What is going into our dogs’ mouth could have future implications on the species.
Scientists at the University of Nottingham in London just released a study showing a decline of sperm quality in dogs they observed over 26 years.
According to their findings, between 1998 and 2014, researchers found more than a 30 percent decline in normal sperm movement.
The team also found a small increase in the mortality rate of female puppies and a 10-fold jump in undescended testicles, .1 percent to 1 percent, according to The New York Times. This condition is a major risk factor for testicular cancer.
When researchers tested the testicular tissue, they discovered concentrations of chemicals — PCBs (now banned) and diethylhexyl phthalate — that had been used in electrical transformers and paints, and still used in plastics. They also found these chemicals in the dogs’ semen, according to the outlet.
The same chemicals were also present in the dogs’ food. Because the chemicals aren’t from additives, the scientists speculated where they come from – with packaging and water being possible culprits.
While the scientists can’t say with 100 percent certainty the changes are connected with dog food, they do believe it is a major factor. The team did not identify the dog food brands used but said they were easily accessible and sold worldwide.
The dogs were from an unnamed breeding facility in which they were raised and trained to be service animals. All studs, the dogs were all pure breeds — Labrador retrievers, golden retrievers, curly coat retrievers, border collies and German shepherds — and between 42 and 97 were studied.
“Although it has not reached a critical point — the dogs are still successfully impregnating — further decline in motility could eventually harm their ability to reproduce,” Richard G. Lea, the associate professor at the School of Veterinary Medicine and Science who led the study, told the outlet. The study could also provide support for past research on the decline of quality in human sperm that has occurred in the last 70 years and a possible connection with environmental factors.
“While further research is needed to conclusively demonstrate a link, the dog may indeed be a sentinel for humans – it shares the same environment, exhibits the same range of diseases, many with the same frequency and responds in a similar way to therapies,” Lea said in a statement.