Tree of Life Exotic Pet Medical Center

Category: Rabbits

  • The Importance of Spaying Pet Rabbits for Long Term Health

    by Heather Bjornebo, DVM, DABVP(Reptile-Amphibian Practice), CertAqV

    Many clients with rabbits are unaware of the important health benefits of spaying rabbits. Spaying refers to the surgical sterilization of a veterinary patient by removing their ovaries and, at least in the United States, their uterus. There are many benefits to having your rabbit spayed that go beyond preventing unwanted litters.

    The biggest benefit is the elimination of the potential to get uterine cancer. Uterine tumors are extremely common in rabbits as they age. Some studies have shown as many as 44% of rabbits developing some form of uterine abnormality in their lifetime. Another important benefit of spaying your rabbit is spayed rabbits are also significantly less likely to get mammary tumors (breast cancer).

    Beyond the medical benefits of spaying your rabbit, there are also benefits that will help her make a better pet for your family. Spayed rabbits are better at using their litterbox and tend to be less aggressive. Spay rabbits are easier going and oftentimes more affectionate.

    So what should you consider when looking for a veterinarian to have your rabbit spayed? Rabbits in general are considered a higher anesthetic risk than dogs and cats so it is very important to find a veterinary hospital where not only is the veterinarian very familiar with your rabbit’s medical needs, but their staff is trained well so your rabbit receives the best care and monitoring during the procedure. While cheaper prices can be found at spay/neuter only practices, often time this lower cost comes with less one-on-one care, decreased monitoring during and after the procedure, and less supportive care such as skimping on IV fluids. Given the special needs of rabbit patients, we recommend rabbits be spayed at a full service exotics practice. To find an exotic veterinarian in your area visit aemv.org and use their find-a-vet search tool.

  • Capromorelin (Entyce®/Elura®) – popular appetite stimulant from Dog/Cat medicine showing promise in exotic pets

    By Heather Bjornebo, DVM, DABVP(Reptile-Amphibian Practice), CertAqV

    One of the things I love about exotic pet medicine is how rapidly things are advancing and progressing. It seems every year we are getting new advanced treatment options for our patients which is so exciting. One medication that I am excited about is Capromorelin.

    Recent studies on capromorelin, sold by the trade names Entyce® (dogs) and Elura® (cats), have shown promise as a medication to help stimulate appetite in sick exotic pets. Classified as a ghrelin agonist mimics the hunger hormone ghrelin where in the brain it acts on the hypothalamus resulting increased growth hormone release by the pituitary gland causing increased hunger and food intake. In addition, capromorelin also increases insulin-like growth factor-1, which increases lean muscle mass.

    One recent promising study published in the Journal of Exotic Pet Medicine and Surgery on hedgehogs showed significant increases in food intake when the medication was administered. Seventy percent of the hedgehogs in this study administered this medication showed an increase over those recieving the placebo consuming on average 11% more food.1

    A study showed capromorelin decreased stress induced weight loss in laboratory mice. The only study group where no benefit was seen with this medication was when patients were receiving the long acting opioid pain medication Buprenorphine-XR.2

    Another recent study in rabbits compared the efficacy of capromorelin versus Mirtazapine on improving appetite. Mirtazapine is another meidcation often used in veterianry medicine to increase appetite in sick animals. It is available as a topical gel that can be applied to the ear lobe. While previous studies in rabbits showed mirtazapine increases fecal output, it did not improve appetite. In this study it showed a positive effect on appetite with healthy rabbits increasing their intake after 2 days. Normal patients given capromorelin also showed significant increase in appetite, though not as profound as those given mirtazapine. Conversely, patients recovering from neuter surgery didn’t demonstrate any significant improvement in appetite on either medication. The overall take home was both medications help appetite, with mirtazapine being more effective and less stressful for the patient due to being topical and not oral. However, both did show promise in treatment of GI stasis.2

    Capromorelin has also been studied in birds. In a study in chickens the medication not only biochemically increased their blood insulin levels, it increased their appetite demonstrated by increased pecks per hour.4

    Definitely, more studies are needed to fully evaluate the use of this medication in exotic pets. So far the initial studies show a lot of promise, even if the results in rabbits suggest topcial Mirtazapine may be the medication of choice in this species. While less effective, it still gives practitioners another tool to treat GI stasis in this species. Hopefully, in the years to come more studies covering its efficacy and use in many other types of exotic pets, including reptiles.

    If you have questions about Capromorelin, contact your family veterinarian.

    References:

    1. Huckins, G.L., Mans, C. and Doss, G.A., 2025. Effects of oral capromorelin on food intake and body weight in healthy, four-toed hedgehogs (Atelerix albiventris). Journal of Exotic Pet Medicine, 52, pp.1-3.
    2. Punger, E.M., Norris, S.L., Stevens, S.C., Santos, K.H. and Christy, A.C., 2024. Investigating the Effect of Enterally Administered Capromorelin on Body Weight in Mice (Mus musculus). Comparative Medicine, 74(5), pp.327-335.
    3. Draper, J.M., Savson, D.J., Lavin, E.S., Feldman, E.R., Singh, B., Martin-Flores, M. and Daugherity, E.K., 2022. Comparison of effects of capromorelin and mirtazapine on appetite in New Zealand white rabbits (Oryctolagus cuniculus). Journal of the American Association for Laboratory Animal Science, 61(5), pp.495-505.
    4. Ceron-Romero, N., Taofeek, N., Thomas, A., Vroonland, E., Sanmartin, K., Verghese, M., Heinen, E. and Vizcarra, J.A., 2021. Capromorelin, a ghrelin receptor agonist, increases feed intake and body weight gain in broiler chickens (Gallus gallus domesticus). Poultry science, 100(8), p.101204.

