BRIAN Pocknee, as chairman,
welcomed more than 90 delegates to
the 25th British Mastitis Conference
at the Sixways stadium near
Worcester.
The opening speaker was Tine van
Werven, a veterinary surgeon at Utrecht
University, who outlined the Dutch
dairy industry experience in reducing
antibiotic usage. There was a national
decrease of 50% in 2012 in the use of
antibiotics in total including pigs,
poultry, veal calves and dairy cattle. The
dairy sector reduced
antibiotic use by 40%.
In 2008 an EU table
showing the ranking of the
prudent use of antibiotics
in humans indicated that the
Netherlands was second but veterinary
use was very high. Concerns about
multiple resistant organisms led to a
political drive to reduce antibiotic use in
food producing animals.
A large study was undertaken to
gain more insight into the total use of
antibiotics and the routes of
administration and to motivate farmers
and increase awareness of a more
prudent use of antibiotics. The
developed programme has been
successful and a target of a 70%
reduction from 2009 is set for 2015.
The use of 3rd and 4th generation
cephalosporins and fluoroquinolones
has been banned.
If the UK were to follow the
Netherlands example, then the term
“animal daily doses of antibiotics per
year” will become familiar. If the
aDD/aY is 5.3, it means that on
average each cow in the herd is exposed
to antibiotics for 5.3 days per year.
Ban in Holland
Trials have shown that more than 65%
of the total antibiotic use in dairy cows
is intramammaries, with dry cow
therapy accounting for 45% of the
total. Now in place in Holland is a ban
on blanket dry cow therapy. Emphasis
is placed on a preventive approach
rather than curative, management not
medicines. Cows with a proven
infection may have dry cow therapy
prescribed by a vet.
The speaker observed that the
“days of treatment” figures have been
well received and understood by the
farmers. A figure of over 6 requires
action (red), between 3 and 6 attention
(orange) and below 3 is target (green).
These figures for cows will now also
include youngstock.
Only medicines that are specified in
the herd health plan are permitted to be
kept on the farm and only one supplier
of medicines is allowed, with a central
database for all prescribed antibiotics.
For 2014 all treatments will be carried
out by vets except for farm-specific use
under the direction of a vet. A clinical
guideline for selective dry cow
treatments is due to be released by the
Royal Dutch Association for
Veterinarians.
Transferring infections
The feeding of non-saleable milk to
calves is also a concern for transferring
infections, resistant organisms and
antibiotics. The risks were highlighted by Karen Bond of the RVC.
For her PhD Karen is studying Johne’s Disease and Mycobacterium avium
paratuberculosis (Map) transfer in milk is
one of her areas of study. Infected
cows shed viable Map and Salmonella
spp. into their colostrum and milk.
Additionally, faecal contamination is a
source of these bacteria and also E. coli,
Listeria monocytogenes and Campylobacter
spp. There are current concerns about
Mycoplasma spp. mastitis with
pneumonia, otitis media and
polyarthritis in calves possibly linked to
feeding with mastitis milk.
The neonatal calf is most
susceptible to Map with 80% of
infections occurring in the first month
of life. Map is shed into the milk by
clinically and subclinically infected cows
and the infection has been recovered
from the colostrum of 22% of
clinically normal cows. Research has
shown that pasteurisation on farm at
60°C for 60 minutes is sufficient to
eliminate Map.
The potential for antibiotic residues
in milk fed to calves has been well
recognised for years. Risks to calf
health are a concern. Antibiotics in
prepared calf feed are now tightly
controlled. The consumption of
unknown and varied antibiotic residues
by calves, in non-saleable milk, is
viewed as a potential risk to humans.
Research updates
There were four short research updates
from Peter Down (University of
Nottingham), Andrew
Bradley (Quality Milk Management Services),
Abhijit Gurjar (Cornell)
and Roger Blowey
(Wood Veterinary
Group).
