In either case, small amounts of mucous, gooey, or even blood tinged stool can be passed and there is a lot of pushing involved. Difficulty urinating can also appear as straining. The point is that if all you have noticed is straining, it may not be constipation. Straining to urinate is often an emergency situation so if there is any question about the pet’s ability to urinate, see the vet right away.
NB-In my experience, freshly-fed, properly exercised and homeopathically treated pets rarely (if ever) become constipated.--Dr. Jeff
Please note: The information provided here is intended to supplement the recommendations of your veterinarian. Do not disregard veterinary advice or delay treatment based on information on this site. Nothing can replace a complete history and physical examination performed by your veterinarian. -Dr. Jeff