Metabolic Diseases of Ruminants: Energy

Question 1

What is gluconeogenesis?

Answer 1

Creation of glucose in the liver to meet the body’s needs for this form of sugar

Question 2

What is the main substrate for gluconeogenesis?

Answer 2

Propionate

Question 3

What is the function of the liver cell (hepatocyte)?

Answer 3

The control center for regulation of energy metabolism

Question 4

What happens when energy demand exceeds dietary intake?

Answer 4

• Insulin concentration decreases
• Glucagon concetration increases
• The animal mobilizes its stores

Question 5

What stores of energy are available?

Answer 5

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!

Question 6

What happens after prolonged energy deficit?

Answer 6

• Insufficient propionate supply from rumen
• Glycogen stores eventually depleted
• Only a finite amount of muscels amino acids and lactate can be mobilized

Question 7

What is left after a prolonged energy deficit?

Answer 7

Ketones

Ketones: Acetoacetate, butyrate, acetone

Question 8

What are ketones a result of?

Answer 8

The result of incomplete oxidation of fatty acids

Question 9

Why are ketones good?

Answer 9

• Important alternate energy source for some tissues
• Oxidized in heart, kidney, skeletal muscle, mammary gland
  ** Ketones serve to spare precious glucose for other needs**

Question 10

Why are ketones bad?

Answer 10

• In high concentrations, ketones can suppress appetite and cause altered CNS function

Question 11

What are the steps of ketosis?

Answer 11

1. Energy gap (negative energy balance)
2. Fat mobilization
3. If the rate of fat mobilization exceeds the liver’s ability to oxidize it into energy
4. Production of ketones

Question 12

What is primary ketosis?

Answer 12

Ration is chronically deficient in carbs

Question 13

What is secondary ketosis?

Answer 13

Diet is fine, but animal has another disease that makes it anorexic

Ketosis occurs seondary to disease-induced anorexia

Question 14

What are clinical signs of ketosis?

Answer 14

• Gradual reduction in appetite
• Lethargy, glassy-eyed stare
• Decreased milk production
• Poor rumen motility
• Acetone odor to breath

Question 15

What is nervous ketosis?

Answer 15

A type of ketosis in which CNS signs predominate.
* Apparent blindness
* Stupor
* Ocassionally agressive

Question 16

How do you diagnose ketosis?

Answer 16

• Measure ketones in blood, milk, or urine
• Hypoglycemia
• Incomplete oxidation of fatty acids = increased concentration of ketones

Question 17

What does treatment of ketosis include?

Answer 17

• 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

Question 18

Why is it important to identify ketosis?

Answer 18

• 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)

Question 19

What could a cow having a history of “not being normal since calving” signify?

Answer 19

Fatty liver/ fat cow syndrome

Question 20

What are some signs of fatty liver?

Answer 20

• Depression
• Anorexia
• Weight loss (usually overnight before calving)
• Decreased rumen motility
• Decreased miilk production
• Ketosis

Question 21

How do you treat fatty liver?

Answer 21

Treatment is difficult
* Treat concurrent diseases
* Treat like ketosis, only more aggressive and intensive care

Question 22

Prevention for fatty liver includes?

Answer 22

• Prevention of obesity in late lactation
• Match energy fed to milk production

Question 23

What is pregnancy toxemia also know as?

Answer 23

Twin lamb disease

Question 24

What is another disease of chronic negative energy balance?

Answer 24

Pregnancy toxemia

Question 25

When does pregnancy toxemia occur?

Answer 25

When late pregnant ewe or doe cannot or does not want to eat enough to meet energy demand

Question 26

What are clinical signs of pregnancy toxemia?

Answer 26

• Separated from the flock
• Star gazing
• Glassy-eyed
• Weak
• Recumbent
• Poor/ no appetite
• Any ill doe or ewe in last 6 weeks of gestation is a possible pregnancy toxemia case

Question 27

What makes pregnancy toxemia unique?

Important i think

Answer 27

• Glucose demand is unrelenting
• Dam will continue to provide fetuses with glucose at her own expense
• Severe hypoglycemia
• Fat mobilization under conditions of carbohydrate deficiency = severe ketosis and fatty liver
• Ketoacidosis can occur

Question 28

What happens pregnancy toxemia remains untreated?

Answer 28

The fetuses will die and the ewe or doe will soon follow

Question 29

What is the most successful treatment of pregnancy toxemia?

Answer 29

To terminate the pregnancy

Question 30

What does treatment of pregnancy toxemia include?

Answer 30

• Remove fetuses (induce parturition, C0 section)
• IV dextrose, propylene glycol, etc. –> like ketosis and fatty liver

Question 31

How can you prevent pregnancy toxemia?

Answer 31

Provide palatable, high energy feeds in late gestation