Dukes' Ch. 45: Ruminant Digestive Physiology and Intestinal Microbiology Flashcards
What is the fate of glucose in the dog?
The glucose will reach the small intestine and be absorbed by Na+/ glucose cotransporters.
Glucose provides about 4 kcal metabolizable energy per gram.
What is the fate of glucose in the ruminant?
The rumen bacteria will anaerobically utilize the energy in glucose by glycolysis.
The end products of anaerobic glycolysis will be a mixture of VFAs and lactic acid, depending on the type of bacteria that takes up each glucose molecule.
The ruminant will derive about 2.2 kcal metabolizable energy per gram glucose.
What is the fate of glucose in the horse?
The glucose will reach the small intestine and be absorbed by Na+/glucose cotransporters.
Glucose will provide about 4 kcal metabolizable energy per gram.
What is the fate of urea if fed to the dog?
The urea will likely be absorbed from the small intestine and some will be immediately excreted in the urine.
The rest may be converted to ammonia in the liver.
If a large amount is fed, the dog will eventually exhibit ammonia toxicity.
What is the fate of urea if fed to the cow?
The bacteria in the rumen will break down the urea to ammonia and then utilize the ammonia to synthesize amino acids, provided there is also a carbohydrate source fed with the urea.
The bacteria use the amino acids to form the various proteins needed for survival.
As the bacteria die or are flushed into the small intestine, the cow’s small intestinal enzymes digest these bacterial proteins to provide essential amino acids.
What is the fate of urea if fed to the horse?
The urea will likely be absorbed from the small intestine and some will be immediately excreted in the urine.
A smaller amount will
leave the blood and diffuse into the lumen of the large intestine, where it can be used by bacteria to produce microbial protein.
It is uncertain how much benefit, if any, the horse can obtain from microbial protein produced in the cecum and colon.
Why does bloat develop in some animals grazing alfalfa pastures?
Saponins in alfalfa cause frothy bubbles to develop in the rumen.
These very stable bubbles are present throughout the gas pocket.
During the eructation reflex the cardia must be cleared of fluids completely before the lower esophageal sphincter will relax and allow gas to enter the esophagus.
Unfortunately, the froth is interpreted by cardia receptors as a liquid and the eructation reflex will not continue to completion.
Gases cannot escape the rumen and distension of the
rumen prevents adequate expansion of the pleural cavity and the animal slowly suffocates.
What happens if a cow eats a piece of wire?
Since cows eat their meals quickly without chewing (they chew later; regurgitation reflex), they are likely to swallow wire if it is accidentally present in the diet.
The wire will enter the reticulum or quickly reach the reticulum as rumen contractions push material into the reticulum.
The wire can be pushed through the reticulum wall and cause peritonitis or be pushed through the diaphragm and cause pleuritis.
How many chambers are found in the camelid “stomach”?
Three, the final chamber also contains glandular true stomach.
What will happen if you treat a rabbit with pneumonia with penicillin?
The pneumonia may respond but the penicillin kills the Gram-positive
bacteria that predominate in the rabbit large intestine.
This will likely kill the rabbit as pathogenic Gram-negative bacteria fill the void left by the death of the Gram-positive bacteria.
