Signs: Decreased appetite and amount and shape of stools. Acting uncomfortable or not moving around or being as active. Grinding teeth, breathing faster.
Causes: Overgrown molars making it hard to chew hay. Not enough grass hay fiber in diet. Not enough fresh greens in diet. Hair, carpet fibers, bedding in stomach. Too many carbohydrates ie treats, fruit, carrots. Digestive tract is similar to a horse - think about the amount of apple or carrot a horse eats compared to body size and compare to a rabbit or guinea pig. A baby carrot, a slice of apple is too much. Rare causes are liver disease, kidney disease, bladder stones, bladder infection, and cancer.
Prevention: Feeding diet with free choice grass hays ie timothy, orchard grass. Do not feed alfalfa hay unless under 9 months old. Limit the amount of pelleted food to ¼ cup per guinea pig and ¼ cup per 3-5 lbs for a rabbit, unless under 9 months old. Feed Oxbow brand pelleted food and hay - can order online for delivery and purchase at PetSmart also. For guinea pigs, additional source of Vitamin C 50mg per day in the form of tablet from Oxbow or fresh kale or green pepper daily. Fresh greens 1 cup twice a day for a rabbit, 1/4 cup twice a day for a guinea pig. Good greens for rabbit are cilantro, carrot tops, parsley, romaine lettuce. Good greens for guinea pigs are kale, green pepper, carrot tops, romaine lettuce. Avoid all of the treats that the pet stores sell. Get treats from Oxbow and limit amount. Limit carrots and fruit. Have teeth checked yearly for rabbits until 5 years old, then twice a year. Have teeth checked yearly for guinea pigs until 3 years old, then twice a year. Dentistry under anesthesia if abnormalities are found on exam. Sharp edges occur on the continuously growing molars and grinding edges can become irregular, making it hard to chew hay properly. Use bedding such as CareFresh to prevent ingestion of fibers from fleece bedding. Monitor when out of cage to prevent ingestion of carpet fibers, etc. For chewing fun, give timothy hay cubes.
Treatment: Try to identify the cause and correct. Supportive care with SQ fluids for hydration, metoclopramide orally every 8-12 hours to promote motility of the GI tract, pain medication as needed, syringe assist feeding with Critical Care Herbivore every 4 hours. May need to stay in hospital for treatments or come back daily for fluids. After Hours Emergency Care in St. Paul which is part of Como Park Animal Hospital can do 24 hour care for sick rabbits and guinea pigs.