Small Mammal GIT Flashcards
What are lagomorphs?
- rabbits
What are hystricomorphs?
- guinea pigs
- chinchillas
- degus
What are myomorphs?
- mice
- rats
- hamsters
- gerbils
What are scuiromorphs?
- chipmunks
- prairie dogs
What are mustelids?
- ferrets
What type of feeder are lagomorphs and hystricomorphs?
- herbivores
What type of feeder are myomorphs and scuiromorphs?
- omnivores
What type of feeder are mustelids?
- carnivores
What is a herbivores mouth design?
- designed for chewing
- narrow gape (cant open mouth that wide)
What is a carnivores mouth design?
- designed for grasping/tearing
- wide gape
What does omnivore mouth design depend on?
- diet
What is the dental formula for rabbits
- I 2/1
- C 0/0
- P 3/2
- M 3/3
What are rabbits premolars and molars called?
- cheek teeth
What teeth in a rabbit continuously grow? and what is this called?
- incisors and cheek teeth
- diphyodont
Rabbits have two sets of upper incisors - What are the ones behind called?
- peg teeth
In rabbits enamel coverage is different between incisors and peg teeth - how?
- incisors have enamel on the outside only
- peg teeth have enamel all the way round
How much do rabbit teeth grow a week?
- Grow 2mm a week
What do normal cheek teeth have in a rabbit?
- should have spur in lingual side but not hooks and should be uniform and vertical
What dental problems do rabbits have?
- Dental overgrowths secondary to inappropriate diet = abnormal spurs
- congenital malocclusion
- traumatic injury
- dental abscess
- ulceration of tongue
How can you look at rabbits teeth?
- by giving them a full anaesthetic (safer than sedation)
What can you do to prevent over growth of rabbit incisors?
- bur them
What is the dental formula for hystricomorphs?
- incisors 1/1
- canines 0/0
- premolars 1/1
- molars 3/3
How do teeth grow in hystricomorphs?
- All teeth constantly growing
How do teeth grow in myomorphs?
- incisors are the only constantly growing teeth
What is dental formula for myomorphs?
- incisors 1/1
- canines 0/0
- premolars 0/0
- molars 3/3
How do teeth grow in scuriomorphs?
- incisors are the only constantly growing teeth
What is the dental formula for scuriomorphs?
- incisors 1/1
- canines 0/0
- premolars 0/0
- molars 3/3
What issues can hystricomorphs have with their teeth?
- misaligned incisors
What issues can myomorphs have with their teeth?
- crossing over incisors
If there are issues with incisors what does this usually stem from?
- issues with cheek teeth and improper grinding
You can remove incisors in the rabbit - what do you need to do in order to do this?
- need to remove germ cells at root of tooth to prevent re-growth
Why is it difficult to remove incisors in the rat?
- not easy to remove incisors in the rat as they sit within the nasal cavity and sinuses and can damage structurers easily
What is the normal dentition of a ferret?
- deciduous initially
- permanent from 7 weeks of age
- strong muscles of mastication allowing clamping onto pray
What can ferrets have wrong with their dentition?
- dental disease like other carnivores
How is food broken down in the hindgut fermenter?
- food is broken down by microorganisms in the caecum
Small herbivores have a fast transit time - why?
- fast metabolism
- very light delicate bones so cannot have too much food as they need to move quickly as prey species
How do small herbivores gain maximal nutritional value?
- food needs to be processed twice = caecotrophy
Why can’t rabbits and rodents vomit?
- due to structure of oesophagus entering stomach
What do rabbits need in their diet in order to grind their teeth?
- good quality forage and roughage
Where is the stomach located in the rabbit?
- cranial abdomen on the left side
Describe the structure of the rabbits stomach:
- large and thin walled
- well developed cardiac sphincter
Describe the small intestine the the rabbit:
- relatively short, location of the majority of CHO and protein digestion
- duodenum, jejunum and ileum
What is the sacculus rotundus in the rabbit (unique to them)?
- dilation at the terminal ileum, at the iloecaecacolic junction composed primarily of lymphoid tissues
In the rabbit what is the proximal and distal colon separated by and what does it do?
- Fusus coli
- separates the high fibre particles from low fibre particles
- specially adapted area of colon which acts as a differential pacemaker for gut motility
What happens to indigestible fibre in the rabbit?
- passes into the distal colon to be passed as dry faecal pellets
What happens to digestible fibre in the rabbit?
- passes into caecum to undergo fermentation producing VFA
What does the caecum do in rabbits?
- contains mixture if microorganism which are involved in the fermentation of the digestible fibre into VFA (mainly aetate) which is absorbed directly
What is the principal species of microorganism in rabbits?
- bacteroides spp
What other species of microorganism can be found in the rabbit?
- E.coli
- Clostridia
- ciliated protozoa
- yeast (saccharomyces)
Rabbits produce what 2 types of droppings?
- faecal pellets (about 150/day)
- caecotrophs usually passed 4-8 hours post feeding, usually at night
What is the appearance of caecotrophs?
- smaller, soft shiny appearance due to mucus coating
How are caecotrophs digested?
- swallowed whole directly from anus
- digested in the intestines to provide microbial protein, Vit B and K and fatty acids
What reasons can lead to hypomotility (gut stasis)?
- poor quality/low quantity fibre diet
- pain (rabbits are sensitive to pain and tend to hide it)
- stress
- systemic disease
- GI obstruction
- Gut stasis is a clinical sign not a diagnosis
hypermotility is rare - what can cause it?
- intestinal flora problems (can be due to antibiotics)
- obesity/arthritis - anything that makes movement to perform caecotrophy hard
Where is the caecum in a guinea pig?
- have a large caecum on the left
What digestive issues can hystricomorphs suffer from?
- anorexia
- gut stasis
- intestinal flora imbalance
- diarrhoea ( particularly in chinchillas fed fruit and beg based diet)
Why are guinea pigs more likely to have diarrhoea?
- due to fruit passing quickly through digestive system and needed this to meet their vitamin C requirement
Describe myomorph digestion:
- omnivores much simpler digestive tract
- varies with diet
- hamsters have a fairly well developed caecum
What type of GI tract do ferrets have?
- simple digestive tract
What is the GI transit time for ferrets?
- 3-4 hours
Why do ferrets need to eat frequently?
- otherwise hypoglycaemia a concern
- they are not starved before a surgery
What are intestinal trichobezoars?
- mat of hair has been ingested
How does hair normally pass through the system?
- normally passed through and excreted within the faecal pellets
When does ingested hair become a problem?
- problems occur when excessive amounts if hair are ingested or hair within the intestines dehydrate and from hard structures which can lead to obstruction
