Food Animal Metabolic: Hypomagnesemia

Question 1

Hypomagnesemia is also known as?

Answer 1

Grass Tetany….Staggers

Question 2

What is the pathophysiology of Hypomagnesemia?

Answer 2

1. Mg is absorbed into the rumen
2. Na+ linked active ATPase dependent
3. Influenced by Na:K ratio, absorption significally impaired <3:1

NO Mg IS STORED IN BODY

Question 3

T/F: Renal excretion of Mg stops when blood Mg is <0.5mg/dL

Answer 3

Super FALSE!!!

<1.8mg/dL

Question 4

How does a cow develop hypomagnesemia?

Answer 4

Eating forage that has low level Mg. Some forage have low Na and Mg and high K and N and it interferese with abdsorption of Mg.

K+ and N+ compete for absorption.

Question 5

What is the signalment for cows most commonly affected by hypomagnesemia?

Answer 5

Nursing cows during early lactation (late winter, early spring)

Question 6

What is th signalment for high risk groups?

Answer 6

Dairy cows 1st 2mo lactation (high Mg demand)

Beef on ferilized LUSH PASTURE

Rapid growing calves on milk diet

Stress induced (transport tetany) cattle/sheep

Question 7

How gets more hypomagnesemia?

a. Ewes
b. Bitches
c. Cows
d. Equine

Answer 7

c. cows

more than ewes and does

Question 8

How do you dx hypomagnesemia?

Answer 8

Usually confirmed by response to tx.

Can do CBC/Chem panel

see decreased Mg in CFS and ocular fluid.

See decreased Ca2+

Question 9

CS seen with hypomagnesemia?

Answer 9

Mostly neurological signs

• Subacute: stiff, hypersensitive, frequent urination/pooping*
• Chronic*: Stiff, unthrifty

Question 10

How do you tx hypomagnesemia?

Answer 10

Ca2+ and Mg comobination is the BEST!!!

200-300ml 20% Mg sulfate IV

200ml 50% Mg sulfate SQ

500ml Ca2+ borogluconate 25%