The San Antonio Express-News has a letter from a visitor which discusses a kitten living in Houston with her owner who had an extremely small stub of a tail. The kitten had trouble controlling her urinary flow. The kitten was seen by a veterinarian who she said that cats with vestigial tails have bladder control problems. The kitten was eventually rehomed because the owner couldn’t cope with what is commonly called ‘inappropriate elimination’. The kitten was found a nice home in the countryside.
This problem of litter box issues with cats with extremely short or no tails is well known states Bonnie Beaver, a professor at Texas A&M Veterinary Medicine. She says that cats with extremely short tails have a condition equivalent to spina bifida in which the nerves of the spinal column which control the bladder and sometimes the rectum are affected. These cats can have a poor control and dribble urine.
Specifically, there is a malformation of the vertebrae and the spinal cord because of the non-fusion of the neural tube and vertebrae arches at the sacrococcygeal junction. In addition to problems with urination, cats with this condition suffer from fetal incontinence (the anus cannot be closed because of nerve problems), megacolon, constipation, hind limb weakness, hind limb incoordination and hopping rather than running.
“The M gene’s presence is not solely demonstrated in the shortened tail. Its effect is present throughout the vertebral column of Manx cats and elsewhere. The M allele disrupts the normal development of the caudal neural tube during the growth of the embryo.” – Michael
If you click on the following link you can read a lot more about the condition which is sometimes called Manx Syndrome. People often don’t realise that Manx cats when poorly bred can suffer from substantial health issues due to the defective gene which creates the appealing stubby tail but which also creates many other associated health issues one of which is inappropriate urination.
There are many random bred cats in the world with very short tails. They may carry the same defective gene as the Manx cat. So these extensive health issues to do with the failure of the nerves from the spinal column to the urinary tract and rectum are not necessarily confined to purebred Manx cats. The American bobtail does not carry this defective gene.