Alimentary - ruminant metabolism and energy imbalance Flashcards
How long does digestion take?
Roughly 2 days to not shock the biome
What are the three phases of digestion?
- Complex sugars to simple sugars with extracellular microbial enzymes
- Simple sugars to pyruvate by intracellular microbial enzymes
- Pyruvate to VFAs and gases (CO2, and methane)
What are the VFAs and their proportions?
Acetate - 60-70%
Propionate - 15-20%
Butyrate - 10-15%
How do the VFAs provide energy?
Acetate and butyrate can produce acetyl CoA
Propionate can produce OAA and glucose-6-phosphate
Both go into the krebs cycle
Where does this all occur?
In the liver
What is it like in an intensive production system?
Animal has a larger glucose demand, which can lead to hypoglycaemia
What are the signs of hypoglycaemia?
Slower and lethargic a leading to ketosis
Do ruminants make their own amino acids?
Yes, they can make their own essential amino acids and can thrive on low protein/poor quality diets.
Why is heat treated soy protein used?
It passes through the rumen and is not digested by the microbes so can increase protein useage
What happens to protein digested in the rumen?
The microbes use it or it is deaminated to VFAs and ammonia.
Where does the rumen sit?
Left hand side, within the sublumbar fossa
Bordered by last rib and subcoxa caudally.
What are the three stages of movement in the rumen?
Primary mixing cycle
Secondary burping cycle
Regurgitation
What is the primary mixing cycle?
Cranioventral contraction
Starting in the reticulum, moving to dorsal and ventral sac of the rumen
What is the secondary burping cycle?
A caudal-cranial wave dorsally leads to burping out of gas.
How much is burped out?
1 ltr/min
What is the regurgitation phase?
Bolus food is regurgitated back up through antiperisalsis of the oesophagus. This is to chew the cud.
How much saliva is produced in a day?
100-150ltrs/day and acts as a buffer to help keep the rumen neutral
What is ruminal tymphany?
A bloat/distension in paralumbar fossa. IF left untreated leads to respiratory distress and death.
What is free gas bloat?
Blockage of the eructation of gas
What can cause free gas bloat?
Recumbency
Physcial obstruction
Lack of rumen/reticulum motility
How does recumbency cause free gas bloat?
Fluid blocks the cardia, and can be caused by a multitude of things
How does physical obstruction cause bloat?
Seen in animals fed potatoes/turnips etc as scoffing. Can be caused by disease e.g. lumpy jaw which is tissue building up around rumen and cardiac sphincter
How does lack of rumen/reticulum motility cause bloat?
Can be caused by tetanus, milk fever, rumen acidosis and vagus damage
What is frothy bloat?
A form of bubbles is found in the rumen, not coalesing and the gas cannot be removed
What causes frothy bloat?
Rich pasture - soluble protein
Grain overload - leads to acidosis, often fine ground
How do you treat free gas bloat?
Stomach tube
Trochar/cannula into rumen
How do you treat frothy bloat?
Antifoaming agent:
- Surfactants
-Bloat guard
-Birp
-Oils e.g. mineral oil or cooking oil
How do you prevent bloat?
Do not turn out onto rich pastures
Do not feed finely ground cereals
Diet has to be 40% forage for chewing of cud to prevent acidosis
What are the problems with the abomasum?
It can be twisted or moved.
Left displaced abomasum
Right displaced abomasum
Torsion (right)
What is left displaced abomasum?
Rises and then traps the rumen full of gas. Seen with animal not eating and off food.
What is right displaced abomasum?
Rises and sits under ribs, less severe than LDA
What is torsion?
Twisted abomasum, cutting blood supply off
How can you diagnose issues with the abomasum?
Occurs in newly calved animals.
Can hear a thump when flicking a healthy cow, but will make a ping if viscous or full of fluid.
What is ketosis?
A rise in ketone levels seen with cow eating less.
How do you test for ketosis?
Stethoscope, detected in blood/urine with dip stick or taken to analyser.
What is primary ketosis?
Energy intake does not meet demand, leading to breakdown of fat/weight loss.
Seen in high yielding animals and intensive situations
What is secondary ketosis?
Caused by other issues such as LDA/RDA, metritis, mastitis or hardware disease
