Metabolic Diseases of Ruminants: Energy Flashcards
What is gluconeogenesis?
Creation of glucose in the liver to meet the body’s needs for this form of sugar
What is the main substrate for gluconeogenesis?
Propionate
What is the function of the liver cell (hepatocyte)?
The control center for regulation of energy metabolism
What happens when energy demand exceeds dietary intake?
- Insulin concentration decreases
- Glucagon concetration increases
- The animal mobilizes its stores
What stores of energy are available?
Glycogen
* In the liver and muscle
* Polymer of glycose
Muscle amino acids
* Can be converted to glucose
Lactate
* Can be converted to glucose
Fat
* In the body, 3 fatty acids are linked to one glycerol to fore triglyceride
* Abundant hydrocarbons for oxidation as fuel!
What happens after prolonged energy deficit?
- Insufficient propionate supply from rumen
- Glycogen stores eventually depleted
- Only a finite amount of muscels amino acids and lactate can be mobilized
What is left after a prolonged energy deficit?
Ketones
Ketones: Acetoacetate, butyrate, acetone
What are ketones a result of?
The result of incomplete oxidation of fatty acids
Why are ketones good?
- Important alternate energy source for some tissues
- Oxidized in heart, kidney, skeletal muscle, mammary gland
** Ketones serve to spare precious glucose for other needs**
Why are ketones bad?
- In high concentrations, ketones can suppress appetite and cause altered CNS function
What are the steps of ketosis?
- Energy gap (negative energy balance)
- Fat mobilization
- If the rate of fat mobilization exceeds the liver’s ability to oxidize it into energy
- Production of ketones
What is primary ketosis?
Ration is chronically deficient in carbs
What is secondary ketosis?
Diet is fine, but animal has another disease that makes it anorexic
Ketosis occurs seondary to disease-induced anorexia
What are clinical signs of ketosis?
- Gradual reduction in appetite
- Lethargy, glassy-eyed stare
- Decreased milk production
- Poor rumen motility
- Acetone odor to breath
What is nervous ketosis?
A type of ketosis in which CNS signs predominate.
* Apparent blindness
* Stupor
* Ocassionally agressive
How do you diagnose ketosis?
- Measure ketones in blood, milk, or urine
- Hypoglycemia
- Incomplete oxidation of fatty acids = increased concentration of ketones
What does treatment of ketosis include?
- Find the underlying cause (what is reducing appetite)
- Jump start gluconeogenesis: Oral propylene glycol, IV glucose, cortisol-based drugs (promote appetite), offer multiple feeds, tube feed, offer molasses in water
Why is it important to identify ketosis?
- Predisposition to other post partum diseases: 70% metritis; 80% displaced abomasum
- Milk production: Reproductive performance, increased risk of culling
- Costly disease: 4% direct (related to ketosis); 96% indirect (other diseases)
What could a cow having a history of “not being normal since calving” signify?
Fatty liver/ fat cow syndrome
What are some signs of fatty liver?
- Depression
- Anorexia
- Weight loss (usually overnight before calving)
- Decreased rumen motility
- Decreased miilk production
- Ketosis
How do you treat fatty liver?
Treatment is difficult
* Treat concurrent diseases
* Treat like ketosis, only more aggressive and intensive care
Prevention for fatty liver includes?
- Prevention of obesity in late lactation
- Match energy fed to milk production
What is pregnancy toxemia also know as?
Twin lamb disease
What is another disease of chronic negative energy balance?
Pregnancy toxemia
