Agriculture Reference
In-Depth Information
of the tissue, which increases up to a maximum at 40
hours.
Histological methods
have been developed which
claim to be able to differentiate between bruises occur-
ring at various times between 48 hours' pre-slaughter
and stunning (McCausland and Dougherty, 1978)
Presence of horns
An important factor in the frequency of bruising is
whether the animal is hornless or horned. The Australian
Meat Board has shown that approximately half the
bruising in horned cattle is due to the horns and that the
incidence of bruising in horned cattle is twice as high as
in hornless breeds. The tipping of horns, by the removal
of 10-15 cm, has been recommended but was not found
to make any significant difference to the incidence of
bruising. The only answer is to have all cattle polled,
either by dehorning young calves or by breeding natu-
rally polled stock.
Rough handling
Observations in over 100 packing stations in the United
States have shown that rough handling and the abusive
use of clubs, whips and electric goads are responsible for
the majority of injuries. If animals become stubborn or
fractious, and refuse to enter or emerge from a vehicle,
they are all too often beaten and shouted at until they
fall, or in the case of pigs are dragged by the ears, sustain-
ing injuries, even fractures and bruises. This senseless
form of animal handling is not confined to the United
States - it occurs the world over. McNally and Warriss
(1996), in a survey carried out in the United Kingdom,
report that over 35% of cattle bruising was due to stick
marks. Giving animals time and space to move is a pre-
requisite not adopted by all handlers. Some knowledge
of animal behaviour, with attention to detail in the design
of animal handling/loading/unloading facilities, can
remove the stress and danger for both handler and
animal.
Three categories of sheep were examined for evidence
of bruising: sheep transported direct from farms and
those transported from local and distant markets in
Scotland (Jarvis, Cockram and McGilp, 1996). In sheep
coming directly from farms, 93% had no bruises com-
pared with 86% from local markets and 74% from
distant markets.
Blood biochemistry showed significantly higher levels
of serum creatine kinase and plasma osmolality in the
sheep from distant markets than in the other two groups,
suggesting greater muscle damage and dehydration,
respectively. However, there were no substantial differ-
ences between the three groups in terms of packed cell
volume, total plasma protein and beta-hydroxybutyrate.
A survey of 4473 cattle delivered to one slaughter
plant from 21 live auction markets in England revealed
an overall prevalence of bruising of 8.1% and of stick
marking of 2.2%. Differences existed between the preva-
lences of both bruising in carcase from steers, heifers and
bulls. Overall, steers had the greatest amount of carcase
damage and young bulls the lowest amount. Variations
also occurred in the frequency of bruising (range 2.4-
17.9%) and of stick marking (range 0-9.6%) from differ-
ent markets. There was no evidence that longer journeys
(distances ranged from 80 to 464 km) were associated
with greater carcase damage. There was a relationship
between a high degree of bruising and stick marking at
one particular market (McNally and Warriss, 1997).
Temperament
The temperament of cattle obviously has an effect on
the incidence of bruising and, as every cattle farmer
knows, temperament varies between breeds and indi-
viduals. It is considered that the bruising of cattle in a
confined space, for example, a cattle wagon or lairage
pen, is due to the natural 'milling about' of a mob of
cattle rather than to malicious aggression. Practical
farmers, however, are unanimous in the assertion that a
bad-tempered animal can create havoc in a mob of cat-
tle, especially under confined conditions, and person-
nel in every abattoir have noticed how an old cow may
persistently harass its fellows. The same occurs with
pigs, where one animal in a group can persistently bully
its mates.
Over-crowding undoubtedly increases aggressiveness
and may be responsible for a high incidence of bruises in
animals awaiting slaughter. Among the food animals, fat
pigs are the most likely to be affected during transport as
their heat-eliminating powers are very limited and they
soon succumb to overexertion.
Stunning box design
Bruising can be produced in an animal both before and
after stunning, but not once the animal has been bled
when the blood pressure drops to zero. The design of the
stunning box can, therefore, be of importance in the
problem of bruising. In Australia, it has been shown that
over 60% of cattle fall from the stunning box so heavily
that they are bruised, the extent of the bruise depending
on the severity of the fall and the time between stunning
and bleeding.
In Australia, bruising in cattle causes an estimated
annual loss of up to $26 million (1976), and horn dam-
age plus stunning box bruising accounts for 48% of this
loss. The incidence of stunning box bruising can be
reduced by a proper design which ensures that the ani-
mal slides out of the box. In some abattoirs, the animal is
ejected onto a thick rubber mat.
