Researchers at the University of Nottingham say they’ve documented a serious decline in the fertility of male dogs — and suggest that dog food or environmental causes may be to blame.
In a study spanning 26 years, researchers tracked the sperm motility levels of five different breeds — Labrador retrievers, golden retrievers, curly coat retrievers, border collies and German shepherds.
They took samples from between 42 and 97 dogs each year, according to the study, published in Scientific Reports.
Between 1988 and 1998, the team recorded a 2.5 percent decline in the amount of motile sperm per year. Between 2002 and 2014, this trend continued at a rate of 1.2 percent each year.
The researchers also found that male pups produced by dogs with declining sperm quality had an increased incidence of cryptorchidism, a condition where one or both of the testicles don’t descend properly.
The study suggests that the sperm quality may have been impacted by contaminants in dog food.
“We looked at other factors which may also play a part, for example, some genetic conditions do have an impact on fertility,” said Dr Richard Lea, leader of the study. “However, we discounted that because 26 years is simply too rapid a decline to be associated with a genetic problem.”
Dogs used for the study were all bred, raised and trained as service animals for disabled people at an unidentified center in England, according to the New York Times.
The scientists said that in addition to collecting samples throughout the study, they examined the testicles collected from dogs that had undergone castration.
Both showed environmental contaminants in high enough concentrations to affect sperm motility. These same chemicals were also discovered in various commercially available dog foods.
The researchers say the findings raise the question of whether a reported decline in human semen quality over the last 70 years could also be a result of environmental factors.
(Photos: Roscoe, a yellow Lab who was not involved in the study, and has no interest in the results, by John Woestendiek)
Posted by John Woestendiek August 12th, 2016 under Muttsblog.
Tags: animals, breeding, chemicals, contaminants, decline, dog food, dogs, food, health, motility, pets, quality, reproduction, research, semen, sperm, study, testicles, university of nottingham
Ten years after a dog was first successfully cloned, scientists have managed to produce the world’s first litter of pups to be born through in vitro fertilization.
In July seven puppies were born through IVF at Cornell University — five beagles and two “bockers,” or beagle-cocker spaniel mixes.
The achievement was not revealed until this week with the release of the research study.
Seems like science would have happened the other way around — that a “test-tube” puppy would have premiered long before we entered the even more science fiction-like era of cloned dogs becoming available on the marketplace.
But, while IVF has been used for decades in other animals, including humans, scientists had never succeeded in using it to produce a newborn pup.
Previous attempts to use IVF in dogs had resulted in very low rates of fertilization, and no live births at all once IVF embryos were transferred to a host.
“Since the mid-1970s, people have been trying to do [IVF] in a dog and have been unsuccessful,” said co-author Alex Travis, associate professor of reproductive biology at the Baker Institute for Animal Health in Cornell’s College of Veterinary Medicine.
What made it so difficult were some of the same factors that proved challenging in cloning dogs — females only ovulate once or twice a year, and their eggs are not transparent, making it harder to see the structures inside of the egg.
The Cornell researchers, in a joint project with researchers from the Smithsonian Institution, found that by waiting an extra day for eggs to mature before extracting them, they met with more success.
Adding magnesium to the environment where the sperm and egg met also helped with fertilization, the team found, according to a Cornell press release.
The achievement was revealed this week in a study published online Dec. 9 in the journal Public Library of Science ONE.
The seven surviving puppies (out of 19 embryos) are genetically the offspring of two different fathers (a cocker spaniel and a beagle) and three different beagle mothers, carried by the same beagle surrogate.
Unlike cloning, which involves transferring an existing (or dead) dog’s DNA into a donor egg, IVF involves the creation of a new genome through fertilization. Each each animal has a unique set of DNA.
The researchers say the development will open the door for preserving endangered canid species using assisted reproduction techniques.
It could also enable researchers to eradicate heritable diseases in dogs and facilitate the study of genetic diseases in dogs and humans, they say.
(Photo: Cornell graduate student Jennifer Nagashima and Smithsonian Conservation Biology Institute research biologist Nucharin Songsasen — lead author and co-author of the study — walk some of the puppies born through IVF; by Jeffrey MacMillan / Cornell University)
Posted by John Woestendiek December 10th, 2015 under Muttsblog.
Tags: animals, assisted, beagles, biology, bockers, cloned, clones, cloning, cocker spaniels, cornell, cornell university, dna, dog, dogs, egg, first, in vitro, in vitro fertilization, ivf, pets, puppies, pups, reproduction, research, science, sperm, study
Here’s a mother — or at least an expectant one — who made sure she’d have plenty of flowers on Mother’s Day, building her nest of pine needles under this budding bush.
I came across her Sunday while visiting my own mom, who has a view of the nesting duck from her living room window and reports that’s she’s been dutifully sitting atop her eggs — about ten of them — for weeks now.
It’s baby duck season at Arbor Acres, the retirement community in which my mother lives, where residents eagerly await the appearance of the year’s first ducklings.
Nobody’s sure who the father is, but many suspect it’s the fellow to the left — he of the poofy hairdo — who is well-known for his amorous behavior and apparently considers himself quite the ladies man.
Then again, if I had hair like that, maybe I would, too.
He is believed to have fathered many of the baby ducks that were born last year, and indications are he’s at it again.
Yesterday, as the nesting mother sat atop her eggs, amid the blooming flowers, it appeared to me — though I’m better at interpreting dog behavior than duck behavior — that poofy head had moved on to new interests.