The most common health issue in capybaras is proper nutrition and Vitamin C deficiencies are common. Capybaras are a lot like great big guinea pigs and in captivity need a variety of fruits and vegetables in addition to grass and hay in order to avoid scurvy. In the wild, they are outdoors all day long in an equatorial climate and get plenty of sunlight. Young capybaras raised indoors need a Vitamin D supplement (found in most milk supplements) in order to grow strong bones.
Here is a link to a guinea pig website with an excellent overview of nutritional needs for this type of rodent. Vitamin C Chart
Here is a link to an article about Scurvy in Capybaras.
If you have a veterinary care question, please contact us at firstname.lastname@example.org. The ROUS Foundation is associated with the veterinary school at Texas A&M University in College station, Texas. We have access to veterinarians who specialize in capybaras who can coordinate with your veterinarian if necessary. In some cases, we can subsidize labwork, tests, or other capybara related veterinary procedures. If you are unable to successfully treat your animal, we may perform a necropsy, at no cost to you. However, you must contact the ROUS Foundation directly (provide us with a phone number where we may reach you) and follow preparation and shipping instructions carefully in order to provide Texas A&M with a specimen suitable for study. Your veterinarian can help prepare your pet for shipping.
The instructions for shipping are here. ROUS Foundation Necropsy Instructions
The medical history form is here. Medical History form