The fertility of dogs may have suffered a sharp decline over the past three decades, a new study has found. The research found that sperm quality in a population of stud dogs studied over a 26-year period had fallen significantly.

The research, published in the academic journal Scientific Reports, found that sperm quality in a population of stud dogs studied over a 26-year period had fallen significantly.

The work has highlighted a potential link to environmental contaminants, after they were able to demonstrate that chemicals found in the sperm and testes of adult dogs -- and in some commercially available pet foods -- had a detrimental effect on sperm function at the concentrations detected.

As 'man's best friend' and closest companion animal, the researchers believe that the latest results may offer a new piece of the puzzle over the reported significant decline in human semen quality -- a controversial subject which scientists continue to debate.