17 causes of constipation in domestic cats

Constipated cat maybe. It looks as if they might be straining. Screenshot.

You will need to be aware of your domestic cat’s toilet habits to assess whether they are constipated or not. Most cats have one or two stools a day but some cats have a bowel movement every two or three days. They are likely to be constipated. If there is a litter box a domestic cat might strain and cry when defecating or avoid the litter box entirely, or not poop at all. They may enter the litter box several times, fail to defecate and vacate the area.

Is this cat constipated? It looks like they might be as they appear to be straining and they pursue their lips which amuses the video maker. And this is a longhaired cat. They are more prone to constipation.

The causes of constipation cats are as follows:

Dehydration. We know that domestic cats are poor drinkers because of their wild cat inheritance and therefore there is perhaps a slight tendency towards constipation.
Although my reference books don’t tell me, logically wet cat food is going to be better to prevent constipation that dry cat food because it contains about 80% water. If a cat is a bad drinker and they are eating very dry food it is more likely that they will become dehydrated. Some vets argue that domestic cats on dry cat food are constantly, at least mildly, dehydrated.
Hairballs are a common cause of hard stools particularly for longhaired cats. There may be hair in the stool or they may vomit hair. There are methods to minimise hairballs.
Over-grooming due to stress can lead to hairballs.
Ingesting substances such as grass, paper, cellulose and cloth (pica) can lead to constipation.
Domestic cats may decide not to defecate because they are in (1) unfamiliar surroundings which are unnerving to them and/or (2) unwilling to use a dirty litter box.
Elderly domestic cats have reduced bowel activity with weaker muscles in the abdominal wall. This slows the passage of waste through the colon. This in turn can lead to retention and increased hardness of stools.
Obese cats are more likely to suffer from constipation.
Megacolon, which is an enlarged, sluggish poorly contracting colon can cause chronic constipation. This condition requires veterinary supervision and a lifelong special diet with stool softeners. Click for info on megacolon.
Tailless cats such as the Manx can suffer from constipation and faecal incontinence as they have developmental deformities of the spine and a lack of full development of the nervous system supplying the colon.
A broken pelvis suffered in an accident may damage the nerves leading to the colon causing constipation. There may also be a narrowing of the pelvic canal which can cause a partial obstruction.
Pain in the spine can cause constipation. This is because defecating is painful and therefore the cat voluntarily stops going to the toilet. Similarly arthritic pain can cause the same behavioural issue. Also, ruptured or impacted anal sacs can cause pain when defecating resulting in a failure to defecate.
Not enough fibre in a cat’s diet.
Inflammatory bowel disease (IBD).
Allergies can cause constipation.
Cancer and narrowing of the colon can also be a cause of constipation.
Other medical conditions that can cause constipation according to my research are hyperthyroidism, diabetes or kidney disease.

Note 1: faecal impaction is as described, a large mass of dry hard stool which develops because of chronic constipation. It can be so hard that it can’t come out of the body. Impacted faeces can be removed using a laxative and an enema. You will need to see a veterinarian.

Note 2: I am not a veterinarian. I sourced the info from Cat Owner’s Home Veterinary Handbook and online veterinary websites to describe the causes in a more succinct style.