Macrominerals imbalances and production animals

Question 1

What does magnesium deficiency cause? 2

Answer 1

staggers and grass tetany

This arises when there is high demand + decreased intake

Question 2

Is Mg regulated homeostatically in ruminants?

Answer 2

No

Question 3

Clinical signs - Mg deficiency

Answer 3

range for per acute to subclinical:
hyperaesthesia
ear twitching
sensitive to sound/hand clap
staggers and collapses
champing of jaws
sudden death

Question 4

Sub acute signs of Mg deficiency - 4

Answer 4

slow onset over 3-4 days
spasmodic urination and defaecation
mm tremor
staggering gait

Question 5

Chronic signs - Mg deficiency - 3

Answer 5

Few signs, poor appetite, depressed milk yield

Question 6

What clinical sign do all types of Mg deficiency show?

Answer 6

increased heart rate (normal cow is 48-84)

Question 7

Cause of Mg deficiency 3

Answer 7

low Mg in diet (fresh grass)
poor feed intake (rain)
poor Mg absorption (K-DCAB, N, passage rate of lush grass)

Question 8

What level of Mg indicates Mg deficiency?

Answer 8

Mg < 0.5 mmol/l

Question 9

Diagnostic sign of Mg deficiency

Answer 9

Look at fluid from vitreum in eye (i.e take sample) for Mg levels

Question 10

Treatment - Mg deficiency

Answer 10

URGENT
Give a bottle of Ca borogluconate with Mg hypophosphate (IV into jugular not milk vein, slowly)
OR
Magnesium sulphate, 25%, SC only

Question 11

Prevention - Mg deficiency - 4

Answer 11

MgO in concentrates (mix with molasses to increase palatability)
Mg bolus oral (just before calving)
Mg tablets/flakes added to drinking water
Avoid K fertiliser where hypomag is known problem.

Question 12

4 diseases that Ca deficiency can causes

Answer 12

bovine parturient paresis
hypocalcemia
acute flaccid paralysis
milk fever

Question 13

Normal blood calcium level

Answer 13

2.3 to 3.2 mmol/l

Question 14

What are the main aspects of Ca homeostasis?

Answer 14

Absorption from GIT, kidney and bone
PTH
Vitamin D3 (converted in kidney)
Calcitionin

Mg cofactor required

Question 15

What stages of calcium homeostasis is a Mg cofactor required? 2

Answer 15

activation of vitamin D3

production and release of PTH

Question 16

Subclinical signs of hypocalaemia? 7

Answer 16

able to stand
hypersensitivity
excitable
tremors
ear twitching
ataxia
bloat/gas in gut (caecum although not hindgut fermenter)

Question 17

What level is calcium in the blood at in subclinical hypocalcaemia?

Answer 17

1.8-2.3 mmol/l

Question 18

What level is calcium in the blood at in clinical - severe hypocalcaemia?

Answer 18

<1.2 mmol/l (moderate hypocalcaemia is 1.2-1.8 mmol/l)

Question 19

Clinical signs - hypocalcemia - clinical moderate

Answer 19

recumbent (sternal)
depressed 
dry muzzle
cold extremities
bloat/gas in gut
no defaecation 
delayed/absent pupil responses

Question 20

Clinical signs - hypocalcemia - clinical severe

Answer 20

reduced consciousness
lateral recumbency
unresponsive to stimuli
mm faccidity
reduced cardiac output
bloat 
death

Question 21

What level is calcium in the blood at in clinical - severe hypocalcaemia?

Answer 21

<1.2mmol/l

Question 22

Treatment - hypocalcaemia

Answer 22

20% Caborogluconate 400ml
40% Caborogluconate 400ml (may not be necessary)
low volume treatments Maxacal 100ml
Also some mixed with Mg, P, glucose

IV, SLOW
Monitor HR (risk of cardiac arrrest if too fast)
Use of Mg?

SC deposit may prevent recurrence

Question 23

Signs that a cow is recovery from hypocalcaemia.

Answer 23

Passes dung
eructates
Then sit the animal up, she will then get up

Question 24

Cause - hypocalcaemia - 3

Answer 24

Demand is not met by supply:

Kidney absorption problem
GIT absorption problem (absorption %, feed intake)
Bone reserves

Question 25

Prevention - hypocalcaemia

Answer 25

Low Ca in dry cow ration
High Ca in milking cow ration
Mg supply
DCAB (way of ensuring the Mg supply)
Drench at calving
Bolus just before calving

Question 26

Cows at risk of hypocalcaemia - 3

Answer 26

Older, fatter and channel breeds (Jersey cow PTH-R make them more likely to suffer from this disease)

Question 27

When do you see problems with phosphorous levels?

Answer 27

It is a local condition - depends on the Ca and P levels in soild

Question 28

Apppearance of a hypophosphataemic cow

Answer 28

Happy downer with no response to Ca/Mg Tx (check for other reasons for being a downer cow such as broken legs, mastitis etc but these typically aren’t happy downers)

Question 29

What is Foston IV

Answer 29

a phosphorous supplement used to treat hypophosphatamia.

Question 30

Define DCAB

Answer 30

Dietary cation anion balance/ diet
Involves:
CATIONS: Na and K
ANIONS: Cl and S
Other examples less important
Analyse them in mmol/kg DM

Question 31

How do you calculate DCAB?

Answer 31

(Na+K) - (Cl+S)

Sum should be lower than -200mmol/kg DM

Question 32

What does a DCAB/acidifying diet do?

Answer 32

Provide excess of anions over cations
decreases blood pH
PTH more effective

Question 33

When to use a DCAB diet?

Answer 33

To prevent milk fever - feed to dry cows so they can cope with decreased Ca levels post-partum when their overall feed intake decreases.

Question 34

Describe anionic salts

Answer 34

Not very palatable and reduce DMI

Can cause NEB, fatty liver, metabolic problems

Question 35

How to monitor the effects of cow diets?

Answer 35

Monitor urine pH (normal is 5.5-6.5)

If it goes down to 5.0-5.5, too many anions are being absorbed. Check several cows (>6) every week.

Question 36

What are macrominerals?

Answer 36

Occur commonly in rations
Include P, Ca, Mg and Na, K, Cl and S
Milk fever (Ca) and grass staggers (Mg) the main clinical presentation
Treatments overlap