We’ve heard a lot of stories lately about pups born without limbs or with other disabilities. But why does it happen?
Just like humans, there are many factors for congenital differences. Most start in gestation. But even after birth, environmental and physical changes (like blood pressure and oxygenation) can cause issues.
During the embryo and fetal stages, genetic or environmental factors can affect development. Insufficient nutrition, medicine, or other chemical exposure can cause over 250 different genetic diseases in dogs.
Changes in DNA can affect the way cells are divided. Another cause of genetic malfunction is inbreeding, which decreases the diversity of the gene pool. The practice of inbreeding and its horrific consequences are one of the many reasons puppy mills are so abhorrent, since they rely on inbreeding over the introduction of new genetic material.
About 6% of dogs are born with developmental abnormalities, ranging from wonky tails to major systemic issues like heart conditions. Physical birth defects, such as missing limbs, result from primary errors in development due to trauma or chemical exposure.
Cleft palates are common in brachycephalic (smoosh-faced) pups, often affecting more than one puppy in a litter, but folic acid supplements before and during pregnancy can help prevent this and other issues.
This fascinating footage of embryonic puppies explains how certain genes create different body parts:
Look at those tiny paws a-swimmin’! (I could watch these all day. Is that weird?) But the video does show that even a puppy in the womb is an incredibly complicated organism that leaves a lot of room for things to go wrong. That’s why gestational health is such an important consideration, and why puppy mills stink.
Still, we are grateful that the world has a diversity of critters, who, thanks to kind and caring humans, can live long and happy healthy lives, no matter what differences they have!