Rabbit Ears

Lop eared rabbits are really prone to ear infections – but why?rabbit-2531800_1280
What is going on with these ears?

Types of ear infections
Otitis external, otitis media and otitis interns – the external ear, the middle ear and the inner ear. This discussion is all about the external or outer ear. In fact, it’s the only part of the ear we can see without more advanced testing.

The outer ear consists of the pinna and the ear canal.  It stops at the eardrum, or tympanic membrane. The middle ear is just on the other side of that thin structure…and hopefully we can’t see into it during a regular ear exam. That would mean your eardrum was ruptured (ouch!).

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In many species the ear canal is broken into two parts – the vertical canal and the horizontal canal. Mainly because part goes up and down while the other is oriented sideways. This doesn’t hold true in rabbits. It’s basically just a slant down to the eardrum. In standard rabbits this canal has cartilage which allows it to maintain its shape – just like in our ears and nose- it’s bendy but holds shape.

In lops, there is cartilage in the outer portion of the canal, but not the inner…so the ear flops over.  Keep in mind that ear canals are designed to help material and debris exit the ear by moving things up and out. Imagine what happens when material starting at the eardrum try’s to get out of a lops’ ear…it hits that right angle bend and comes to a halt.

So what happens?
…debris builds up, bacteria or yeasts get stuck, maybe things get a little moist…and you get an infection.

Sometimes this infection starts in the middle ear and bursts through the ear drum to extend into the outer ear. Sometimes the reverse happens. But we can’t see the ear drum once debris or infection has set up shop. In order to find out more we can try to flush and clean the ear canal under anesthesia or image it using CT scans. X-rays of the skull can provide us with some info but a CT really gives you a great view of what is going on.

Now I know that a CT scan for your bunny may be out of reach financially. But I look forward to when they become cheaper and more common. Already there are researchers studying how to take awake CT scans. This helps both your pocketbook and your bunny since no matter how hard we try to minimize it…there is always some health risks with anesthesia.

So what do we do?
The answer is not clear but the more we look into it, the better our chance of figuring this out.  Right now, there is some thought that prophylactic ear cleaning may be helpful. Products containing tris-EDTA are a good choice. Please be careful what you put in your bun’s ears and check with your rabbit vet. I’ve heard of stories of folks putting bleach in animal ears and I’m sure they wouldn’t have done so if they knew just what pain and damage they were causing.

Rabbit and Rodent – Gut Stasis

Huh?  Gut Stasis?Guinea Pig
If you’re new to rabbits, guinea pigs and chinchillas you may not be familiar with a common problem – gut stasis.  This is a condition, from mild to severe, where normal gut movements start to slow down or stop entirely.  Without intervention your pet can die from this problem.

Let’s Back Up to Some Anatomy
rabbit giRabbits and some rodents (like guinea pigs and chinchillas) are hind gut fermenters.  Anyone familiar with horses knows what this means – they have a ton of large intestines and do most of their food processing there.  They do this through a large number of bacteria, hence fermentation.

Since it’s really difficult to digest grass or hay, these guys have a cecum and colon that actually separates large indigestible fibers from small fermentable particles and fluids.  The gut actually has two phases and switches from production of normal “hard feces” to cecotrophs of “soft feces” periodically throughout the day.  The cecotrophs are small, dark, soft feces that are packaged in a protective mucus coating.  You shouldn’t really see these as they get eaten as they are produced.  The mucus helps protect the cecotroph as it passes through the stomach in order to be re-digested.

What Causes the Gut to Slow Down?
Oh boy…here you go:

  • Pain
  • Diet (changes, not enough fiber, too many carbohydrates or proteins)
  • Stress (fright, fear, pain, poor home care, thunderstorms, the construction down the street…)
  • Husbandry Errors (overcrowding, lack of cleanliness…)
  • Other Illness (causing pain or stress)
  • Dental Disease
  • Diseases that Interfere with Eating
  • Medications that Disrupt the Gut
  • Certain Antibiotics (that disrupt the normal gut bacteria)

The Downward Spiral
So, once it starts it gets worse.  Slowed gut motility can lead to the build up of material in the stomach (trichobeozars), gas build up in the GI tract (resulting in pain), stomach ulcers, disruption of normal gut bacteria resulting in overgrowth, fatty liver disease … all things that contribute to making the problem worse.  As the food stays within the intestines, the body continues to remove fluids from the digesta.  Sometimes this can create a wad that is hard to get moving again or actually results in a fecal impaction.

