PRESENTED BY

THE DOMESDAY BOOK OF DOGS

 Fixing Type In Your Strain.

   For anyone interested in purebred dogs there is an excellent breeding regime expounded by the late Dr. Clarence C. Little in his book the Inheritance of Coat Colour in Dogs, 1957.  Using Dr. Little’s method it may be possible to achieve their ideal type in a breed without too much outlay.  The actual concept can be summarised in three steps:

Step 1.  Choose three individuals, one dog and two bitches, that best fit your aspirations.  This will be your P1 or parental generation.

Step 2.  Mate the dog to the two bitches and this should supply you with two litters.  This is to produce your F1 or first filial generation.  Compare the two litters together and pick the single best male out of all the pups.  Then from the opposite litter choose the best two females.  Your F1 generation should now constitute one dog and two bitches.

Step 3.  Mate the dog to the two bitches (his half-sisters) to produce your F2 generation.  Compare the resulting two litters and repeat as explained in step 2.  Do the same with your F3 generation, and so on.

   That’s Dr. Little’s breeding programme but there are a few things that need to be considered:

Note 1).  As you could, in theory, use the services of practically any male in the country the dog in the P1 generation might be regarded as redundant, i.e. you could start your breeding plan with just the two bitches whilst using the services of any appropriate stud (or studs).  Your initial choice of breeding stock must be the best available.  Always bear in mind that you will struggle to produce, say, show winners if you commence breeding with mediocre or faulty stock and a limited gene pool.

Note 2).  Find out what genetic disorders (if any) exist in your preferred breed.

Note 3).  Inbreeding depression is the opposite of heterosis, it can be avoided by breeding from the genetically fittest individuals; you may have to retain at least some of the pups for several months to see if they’re suitable for your strain.  You may also need to ‘test mate’ either within or outside your strain to check for the presence (or absence) of recessive genes.  Don't be afraid to outcross, either to other strains within the same breed, if available, or an outcross even more drastic; heterozygosity is preferable over homozygosity.  Consider in advance what you intend to do with surplus pups from two litters that you may be producing every one or two years.

Note 4).  You have three options if you accidentally lose a chosen male before he’s been used at stud.

a)  With enough generations under your belt you could revert to a grandparent (or beyond) and use him as your new stud.

b)  Keep a spare male for each generation, the litter-brother of your prospective stud, and dispose of this male after the stud has been used.

 c)  Revert to step 1 of Dr. Little’s breeding regime, except that this time you already have your two bitches and simply require a stud that best suits your ideal.  In other words, this would be a new P1 generation.

Note 5).  Should you lose a prospective breeding bitch you may have a problem.  You might keep a spare bitch from each generation or you could go up through the generations of your strain to find a suitable bitch for your stud.  Care must be taken to avoid inbreeding, i.e. mother to son, brother to sister etc.  The more homozygous your strain becomes the more likely it is that you will throw up latent, undesirable traits.  If they exist in your strain, as recessives, these traits will almost certainly turn up eventually but, maintaining some form of heterozygosity for as long as possible should, all being well, give you the opportunity to address any serious faults one at a time.  Laboratory rats are bred from thousands of generations of brother to sister matings, but they are test mated and the less vigorous are ruthlessly culled.

Note 6). Consistently smaller-sized litters (quantity or weight) are a sure sign of inbreeding depression and should start alarm bells ringing: this is time for test matings.  Inbreeding depression can be averted to some extent by doing test matings before the problem arises within your strain and only keeping breeding stock from your larger litters.

Note 7).  Always keep records.

Part II

  If one were to run two breeding regimes simultaneously then an interesting concept occurs.  The original stock for the second, parallel regime would need to be as different as possible to that used in the first breeding regime.  Then after a few generations if the stock appears to be getting hopelessly inbred simply swap the two studs.  Something similar to this technique was used in the days of cock-fighting when two very inbred strains of game fowl would be outcrossed to each other (Grzimek, 1961).  The resultant offspring would have the required hybrid vigour and the males could be expected to excel at cock fighting.

Frankling Eleanor.  Practical Dog Breeding and Genetics.
Popular Dogs Publishing Co. Ltd. 1961.

Serengeti shall not die.  Grzimek, 1961.
Dutton, New York.

Little, Clarence C.  The Inheritance of Coat Colour in Dogs.
Comstock Publishing Associates, Cornell University Press 1957.

Terrierman's Daily Dose. Friday, May 26th 2006

Inbred thinking.

 Back to HOME PAGE