7 / 24
AUTUMN 2015 ISSUE
LIVESTOCK MATTERS
6
CAMPY LOBACTER
Eradication and vaccination
strategies
The Waight family of Compton Farm near
Marlborough in Wiltshire have had two
encounters with the disease.
Bruce and his son James run a 450-cow
suckler herd on Salisbury Plain, on land
rented from the MOD. The 10,000 acres
of grazing are mainly permanent pasture,
and are farmed organically. The system is
very extensive, and 100-cow groups are
run with three bulls.
The bull breeds currently on the farm are 12
Charolais, three South Devon, and three
Aberdeen Angus. It is predominantly a
spring-calving herd, with a smaller block of
autumn calving animals. Bulls are monitored
closely during the breeding season to make
sure they are working properly, and routine
breeding soundness examinations are
carried out.
According to the Waights’ organic
regulations, the buying in of heifer
replacements is limited to being no more
than 10% of the herd. Previously heifers
were purchased from a number of sources,
but nowadays around 30 Hereford x
Friesians heifers are purchased each year
from a closed dairy herd in Dorset. This herd
has a high health status – being free of
BVD, Johnes’ disease and leptospirosis.
All the bulls, cows and new arrivals to
the farm are vaccinated against BVD,
leptospirosis and clostridial diseases. They
are also vaccinated for Campylobacter
using a custom-made vaccine.
Bruce Waight first started the herd in 1990,
and to begin with bulls were hired in. This is
how Campylobacter is believed to have
entered the herd in the mid 1990’s. One
year, instead of achieving fertility of over
90%, it was around only 60%.
Keith explains: ‘The infection is spread by
natural service. Therefore virgin heifers and
bulls cannot be harbouring the bacterium. In
the absence of a vaccine, the solution was
to split the herd into two, one for ‘clean’
animals and one for ‘dirty’.
‘Each year, the next batch of heifers – virgins
– can join the clean herd. Over time, the
cows in the dirty herd develop immunity to
the bacterium and their fertility resumes.
Some of them will also be culled out, so over
time the farm can rid itself of Campylobacter.‘
‘However, bulls never develop immunity and
the bacterium will persist in the folds of their
prepuce. So only virgin bulls are added to
the clean herd.‘
However, in 2012, Campylobacter once
again entered the herd.
‘We think it came from a cow jumping the
fence out on the plains,‘ explains Bruce.
This time, Keith carried out vaginal washings
and was able to isolate the organism itself. It
was cultured and an autogenous vaccine
was created. This was licensed only for use
on Compton Farm, but could be made up in
quantities, as and when required.
James explains: ‘Nowadays, heifers are given
two doses of vaccine, and cows just one,
about three weeks after calving – which is six
to eight weeks before being put in with the
bulls again. The bulls are also all vaccinated.‘
The previous Campylobacter episode was
several years ago now, and it is possible
that the bacterium is no longer present in the
herd. However, the Waights have decided
to continue vaccinating.
Bruce adds: ‘I think it would be dangerous
to stop it because of the significant effects
that it has on fertility.‘
Keith agrees: ‘Suckler herd income is reliant
on the annual production of a calf from each
cow. So whilst the culture is still live and the
vaccine can be made, then it is wise,
considering the relative costs, for the
Waights to continue vaccination.
‘After all, the herd is grazed on land where
tanks can take out the fencing on their
overnight manoeuvres and so there is always
the threat of neighbouring groups of suckler
cattle mixing, and an infected animal from
another herd serving/being served.‘
Given the problems that Campylobacter can
cause, and the difficulty in eliminating it,
then it is better to prevent its introduction in
the first place.
Keith explains: ‘Virgin heifers and bulls
cannot have contracted the infection – that’s
assuming they really are virgins! Ideally all
replacement stock should be virgins, and
sourced from a reputable supplier.
‘Non-virgin bulls should be treated with
antibiotics on arrival at the farm and
sheath-washed by a vet with an antibiotic
solution for three consecutive days.‘
•
A cloudy vaginal discharge 10 days after serving
•
Irregular and/or abnormally long intervals
between heats
•
Abortions after 5-7 months of pregnancy
•
There are no visible signs in bulls
Signs of Campylobacter infection
Autogenous vaccine
Campylobacter is spread from cow to bull
during natural service
Biosecurity measures
Clean and dirty herds
In bulls, Campylobacter lives in the folds and
crevices of the prepuce (foreskin), where it can
persist for life without treatment