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THE ROBOT EVENT
Almost half of infections may never develop
into clinical mastitis, but will self-cure. So to
prevent mastitis becoming over-diagnosed,
it is up to farmers, in conjunction with their
vet, to judge where to set the thresholds in
the robot’s computer software for mastitis
alerts. Every farm is different, but finding
the right parameters will ensure enough
attention for the real cases without too
many false positives.
In robotic systems, managing cases can be
very disruptive: without a parlour which cows
visit twice a day, it is inconvenient to tube
them. So for this reason, some robot users
are much stricter on culling cows which have
recurring cases of mastitis.
In selecting what type of treatment therapy to
use for mastitis cases, injectable antibiotics
can be easier to administer than tubes, and
where the robot has identified more than
one quarter is affected, then such systemic
therapies become a logical choice.
Most clinical mastitis cases in robotic systems
are caused by environmental pathogens
like E.coli. So cow cleanliness is key - it’s
advisable to clip cows’ udders, flanks and
tails regularly, and also ensure clean bedding
in cubicles.
‘Even a mild case of mastitis can reduce the
lifetime milk yield of a cow,’ explained James
Allcock. ‘An achievable goal is to aspire to
have fewer than 20 quarter cases/cow/year.
He advised robot users: ‘As a policy - before
you give any cow antibiotic treatment for
mastitis, first go to the computer and put
her milk on exclusion, as it can be easy
to become distracted and forget to do
it afterwards.’
Judith Roberts also commented: ‘With robots,
antibiotic treatments are often used off-label,
so farmers should take extra care to avoid
antibiotic failures. Don’t let the robot make
the decisions - put it on manual override.’
But whilst it is usual to see a reduction in
mastitis cases with automatic milking
machines, it doesn’t necessarily happen
every time, warned Ian Cure.
Ian recounted his experience with two very
similar farms which took different approaches
to ‘going robotic’.
‘The first farm planned which cows to keep,
and overbred for replacement heifers using
sexed semen. This meant they could afford to
cull out certain cows - the old and high cell
count animals. Cell counts went down.
‘But on the second farm, no such preparations
were made, and cell counts increased.
This was because they were concerned about
maintaining their milk output to provide the
income to pay for the installation. So no cows
were culled. This resulted in high cell count
cows remaining in the herd, but not getting
any extra attention at milking - because all
cows were treated the same by the robot.
‘There’s also no control over which order
cows are milked in, so it’s not possible to
separate the high cell count cows and milk
them last to reduce cross-contamination.’
Ian advised: ‘Mastitis and cell counts are
aspects of herd management in which control
is lost when milking by robot. So it’s essential
to plan ahead, consult with the farm’s vet,
and make a hit list of cows to cull out.’
Milk
– an indicator of health and fertility
Not only can robotic milking machines
provide an on-line evaluation of whether
a cow’s milk is showing early signs of
mastitis infection, they can also provide a
variety of information on the state of health
and fertility of an animal, depending on
the specific make of robot.
Fullwood’s John Baines and DeLaval’s Andre
De Leeuw explained how changes in levels
of milk constituents and reproductive
hormones can guide - or clearly instruct
on - feeding and breeding decisions.
Andre De Leeuw
DeLaval
John Baines
Fullwood
Ketosis
An on-line analysis of milk constituents -
butterfat, protein and lactose - can be used
to indicate a cow’s energy status.
After calving, when the energy taken up in
producing milk is greater than her energy
intakes, a cow develops a negative
energy balance, which if prolonged can
reduce fertility. In response, the cow
mobilises her body fat reserves.
This also changes the composition of the
milk. So certain robot systems can give an
early warning of ketosis when milk shows
increased butterfat levels, a fat:protein ratio
above 1.5, together with a reduction in
daily yield.
One of the automatic systems available
can directly measure the increased levels
of ketones (beta-hydroxybutyrates, BHB) in
the milk, and identify the degree of ketosis.
Heat detection
One of the automatic milking systems
available has the technology to track the
rise and fall of the level of progesterone in
milk, and thus can signal when a cow is on
heat. This is especially useful for detecting
silent heats, and for checking whether the
cow is pregnant, or has had an abortion.
By looking at a period of time, the
information can be used to investigate
follicular cysts or prolonged anoestrus.
Similarly, milk composition can be used to
assess rumen health and give an early
warning of sub-acute ruminal acidosis
(SARA), which depresses feed intakes.
SARA can occur when rations are too
high in starch and/or have inadequate
levels of fibre.
In milk, evidence of SARA is seen by a
decrease in milk fat content. So if a cow
is within the first 200 days of lactation
and has a fat:protein ratio of less than
1.0 or a butterfat content of less than
2.5%, this indicates SARA.
If more than 10% of the herd is showing
signs of SARA, then the feeding regime
needs to be investigated. Resolving the
matter may include re-formulating the
diet, minimising the sorting of feed, and
pushing rations up to the feed barrier
more frequently.
Sub-acute Ruminal Acidosis
SUMMER 2013 ISSUE
Fullwood - on farm
LIVESTOCK MATTERS
12