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LAMB GROWTH
SPRING 2012 ISSUE
LIVESTOCK MATTERS
10
Lameness is a major health issue for
all ages of sheep. If your flock has a
lameness incidence of over 4% it is a
problem that needs further investigation.
Lambs afflicted with scald, footrot or
CODD (contagious ovine digital
dermatitis) will not thrive as well as their
contemporaries due to debilitation and
disrupted feeding. Lameness will prevent
lamb sales through the mart and can also
prevent their transport to slaughter. It is
therefore essential that an effective plan is
in place for dealing with lameness issues.
If greater than one in 25 sheep is lame
then your current plan needs changing.
Lameness
Gut worms
Whilst gut worms (parasitic gastroenteritis) are
one of the most significant influences on sheep
production, current strategies of worm control
make up a whole article in their own right.
Young lambs have no immunity to worms,
and increased worm egg production in ewes
around lambing makes them more susceptible
to disease. Unlike adult sheep, lambs are also
susceptible to Nematodirus battus worms.
Coccidiosis
Coccidiosis is another parasite which has
major impact on lamb growth by destroying the
gut lining so the lamb cannot absorb nutrients.
Infections are seen most often in intensive
systems in lambs between 3-8 weeks, although
older lambs may also be affected on heavily
contaminated paddocks. It can cause sudden
death as well as dull, tucked-up lambs with
diarrhoea and dehydration. Lambs which
survive can have reduced growth rates for
weeks afterwards. If lambs are only exposed
to a low grade level of cocci they will develop
a good immunity. Monitor by regular FEC in
conjunction with signs as some cocci lay eggs
but cause no disease.
The appropriate timing and choice of
wormer is essential to control emerging
resistance and disease. Each farm should
have a plan tailored to its own needs.
Selenium and Cobalt
deficiencies
Both selenium and cobalt deficiencies are
common causes of ill-thrift in growing lambs.
These can be diagnosed by group blood
sampling. Deficiencies can be corrected by
appropriate supplementation. Indiscriminate
mineral and trace element supplementation is
at best wasteful, and at worst dangerous -
over supplementation can cause further
complications - such as death seen in
Texel-type lambs provided with too much
copper. It is important the correct trace
element is given and the right method of
administration is employed. Ad-lib minerals
are best avoided as you cannot guarantee
each animal will receive adequate levels.
Drenches, injections and boluses are
available in a huge number of combinations
with varying lengths of action - speak to your
vet about the most appropriate product for
your lambs.
Clostridial diseases
Ewes provide lambs with some immunity to a
range of diseases they may encounter early in
life through colostrum. Ewes should have
received vaccination against the common
clostridial diseases pre-lambing to protect the
lambs from conditions like
pulpy kidney
. Pulpy
kidney is commonly seen in growing lambs
between one to two months, and usually affects
the 'best' lambs in the group. Cases are seen as
sudden deaths, and those lambs found alive
invariably die due to massive toxin overload.
Diseases encountered early on in the life of
the lamb can have ramifications for future
development. Joint ill can result in irreversible
joint damage and hinder subsequent growth.
Navel ills and abdominal infections can result
in a variety of problems including liver
damage and sudden deaths.
Scald
Footrot
While lamb prices are good at the
moment you should be striving to
increase your flock performance
(growth rate). Failure to do so will
have long term consequences for
your flock's potential and its
future profitability.
Ectoparasites
Fly strike
in spring and summer months can be
massively debilitating to young lambs. Severe
infestations can cause death and milder cases
varying degrees of growth disruption. Selecting
products to protect the lambs before the threat
from flies occurs is important, as is making sure
the duration of action is long enough. If lambs
are close to finishing, products with a shorter
duration of action and meat withdrawal may
be more appropriate.
As well as the direct debilitation of skin
disease caused by
scab mites and lice
,
the itching behaviour disrupts feeding patterns
and reduces feed intake. It is important that
scab and lice infestations are differentiated
between as the treatment for each is different.