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DRY COW THERAPY
Selective Dry Cow Therapy:
Why and how?
The blanket use of an intra-mammary antibiotic at drying-off used to be best practice for
all dairy herds. But times have changed. In well-managed dairy herds, the selective use
of dry cow antibiotics, together with a teat sealant for all, is now best practice. Here, vets
Julian Allen and Helen Rogers from Friars Moor Vet Practice, explain the ‘why and how’
of Selective Dry Cow Therapy (SDCT), and together with two farmers, provide some
practical tips.
Why selective use?
Julian explains: ‘There is mounting pressure
to reduce the use of antibiotics in livestock
farming, particularly where they are used
in healthy animals for the prevention of
infection, rather than treatment.
‘In the dairy sector, the prime example of this
is the use of whole herd antibiotic dry cow
therapy (DCT). In many herds, where mastitis
is well controlled, a significant number of
cows will be uninfected at drying off, and
it is hard to justify the use of antibiotics in
these individuals.
‘As a result, an increasing number of dairy
farmers are choosing to selectively treat cows
with intra-mammary antibiotics at drying off
rather than using the traditional ‘blanket’
approach to DCT across the herd.
‘There are cost savings to be made of course
as fewer dry cow antibiotic tubes are used.
There will also be less antibiotic contamination
of colostrum – so potentially less risk of
antimicrobial resistance developing.
‘In addition, research has shown that giving
one commonly used dry cow antibiotic, plus
a teat sealant, to low cell count cows
actually led to a 12-fold increase in risk of
E.coli
mastitis in the following lactation, when
compared wit using a teat sealant alone.
This is thought to be due to the antibiotic
removing some of the ‘normal’ protective
bacteria from the teat and udder.’
The dry period
‘The success rate of antibiotic treatment
during the dry period is generally much
higher than during lactation. So we need
to take full advantage of this to ‘clean up’
infected cows while they are dry,’ says Julian.
Dry cow therapy has two aims:
1) To remove
mastitis pathogens that are present in the
udder at the end of the lactation; 2) to protect
the udder from new mastitis pathogens, as
this period is often the highest risk time for
new intra-mammary infections.
‘Protecting the udder from new infections is
best achieved with a teat sealant, as these
provide a physical barrier which persists for
the entire dry period.
‘So every cow should receive a teat sealant
at drying off, irrespective of her infection
status.’
Adopting a selective approach
Julian explains: ‘The selection of cows for
treatment with only a teat sealant needs to
be done carefully, and in consultation with
your vet.
Helen adds: ‘Our advice is made on a
farm-by-farm basis. The protocol is based on
the bulk milk cell count and knowledge of the
principle pathogens causing clinical and
subclinical mastitis in the herd. Plus individual
cow factors – their previous mastitis and cell
count history, as well as parity.
WORKING
TOGETHER
FOR A HEALTHIER FUTURE...
9
LIVESTOCK MATTERS
JULIAN ALLEN AND HELEN ROGERS,
FRIARS MOOR VETERINARY CLINIC
Veterinary surgeons
Julian Allen and
Helen Rogers
XLVets practice
Friars Moor Veterinary
Clinic
Correct technique for inserting teat sealant
Thorough teat cleaning with surgical spirit and
cotton wool technique for inserting teat sealant
Dry cows at Longmoor Farm