3543E.Asst ANSI #4. Allison Thompson
1. Explain why ruminants, cecal fermenters, and monogastrics have such
different abilities for digesting forages. It is to each animals advantage to
develop an evolutionary niche which is different from the animals around it. To
this effect, different digestion systems have been developed to process different
types of forage. Ruminants have developed the ability to chew and digest
cellulose (fibrous plant material) which other species derive essentially no
nutrients from, and this requires a fairly complicated digestive system. The cecum
allows some species, like horses, to utilize bacteria and other microbes to assist
them in digestion, and this requires a special intestinal compartment.
2. Compare and contrast the end products of protein carbohydrate
digestion and between the pig and the cow. (Enzymatic digestion of pig compared
to microbial digestion of ruminant, followed by enzymatic digestion.) Pigs
start digesting with enzymes beginning with their saliva, but cows do not have
salivary amylase. A huge portion of a pigs consumable energy is in the form of
starch, which is more easily digested and can be digested by enzymes the pig
excretes itself. A cow, on the other hand, relies on the digestion of cellulose,
which is fairly difficult to digest. To properly break down cellulose a cow relies
on bacteria and protozoa, which reside in the rumen and the reticulum. The cow
is then also able to break down some starches using their own enzymes.
3. Explain the digestion of a bite of mixed feed in a cow and a pig.