Oral Anatomy and Dental Care for Rabbits
The oral cavity of a rabbit typically contains twenty-eight teeth. Among these are two pairs of upper incisors. The second pair of upper incisors is hidden behind the prominent front incisors and is short, flat, and called peg teeth. The lower incisors consist of a single pair. When the upper and lower incisors come together, they create a scissor-like action that helps the rabbit cut food for eating.
Both the incisors and molars of rabbits continuously grow throughout their lives. Therefore, rabbits need to engage in gnawing behaviors to wear down their teeth. The incisors are worn down vertically through regular biting and chewing activities. Other behaviors like gnawing on wooden toys or furniture can also help wear down the incisors, but only the front teeth.
Rabbits grind their molars horizontally, so they rely heavily on eating large amounts of hay to maintain proper tooth wear. Chewing sticks, wood, or even furniture cannot effectively wear down the molars. If the molars fail to wear down, the tooth roots can overgrow either upwards or downwards, which can be fatal.
Some rabbits suffer from congenital or acquired conditions that prevent their upper and lower teeth from aligning properly to grind against each other. This leads to malocclusion and the development of overgrown teeth, commonly known as buck teeth.
The lower jaw can move freely forward, backward, and vertically, but lateral (side-to-side) movement is limited. Rabbits have four pairs of salivary glands: the mandibular glands, parotid glands, sublingual glands, and zygomatic glands.
Rabbit Gastrointestinal System
The two largest organs in the abdominal cavity of rabbits are the stomach and the cecum. When the stomach expands, or when hairballs, gas, or an enlarged liver press against the stomach, it causes contraction of the pyloric region to prevent the contents inside the stomach from being expelled.
Due to the anatomical positioning of the cardia and the stomach, rabbits are theoretically incapable of vomiting.
Structure of the Rabbit Ileum
The terminal end of the rabbit's ileum, near the cecum, forms a swollen, small round sac known as the sacculus rotundus. This structure consists of a honeycomb-like arrangement made up of a large number of lymphatic follicles. It is also the site most susceptible to blockage by ingested foreign matter.
Rabbit Cecum and Colon Function
The large intestine section: The cecum is the largest and most prominent organ in the rabbit's abdominal cavity. Contraction of the colon muscles can separate the fibrous and non-fibrous parts of the food. Non-peristaltic contractions send the non-fibrous particles and liquids backward into the cecum to facilitate fermentation.
The cecum can also contract to send its contents and fermentation products into the colon, which are then expelled through the anus and re-ingested by the rabbit. These reusable cecal contents are known as soft feces or cecotropes. Unlike the hard feces, which are typically expelled as individual pellets, this type of feces is generally excreted in clusters.
Rabbit Pancreas and Gallbladder Anatomy
The pancreas of a rabbit is very dispersed, making it difficult to distinguish from the surrounding mesentery of the intestines. The bile duct and pancreatic duct each enter the duodenum through separate openings. Bile secretes biliverdin rather than bilirubin.
