Hello, I'm Dr Ralston. Thanks for your question.
Well constipation is definitely a possibility. When was the last time you saw Basil defecate? Most dogs will defecate daily, sometimes twice daily. If you see him straining outside this could be a sign of constipation for sure. Sometimes after a recent period of diarrhea they will also strain like this. So, it can be difficult to tell.
Abdominal palpation can sometimes feel the feces backed up in the colon. And in some instances we need an x-ray of the abdomen to be sure.
BUT, I would like to suggest another possibilty.
It just might be anal gland issues. All dogs have small scent glands just inside their rectum. These glands produce a very strong musky odor that may have at one time been used for marking territories. The most advanced
glands can be found in the hyena, whose markings can last on trees for months at a time.
The anal gland fluid is normal. It builds up overtime in the glands of all dogs.
Most dogs will express the secretion while defecating normally on their own before it starts to leak out. However, if they do not the secretion can build up in the gland over time causing the gland to become swollen and painful. They might even become infected
and can rupture through the skin.
When they fill up they become painful, and the pet may chew at the area around the tail or lick a lot.
You can help prevent this at home by feeding your pet a diet higher in fiber like a weight control diet, or by adding pumpkin to the diet (1/2 TSP per 10 pds per day). That will help bulk up the stool and push out the gland
In dogs that don't express the glands on their own, they will need to be expressed regularly. Some pets may require monthly or less frequently, where others will need them expressed every other week or so. This is usually done by any groomer or by the vet.
Your Vet can even teach you how to do it at home. But in my experience after one experience expressing this strong smelling oily stuff, people are usually glad to have somebody else do it for them.
IN severe cases there is also surgical correction which entails removing the glands. This is not done often, and usually only by a specialist. A possible complication is damage to nerves which are near the anal glands which could result in fecal incontinence.
This last link I want to share with you gives a little more information on anal glands. Click here
I hope that information helps.
Please feel free to follow up with any questions you might have and we can continue our conversation. Ok?