Oorsig/Review
PART 02
COMMON PRODUCTION DISEASES:
MILK FEVER OR PARTURIENT PARESIS
Milk fever or parturient paresis
Milk fever is a production disease of dairy
cows (usually high producing, older cows) that
occurs around parturition and the beginning
of lactation and that is associated with clinical
hypocalcaemia. The name “milk fever” is a
classic historical misnomer because in fact most
cows with hypocalcaemia have a lower than
normal temperature due to reduced muscle
tone and reduced circulation. The condition is
characterized by an imbalance of blood mineral
levels especially low serum calcium; general
muscular weakness; depression of consciousness;
circulatory collapse and eventually coma and
death. Milk fever has quite an interesting history:
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The condition was first described in 1793 by
Eberhardt
During the 19th century several descriptions
were made of the epidemiology that is still
relevant today.
Treatments advocated during the 19th
century included drenching with various
organic and inorganic compounds including
boiling ale.
Bleeding of susceptible cows before calving
was used for prevention, about 5 litres of
blood had to be removed.
In 1897 Schmidt described a method to
treat milk fever that reduced mortality from
40-60% to 10-24%. The method used was
insufflation of the udder with potassium
iodide and air. It was believed that the
condition was caused by a neurological toxin
similar to botulism that originated in the
udder.
In the 20th century it was discovered that the
condition was caused by lowered serum Ca
levels, and around the mid 1920’s treatment
with Ca borogluconate was first started.
It was then believed that dietary intake
could not sustain Calcium loss through milk
production.
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Early in the 20th century the role of
parathyroid hormone in Calcium metabolism
was described, but in the middle of the 20th
century prevention was mainly achieved by
administering synthetic vitamin D. This at
first caused problems with metastatic soft
tissue calcification and when the product
was improved still only had adequate effect
if treatment was administered 3 to 6 days
before calving. Since it is not always possible
to predict the exact onset of calving, the
treatment was later combined with 5mg
flumethasone in order to induce parturition.
This practice continued into the 1970’s.
During the 1970’s and 1980’s changes were
being made to dry cow rations to reduce Ca
intake in order to “prime” Ca metabolism as
was then understood. This is still a viable
option today (see later)
During the 1990’s and 2000’s Goff and others
developed the DCAB theory to prevent
milk fever, and this is now widely used in
combination with Calcium drenches post
partum.
Despite the above improvement of our
knowledge of hypocalcaemia and milk fever
it remains one of the most important and
most challenging production diseases in a
dairy.
Milk fever as a production disease
In most cases, hypocalcaemia is caused by a basic
metabolism output problem. A fall in serum Ca
levels is seen in all adult cows at the onset of
lactation. This is assumed to be due to the sudden
outflow of Calcium due to the onset of lactation
in combination with a failure to rapidly mobilize
calcium reserves from bone, and/or to rapidly
absorb calcium from the gastro intestinal tract.
Phosphate, magnesium and to a lesser extent
potassium may also play subsidiary roles. Milk
fever is caused by an imbalance in Ca throughput/