My dog is half Mastiff and half Pit Bull. He eats two and a half cups of dog food twice a day. He has looked healthy until now — his ribs are showing and his “waist area” looks sunken in. What could it be?
It is possible that your dog has intestinal worms. Make sure you worm him with a trusted brand of dog wormer (e.g., Canex or Drontal). However, there are many other common reasons that cause sudden weight loss.
It is best that your dog is checked out by your vet for conditions such as diabetes, kidney failure, cancer, and also old-age conditions. He needs a full evaluation, as any sudden weight loss is always very worrying.