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Reducing flies at source
The first step was to identify the main fly
breeding sites on the farm. Flies breed in
relatively predictable areas - in stale
manure and in loose-bedded areas that
are left undisturbed. In straw yards, flies
will breed around the edge of the pens,
but not in the centre where animals are
compressing the bedding. Calf pens are
often the biggest breeding ground
because they combine lots of pen edges,
lots of animals to bite, and lots of sweet
manure and milk.
Ruth explains: ‘It's vital to take action
early in the breeding season, to stop
the fly population developing in the
first place.’
At Hatton House Farm, the identified
breeding areas were treated aggressively
in late April with the larvicide, Neporex
TM
.
This was diluted in water and a watering
can with a rose (coarse nozzle) used to
apply it onto bedding and manure in the
fly breeding areas. This initial treatment
took about 4 hours and included
applying the larvicide to a large
muck heap.
In addition to the farm's cattle receiving
an anti-fly pour-on, two other products
were used in the environment to kill flies
already at the adult life stage.
Ruth explains: ‘One was SpY
TM
, which
contains a fly pheromone and attracts
flies to consume it, after which they then
die. This was used by taking A4-sized
pieces of board, applying wallpaper
paste and then sprinkling the product
over the board. These boards were
hung up in the calf house and around
the dairy.
‘In addition, Oxyfly
TM
a more traditional
knockdown product with a long
duration of action, was applied to all
walls and fly resting areas using a
knapsack sprayer.’
Monitoring the fly
population
Throughout the summer, the fly population
was monitored to determine if and
when further environmental treatments
were necessary.
Monitoring was simple and objective:
an area of between 0.5-1m
2
was
chalked out on a wall at several points
around the farm. Then, three times each
week, the number of flies in the square
at a given moment, were counted and
recorded. With effective control, this
typically ranged from one to three. But as
soon as an exponential increase in flies
began and numbers were jumping up to
6 or 9, then Neporex
TM
was re-applied in
the fly breeding areas.
In the end, two further treatments were
deemed necessary. Repeat applications
were made, using Neporex
TM
in dry
powder form, mid-June and early
August - everywhere but the muck heap.
Ruth explains: ‘The cost of treating the
environment with the larvicide was
around £500. So we considered that this
fly control strategy was well worth doing,
as it was equivalent to preventing two
cases of mastitis.
‘For the Kellets, the benefits were even
clearer - happier cows and less stressful
milkings. And so they will be continuing
to take this approach each summer,’
says Ruth.
She advises: ‘It's important to
recognise that every farm is
different. Some farms will have fly
breeding risks that are difficult to
control economically. So it's
a good idea to ask your vet for a
farm assessment first. What is for
sure is that tackling the emerging
fly population in the environment,
can make a big difference.’
F LY CONTROL
SUMMER 2012 ISSUE
LIVESTOCK MATTERS
12
At Hatton House Farm, near
Harrogate, brothers Glen and
Roger Kellet milk 250 cows.
Despite running a tidy unit,
the farm suffers quite badly
from flies in the warmer
months and milking time had
become fairly intolerable for
man and beast alike.
Cattle received a pour-on to prevent fly
biting and before each milking, a fogger
loaded with a pyrethroid 'knockdown'
insecticide would be set off in the parlour
to kill any adult flies present.
Yet flies were still causing problems, as
Glen Kellet explains: ‘The hassle factor
for all those working on the farm, as well
as the upset caused to the cows was just
as big an issue as the economic losses
that went with the additional cases of
mastitis that we undoubtedly got when
flies were bad.’
The issue was mentioned to Ruth on one of
her regular visits last year. She suggested
that, as well as stepping up the control of
adult flies, the farm environment be
treated with a larvicide to prevent adult flies
emerging. The Kellet brothers were a bit
sceptical, but agreed to try it and Novartis
Animal Health kindly supported the trial
with the necessary fly products.
Case Study:
Hatton House Farm