Ca and Ph endocrine diseases

Question 1

What is milk fever

Answer 1

HYPOCALCAEMIA - low Ca

Question 2

Clinical signs hypocalcaemia/ Milk fever

Answer 2

1. Hypocalcaemia = low Ca therefore reduced ionised Ca in ECF so results in skeletal muscle weakness, tremors, ataxic, recumbent
2. Lying down
3. head tucked into flank- neck muscles have less activity
4. Hypothermia – rectal temperature below normal – not moving much and skeletal muscle contraction generates a lot of heat
5. Bloat – due to affect of low blood calcium on smooth muscle of gut, reduction in muscle gut contractions so animal doesn’t eructate properly and get rid of gases
6. Constipated – no contraction of rectal muscles
7. Urine retention – bladder atony – smooth muscle of bladder not contracting
8. Dystocia due to uterine inertia
9. Dilated pupils

Question 3

Why does milk fever occur?

Answer 3

• Dairy cows bred to produce large volumes of milk
• Run up to parturition – alveolar cells in mammary glands are sequestering huge amounts of free calcium from the extra cellular fluid
• Normal homeostatic mechanisms (parathyroid hormone, Vit D) that would normally drive inc in ionised calcium can’t keep up with this demand
• Cows have LOADS of calcium in body as bone is a large store of calcium and phosphorus – not enough ionised calcium in extracellular fluid!

Question 4

is hypocalcaemia more common in older or younger animals and why?

Answer 4

MILK FEVER

OLDER more common
• Bone remodelling is occurring to a much less degree in older animals – more in young as skeleton is modelling so increased activity of osteopaths and blasts so able to react much more quickly changes in homeostatic mechanisms
• 1st lactation cows tend not to suffer as respond much more quickly to parathyroid hormone and Vitamin D in terms of the activity in bone

Question 5

Can hypocalcaemia occur in other animals? and when?

Answer 5

YES

1. Sheep - during gestation about 3-4 weeks before giving birth if multiple foetuses due to them drawing calcium from extracellular fluid from mum
2. Small breeds of dog – if had large litters. Tend to see at peak lactation. Muscles become very twitchy

MILK FEVER

Question 6

What drug can we use to treat hypocalcaemia?

Answer 6

Hypocalcaemia/ MILK FEVER

Use calcium salts to replace lost Ca

Question 7

MOA calcium salts

Answer 7

Absorbed from SI

Better achieved by increasing dietary Ca2+ and administering vitamin D3

Question 8

Route of admin Ca salts

examples of them

Answer 8

Oral administration
Injectables
Calcium gluconate
Calcium carbonate
Calcium chloride
Calcium borogluconate

Question 9

Adverse affects Calcium salts

Answer 9

Hypercalcaemia (particularly detrimental with cardiac/renal disease)
Rapid IV effects on the heart (arrest/arrhythmias)