|
Enteritis Complexes:
Coccidiosis, Mucoid Enteropathy, and Enterotoxemia
Enteritis complexes are some of the biggest killers of rabbits. Why, it is not certain, but there does seem to be a definite relationship between diet and gastrointestinal status, especially as pertains to the fiber content of the diet In this article we will discuss the three top complexes, their actions, and the treatments commonly used.
Coccidiosis
Coccidiosis is a commonly-seen cause of diarrhea, especially in the young animal. The organism responsible is a protozoan parasite, Eimeria steidae. Other forms of the Eimeria species can also cause disease.
There are two distinct forms of coccidiosis; liver and intestinal. Liver coccidiosis is usually affects the young to yearling animal, and is manifested largely on a non-clinical level, save for possible lack of gain, and perhaps a slight persistent diarrhea.
The intestinal form is more common, especially in those animals on high carbohydrate, low fiber diets. Signs are seen anywhere from three weeks of age through adulthood as populations of Eimeria become high enough to cause problems for GI tract.
Some signs of intestinal coccidiosis are: severe diarrhea with a sudden onset; persistent non-responsive diarrhea which is not alleviated by increasing fiber levels in the diet; or a positive fecal flotation test for coccidiosis.
Eimeria is a small protozoan parasite which colonizes the crypts of the intestinal wall. As higher numbers accumulate, damage may be done to the wall of the gut, and a diarrhea with an extremely distinctive odor is released.
Once smelt, never forgotten; a fecal flotation test should be performed immediately to differentiate coccidiosis from other causes. A positive result means it is time to treat the herd and step up one's disinfection program.
Coccida are parasites, and as such, shed eggs which are infective after 24 hours out of the body, which is why a disinfection program is essential. Daily removal of all fecal material from the cage wires, resting boards, and floors will aid greatly in reducing the occurrence of coccidial enteritis.
Liver coccidiosis is not usually a great cause of diarrhea, but is a significant cause of unthrifty appearance and lack of gain due to liver damage.
The damage done to the liver and bile duct can appear as small, pencil-point white areas on the liver; in some very severe cases, larger areas of the liver may be discolored.
These livers are not safe for human consumption and must be discarded, which is a complaint often heard from the processor as well.
Treatment of coccidiosis of either type may be accomplished by a common method. This is the use of a sulfa drug such as sulfadimethoxine, sulfaquinoxaline, or sulfamethazine as directed by the veterinarian.
This drug class is one of the small number approved for rabbits; however, dosage should be determined by the veterinarian and caution must be taken to observe the prescribed withdrawal period before using the animals for meat of any kind.
Once treated, the animals generally recover without major recurrence. Outlook after treatment is promising, and unless the animal experienced severe and prolonged dehydration, recovery is swift and uneventful. Keeping dietary fiber levels high is helpful in encouraging recovery.
Mucoid Enteropathy
A second common diarrheal complex is what was formerly called mucoid enteritis, named that for the clear jellylike stools which appear as the disease progresses. As time and research have shown, mucoid enteritis was not entirely accurate as a name, so the title mucoid enteropathy was adopted to take in the many ramifications involved.
Mucoid enteropathy, or ME for short, affects usually young fryers on a high carbohydrate, low fiber diet, although there have been cases when a different diet composition was used. The initial signs appear as a slight listlessness and lack of appetite, combined with an insatiable thirst. The affected animal will commonly sit hunched, with its head high and front feet in the water crock. With automatic watering systems, the animal will again sit hunched directly beneath the valve and hold the head high. As this continues, grinding of the molar teeth will begin and a very liquid diarrhea will erupt.
After a period of 12-48 hours at this stage, the young animal will be extremely weak and begin discharging a clear, jellylike substance that may even be formed into stoollike pellets. The definitive diagnostic method for mucoid by the average rabbit breeder is to pick the animal up and shake it gently. If ME is present, this movement will produce a sound like a half-full Thermos bottle.
Dehydration in ME is a killer; animals provided with sufficient subcutaneous or IV fluids have a better chance to recover. Feeding straight fiber sources to encourage gut peristalsis recovery has been proven to be of value. If palpated, some animals will have a distended and doughy to hard cecum. For the commercial breeder, these animals are usually counted as a dead loss, as recovery is possible, but hardly worth the effort to them; the growth rate afterward is severely depressed. Affected animals are usually culled.
Preventive measures have varied over the years; from copper in the feed to a very high fiber level. A high incidence of ME is normally diet related; the precise cause is not yet known.
A finding linked to the impaction of the cecum is a pleural effusion, or fluid accumulation in the lungs. Animals with this phenomenon might recover in time also; but this result is doubtful.
Outlook is poor, few animals recover from this disease, and of those that do, virtually none do as well as they might.
It does seem to vary in incidence between geographical areas; perhaps this is something which might be intriguing to study.
Persistence, patience, and lots of good clean oat or grass hay seem to be the best and most available remedy and preventive at this point in time.
Enterotoxemia
The third diarrheal problem discussed here is the most severe and dreaded, enterotoxemia. Enterotoxemia. is a disease usually of the young animal, and is caused by the iota toxin released by a bacterium called Clostridium spiroforme.
Also called 'carbohydrate overload of the hindgut', enterotoxemia is a quite fast disease, and often results in death due to the systematic effects of the toxin.
C. spiroforme is a normal inhabitant of the cecum, a member of the cecal flora, and it is well-regulated by the growth of other normal flora until a larger amount of nutrients unused by other bacteria becomes available.
When this occurs, C. spiroforme initiates a population explosion, and, in the presence of glucose, begins to release its deadly chemical toxin.
The first sign the breeder will see is a sudden, messy diarrhea which may be so severe that fluid fecal material simply oozes or flows from the animal. The smell. is sour, unlike normal feces. A fecal flotation will reveal few or no coccidial oocytes (eggs).
The rabbit will be quite depressed, which makes sense ... they feel lousy, after all, and their belly may be very painful upon palpation. They will also become dehydrated rapidly, and this is the major cause of death in these young animals.
This disease is not limited to young stock; older animals may also contract it and die in large numbers.
Administration of antibiotics to reduce the population of C. spiroforme and electrolyte-containing fluids by mouth as well as given by injection are the main medical treatments for this disease at this time.
Competitive inhibition of C. spiroforme might be achieved by the use of probiotics such as live culture yogurt or commercial probiotic products. An immediate increase in the amount of crude fiber in the diet may also be of help. The outlook is grim, but recovery is possible.
As the main cause of the actual disease is a toxin, an antitoxin would be nice to have, as there is for tetanus. It is unfortunate that no such product is available.
Since we have no antitoxin, our best hope is to give the animals enough time to recover a balance of normal flora in the gut as well as removal of toxin from the system via normal metabolic processes.
Enterotoxemia is not a transmissible disease, unlike coccidiosis. As few as one, or as many as dozens of animals in the barn may be affected, old and young, dependent on just how high the carbohydrate might be in the diet.
Again, the outlook is grim, but be persistent and patient, and it will run its course.
|
