Ruminant Metabolic Dz Flashcards
Define metabolsim
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
What is most at risk for metabolic dz?
- dairy cattle
- small ruminants
- 3 to 4 weeks post-parturition
Name the 3 ketone bodies found in ruminants
Acetoacetate (AcAc)
Acetate (Ac)
Beta-hydroxybutyrate (BHBA)
Characteristic metabolic abnormalities that occur with ketosis
increases of ketone concentration in blood, urine, and milk in combination with a decrease in glucose concentrations of the blood (hypoglycemia)
What are the 3 sources of ketones?
- diet
- rumen epithelium (produced as result of starch and cellulose digestion)
- Liver (produced via conversion of non-esterfied fatty acids from adipose tissue
How do ruminants get glucose for metabolic use?
- 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
When does ketosis occur? How are ketones produced under abnormal conditions?
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
Are ketones part of a ruminant’s normal energy source?
Yes. They can enter the TCA cycle and provide energy to the heart, kidneys, skeletal muscles, and mammary glands
What is the result of ketones being produced by the liver via fat meatbolism?
increased amounts of ketones leading to ketones in blood, urine, and milk
List the 3 types of Ketosis
Primary
Secondary
Dietary Intake of Ketones
What is primary ketosis
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
How long can it take before a cow eats enough to compensate for energy expenditure at peripartum time frame?
10 weeks postpartum
What is secondary ketosis?
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
What are some Dz examples that can cause secondary ketosis?
metritis
DA
pneumonia
Where might ketones come from in the diet?
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
What is subclinical ketosis? How does it affect the body?
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
What is clinical ketosis?
Same as subclinical but with presentation of clinical signs
What are clinical signs associated with ketosis?
- 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)
What is the gold standard for detecting ketosis in an individual?
detection of excessive amounts of beta-hydroxybutyrate in blood
Is the field test that uses urine reliable?
- no
- false positives common
How much ketone does urine have in it vs blood?
4x that of blood
Is the field test that uses milk reliable?
- -yes
- false negatives in colostrum
How much ketone does milk have in it vs blood?
1/2 as much as blood
What is the goal of ketosis Tx?
to raise blood glucose concentrations to normal, which will decrease the production of ketones by the liver
3 Treatments for ketosis
IV Glucose 50% Dextrose
Oral Admin of Glucose Precursors
Corticosteroids
Con of IV glucose
doesn’t fix underlying problem
Con of oral glucose precursors
side effects
Con of corticosteroid use
increases BG but may cause hepatic lipidosis if given longer term
List 3 ways to prevent ketosis
- proper conditioning
- maximize feed intake & propionate production in peripartum period
- avoid ketogenic diets
How should a ruminant be conditioned to prevent ketosis?
- 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
How can feed intake and propionate production be maximized in peripartum period?
- 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
