What is a swimmer puppy? What causes the flattened chest and deformed ribs? Are single-puppy litters more likely to produce a swimmer due to lack of stimulation?
Swimming Puppy Syndrome
Barbara J. Andrews, Publisher TheDogPlace.org - June 2014
What is a “swimmer puppy”? What causes the flattened chest and deformed ribs? Are singleton puppies more likely to become swimmers?
How can you prevent the swimmer puppy from turning into a walrus with permanently flattened chest? Can the deformity be corrected while the chest and rib cage bones are still pliable? If so how? Does the flat chest come first or does it develop, forcing the whelp to become a swimmer? Is there a genetic component? What about an external factor?
If you are an active breeder, depending on your breed of choice, sooner or later, you are likely to have a “swimming puppy.” The affected pup fails to crawl normally. Instead, the swimmer moves with legs splayed out to the side in what has been compared to a swimmer’s breast stroke but more resembles the way a turtle walks. Thus, crawling or resting, the front legs don’t properly support the chest which allows the whelp’s weight to flatten the sternum and spread the rib cage.
An otherwise normal “swimmer” is not the same as pectus ecavatum which is the term for a severe deformity wherein the sternum (breastbone) actually protrudes into the chest cavity. A normally rounded chest can begin to flatten within hours of birth but may go undetected in a large litter. Early diagnosis depends on astute observation and frequent handling of puppies. An astute breeder can detect a “flat feeling chest” by holding the whelp chest-side down in the palm of one’s hand. If flattening is detected, extra care and attention may prevent serious deformity of the chest and rib cage.
While it is true that the stimulus of struggling for the teat keeps large-litter whelps more active, there’s no proof that exercise prevents the chest wall and rib cage deformity. In a litter of only one or two pups, a swimmer is more readily apparent and breeder records suggest that swimmers appear more frequently in single-puppy litters. Experienced breeders will be alert for signs of a “singleton” developing into a swimmer.
It is rare for an entire litter to be affected. Some studies have shown that “swimmer puppy syndrome” is highest in obese puppies. The debate then is whether that’s because fewer calories are expended in struggling for a teat. There could be a genetic component linking small litter size with fetal obesity.
Can flat chest syndrome be prevented?
The big story is in the newspaper! The one in your whelping box… Swimmers were more common when puppies were whelped and reared on newspaper. That fact, in and of itself, is a good indication that it is less genetic, prenatal, or weight-related than it is environmental. Admiring my first purebred litter, I noted the newborn’s back feet slipping on newspaper as they struggled to propel themselves forward to the teat. I immediately switched their bedding to rags and rugs. In over half a century and litters ranging from Akitas to Toy Fox Terriers, we bought countless bolts of carpet but I have never had a swimmer.
Ineffective Righting Reflex may indicate inner ear defect.
It has been reported that early symptoms of the flat-chest syndrome are a puppy that cannot or chooses not to relax on his side. He will “right” himself by rolling back onto his belly, thus putting pressure on the chest.
Sophisticated testing may be needed to determine whether the whelp actually suffers a defect in the righting reflex, which is an instinctive knowledge of position. There may indeed be a genetic component related to embryonic development of the inner ear. The ear is closed at birth but the inner ear is rich in nerve endings that send electrical impulses to the infant brain. One of those signals is the righting reflex and within a few days, the whelp will begin to struggle when held on his back in your hand. If his littermates wiggle and squirm but one pup lays limp, there is cause for concern.
Most whelps nurse from any position, from belly-down to upside-down or lined up on their sides like little sausage links. The newborn that can only nurse (and sleep) belly-down stands out early as potential swimmer and bears watching. When the dam is ready to let her milk down, quietly put the suspect swimmer on a good nipple that he likes. But place him on his side. If he turns belly-down, turn him back until he relaxes in that position and goes about the business of feeding before mom shuts the spigot off. The theory here is that his swimmer-position is just a silly preference and he can be re-programmed. Watch him each time he nurses to be sure he stays on his side.
Another trick, this time mechanical, is found on the Scottish Terrier parent club website (1) which involves an ingenious method of taping a walking-age pup’s back feet. Use of a sort-of belly-band then makes him push with his back feet, thus strengthening the muscles which he previously had not used, having preferred to just remain chest down and lazy.
The flat chest, swimming puppy syndrome seems to occur with slightly more frequency in short-legged dogs with wide chests and/or long bodies. Example breeds would be the bulldog, basset, and Scottie but no breed is immune to the deformity which can vary in degree from slight to crippling.
The Bulldog Club of America (2) also has excellent information on the swimming puppy. Like Scotty breeders, Bulldoggers are an inventive lot and have used mechanical support devises to lessen splaying of the front legs and encourage proper development.
A simple summation:
Don’t lose sleep worrying that it will happen to your litter, don’t spay a valuable bitch if someone tells you it is genetic, and never raise puppies on newspaper! Handle and examine your puppies from birth and you will be aware of any abnormalities. Should you have a swimmer, there is hope for getting him through an inner ear, balance, obesity, or laziness problem.
Swimmer puppies don't know they are afflicted so it is up to the breeder to make the right decision. Common sense says, don’t breed a swimmer.
(1) STCA.biz Reproduction, Birthing, and Neonatal Care
(2) The Bulldog Club of America - Swimming Puppy