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Prevalence of pyometra and mammary tumour in dobermanns

Swedish researchers (1) have published rankings for incidence of pyometra and mammary tumour in dogs by breed. They examined Swedish insurance records for about 260k bitches, including 1744 dobermanns. Apparently, in Sweden 90% of bitches are unspayed, so this is a good population for such an assessment. In dogs up to 10 years of age, almost two thirds (62%) of the dobes had been diagnosed with either or both of pyometra and mammary tumour (average across all breeds 30%). This ranked dobes 8 out of over 100 breeds, making ours a very high-risk breed. Taken separately, pyometra was diagnosed in 43% (average 19%) and mammary tumour in 42% (average 13%). Obviously, if they had been able to include dogs older than 10, the rates might well have been even higher.

They do not give information for other age bands – for instance, it would be useful to know age at diagnosis in order to understand the reduction in risk that would result from spaying at 7 or 8 years of age, after reproductive duties have finished. Spaying itself is not without risk, as it can increase risk of other illnesses, such as cancers and joint disorders. However, despite not being able to find data on incidence of these specifically in dobermanns, anecdotally they seem likely to be lower risk than pyometra/mammary tumour, so I conclude that spaying in ‘middle age’ is well worth considering.

As for bitches that will not be used for breeding, owners need to discuss the pros and cons with their vet and/or breeder. However, one thing that is increasingly clear is that spaying at a very early age is deleterious. New research on golden retrievers (2) reports that a number of cancers and joint disorders, whilst more prevalent generally in neutered dogs, are very much more prevalent in dogs neutered before 1 year of age.

© 2013 Sue Thorn

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1. S Jitpean, R Hagman, B Str?m Holst, OV H?glund, A Pettersson and A Egenvall, 2012, Breed variations in the incidence of pyometra and mammary tumours in Swedish dogs, Reproduction in Domestic Animals 47 (Suppl. 6), 347–350
2. G Torres de la Riva, B L Hart, T B Farver, A M Oberbauer, L L McV Messam, N Willits, L A Hart, 2013, Neutering dogs: effects on joint disorders and cancers in golden retrievers, PLoS ONE 8(2): e55937. doi:10.1371/journal.pone.0055937

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