Unit 1 - Metabolic Disease Flashcards
What causes ketosis in dairy cattle?
There is an increase in energy requirements and inadequate DMI (dry matter intake)
What causes an increase in energy requirements in dairy cattle that can lead to ketosis?
lactogenesis
What is the primary cause of a negative energy balance in pregnancy toxemia cases?
The actual process of making the baby
When does ketosis typically occur in dairy cattle?
Typically recently post parturient
What will the dairy likely first recognize in a cow that has ketosis post partum?
That the cow is having decreased milk production when it should be increasing
When does pregnancy toxemia typically occur?
2-6 weeks prepartum
What clinical signs are associated with ketosis?
Loss of appetite, decrease in milk production, and a more profound weight lost than normal
What clinical signs are associated with pregnancy toxemia?
Loss of appetite, separation from flock/herd, limb edema, and recumbency
What are the possible treatments for ketosis?
Propylene glycol, corticosteroids, IV dextrose
Which ketosis treatment should not be used for pregnancy toxemia and why?
Corticosteroids should not be used because they can induce parturition or abortion
They should only be used if you want to induce
What happens if you give too much propylene glycol in ketosis treatment?
You can kill off the rumen microbes
If you choose to use a corticosteroid, which should you use to treat ketosis?
Dexamethasone
Note: corticosteroids are not recommended because they drive gluconeogenesis and decrease milk production
Why shouldn’t Predef-2X be used to treat ketosis?
Because it is a mineralcorticoid and not a glucocorticoid. This is bad because it can influence the K levels
You are on a farm call and see a market value cow that is showing signs of ketosis. How would you confirm your suspicion?
Check blood BHBA levels (if you can’t you cant try urine or milk)
You are on a farm call and see a market value cow that is showing signs of ketosis. The blood BHBA is indicative of ketosis. What would you treat this cow with?
Propylene glycol in a paste or via a stomach tube - 300 mL a day for 3-5 days
You are on a farm call and see a high genetic value cow that is showing signs of ketosis. How would you confirm your suspicion?
Check blood BHBA levels (if you can’t you cant try urine or milk)
You are on a farm call and see a market value cow that is showing signs of ketosis. The blood BHBA is indicative of ketosis. What would you treat this cow with?
IV dextrose CRT
What is the best testing method to monitor for subclinical ketosis (and just ketosis in general)?
Blood BHBA
What animals should be tested (stage of production) when using BHBA to monitor a herd for subclinical ketosis and how many?
Sample 12 animals that are in early lactation and less than 35 days in milk (DIM)
When should you test the blood BHBA levels in relation to eating when you are monitoring for subclinical ketosis?
4-5 hours post eating
What is the alarm level for subclinical ketosis (with BHBA)?
If 10% of the cows tested are above the threshold - reevaluation needs to occur at this point
How do you know a cow has subclinical ketosis (with BHBA)?
If the blood BHBA level is >1.2, but they are showing no clinical signs
What is BHBA level indicates hyperketonemia?
Anything greater than 1.2
What does BHBA stand for?
Beta-hydroxybutyric acid - makes up 80% of the ketones
What are cows with subclinical ketosis at a higher risk for?
3x increased risk for LDA or clinical ketosis
What animals should be tested (stage of production) when using NEFA to monitor a herd for subclinical ketosis and how many?
Sample 7-12 animals 2-14 days before calving
Make sure to remove animals that have calved within 72 hours post-sampling
What is the alarm level for NEFA testing when you are looking for subclinical ketosis in a herd?
10% of the herd is above the cutpoint
What is the cutpoint for NEFA for subclinical ketosis?
> 0.4 mEq/L
When should NEFA testing occur in relation to feeding?
just prior to feeding
True or False: NEFA samples should be kept warm.
False - they need to be kept cool or frozen
What is the mechanism of action of propylene glycol in treatment of ketosis?
It is a precursor for proprionate which is an important volatile fatty acid that is metabolized to glucose in the liver
What is the mechanism of action of IV dextrose in treatment of ketosis?
