Ruminants

• what are ruminants?

  they are a group of herbivores, including cows and sheep, that use a rumen in digesting their food
• what are 2 examples of ruminants?

  • cow
  • sheep
• what is the main type of food that ruminants digest?

  much of their food is cell wall material, mainly cellulose
• what can animals not make?

  cellulase
• what can’t animals digest?

  the beta-glycosidic bonds in cellulose
• what to ruminants rely on to secrete the enzymes?

  ruminants rely on mutualistic microbes living in their gut to secrete enzymes
• what do the mutualistic microbes that live in the gut of ruminants include?

  • bacteria
  • fungi
  • protoctista
• where do the mutualistic microbes in the gut of rumen live?

  they live in a 150dm$^3$chamber, the rumen
• how does cellulose digestion take place in cows?

  • the grass is cut by the teeth and mixed with saliva to form the cud, which is swallowed down the oesophagus to the rumen
  • the rumen is the chamber in which the food mixes with microbes - the microbes secrete enzymes which digest cellulose into glucose
  • the glucose is fermented to organic acids that are absorbed into the blood, and are an energy source for the cow
  • the waste products, carbon dioxide and methane are released
• what is a ruminant?

  a cud-chewing herbivore possessing a ‘stomach’ divided into 4 chambers, the largest of which is the rumen, which contains mutualistic microbes
• what is a rumen?

  chamber in the gut of ruminant herbivores, in which mutualistic microbes digest complex polysaccharides
• what is mutualism?

  a close association of organisms from more than one species, providing benefit to both
• what happens to the fermented grass in cellulose digestion of ruminants?

  the fermented grass passes to the reticulum and is re-formed into cud - it is regurgitated into the mouth for further chewing
• how many times does the cud of ruminants be swallowed and regurgitated to the mouth?

  it may happen several times
• after the cud is done being swallowed and regurgitated several times, what happens to it?

  the cud passes next into the omasum where water and organic acids made from fermented glucose are absorbed into the blood
• what happens at the fourth chamber of the stomach in ruminants?

  the fourth chamber, the abomasum is the ‘true’ stomach, where protein is digested by pepsin at pH2
• where does digested food pass into during cellulose digestion in ruminants?

  digested food passes to the small intestine, from where the products of small digestion are absorbed into the blood
• what is the function of the large intestine in cellulose digestion in ruminants?

  the functions of the large intestine are comparable with those of a human - absorbs water and electrolytes from digested food
• what is this an image of?

  a ruminant gut and everything thats involved in cellulose digestion