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D A I R Y F E A T U R E
T
ony Kemmish of St Boniface Vet Practice in Crediton outlines the causes
of milk fever (hypo-calcaemia) and the preventative options available.
And herd manager Adrian Salter explains how working with Tony, he
has changed the nutrition and routine for newly calved cows to help reduce
milk fever cases and also improve herd fertility.
Veterinary Surgeon
Tony Kemmish
XLVets Practice
St Boniface, Crediton
Binscarth Farms
Tony explains: ‘When a cow goes down
with milk fever after calving - the traditional
'downer cow' syndrome - it's because of a
drop in calcium levels in the blood which
means she can't support normal nerve and
muscle function. Moreover, it's an indication
that many of the transition cows are probably
suffering sub-clinical levels of hypo-calcaemia,
and could also become clinical cases
themselves.
‘As a cow or heifer approaches calving,
there is a massive demand for calcium to be
unlocked from her bones to support growth of
the calf and to provide colostrum and milk.
‘Calcium is involved with muscle contraction.
Most visibly, in clinical cases, the cow can
no longer stand. But low calcium levels also
compromise gut movement, resulting in poor
appetite and constipation, and there is an
increased risk of mastitis as the teat sphincter
may relax.
The uterus is also very muscular, and after
calving it should shrink down in size,
expelling any mucous and infection from the
birth - a process known as involution.
However when cows are hypo-calcaemic,
the lack of muscle contraction means the
uterus can remain open, thereby increasing
the risk of infection. If the cow returns to
cycling and is inseminated, the fertilised egg
may not be able to implant in the uterus.
So there's a knock-on effect on fertility.
Treatment for clinical cases, involves an
injection of calcium into the vein combined
with other supportive therapy. However,
prevention should be the focus, and for this,
attention to the management of dry cows
and to their transition diet is essential.
There are three main nutritional
strategies:
1
Feed cows a low calcium diet pre-calving
so that calcium is already being mobilised.
2
Feed anionic salts - like chlorides or
sulphides - to reduce the pH of the blood
and draw out the calcium.
3
Drenching with calcium solution around
calving giving an instant boost to blood
calcium levels (see the previous issue of
Livestock Matters).
Preventing Milk Fever
in dairy cows
15
LIVESTOCK MATTERS
WORKING
TOGETHER
FOR A HEALTHIER FUTURE...