  • Rabbit Hemorrhagic Disease is in Arizona, is your rabbit protected?

    Rabbit hemorrhagic disease (RHDV2) is endemic in southern Arizona, meaning it can’t be eradicated. The disease is highly contagious and can be spread through direct contact with infected rabbits, their feces, urine, and contaminated materials. It can also be transmitted by insects, such as flies, which can carry the virus. 

    Here are some things you can do to protect your pet rabbit and prevent the spread of RHDV2:

    Not using any equipment, clothing, or boots for field work that you use with your pet rabbit

    Vaccinate your pet: Get your pet rabbit vaccinated twice as soon as possible. You can get your pet vaccinated at select private exotic animal clinics. 

    Keep your pet indoors: Ideally, all pet rabbits should be housed indoors. 

    Take precautions when handling wild rabbits: If you work with or hunt wild rabbits, take special care to prevent your pet rabbit from coming into contact with them. You can do this by:

    Removing any field clothing and showering after handling wild rabbits .

    For more information on RHDV2 click here.

  • Cerenia – What is it and why is it used so wildly in veterinary medicine?

    Maropitant (a.k.a Cerenia)

    Cerenia, generically known as Maropitant, is a neurokinin-1 receptor antagonist. It mediates effects of central and peripheral substance P, an excitatory neurotransmitter and is in a class of peptides known as neurokinins. Substance P binds neurokinin-1 receptors which are G protein coupled receptors. As an antagonist, maropitant and others like it, blocks the action of substance P.

    Where are neurokin-1 receptors located?

    They are located in the central nervous system, heart and blood vessels, genitourinary system, immune system , and gastrointestinal tract.

    What are the effects of Cerenia in the body?

    These neurokin-1 receptors are involved in blood cell production, wound healing, neurogenic inflammation, cell survival, cell proliferation, pain transmission, endocrine and paracrine secretions, dilation of blood vessels. They are involved with neuronal transmission associated with depression, stress. Cerenia antagonizes the affects in these areas as well as acts on two areas in the central nervous system to stop vomiting: area postrema and nucleus tractus solitaries.

    So if rabbits and rodents cannot vomit, why is it often used in exotic companion mammals?

    While the anti-vomiting effects in rabbits and rodents not seem as important since they cannot vomit, it does not necessarily mean they cannot feel nausea. Efficacy of maropitant for preventing vomiting is also associated with pmotion sickness in dogs where it blocks final common pathway in the vomiting center of the brain. Studies showed it was very effective in preventing vomiting in dogs premedicated with hydromorphone, an opioid drug often associated with nausea and vomiting in patients. There are reports on Veterinary Information Network as well about its use with rabbits during head tilt and it is thought to maybe be helpful to reduce nausea from vestibular disease. It is also used in ferrets and birds as an anti-regurgitation drug.

    What about its use in pain control?

    As a neurokinin-1 receptor antagonist, Maropitant has shown to reduce anesthetic requirements of dogs undergoing surgery and can be used to reduce visceral pain. In rabbits, Maropitant reduced the viscerosensory response caused by colorectal distention and it is often in rabbits and guinea pigs as pain control for gastrointestinal stasis.

    It also has anti-itch effects!

    Since neurokinin-1 receptors are involved in mediating some itch pathways. Substance P is found in nerve fibers in the skin and it plays a significant role in the nerve pathways that are involved in inchiness. antagonizing, or blocking these pathways, can be helpful to reduce itch. Studies have shown similar drugs reducing itch in humans and Maropitant signficantly reduced the itchiness of ulcerative dermtitis lesions in mice.

    It can also reduce the creation of abdominal adhesions forming after surgery!

    Antagonizing neurokinin 1 receptors decreases postoperative adhesion formation and increases peritoneal fibrinolytic activity. Research in a rat model with the use of a neurokinin-1 receptor antagonist (NK-1RA) was found to decrease postoperative peritoneal adhesion formation by up to 53% at higher doses studied compared to saline controls. This research indicated that the antagonist used blocked the binding of substance P to neurokinin receptors. Left unblocked, substance P is proinflammatory and results proliferation of scar tissue and stimulates excessive blood vessel formation. Furthermore, antagonism appears to increase expression of tissue-type plasminogen activator an important enzyme in the production of plasmin, a protein that breaks down fibrin and scar tissue production. Research in rabbits has shown that intestinal adhesions can be reduced compared to controls when tissue-type plasminogen activator is given intraperitoneally.

    But wait… there’s more… how about in respiratory disease

    Maropitant has been used to treat canine chronic bronchitis. Substance P acts on the neurokinin-1 receptor in airway inflammation and the cough reflex. Antagonizing substance P showed a significant decrease in cough frequency and severity but no change in inflammation.

    So are their side effects for Maropitant we should consider?

    Some recommend not giving for more than 5 days in a row since the enzyme responsible for its metabolism, CYP2D15, becomes saturated. It should also be used with caution with highly protein bound drugs as these drugs compete with Maropitant for protein binding and there can be increases in unbound Maropitant in the blood. Also it should be used with caution with calcium channel antagonists as maropitant has an affinity for Ca and K channels. Excessive use may also decrease intestinal motility and it induced intestinal motility disorder in mice.