Macrominerals imbalances and production animals Flashcards
What does magnesium deficiency cause? 2
staggers and grass tetany
This arises when there is high demand + decreased intake
Is Mg regulated homeostatically in ruminants?
No
Clinical signs - Mg deficiency
range for per acute to subclinical: hyperaesthesia ear twitching sensitive to sound/hand clap staggers and collapses champing of jaws sudden death
Sub acute signs of Mg deficiency - 4
slow onset over 3-4 days
spasmodic urination and defaecation
mm tremor
staggering gait
Chronic signs - Mg deficiency - 3
Few signs, poor appetite, depressed milk yield
What clinical sign do all types of Mg deficiency show?
increased heart rate (normal cow is 48-84)
Cause of Mg deficiency 3
low Mg in diet (fresh grass)
poor feed intake (rain)
poor Mg absorption (K-DCAB, N, passage rate of lush grass)
What level of Mg indicates Mg deficiency?
Mg < 0.5 mmol/l
Diagnostic sign of Mg deficiency
Look at fluid from vitreum in eye (i.e take sample) for Mg levels
Treatment - Mg deficiency
URGENT
Give a bottle of Ca borogluconate with Mg hypophosphate (IV into jugular not milk vein, slowly)
OR
Magnesium sulphate, 25%, SC only
Prevention - Mg deficiency - 4
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.
4 diseases that Ca deficiency can causes
bovine parturient paresis
hypocalcemia
acute flaccid paralysis
milk fever
Normal blood calcium level
2.3 to 3.2 mmol/l
What are the main aspects of Ca homeostasis?
Absorption from GIT, kidney and bone
PTH
Vitamin D3 (converted in kidney)
Calcitionin
Mg cofactor required
What stages of calcium homeostasis is a Mg cofactor required? 2
activation of vitamin D3
production and release of PTH
Subclinical signs of hypocalaemia? 7
able to stand hypersensitivity excitable tremors ear twitching ataxia bloat/gas in gut (caecum although not hindgut fermenter)
What level is calcium in the blood at in subclinical hypocalcaemia?
1.8-2.3 mmol/l
What level is calcium in the blood at in clinical - severe hypocalcaemia?
<1.2 mmol/l (moderate hypocalcaemia is 1.2-1.8 mmol/l)
Clinical signs - hypocalcemia - clinical moderate
recumbent (sternal) depressed dry muzzle cold extremities bloat/gas in gut no defaecation delayed/absent pupil responses
Clinical signs - hypocalcemia - clinical severe
reduced consciousness lateral recumbency unresponsive to stimuli mm faccidity reduced cardiac output bloat death
What level is calcium in the blood at in clinical - severe hypocalcaemia?
<1.2mmol/l
Treatment - hypocalcaemia
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
Signs that a cow is recovery from hypocalcaemia.
Passes dung
eructates
Then sit the animal up, she will then get up
Cause - hypocalcaemia - 3
Demand is not met by supply:
Kidney absorption problem
GIT absorption problem (absorption %, feed intake)
Bone reserves
Prevention - hypocalcaemia
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
Cows at risk of hypocalcaemia - 3
Older, fatter and channel breeds (Jersey cow PTH-R make them more likely to suffer from this disease)
When do you see problems with phosphorous levels?
It is a local condition - depends on the Ca and P levels in soild
Apppearance of a hypophosphataemic cow
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)
What is Foston IV
a phosphorous supplement used to treat hypophosphatamia.
Define DCAB
Dietary cation anion balance/ diet Involves: CATIONS: Na and K ANIONS: Cl and S Other examples less important Analyse them in mmol/kg DM
How do you calculate DCAB?
(Na+K) - (Cl+S)
Sum should be lower than -200mmol/kg DM
What does a DCAB/acidifying diet do?
Provide excess of anions over cations
decreases blood pH
PTH more effective
When to use a DCAB diet?
To prevent milk fever - feed to dry cows so they can cope with decreased Ca levels post-partum when their overall feed intake decreases.
Describe anionic salts
Not very palatable and reduce DMI
Can cause NEB, fatty liver, metabolic problems
How to monitor the effects of cow diets?
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.
What are macrominerals?
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
