his own club, dedicated to breeding only long-tailed  PLS.

 

Same or different?

At present there is some evidence that short tails can be determined by at least two different genes (group of genes) and these may be different in different breeds.  But the exact type of the gene in PLS is yet to be established. Before DNA analysis clarifies this point, here is what we have already established.

 

Let facts speak

Years ago a report was published by Pindera (1989), who had studied the possible influence of bobtail gene(s) on the average number of puppies born. She analyzed 123 litters, of those 21 were produced by short-tailed parents. Apparently, her sophisticated statistical analysis did not support Raber’s observations. Quite the contrary –  the average number of pups was even higher in short-tailed litters (5.80 vs  4.08) and it was “statistically significant”. Unfortunately, no further data have been ever collected since.

 

Similar and far more numerous data were collected in Norway for Pembroke Corgis. They compared the average number of puppies in litters by two short-tailed parents, one short- one long-tailed and two long tails. Each category consisted of more than 500 pups.  There were no significant differences in litter size.

 

We are rather short of data on any coincidence between short tails and congenital vertebral deformities (e.g. spina bifita, a serious malformation of the spine). Accidentally,radiographs were taken some years ago of a litter still in mother's womb. The bitch was a short natural bobtails and so were the puppies. Their spines were perfectly normal and they were delivered and developed well (Hudecka, 1992). When I asked the breeders of australian stumpy tailed dogs in Australia (in this breed any tail longer than 10 cms bans from breeding) they answered that spina bifida occured slightly more often than in other breeds. In any case, though, it is not an alarming increase.

 

HD results collected both in Poland and in Great Britain some years, did not show any difference between long- and short tailed dogs.  At that time numbers of x-rayed dogs were pretty low, so we were not able to confirm results with statistical analysis.

 

To sum up, it seems that earlier reports on fatal or deteriorating influence of bobtail gene(s) may have been exaggerated. Let’s hope that modern research will finally clear the matter!

 

Miroslaw Redlicki