Dog Longevity 

Created by Dr. Kelly M. Cassidy, 2007

 

 

 

 

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Longevity Trends

Last updated 02/01/2008

Are purebred dogs living longer?

Many dog breeders now test their dogs for conditions common in their breed.  Most breeders, if asked, will say health is one of their highest priorities.  Veterinary medicine has made large advances in treating the common dog killers like cancer and heart disease, as well as many uncommon conditions, such as laryngeal paralysis. 

Have these factors led to greater longevity among purebred dogs?

There are very few studies done with similar methodologies comparing dog longevity over different time periods.  This is a list of the ones I have been able to find that seem to be reasonably reliable.

Breed Source Time Period (TP) 1 Time Period (TP) 2 Lifespan, TP 1 Lifespan, TP 2 Change
Australian Shepherd John Armstrong's on-line survey in the 1990s. Total N about 350, but N for each time period unknown. Born pre-1980 Born 1980 to 1998. Data corrected to adjust for dogs still living. 13.0

(?)

11.8

(?)

down 1.2 yrs.
Australian Terrier Australian Terrier Club of America 2002 Health Survey Before 1997, but the time period is unclear Before 2002, but the time period is unclear 11.0

(65)

11.0

(165)

0
Boxer Boxer Klub (German) comparison of 1983 and 1989 longevity surveys 1983 (not sure of years included) 1989 (not sure of years included) 8.5

(1271)

8.9

(546)

up 0.4 yrs.
Chesapeake Bay Retriever American Chesapeake Club Health Survey, 2004 All dogs in the 2004 survey The dog in the household that had died most recently 9.4

(731)

9.2

(~377 ?)

down 0.2 yrs.
English Cocker Spaniel English Cocker Spaniel Health Surveys from 1998 and 2002 Before 1998, but the time period is unclear Before 2002, but the time period is unclear. 12.2

(257)

12.0

(450)

down 0.2 yrs
Irish Setter Irish Setter Club of America National Health Survey, 2003 Unclear. From the 1997 survey, prob. circa 1990 to circa 1996. Jan. 1 1996 to 2003 11.2

(209)

11.3

(242)

up 0.1 yrs.
Kerry Blue Terrier United States (Kerry Blue Terrier) Health and Genetics Survey, 1999 Dogs born 1960 to 1982 Dogs born 1983 to 1999 10.6

(160)

8.4

(193)

down 1.9 yrs
Standard Poodle John Armstrong's on-line survey in the 1990s. Born pre-1982 Born 1982 to 1999. Data corrected to adjust for dogs still living. 12.7

(361

11.5

(627)

down 1.2 yrs.

References

Click on the link on the breed name to go to the breed on the Single Breed study reference page.

Discussion

For this small group of 8 breeds for which there is any data for longevity at two time periods, 4 breeds show virtually no change in longevity (-0.2 yrs to +0.2 yrs between the two time periods) 3 breeds show declines of 1.2 to 1.9 yrs between the two time periods, and 1 breed showed an increase of 0.4 yrs between a time period of 6 years.

Unfortunately, the 3 studies showing dramatic declines have methodological problems.   The methodological problems were most severe in the Kerry Blue Terrier study, in which longevity in the later time period was based on dogs born between 1983 and 1999, for a survey conducted in 1999.  Dogs born late in the time period would have either been still alive or would have died young, so, with no correction to adjust for dogs still living, longevity would be skewed towards short-lived dogs.

The problem of skewing of data towards shorter-lived dogs in the later time period was recognized by John Armstrong in the Standard Poodle and Australian Shepherd dataset.  He corrected the data to adjust for still-living dogs, but his method of adjustment is not stated on the web site with the data. (He died before the studies were published.)  These two studies have other possible methodological problems, but their impact, if any, is not clear. The data were gathered from breeder records, published memorials to dogs, and owner memory.  Owners may exaggerate the length of time that a favorite dog lived, or they may be more likely to remember the dogs that were in their lives the longest.  Breeders, with a vested interest in the breed or their own kennel's dogs, may exclude some dogs that died young.  Memorials are more likely to written and published for dogs that lived long lives. 

The study showing an increase in longevity of boxers had some problems, too. There was a reduction in dogs dying of accidental causes from 11.7% in the 1983 study to 4.9% in the 1989 study. Because dogs that died of accidents tended to die young, the reduction in accidental deaths might have accounted for much of  the increase in lifespan between the two time periods.

Even with consideration of possible methodological problems with some of the studies, the data are very discouraging.  There have been dramatic improvements in veterinary medicine, particularly in treatments of the most common killers of dogs (cancer and heart disease).  If breed health is staying about the same, then breed life spans would be expected to be increasing because of improved veterinary care.  If breed life spans are staying about the same, then improved veterinary care may only be compensating for declining breed health.  

 

 

 

 

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