Agriculture Reference
In-Depth Information
The
site
of the injection has to be selected carefully
and must not be an area which is associated with the
more expensive cuts. It is imperative, for example, that
piglets are not injected with iron into the ham and that
the hindleg is avoided when injecting lambs with antibi-
otics. Subcutaneous and intramuscular injections should
be given either high up on the neck or on the lower rib
cage. In sheep, the fold of wool-less skin behind the
foreleg is a useful site. Sharp needles, with a metal rather
than a plastic mount, are less likely to break during the
injecting process. A 16 gauge needle is recommended for
use in adult cattle and sheep.
Some anthelmintics which are injected subcutane-
ously in cattle and sheep can cause a very severe reaction
and staining at the site of injection. This makes it
imperative not only that sterile technique is observed
but that the very long withdrawal period, of 60 days
in some cases, is adhered to.
With the usual multidose injectors, it is impossible for
the needle to be disinfected between each injection.
However, a sleeve attachment is available which can sanitise
the needle, by passing it through a polypropylene cap
containing a biocide-impregnated foam, each time the
needle is pushed through the animal's skin and withdrawn.
The system works well for pigs where injections are made
with the syringe at right angles to the surface of the skin, but
less well in cattle and sheep where subcutaneous injections
require the needle to pass through the skin at an acute angle.
The use of anthelmintics and feed additives requires the
producer to be vigilant with regard to
withdrawal periods
.
The keeping of good drugs records is both a practical
necessity and a legal requirement. The improper use of
drenching guns
may lead to damage to the oral cavity and
subsequent abscess formation in the mouth and throat.
The effect of this legislation is that within the EU
the clean livestock policies introduced by competent
authorities are largely redundant since it is the slaughter-
house operator who decides what is clean enough to be
slaughtered within the context of their 'food safety
management system. The official veterinarian's role is to
verify that the slaughterhouse operators follow whatever
procedures they have decided are appropriate to deal
with animals that are not clean.
Healthy livestock
The connection between animal and public health, while
known for decades, has become popularised over the last
few years since avian and swine influenza have been iden-
tified as the cause of deaths in the human population
worldwide. This concept of 'one health' extends to food
where the transmission of bovine spongiform encepha-
lopathy,
E. coli
O157:H7,
Salmonella
and
Campylobacter
through meat to humans emphasises the link between
animal production and public health. A number of
incidents across Europe where animal feed contamination
with dioxins has led to widespread product withdrawal
and consumer concern only emphasise the links. An
ethos
of good husbandry and stockmanship
on the farm is there-
fore essential if healthy animals are to be produced con-
sistently for slaughter. This is particularly so where animals
are cared for under intensive systems of agriculture, where
attention to nutritional balance and preventive medicine
programmes entailing the use of vaccines, anthelmintics
and feed additives are of particular importance.
The use by farmers of veterinary herd health pro-
grammes to establish potential animal and public health
hazards on farm and control them is essential under these
circumstances but useful in all. While veterinary led,
these schemes should involve a multidisciplinary team
in their development, require the farmer to be actively
engaged and should be regularly reviewed and updated.
Safe disposal of animal waste
An aspect of good management which is worthy of dis-
cussion on its own merit is the correct and safe disposal
of animal waste. Incorrect disposal of farm animal excreta
can present a potential hazard to public health, animal
health and the environment. In recent years, the quantity
of slurry in particular produced by intensive systems of
agriculture has become, in some cases, the limiting factor
to the further expansion of production. This is particu-
larly so with the pig industry in the Netherlands, where
it has been suggested that the country is in danger of
disappearing beneath a sea of slurry (Table 6.3).
Slurry may be applied to the pasture or arable ground
by tanker spreader, rain gun or injection. The production
of aerosols by the first two of these methods has been
demonstrated as spreading bacteria in a high concentration
for at least 5 miles (Jones, 1980). For this reason, as well as
for reasons of odour control and contamination of rivers
Safe use of animal medicines
Careless and unhygienic use of the
hypodermic syringe
is
responsible for much unnecessary pain in animals and
for considerable damage to carcases and consequent par-
tial condemnation due to the production of
abscesses
,
and in some cases
necrosis
, at the site of injection. If ani-
mals are injected outdoors, a dry day should be selected
and the injections should be made on clean animals. It is
imperative that needles are changed frequently, for
example, every 6 cattle or 25 sheep, and when there is a
break in the work. A survey in the United States (Dexter
et al.
, 1994) recorded the incidence of injection-site
blemishes in top sirloin butts to be 10.87 and 2.99%. The
average weight per blemish was 123.39 and 5.48 g.
