Lactation tetany, also known as hypomagnesaemic tetany or grass tetany, is a metabolic disease of lactating ruminants characterized by low magnesium levels and clinical signs of hyperaesthesia, tetany, and convulsions. It occurs in cattle grazing on pastures high in potassium 2-4 months after calving, which decreases magnesium absorption. Affected cattle experience sudden onset of muscle twitching and spasms, leading to staggering, falling, and potentially fatal convulsions. Diagnosis is based on clinical signs and low serum magnesium levels below 2.5 mg%, and treatment involves intravenous calcium followed by magnesium supplementation.

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LACTATION TETANY
(Hypomagnesaemic tetany ,
grass tetany, grass stuggers )
Prof Mohamed Ghanem
Professor of Veterinary Internal Medicine
Head of Department of Animal Medicine
Faculty of Veterinary Medicine Benha University

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LACTATION TETANY
(Hypomagnesaemic tetany ,
grass tetany, grass stuggers )
 Definition:
 Highly fatal metabolic diseases of
lactating ruminants, characterized clinically
by hyperaesthesia, tetany and convulsions
and biochemically by hypomagnesaemia.

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Incidence, occurrence :
 (A) Incidence:
 (a) Species incidence : Cattle
(sometimes sheep ).
 (b) Age incidence : 7-10 years old
(5-8 Lactation).
 (c) Time incidence : 2-4 months
after parturition.


4. (B) Occurrence:
 (a) Lactating cattle grassing on high
potassium spring lush pastures and green
cereal crops ( High potassium levels
decreases Mg. Absorption ).
 (b) Lactating cattle fed diet intoxicated
with potassium fertilizers or urea (reduces
availability of soil magnesium).
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Predisposing factors
 (a) Starvation : 24-48 hours depress
serum magnesiums significantly.
 (b) Diarrhea : Reduce magnesium
absorption from intestines
 (c) Cold weather stress : Increase
urinary excretion of magnesiums.
 (d) Long transport: Depress serum
magnesium and calcium.

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Etiology and pathogenesis
 Basic biochemical finding in lacation
tetany is hypomagnesaemia 1-2 mg% ( N
2.5 – 3 ).
Why tetany occurs?
 - Calcium ions activator for acetylcholine
responsible for muscle contraction.
 - Magnesium ions activator for
cholinesterase responsible for Muscle.
relaxation.

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Clinical signs
(A) Acute form:
 1- Sudden onset of hyperaesthesia and
muscle twitching .
 2- staggering in gait followed by falls down
with tetany and convulsions.
 3- During episodes (attack) there are:
 a) Opithotonus (back-head).
 b) Pricking of ears.
 c) Nystagmus (Rotation of eye ball).
 d ) Retraction of eye lids.
 e) Champing of jaw.
 f) Frothing at from mouth.

8. (A) Acute form
 4- Between episodes animal lie quiet but
any noise or touch starting other attack .
 5- Pulse and respiration accelerated.
 6- Temperature moderatly elevated (due
to muscular spasm).
 7- Death from respiratory failure.
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B) Subacute form :
 Same signs of acute but onset gradual and
course longer.
(C) Chronic form :
 Animal have low serum magnesium but
shows no symptoms.

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Opithotonus (hypomagnesemia)

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Dr Ghanem

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Dr Ghanem

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Dr Ghanem

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The same calf between episodes
Dr Ghanem

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Diagnosis
 History:
 Clinical signs:
 (C) Laboratory diagnosis:
 (a) Serum magnesium level commonly between
 1-2mg % (normal 2.5-3 mg%).
 (b) Low urine magnesium level.
 (c) Low CSF magnesium level.
 (d) Bone biopsy from ribs commonly revealed disturbed
Ca: Mag. ratio.
 (D) Diagnostic therapy (Therapeutic diagnosis):
 Diseased animals respond well to calcium-magnesium
therapy.

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Differential diagnosis
 The disease must be differentiated from
other causes of nervous manifestations
such as
 BSE
 Rabies,
 Encephalomyelitis
 Poisoning

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Treatment
 Contraindicated to use Mg compounds alone
(may cause cardiac arrest).
 Safe therapy to use combined calcium-
magnesium preparations as follow:
 1- Calcium borogluconate 15% (I/V 500 ml).
 2- Followed by: Magnesium lactate 15% (S/C 250 ml).
 3- Followed by: Magnesium sulphate (oral 125 gram).
 Preparations: Cal-D-Mg (Pfizar). Calphomag
(Vibrac).
 Tranquilizer e.g: Chloropromazine Hcl
(Neurazine) used and useful before calcium-
magnesium therapy in severe cases.

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Prevention of the disease
 l- Magnesium supplementation of diet with
crude magnesium 60 gm/head which can
be mixed with molasses:
 2- Magnesium Bullets placed in reticulum
for slow liberation of constant traces of
magnesium daily for long period as long
as several months or even years.

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Questions