Peter has investigated
the many parameters that
make up the costs of
clinical mastitis. He has
concluded that in order to minimise the economic impact, great
emphasis should be placed on the
reduction of pathogen transmission
from cows with clinical mastitis to
uninfected cows. A doubling of the
transmission rate increases the cost of
clinical mastitis in a herd by 60%.
Andrew has identified
staphylococcal isolates from over 6,000
samples submitted from over 500
farms. Twenty different staph species
were identified with Staph. aureus the
highest incidence, accounting for 36%
of clinical and 37% of subclinical staph
isolates. More coagulase negative
species were isolated in later lactation.
The percentage of antibiotic-
resistant Staph aureus was lower than
previously reported and cell counts
were significantly higher than other
staph species. Staphylococci haemolyticus at
17% clinicals and 13% subclinicals
showed a higher incidence than
previously recognised.
Abhijit presented the results of a
study showing that the combination of
antibiotic plus corticosteroid in the
treatment of coliform intramammary
infections demonstrated a synergistic
effect. Cows were treated with
antibiotic alone and in combination and
slaughtered for tissue analysis. Full
inhibition of bacterial growth in the
udder was recorded at 36 hours with
the antibiotic alone and at 18 hours
with the combination therapy.
The addition of prednisolone to
cefapirin resulted in a lower density of
leukocytes in tissue and milk. No
immune suppressive effects with 20mg
of prednisolone were recorded.
Homoeostasis in the udder was more
quickly restored with the combination
therapy.
Roger has been considering the
benefits and risks associated with
recycled manure as dairy cow bedding.
The manure has high levels of bacterial
contaminants but offers a low cost
material that is comfortable for the
cows. Having passed through a
“squeezer”, the bedding is 65% dry
matter and dries out further when put
onto cubicles.
The manure should be used on the
day of production and not stored. It is
important to understand the risks of the material and gather
the experiences of on
farm use. It may be that
the addition of a premix
to raise the pH would
reduce the infection risks.
Sensor technoloy
Neils Rutten of Utrecht
University is studying
sensor technology and an
initial literature search has shown that comparisons of
different applications and technologies
are difficult. “Sensors do not
outperform farmers,” he said.
No sensor systems have been
found to match the ISO standard for
sensitivity and specificity but sensor
systems are essential to allow effective
cow management with automated
milking. In developing sensors, a clear
aim is to know what information
about the cow’s health is being
detected. For clinical mastitis, sensor
research is needed to indicate cases
requiring treatment.
Detection of the changes in cow
behaviour have the potential to
accurately predict the onset of a
clinical mastitis event and Jenny
Gibbons of DairyCo explained the
role of behavioural and physiological
indicators in monitoring animal health.
Mastitis is painful for cows and
indicators of pain have the potential
to improve mastitis detection and
early treatment. Lying time, lying side
preference, stepping during milking,
gait, weight shifting and eating
behaviour have been studied. A
combination of physiological changes
(e.g. temperature) and behavioural
patterns offer improvements for the
future.
Robotic systems
The final presentation from Frederick
van Essen of Lely outlined that with
robotic systems 85% of mastitis cases
are detected. There is continuous cell
count monitoring and a change in
viscosity means the cow is
automatically diverted to a treatment
pen and the milk separated from the
bulk tank.
Globally there are 15,000 robots in
use and the largest number on one
farm is 22. Yields increase, not least
because the cow is milked more often.
Early research showed that cell count
increased when a robot was installed
but modern installations show a fall.
Posters
There were 10 poster presentations
and the best poster award was
collected by Neal Thornber of the
Dairy Group. The Dairy Group,
jointly with Ambic Equipment Ltd,
assessed teat coverage and concluded
that the objectives for mastitis control
are not being achieved.
The conclusion is that an
automatic system, applying the
product consistently to cover the teat
barrel and teat end, would be
advantageous.
n Proceedings, including the national
mastitis survey 2013, are available – e-
mail bmc@thedairygroup.co.uk.
