Genetic Gain - There is no magic recipe for breeding champion greyhounds
But it is easy enough to breed duds. So, why should we bother with Genetic Gain, when we are playing a game of chance? It is all about loading the odds to be as much in your favour as you can.
Feeding, rearing, breaking, training, race selection and spelling are all part of the science and art of successful greyhound racing. But at the end of the day, you are limited by the genetic quality of the dog you are working with. So, how should the greyhound breeder go about maximising their chances of getting a superior dog? Animal breeding is based on the fact that the DNA of the parents is more or less reflected in their offspring. Most physical attributes of an animal are substantially influenced by the genes inherited from the two parents, which each have two pairs of 39 chromosomes, each chromosome carrying thousands of genes. Mostly these genes have only a small incremental effect on the phenotypic traits such as racing speed, endurance, temperament and physical robustness that we are interested in.
The genetic contribution to the offspring from the sire is equal to the contribution from the dam. The rules of Inheritance drive this when a part of the dam’s DNA is combined with the sire’s DNA at conception. The dam plays a further important maternal role during pregnancy, whelping and through until weaning. However these maternal effects quite often differ from litter to litter.
The risks associated with choosing a sire are very different to the risks of choosing a dam. Once a sire has 80 or so pups that have had a reasonable shot at a racing career, the evidence of his genetic merit and perhaps more importantly, his ability to pass this genetic merit on to his offspring has been tested, and while more pups refine our confidence in his ability or otherwise, there is not much more that can be done to reduce the risk of failure. Using proven sires reduces the costs of rearing a greyhound that never makes it to race. In a similar way, bitches that have reared a successful litter also reduce the risk of generating uncompetitive pups.
If we wanted to do better, we would evaluate sires’ standing in both New Zealand and Australia using summary statistics to untangle genetic and nongenetic drivers of racing performance in New Zealand. When some sires get mated to better bitches, and the resulting pups are managed by great rearers, and go on to be raced by highly successful trainers, these sires and their progeny look better than their true genetic potential. This is of even greater importance when trying to find the best young unproven breeding candidates to become the sires and dams of the future.
The big challenge in breeding is to find the next generation of leading sires, and the maiden bitches that will go on to produce highly successful litters. These must be identified from their own performance, and also from the performance of their ancestors. A critical approach to bitch selection is essential if we are to reduce instances where pups are not suitable for a successful racing career. Some outstanding performers do not breed on. They may have inherited combination of genes in patterns that do not get passed on to their progeny. Or they may have just had a great environment. The better and more consistently they have performed over their racing career, the more likely that they have good genes to pass on. Some animals may not have performed well through no fault of their genes, for example they may have had
restricted blood flow in their mother’s uterus or have had an unlucky accident early in their racing career. While these animals may still carry good genes, they represent a greater risk, because the package of genes that they have inherited remains untested. Pedigree background is useful and important, but there is a risk that too much attention gets paid to distant ancestors, that most likely contribute only a small proportion of genes to the animal of interest. Top sires are present in many, if not most pedigrees often in multiple places in the pedigree.
For every champion with a specific combination of ancestors, scores of poor performing similar pedigree backgrounds can usually be found. Remember, that breeding a champion involves a substantial amount of luck. However, selecting animals to become parents that have not had a stellar racing career, are not functionally sound, and without a strong pedigree background is a sure way to reduce your odds of a solid racing performance. The best dogs need to be mothered well, reared with the best possible diet with frequent and positive human contact, and broken and trained by a skilled and experienced licensed person or their potential will not be realised.
This article was written by Ray Amer, who teamed up with Dr Peter Amer , a livestock geneticist at AbacusBio based in Dunedin.
Originally published in Greyhound Racing NZ magazine On Track in October 2018.