| Subject: o excrement |
Author:
nucking futz
|
[
Next Thread |
Previous Thread |
Next Message |
Previous Message
]
Date Posted: 09/ 3/06 1:50pm
In reply to:
Patrick McGee
's message, "A Point We All Maybe Should Ponder......" on 09/ 3/06 9:21am
a ruminant is an animal that chews the cud, cud being defined by the shorter oxford dictionary as "the food which a ruminating animal brings back into its mouth from its first stomach and chews at leisure." in ruminants, the stomach consists of several compartments; to be precise, the true digestive stomach (the abomasum) is preceded by several large compartments, reticulum, rumen and omasum. the rumen serves as a large vat in which the food, mixed with saliva, undergoes extensive fermentation - "a slow decomposition of organic substances induced by micro- organisms". large numbers of both bacteria and protozoa are found in the rumen. these micro-organisms are responsible for the breakdown of cellulose, the breakdown products becoming available for further digestion. the fermentation products (mostly acetic, propionic, and butyric acids) are absorbed and utilized; carbon dioxide and methane (CH4) formed in the fermentation process escape by belching (eructation). rumination, evident as "chewing the cud", involves the regurgitation and re-chewing of undigested fibrous material, which is then swallowed again. as the food re-enters the rumen it undergoes further fermentation. broken-down food particles gradually pass to the other parts of the stomach where they are subjected to the usual digestive juices in the abomasum (or "fourth stomach" - which corresponds to the digestive stomach of other mammals).
cellulose digestion in many non-ruminant mammals is also aided by micro- organisms. in some non-ruminant herbivores, the stomach is large and has several compartments, and the digestion is very similar to that of ruminants, save for the absence of the regurgitation and re-chewing of food which is the distinctive feature of the ruminant. in other herbivorous mammals, the major fermentation of cellulose takes place in a large diverticulum from the intestine, the caecum.
microbial fermentation in the caecum is similar to fermentation in the rumen, but the rumen has two definite advantages over the caecum. one is that rumen fermentation takes place in the anterior portion of the gastrointestinal tract, so that the products of digestion can pass through the long intestine for further digestion and absorption. the other advantage of the ruminant arrangement is that the mechanical breakdown of the food can be carried much further; coarse and undigested particles can be regurgitated and masticated over and over again. this difference is clearly visible if we compare the faeces of cattle (ruminants) and horses (non-ruminants). the faeces of the former are a well ground-up smooth mass with few large visible fragments, whereas those of the latter have coarse fragments of the food intact in the faeces.
the four sections of a deer's stomach are the rumen, the reticulum, the omasum, and the abomasum. first, the food goes into the rumen which stores 8 to 9 quarts of unchewed food and acts as a fermentation vat. most of the digestion occurs in this area of the stomach. deer depend on billions of microorganisms that live in its stomach. these microorganisms break down the fibers, cellulose, and other basic plant components, and convert them into materials that can be used by the deer's digestive system. the lining of the rumen has small spaghetti-like fringes called papillae, which vary in length from 3/8 to 1/2 inch. over 40 percent of a deer's energy is derived from the acids absorbed through the papillae and the walls of the rumen.
after the deer has filled its paunch, it lies down in a secluded place to chew its cud. after chewing its cud for awhile, the deer re-swallows the food, which then passes to the second portion of the stomach, the reticulum. the reticulum has a lining that looks like a honeycomb. the reticulum holds the food in a clump, which can grow to the size of a softball. the main function of the reticulum is to filter out any foreign material. after about sixteen hours, the food passes to the third chamber, the omasum, where intensive digestion and absorption take place. the omasum's lining has forty flaps of varying heights, which absorb most of the water from the food.
the last compartment, the abomasum, has a very smooth, slippery lining with about a dozen elongated folds. the abomasum produces acid to break down the food pieces for easier absorption of nutrients. the food eventually passes through 67 feet of intestines, where most of the liquid is absorbed, leaving an impacted mass of undigested particles. these particles are passed out as excrement. a deer goes to the bathroom" an average of 13 times every 24 hours. usually 65 percent of the food will be used by the animal, and 5 percent is lost as methane gas, 5 percent as urine, and 25 percent as feces in the form of pellets.
[
Next Thread |
Previous Thread |
Next Message |
Previous Message
]
| |
Feedback: 