Ruminants

• What is a ruminant?

  An animal with a stomach which consists of 4 chambers
• Label this diagram of a ruminant stomach

  A) small intestine

  B) rumen

  C) abomasum (true stomach)

  D) omasum

  E) reticulum

  F) oesophagus

  
• What happens in the rumen and reticulum?

  -swallowed food is fermented by bacteria

  -cellulose is fermented to form organic acids, which are absorbed by the ruminant and used as energy sources
• How is the rumen/reticulum adapted?

  -villi and honeycomb like surface, providing a large surface area for absorption
• What happens to rumen fermentation products that are not absorbed?

  CO2 and methane are expelled via the mouth
• Why is this an example of mutualism?

  Both bacteria and the host benefit from the relationship. Bacteria are provided with cellulose (energy source), and the cow absorbs the products of cellulose fermentation (energy source).
• What is rumination?

  When partially digested food is regurgitated and rechewed.
• What happens following rumination?

  Food is reswallowed and passes rapidly through to the third chamber (omasum) and then to the true stomach (abomasum). From here, digestion occurs in the same way as it does in humans
• What is the role of the caecum/appendix in rabbits/horses?

  Stores bacteria that ferments and breaks down cellulose
• Coprophagy/refection is where herbivores eat their own faeces. Why do they do this?

  Faeces contains the products of cellulose digestion (e.g. beta glucose). Eating faeces means the beta glucose can then be absorbed