Declawing linked to aggression and other abnormal behaviors in cats
Declaw surgery (onychectomy) is illegal in many countries but is still a surprisingly common practice in some. It is performed electively to stop cats from damaging furniture, or as a means of avoiding scratches. Previous research has focused on short-term issues following surgery, such as lameness, chewing of toes and infection, but the long-term health effects of this procedure have not to date been investigated.
According to research published today in the Journal of Feline Medicine and Surgery, declawing increases the risk of long-term or persistent pain, manifesting as unwanted behaviors such as inappropriate elimination (soiling/urinating outside of the litter box) and aggression/biting. This is not only detrimental to the cat (pain is a major welfare issue and these behaviors are common reasons for relinquishment of cats to shelters), but also has health implications for their human companions, as cat bites can be serious.
For the study, the author group, based in North America, investigated a total of 137 non-declawed cats and 137 declawed cats, of which 33 were declawed on all four feet. All 274 cats were physically examined for signs of pain and barbering (excessive licking or chewing of fur) and their medical history was reviewed for unwanted behaviors. They found that inappropriate toileting, biting, aggression and overgrooming occurred significantly more often in the declawed cats than the non-declawed cats (roughly 7, 4, 3 and 3 times more often, respectively, based on the calculated odds ratio). A declawed cat was also almost 3 times more likely to be diagnosed with back pain than a non-declawed cat (potentially due to shortening of the declawed limb and altered gait, and/or chronic pain at the site of the surgery causing compensatory weight shift to the pelvic limbs).
The surgical guideline for performing declawing, as recommended by Diplomates of the American College of Veterinary Surgeons, is to remove the entire third phalanx (P3), which is the most distal bone of the toe. Despite this, P3 fragments were found in 63% of the declawed cats in this study, reflecting poor or inappropriate surgical technique. While the occurrence of back pain and abnormal behaviors was increased in these cats, the authors emphasize that even optimal surgical technique does not eliminate the risks. They explain that removal of the distal phalanges forces the cat to bear weight on the soft cartilaginous ends of the middle phalanges (P2) that were previously shielded within joint spaces. Pain in these declawed phalanges prompts cats to choose a soft surface, such as carpet, in preference to the gravel-type substrate in the litter box; additionally, a painful declawed cat may react to being touched by resorting to biting as it has few or no claws left to defend itself with.
Lead author of the paper Nicole Martell-Moran, a veterinary practitioner in a cat-only clinic in Houston, Texas, USA, comments: 'The result of this research reinforces my opinion that declawed cats with unwanted behaviors may not be "bad cats", they may simply need pain management. We now have scientific evidence that declawing is more detrimental to our feline patients than we originally thought and I hope this study becomes one of many that will lead veterinarians to reconsider declawing cats.'