Researchers at the University of Nottingham collected semen from between 42 and 97 stud dogs every year over 26 years at an assistance dogs breeding centre. Semen samples were then analysed to assess the percentage of sperm that appeared normal and had the expected pattern of motility.

Sperm motility declined by 2.5% per year between 1988 and 1998, and then at a rate of 1.2% per year from 2002 to 2014.

Professor Allan Pacey, spokesperson for the British Fertility Society (BFS), said:

“This is an interesting study which suggests that the sperm quality in a population of dogs enrolled in a breeding programme in the UK may have declined over a 26 year period, in a manner which mimics what others have claimed may have happened in the human male over the last century.

“Although there is conflicting evidence to suggest that sperm quality in humans has declined significantly, this study is particularly interesting as the results suggest an increase in problems of the dog’s testicles and a decline in the number of female dogs born over the study period. In addition, concentrations of some environmental chemicals in the dog’s testicles as well as in commercial dog foods were also detected. Indeed, because dogs share the human home, this could suggest that they might be a useful model species to detect possible threats to male reproductive health.

“From these results alone, we cannot determine any impact these results may have on human public health. This data must therefore be interpreted with caution and used to guide further studies.”

For media enquiries please contact the RCOG press office on 020 7045 6773 or email pressoffice@rcog.org.uk