It bypasses the need for the liver to convert proprionate into glucose, and instead the glucose is in the blood stream
What risk is associated with using IV dextrose to treat ketosis?
You run the risk of inducing other electrolyte abnormalities in order to make the ketosis better
What is the mechanism of action of corticosteroids in the treatment of ketosis?
They can increase glucose levels by reducing the action of insulin
What is the mechanism of action of niacin in the treatment of ketosis?
It plays an important role in the transfer of propionate into the TCA cycle (this reduces the amount of fat in the liver)
Why is an increase in glucose so important in the treatment of ketosis?
When there are NEFA in the liver they can take two pathways, one results in the formation of ketones via oxidation and the other results in the formation of triglycerides via esterification. If there isn’t enough glucose, the oxidation pathway is preferred and we get more ketones. SO when we are treating for ketosis we need the NEFAs to be converted into triglycerides and not ketones, therefore we need more glucose
You have a cow that is non-responsive to treatment, obese, and post-partum. What is your top differential?
Hepatic lipidosis
What confirmatory tests can be done in ruminants for hepatic lipidosis?
Diagnostic ultrasound and percutaneous liver biopsy
How is hepatic lipidosis treated?
Oral propylene glycol or IV glucose if possible
Insulin can be used in some cases
Why are ruminants at a higher risk of developing hepatic lipidosis than other species (like small animals)/?
Because they do not readily move fats out of the liver like other species do
How are ruminants and small animals different in regards to their risk/predisposing factors in developing hepatic lipidosis?
Emaciated small animals are at a higher risk of hepatic lipidosis
Well-conditioned or over conditioned ruminants are at a higher risk of developing hepatic lipidosis
skinny cat, fat cow
What role does preparturient fatty infiltration of the liver play in the development of ketosis?
A negative energy balance has started prior to calving and resulted in the fatty infiltration into the liver. This results in decreased liver function making the negative energy balance even worse
Why is glucose availability important in the treatment of hepatic lipidosis in ruminants?
It can provide continuing energy and induce an insulin/glucagon ratio that will decrease hormone-sensitive lipase mobilization of fatty acids and stimulate production of VLDLs (lipoproteins). Lipoproteins are what carry triglycerides, cholesterol, and other fats around the body (thus out of the liver)
How can insulin treat hepatic lipidosis?
It can induce the insulin/glucagon ratio that will decrease hormone-sensitive lipase mobilization of fatty acids and stimulate production of VLDLs
How can proprionate salts treat hepatic lipidosis?
They can change the volatile fatty acid profile and increase proprionate which is needed for gluconeogenesis
How do other periparturient disease processes such as metritis, LDA, and mastitis play a role in the development of metabolic disease?
These disease processes can cause a negative energy balance and thus fat mobilization and ketone production in the cow which will result in the development of a metabolic disease
How does metabolic disease predispose animals to other disease processes?
They leave the animal’s defenses and immune system weak which ultimately makes them vulnerable to disease processes
What causes hypocalcemia?
metabolic alkalosis
What is the pathophysiology of hypocalcemia?
If we have a high potassium diet we will have a decreased presence of hydrogen ions which results in metabolic alkalosis. The PTH receptor protein is then altered and its ability to bind to PTH is weakened. PTH is needed for calcium to be mobilized out of the bones, into the blood, and then integrated into the milk.
The PTH receptor has a magnesium cofactor as well so if we are low on magnesium the receptor will not recognize the PTH
When does hypocalcemia manifest in dairy cattle?
after parturition
When does hypocalcemia manifest in beef cattle and small ruminants?
Prior to or after parturition
What clinical signs are associated with hypocalcemia?
Reduced smooth muscle contraction Reduced feed intake Impaired immune cell function Recumbency with a bent neck Fine muscle fasciculation Muffled heart beat due to poor contraction Tachycardia Ambient temperature
How/Where does reduced smooth muscle contraction manifest in cases of hypocalcemia?
