Evaluating the dam and sire over time

A breeding dog is eventually judged on something it cannot show you itself — what its offspring became — and the confidence of that judgment depends almost entirely on how many offspring there are.

A producer is not the same animal as an individual

Assessing a dog as an individual and assessing it as a producer are different exercises with different evidence. As an individual, the dog is in front of you: you can measure, score, test and watch it, and the result describes that animal accurately. As a producer, the dog is only visible through its offspring, which arrive slowly, are raised by other people, and are shaped by the mates it was given.

That difference has an awkward consequence. The traits you selected the dog for are often the ones its own appearance tells you most about and its offspring tell you least about, because by the time enough offspring are mature the dog may be too old to use on what you have learned. Progeny assessment is therefore usually retrospective for the dam and prospective for the sire, which is one reason why stud dogs accumulate reputations faster than brood bitches do.

The practical discipline is to keep two assessments of each breeding animal rather than one, and to resist merging them. The dog that was correct, sound and typical as an individual may not transmit it; the moderate bitch may produce better than herself. The frameworks in evaluating breeding stock and choosing a breeding prospect describe the individual assessment; what follows concerns the second one.

One rule sits above every producer evaluation: a dog that itself develops an inherited condition causing pain or shortening life should not be bred again, however strong its offspring record. If a breeding dog develops new symptoms, have it examined by your vet before its next planned mating.

Sixty offspring and nine

A sire used widely in a popular breed may have sixty or a hundred offspring from twenty dams. A bitch who has had three litters has perhaps eighteen offspring from one or two sires. Those are not merely different sample sizes; they are different kinds of evidence. The sire’s offspring come from many maternal backgrounds, so what recurs across them is more likely to come from him. The bitch’s offspring share her, her uterus, her milk, her early maternal behavior and often one sire, so almost nothing can be attributed to her genetics alone.

This asymmetry is not a reason to assess bitches less rigorously, but it is a reason to say less about them with confidence. What a dam’s record can support is a description: how she conceived, carried, whelped and reared, how uniform her litters were, and what recurred across them. What it rarely supports is a claim that she transmits a particular trait, unless the trait appeared in offspring by different sires.

For both sexes, one litter is not an assessment. If a trait appears in one puppy in one litter you have an observation; if it appears in several offspring by different mates, you have something worth acting on. Everything in between is a judgment call, and the honest form of that judgment names the number of offspring it rests on.

What relatives tell you before the offspring can

Because offspring data arrive late, the usable information early on comes from relatives. Siblings, half-siblings and parents all carry information about the same genes, and health schemes exist largely to make that visible. An open register in which siblings’ and offspring’s results can be read together turns a single result into a family picture, which is why the arguments in health screening schemes and health databases and interpreting results matter to the producer question rather than only to the individual one.

A producer’s record is only as complete as the offspring you can see. Encourage every puppy owner, pet homes included, to have the breed’s recommended screening done. Researchers have found that breeding values drift when only the best results are submitted. Pet offspring, who are rarely screened, are often the missing half of a dog’s record.

Estimated breeding values formalize this. They combine a dog’s own screening result with the results of its relatives, weighted by relationship, and express the dog’s genetic risk relative to the breed average. The Royal Kennel Club’s hip and elbow values illustrate the gain: a dog with its own score and no scored relatives has around 60 percent confidence, a dog with no score of its own but both parents scored around 40 percent, and one scored parent around 30 percent. Values are recalculated several times a year, so they improve as siblings and then offspring are scored, and the published guidance is to prefer a below-average value at 60 percent confidence or better.

The size of the improvement over simpler methods has been measured. In an analysis of 15 UK breeds covering 142,287 hip scores and 13,908 elbow scores, heritability averaged 0.38 for hip score and about 0.22 for elbow score (elbow data came from five of the breeds), and selecting on breeding values was 1.16 to 1.34 times as accurate as selecting on individual or parental scores. In some breeds the practical gain was much larger: the proportion of young dogs for which a breeding value beat parental scores rose from 6 percent to nearly 80 percent in one breed’s elbow data. The same analysis is clear that values depend on continued scoring, so a breed that stops screening loses them.

