Ruminant Metabolic Dz

Question 1

Define metabolsim

Answer 1

the sum of the processes in the buildup and destruction of protoplasm; specifically the chemical changes in living cells by which energy is provided for vital processes and activities and new material is assimilated

Question 2

What is most at risk for metabolic dz?

Answer 2

• dairy cattle
• small ruminants
• 3 to 4 weeks post-parturition

Question 3

Name the 3 ketone bodies found in ruminants

Answer 3

Acetoacetate (AcAc)
Acetate (Ac)
Beta-hydroxybutyrate (BHBA)

Question 4

Characteristic metabolic abnormalities that occur with ketosis

Answer 4

increases of ketone concentration in blood, urine, and milk in combination with a decrease in glucose concentrations of the blood (hypoglycemia)

Question 5

What are the 3 sources of ketones?

Answer 5

1. diet
2. rumen epithelium (produced as result of starch and cellulose digestion)
3. Liver (produced via conversion of non-esterfied fatty acids from adipose tissue

Question 6

How do ruminants get glucose for metabolic use?

Answer 6

• Ingested glucose is used by the microbes in the rumen

- body must make glucose from precursors like propionate (a VFA produced in the rumen) and protein

Question 7

When does ketosis occur? How are ketones produced under abnormal conditions?

Answer 7

Occurs when the production of (or availability of) ketones exceeds the ability of the body to use them

available glucose or precursors decreases –> body switches to using adipose tissue for energy production –> fat mobilized to liver —> liver metabolizes fat –> ketone bodes produced

Question 8

Are ketones part of a ruminant’s normal energy source?

Answer 8

Yes. They can enter the TCA cycle and provide energy to the heart, kidneys, skeletal muscles, and mammary glands

Question 9

What is the result of ketones being produced by the liver via fat meatbolism?

Answer 9

increased amounts of ketones leading to ketones in blood, urine, and milk

Question 10

List the 3 types of Ketosis

Answer 10

Primary
Secondary
Dietary Intake of Ketones

Question 11

What is primary ketosis

Answer 11

Large amount of propionate and lactate are used by lactating cows to produce lactose needed for milk production
+
body expending energy for birth and milk production
= not enough energy intake through food to compensate
= energy deficit

Question 12

How long can it take before a cow eats enough to compensate for energy expenditure at peripartum time frame?

Answer 12

10 weeks postpartum

Question 13

What is secondary ketosis?

Answer 13

Presence of other Dz that increases energy demand on the cow and results in decreased energy intake so cow won’t be able to meet energy demands

Question 14

What are some Dz examples that can cause secondary ketosis?

Answer 14

metritis
DA
pneumonia

Question 15

Where might ketones come from in the diet?

Answer 15

Excessive wet silage is prone to growth of clostridium which ferments carbs to butyric acid instead of lactic acid. Excessive butyric acid production will lead to ketosis

Question 16

What is subclinical ketosis? How does it affect the body?

Answer 16

Documented abnormal increase in blood ketone concentrations and decrease in BG concentrations in ABSENCE of clinical signs

Affect on Body –> decreased milk production due to insufficient energy

Question 17

What is clinical ketosis?

Answer 17

Same as subclinical but with presentation of clinical signs

Question 18

What are clinical signs associated with ketosis?

Answer 18

• Decreased feed intake often starting with refusal of grain
• Dry feces/decrease in amount–> due to decreased feed intake
• Weight loss and decreased BCS
• CNS signs due to hypoglycemia (aimless wandering, blindness, ataxia, dementia, pica)
• predisposes cow to peripartum Dz like DA
• Hypoglycemia (BG 40-60 mg/dL)
• Elevated liver enzymes –> mobilization of fat to liver causing hepatic lipidosis (fatty liver)

Question 19

What is the gold standard for detecting ketosis in an individual?

Answer 19

detection of excessive amounts of beta-hydroxybutyrate in blood

Question 20

Is the field test that uses urine reliable?

Answer 20

• no

- false positives common

Question 21

How much ketone does urine have in it vs blood?

Answer 21

4x that of blood

Question 22

Is the field test that uses milk reliable?

Answer 22

• -yes

- false negatives in colostrum

Question 23

How much ketone does milk have in it vs blood?

Answer 23

1/2 as much as blood

Question 24

What is the goal of ketosis Tx?

Answer 24

to raise blood glucose concentrations to normal, which will decrease the production of ketones by the liver

Question 25

3 Treatments for ketosis

Answer 25

IV Glucose 50% Dextrose
Oral Admin of Glucose Precursors
Corticosteroids

Question 26

Con of IV glucose

Answer 26

doesn’t fix underlying problem

Question 27

Con of oral glucose precursors

Answer 27

side effects

Question 28

Con of corticosteroid use

Answer 28

increases BG but may cause hepatic lipidosis if given longer term

Question 29

List 3 ways to prevent ketosis

Answer 29

1. proper conditioning
2. maximize feed intake & propionate production in peripartum period
3. avoid ketogenic diets

Question 30

How should a ruminant be conditioned to prevent ketosis?

Answer 30

• before parturition, make sure not over conditioned
• dry cows should not gain too much weight prior to lactation
• house dry cows separately
• excessive adipose tissue can predispose cows to mobilize fat to liver as feed intake declines in peripartum period

Question 31

How can feed intake and propionate production be maximized in peripartum period?

Answer 31

• switch from dry cow rations to lactating rations slow enough to prevent rumen acidosis but fast enough to increase energy intake relative to energy expenditure during lactation
• feed small amount grain before calving and gradually increase postpartum