Flaccid uterus, decreased rumination, bloating of the abomasum, relaxed teat sphincter, recumbency, decreased fecal output, and bloat
What can cause hypomagnesemia?
lactation demands and lush pasture
When does hypomagnesemia manifest?
When on pasture or in early lactation
What can exacerbate hypomagnesemia?
stressors
What clinical signs are associated with hypomagnesemia in cows?
hyperexcitability, tetany, convulsions, sudden death, reduced feed intake, muscle twitching, chomping of the jaws, frothy salivation, head arched, rapid loud heartbeat, hyperthermia from muscle activity, nystagmus
What clinical signs are associated with hypomagnesemia in small ruminants?
depression, standing on their own, reluctant to move, progress to tetany and convulsions
What causes hypophosphatemia?
Elevated PTH associated with hypocalcemia increases renal and salivary secretion of phosphorus
When does hypophosphatemia occur in beef cattle and small ruminants?
late gestation
When does hypophosphatemia occur in dairy cattle?
milking due to increased pull
What clinical signs do beef cattle and small ruminants show when they have hypophosphatemia?
recumbent but alert and eating
What clinical signs do dairy cattle show when they have hypophosphatemia>
unresponsive downer cattle
What causes hypokalemia?
Anorexia and GI stasis
What drug is hypokalemia associated with?
Isoflupredone acetate
When is the onset of hypokalemia?
typically less than 60 days in milk
What clinical signs are associated with hypokalemia?
flaccid paralysis, recumbency, and abnormal neck position
Why does feeding low calcium diets in the dry period not always work well for prevention?
Long story short - the method is only effective if you can get Ca low enough and it is difficult to do with routine feed sources. You may just be giving them hypocalcemia without activating their osteoclasts
How do you manage a herd’s diet in order to minimize hypocalcemia in dairy cattle?
i. Set dietary Na, Ca, Mg, S, and P concentrations at fixed levels. Formulate the ration to have as low a K as possible and then add Cl at a rate 0.5% lower than the K inclusion
When should you check the urine pH in regards to feed change to an anion diet?
48 hours or more after the feed change - use mid stream urine
What is the goal urine pH of holsteins? Jerseys?
Holsteins - 6.2-6.8
Jerseys - 5.8-6.3
When are anion diets fed?
during the last 3 weeks or so prior to calving
Which electrolyte abnormalities do you need to make sure to treat rapidly?
hypocalcemia and hypomagnesemia cases
What can result if you do not treat hypocalcemia quick enough?
compartmental disease or crush disease
How is hypocalcemia treated?
IV injection of Ca SLOWLY
Can do SQ it just takes longer
What happens if you give IV Ca too quickly?
you can give the cow a fatal arrhythmia
Why shouldn’t you use Caldex as a SQ calcium treatment?
It can cause an abscess
How do you treat hypomagnesemia?
IV 1.5-2.25 g of Mg or rectal Mg, or Oral Mg sulfate (200-400 mL)
How is hypophosphatemia treated?
Oral 50 g P supplied as 200 g monosodium phosphate drench
OR
IV 6g of P supplied as a 23 g monosodium phosphate dissolved in 1 L
How is hypokalemia treated?
KCI orally at 50g/100 kg BW or IV (don’t exceed 0.5 mEq of K/kg/hr)
What supportive care should be done when treating hypokalemia?
Nursing care - rolling from side to side to prevent myonecrosis, float tank, and/or treat the dehydration
What complications are associated with downer cattle?
Secondary muscle and nerve damage leading to decreased blood flow and myonecrosis
Sciatic and peroneal nerve deficits
Trauma during attempts to rise - adductor rupture
How do you treat downer cattle?
Correct the primary cause
What supportive care is done for downer cattle?
Frequent rolling from side to side (q2-4 h), deep bedding or padding
IV fluid and maintain cardiovascular support
NSAIDs
Assistance standing or getting weight off
