How many litters can a female dog safely have?
Number of Litters for Female Dogs
It’s possible for a female dog to have a maximum of three litters a year. Female dogs can go into heat around the age of six to 12 months and do not go into menopause. Assuming a dog lives to the average age of 11, a dog could have up to 30 litters.
Factors affecting life expectancy across breeds
Between purebred and mixed breed dogs, both purebred status and body size affected the key parameters of mortality trajectories (Table S3, ESM2). Compared to mixed breed dogs of a given size class, purebred dogs had a significantly lower adult life expectancy ( , ). On average, mixed breed dogs lived 1.2 years longer than purebred dogs. Together with body size, purebred status explained 95% of the variance in mean life expectancy, with purebred status alone explaining 46% of the variance. Purebred dogs had a significantly higher baseline hazard, with purebred status alone explaining 60% of the variance. Purebred dogs also had a significantly higher absolute rate of aging, which explained alone between 8% (at age 10) and 40% (at age 4) of the variance. Counterintuitively, the relative rate of aging was higher for mixed breed dogs, albeit not significantly different. Alone, purebred status explained 15% of the variance. As expected (Kraus et al. 2013), body size mainly affected life expectancy via the absolute rate of aging.
| Key parameter | Purebred status | Body size | Radj2 | ||||||
|---|---|---|---|---|---|---|---|---|---|
| β | se(β) | t | P | β | se(β) | t | P | ||
| e(2) | − 1.216 | 0.123 | − 9.928 | < 0.001 | − 0.036 | 0.003 | − 10.34 | < 0.001 | 0.949 |
| a | 0.019 | 0.004 | 4.403 | 0.002 | 0.015 | 0.0001 | 1.980 | 0.079 | 0.660 |
| log(h′(4)) | 0.365 | 0.032 | 11.33 | < 0.001 | 0.012 | 0.001 | 13.69 | < 0.001 | 0.966 |
| log(h′(7)) | 0.290 | 0.053 | 5.459 | < 0.001 | 0.015 | 0.001 | 10.38 | < 0.001 | 0.925 |
| log(h′(10)) | 0.215 | 0.094 | 2.271 | 0.049 | 0.019 | 0.003 | 6.988 | < 0.001 | 0.825 |
| b | − 0.025 | 0.016 | − 1.605 | 0.143 | 0.001 | 0.0004 | 2.363 | 0.042 | 0.359 |
Across breeds of purebred dogs, adult life expectancy (adjusted e(2)) was negatively correlated with both body size (r = − 0.57) and coefficient of inbreeding (F) (r = − 0.14). Since body size and F were significantly positively correlated with each other, however, it was unclear whether the association with life expectancy was driven by body size, F, or both. Multiple regression analysis of the effects of body size and F on adult life expectancy showed that lifespan is highly significantly related to body size while variation in F had no additional effect ( ). This result supports the hypothesis that reduced lifespan in large breeds is mainly driven by their increased body size, and not by variation in the level of inbreeding between breeds.
What breed of dog has the longest life expectancy?
An Australian Cattle Dog called Bluey holds the record for the longest-lived dog – reaching an incredible 29 years of age. The breed normally lives for around 15 years.