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AUTUMN 2012 ISSUE
LIVESTOCK MATTERS
6
PNEUMONI A
Case Study
Update
In winter 2011 we featured a case study
from a beef bull enterprise, here we have
an update from Miranda on progress
following the initial assessment. Dairy bull
calves are bought from mixed sources in
batches of 20-22 calves, at 3 weeks old.
Disease as a result of pneumonia is
frequent, and it is not uncommon for a
couple of calves per batch to die. Problems
are mainly seen when calves are 8-9 weeks
old. The single shed houses a total of
around 80 animals in four groups at any
one time, with ages ranging from three
weeks to 15 months. All calves are dosed
with Zactran
TM
on arrival.
In ventilation terms, the shed was found
to be extremely good. Space boarding
provides ample inlet, there are no draughts,
and the 30cm gap running almost the full
length of the ridge provides generous outlet.
Warmth
Several weeks after my visit, however,
I became concerned that whilst the shed
was not draughty, it was not warm.
At our CPD event in January 2012, speaker
and housing expert Jamie Robertson made
much of the fact that cattle enterprises are the
only sector of the UK livestock industry which
does not provide heat sources for very young
animals. Pre-weaned, i.e. pre-ruminant,
calves are unable to generate the degree
of body heat that older cattle do.
Being too cold significantly depresses the
body's ability to fight disease. Thin calves
with spiky coats indicate a severe problem;
however losses are likely to occur before
this is seen, and this was thought to be an
issue on this farm.
There are various ways of addressing
this. Very young calves may need an
external heat source such as a heat lamp.
A practical method for slightly older calves
is to place group hutches within the
building. On this farm, the same effect was
achieved by creating canopies, as pictured
in Figure 1. It was gratifying to visit on a
cold February morning and see two thirds
of the calves nestled cosily underneath.
Moisture
It was also felt that, in our rainy Cornish
climate, too much water was entering
the building. The ridge has therefore
been protected.
Importantly, protecting this ridge has
NOT reduced the available outlet area,
so has not compromised the ventilation
of the building.
Leaking gutters and downpipes and poorly
sited feed and water troughs are another
common culprit resulting in excessive
moisture in a building. Concrete floors can
also be problematic, as they do not allow
water to soak away.
The risk factors were identified as not
being from poor ventilation, but from
a variety of other causes, mainly:
1. Insufficient colostrum at birth
2. Stress of transport and mixing
3. Mixed ages in the same airspace
Conclusion
There is a lot more to pneumonia than
a bottle of antibiotic. The response
from our farmers to the Grassroots
Pneumonia campaign has provided
convincing support as to the value of a
co-ordinated approach to respiratory
disease. The nature and complexity of
respiratory disease means that there
will always be a need for pneumonia
treatments, but it feels good to be
dispensing a healthy dose of sound
advice along with the drugs.
Three essential requirements
for cattle housing
MOISTURE
Too much moisture favours bacterial growth
and hence disease. It also absorbs energy,
meaning that what you feed will be keeping
the cattle warm rather than helping them
grow. In young animals it will also make
them more prone to disease (pneumonia,
coccidiosis etc).
FRESH AIR
Lack of fresh air increases the survival time
of airborne bugs, and hence increases the
risk of disease. Noxious gases may also
build up.
AIR SPEED
Excessive air speeds, or draughts, are
associated with energy losses, reduced
growth rates and increased risk of disease.
Too little is associated with lack of fresh air.
Good ventilation
(enough inlets and
outlets) is essential in order to fulfil the
above requirements.
Attention to detail is also
important.
The following points
apply to housing in general:
l
Don't forget the importance of
maintaining gutters and downpipes
in reducing moisture.
l
Site feed and water sources away from
bedded areas, and make sure troughs
aren't leaking.
l
Space boarding should have a gap of
NO MORE THAN ONE INCH between
boards - greater than this and you will
lose control of air speed.
l
Avoid any draughts at animal level - in
particular gaps between the floor and
the bottom of a solid door. For example
attach rubber sheeting to the bottom of
the door to block up the gap.
l
Bedding (and forage) quality is
important, especially for young calves
(under 5 months old) as they cannot
cope with dust and mould. When you
find a good straw bale, set this aside
for baby calves.
Figure 1: Calves cosying up under the canopy
Cap protecting the 30cm open ridge, but not
reducing the available outlet, by sitting 15cm
above it.