Hello Lagomorpheus…
Here is some info I pulled off a website, that fits with what your vet and Sarita told you… In short maybe his veggies don’t have to go, but his kibbies should and any fruit or starchy veggies (carrots, apples etc)…Maybe increase his lettuce and feed timothy (as I’m sure you do) with some other types of hay! Also, i only included the dietary problems part, as your vet does not think it is a physical/mechanical problem…
Unformed Cecotropes: Mushy or Runny Stool
The cecum is a delicately balanced ecosystem. If the intestine is moving too slowly, or if the rabbit is getting a diet too rich in digestible carbohydrates and too low in crude fiber, the complex population of bacteria in the cecum can become “unbalanced.” This condition, known as CECAL DYSBIOSIS. Simply put, cecal dysbiosis means that the beneficial bacteria (e.g., Bacteroides spp. and a variety of others) are outcompeted and outnumbered by less desirable inhabitants such as yeast (a fungus, usually Saccharomycopsis sp.) or even very harmful bacteria such as Clostridium spp., related to the ones that cause tetanus and botulism.
A rabbit suffering from cecal dysbiosis will produce cecotropes that are mushy, pasty or even liquid. They are usually quite foul-smelling, and often stick to the bunny’s back end in great, nasty clumps. These unformed cecotropes are not a primary disease, however. They are a symptom of a disorder somewhere in the bunny’s system. In order to cure the runny stool problem, the underlying cause must be addressed.
Dietary Problems
Starch-rich Diet
Rabbits, like horses and cattle, are strict herbivores. The rabbit intestine–and its normal bacterial flora–has evolved to feed almost exclusively on grass and herbs. >br> Does your rabbit get starchy treats such as oatmeal, crackers, bread or sweets? Some rabbits with very sensitive intestines can suffer from runny cecotropes even from being fed commercial pellets. Fruit, as healthy as it is for humans, can be too much of a good thing for rabbits. The high level of sugar and starch in table fruit makes them too rich for a bunny except as a very small, occasional treat. A diet too rich in digestible starch is one of the most common causes of runny cecotropes in companion rabbits.
Fiber-poor Diet
A rabbit should be fed unlimited grass hay, such as timothy, brome, wheat or oat. DO NOT use alfalfa, as this is far too rich in calories and protein for good rabbit health. If a rabbit does not get unlimited grass hay to nibble on throughout the day, the muscles of the intestine may become flabby, and the normal peristalsis (muscular movements that push food through the gut) will become sluggish. This causes the passage of food through the cecum to be too slow to properly “flush” the bacterial populations, and cecal dysbiosis can result. The high fiber content of grass hay also helps to “dilute” the starch of other dietary items, and helps to provide a healthy intestinal environment. In preventing and curing a runny stool problem, it is very important to provide a complete and healthy diet.