Breeding values and the limits of your own eye

What breeding values do not do is replace the dog’s own result. A score describes the joints the animal actually has; a breeding value estimates what it is likely to transmit. The Royal Kennel Club is explicit that values are estimates, do not account for non-genetic influences on severity, and cannot guarantee unaffected puppies. They also exist for only a few traits in a few breeds, which means most of what you want to know about a producer has no published value at all.

For everything else, you are left with your own records and the breed’s, and the most useful finding in this literature is about selection intensity rather than methodology. Genetic progress against hip and elbow dysplasia in those 15 breeds was real but slow, equivalent to between about 0.12 and 0.82 genetic standard deviations for hips over two decades (elbow progress was smaller, about 0.13 to 0.21 over 2000–2011), and the authors attribute the modest pace largely to weak selection: even in the breed selecting hardest on hips, the pattern corresponded to excluding at most 18 percent of the highest-risk dogs. The limiting factor was not the accuracy of the tools but the willingness to leave dogs out.

That reframes the producer assessment. Its purpose is not to arrive at a confident statement about a dog’s genetic merit, which the data rarely support. Its purpose is to decide, under acknowledged uncertainty, whether this dog should be used again, used more narrowly, or not used — and the evidence suggests most programs err by using too many dogs rather than by choosing the wrong ones.

Taking a popular dog out of breeding

The hardest version of this decision concerns a dog that is admired, in demand, and probably the reason your kennel has a reputation. Offspring data accumulate fastest on exactly such dogs, so they are also the dogs on which an uncomfortable pattern appears first, and the cost of acting on it is highest.

Two considerations make it easier. The first is that heavy use of one animal is discouraged independently of its quality: the Fédération Cynologique Internationale recommends that no dog produce more than about 5 percent of a breed’s puppies over five years, and pedigree analyses show how much that threshold varies — from fourteen offspring in a numerically small breed to well over a thousand in a popular one. Simulations in those breeds suggest capping each sire’s contribution can help: in one French breed, the Coton de Tulear, a cap of fifty offspring lowered mean kinship by about 15 percent, although the right cap differs by breed. Withdrawing a popular dog therefore has a benefit that does not depend on being right about the pattern you saw.

The second is that withdrawal need not be total. Restricting a dog to a few carefully chosen mates, to bitches unrelated to the suspect line, or to a single further litter while you wait for more offspring to mature, are all available and all more proportionate than either continuing freely or stopping dead. What is not available is continuing to use the dog widely while privately suspecting the pattern is real; that choice is made at the breed’s expense, and it is the mechanism by which a problem becomes a breed problem. How those decisions feed the next cycle belongs in dog breeding strategy.

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Sources & further reading

1. Lewis T. W., Blott S. C. & Woolliams J. A. — Comparative analyses of genetic trends and prospects for selection against hip and elbow dysplasia in 15 UK dog breeds. link.springer.com
2. The Royal Kennel Club — Estimated breeding values. royalkennelclub.com
3. Fédération Cynologique Internationale — FCI international breeding strategies. fci.be
4. Leroy G. & Rognon X. — Assessing the impact of breeding strategies on inherited disorders and genetic diversity in dogs. vin.com
5. Jerold S. Bell, DVM (Tufts, via VIN) — Breeding Strategies for the Management of Genetic Disorders. vin.com
6. Wilson et al. (2013), PLOS ONE — Estimated Breeding Values for Canine Hip Dysplasia Radiographic Traits in a Cohort of Australian German Shepherd Dogs. pmc.ncbi.nlm.nih.gov
7. Lewis T. W., Abhayaratne B. M. & Blott S. C. — Trends in genetic diversity for all Kennel Club registered pedigree dog breeds. cgejournal.biomedcentral.com

Where evidence is limited, recommendations rest on established practice and expert judgment, and may be updated as knowledge develops. The offspring of one breeder’s dogs are too few for statistical inference, so a producer assessment records patterns across mates and the decisions taken under uncertainty, rather than establishing that any difference is real.

Next steps

• Read next: Evaluating breeding stock.
• Related: Estimated breeding values and risk assessment · Fertility in the offspring: what the evidence shows.
• Return to the area hub: Closing the loop: follow-up and the next generation.