As an Equine Shiatsu practitioner I totally agree with this accupressure point as it's on the stomach meridian. In most species these points are pretty much in the same location, be it horse, human, dog, etc.
The area they are showing on the front of the hock has 2 points, both are good for abdominal disorders & 1 is good for regulating the circulation of Qi (energy) & also eases pain. By massaging that area you would cover both points.
If I was treating a horse, I would also massage the centre of the front of the hind foot above the hoof with my thumb then wrap my hand round so that my fore or middle finger was in the centre of the back of the foot by the heel. This is quite easy to replicate with a dog paw. The point at the front has an effect on the whole stomach meridian. The one at the back helps with shock, fever, exhaustion, calming, etc.
When dealing with colic (which is the horse equivalent of bloat) in my own horse I gently stretch a front leg forward then a hind leg backwards.
Massaging around the base of ears has a calming effect & alleviates pain.
I cannot stress enough that these methods should only be used to help the animal whilst waiting for vetinary treatment.
VETERINARY TREATMENT MUST ALWAYS BE SOUGHT WHEN DEALING WITH BLOAT. YOU MUST ALSO TELL THEM YOU HAVE DONE SOME ACCUPRESSURE AS THESE POINTS CAN DISTORT THE SEVERITY OF A PROBLEM AS THEY HAVE A CALMING EFFECT & LOWER HEART RATES.
I hope this maybe of help.
Debbie