11 / 20
AUTUMN 2016 ISSUE
LIVESTOCK MATTERS
10
JOHNE’S DISEASE
Good quality colostrum from Johne’s free cows is
frozen to feed calves snatched at birth
The new calving area for Johne’s positive cows
AND all the progeny of Johne’s positive cows
Control focus
The predominant transmission route is
faeco-oral as the newborn calf ingests MAP
from Johne’s positive cows, from muck on the
teats or in the bedding. Milk and colostrum
from infected dams are another source of MAP
infection.
‘So control of Johne’s requires a focus on the
management of Johne’s positive cows and all
newborn calves,’ says Kate.
Control strategies at
Hook Farm
One of Drove’s clients who is facing up to
the long term challenge of eradicating Johne’s
disease from his herd is Richard Woolford,
of Hook Farm near Royal Wootton Bassett.
Here, 240 cows are milked giving 10,500
litres/cow on an all year round calving system.
‘I can understand why some farmers are
reluctant to look for Johne’s,‘ says Richard. ‘It
might open a can of worms! It’s certainly a
long term battle. We’ve been working at it for
10 years, stepping up the process over the
past 5-6 years. We are making progress!‘
The first cases of Johne’s disease appeared on
the farm around 12 years ago. Classically, it
was in cows that had just calved; they started
scouring, losing body condition and coat
condition. They were still eating, but milk
yields were lower than predicted.
Richard explains: ‘We had conversations with
our vet, we knew we needed to do something.‘
A 30-cow screen was carried out by Richard’s
milk recording company and more Johne’s
positive animals were found. So quarterly milk
testing of the whole herd was then instigated,
and cows are ranked as ‘high’ or ‘medium’
positive for Johne’s.
Kate explains: ‘Where a herd has low
numbers of Johne’s positive animals then they
could be culled out, as they are identified.
But in Richard’s case, a longer term approach
was needed.
The herd is kept closed, and all Johne’s
positive cows are bred only to beef sires, so
none of their progeny enter the milking herd.
Snatch-calving is also carried out on calves
of Johne’s positive cows. Kate explains:
‘This helps prevent the calf from suckling
colostrum that is infected, but more
importantly it removes that calf from the
environment contaminated with potentially
MAP-infected dung.‘
Separate calving area
Recognising the need to keep all newborn
calves away from Johne’s positive cows, but
with no separate space available, Richard
initially tried leaving the Johne’s cows in the
cubicles for longer. Then moving them in with
the ‘hospital’ group of milkers to calve. ‘This
was quite a compromise though,‘ explains
Richard. ‘They weren’t getting the transition
feed, and it was extra work having them mixed
in with the milkers.‘
In 2012, a better opportunity presented itself.
A new building for the parlour and dairy was
being built, which included a covered
collecting yard and handling area. The design
left an unused corner and Richard has turned
this into a straw-bedded covered area and
yard especially for Johne’s positive cows.
Richard explains: ‘It’s away from the main
calving pen, but still easy to keep an eye on
the cows. It has made Johne’s management so
much easier, and cows can receive their
transition ration too.‘
Richard has taken a ‘belts and braces’
approach, and also puts the daughters of
Johne’s positive cows into this new calving
area. Some of these daughters may not have
been snatch-calved and there is a small risk
they may go on to test Johne’s positive.
Keeping track
Some farms use red ear tags or coloured leg
bands to identify Johne’s animals. Richard
explains: ‘I’m not keen on the tags as these can
get lost, and we already use different coloured
leg bands for mastitis management. Besides,
it’s the ear tag number or freeze marks that we
look at when drying cows off or selecting
semen straws.‘
So at Hook Farm, Johne’s positive results are
recorded on the Interherd software programme
as a ++ or + after the animal ID, to denote
high or medium infection.
As it can take several years for the disease to
appear, Richard also keeps track of the progeny
of Johne’s positive cows on the system. They are
identified with a ** or * after their number.
Lists of all the cows are then pinned up onto the
office noticeboard, with a fluorescent pen used
to further highlight the Johne’s cows making it
easy for all staff to check the status of any
animal, and follow the appropriate protocols.
Kate adds: ‘Richard has created his own
system which works well for his farm. Drove’s
DEW Club monthly report also includes lists
which highlight the Johne’s positive cows due to
calve or be served, as an aid for farmers.‘
Every farm
Kate says: ‘Milk buyers are starting to demand
that farmers find out their herd’s Johne’s disease
status. But every farm should know this anyway!
‘The main transmission route for Johne’s disease
is the faeco-oral route so management of the
calving cow is key to preventing its spread.
However the strategy and tactics taken will
vary from farm to farm.
‘Richard had the luxury of space to make a
calving pen for dry cows with a Johne’s record.
But everyone can do something once they’ve
started testing and are finding Johne’s positive
animals. The establishment of policies for the
breeding, calving and culling of Johne’s
positive animals is a good start on controlling
this insidious disease.‘
The original calving area – now only houses
cows and heifers with no family history of Johne’s
disease
The Johne’s status of all cows can be seen on the
office noticeboard