What About Obstructions?
We used to think the trichobeozar in the stomach was the cause of their problems and needed to be removed – not anymore!  Experiments in the early ’80s proved the trichobeozar was the result of gut stasis and not the cause.  We don’t need to remove it unless there is a true foreign body present.  But they can get true obstructions – these are emergencies.  Your rabbit will be very sick and getting more sick very quickly.  Low body temperature is serious for both obstructions and more standard gut stasis.

What Can I Do?
Hind gut fermenters should never have an empty stomach – if there is any change in appetite or droppings start giving Critical Care until you can get to a vet.  The more abnormal your pet, the quicker you should get help.

What Does the Vet Do?
We may want to run some tests to better Guinea pig critical care feedingidentify your pet’s disease – radiographs and blood work can tell us a lot.  High blood glucose levels are actually more common in cases of obstruction.  The good news is that most of these animals can be managed with medical treatment such as Critical Care and fluids.  We will also consider if anti-gas medications, antibiotics or even medicines that promote motility should be used.

Can I Prevent Gut Stasis?
Yes…and no.  You can reduce the risks by feeding your pet a good quality grass hay with some leafy greens and a small amount of pellets.  Alfalfa hay has too much protein for regular bunnies, guinea pigs or chinchillas.  Lots of pellets means fewer long fibers that are so important to maintain normal gut movements.  A good healthy home environment can reduce stress as well.  Annual checkups with your vet are the best way to detect problems early and make sure problems you might not see (like dental disease) are identified as soon as possible.  Always brush your pet when they are shedding – if you have a long haired variety you’ll already be brushing very, very frequently just to keep the hair clean and prevent matts from forming.

Anemia – Where Did Those Red Blood Cells Go!

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Any animal that has red blood cells can present with anemia (a reduction in red blood cells), so of course that means most creatures on this planet!

But why does it happen and should you be worried and what do you do about it?

How is Anemia Defined?

Each species, be it bird, rabbit or snake, has a specific expected range of normal for the red blood cells (RBC). We look at the PCV (Packed Cell Volume) to determine the percentage of RBC present in the blood.

A Golden Eagle has a normal range of 35-47% while a Red Eared Slider can have anywhere from 25-35%. In order to know something is wrong, we have to know what the normal range is…but we can get an idea by looking at similar animals if we don’t have any numbers to work with. You can see that a turtle has an overall lower range than an eagle.

Anemia is simply having fewer than expected RBC or a lower PCV. It can be mild (30% in a rabbit) or severe (12% in a cockatiel) or anywhere in between depending on the cause and the duration of illness.
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What Causes Anemia?

There are 3 basic causes of anemia.

– Loss of RBC
– Lack of Production of RBC
– Destruction of RBC

Destruction!

In the exotics world we are lucky not to see a lot of destruction based causes of anemia. The big one to worry about is an autoimmune disorder such as IMHA (Immune Mediated Hemolitic Anemia). With IMHA the body sees RBCs as invaders and attempts to wipe them out. Actual diseases of the RBC such as blood parasites will cause the body to destroy the RBC in an attempt to destroy the parasite.

 Loss!

This occurs where there is bleeding either outside or inside the body. Trauma, resulting in bleeding, is a common cause. Other common causes include toxins such as lead (causing bleeding into the gut), ulcers or ulcerated tumors.

 Production Failure!

The most common cause of failure to produce red blood cells is call Anemia of Chronic Disease (ACD). ACD is usually due to a long standing inflammatory or infectious condition or neoplasia. The red blood cells have a shorter life span and aren’t being produced at the normal rate.

 

What Can We Do?

First and foremost, identify and treat the underlying problem. Is there an infection? Heavy metal toxicity? An open wound?

Second, support the anemia. Medications such as iron or vitamin K are useful in some situations. Transfusions can even be considered. We don’t use products such as epogen in exotics medicine…but that may change with time.

It’s always important to follow up and make sure that the anemia is responding to what is being done.
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