Methods of
auditing pig wellbeing/welfare
Dr John Carr
Introduction
The pig industry worldwide is
progressively embracing methods to enhance pig welfare. The method generally chosen has been using
audits and checklists. These ‘audits’ range
from relatively a simple checklist with few questions (Malton Code UK 1990’s)
to comprehensive assessments with scoring of farm systems with detailed
booklets on compliance – SWAP programme (USA 2004).
The veterinary profession has
been instrumental in many of these programmes and is generally regarded as
being a key fair and impartial ‘auditor’ by all parties – from the farmer,
slaughterhouse and pork consumer.
However, is the veterinarian really able to see the farm from the pig’s
perspective?
The basis of most ‘audit’ systems
relies on a checklist on the farm equipment and its interaction with the pigs
in the building. The primary assumption
is that if the building facilities do not injure the pig – then the pig’s
welfare is being adequately catered.
However, while this method is a good basis for a clinical examination of
a farm it is not a good indicator of a pig’s welfare.
To audit the pig’s welfare, the
assessor needs to understand the pig and their needs – which is fundamentally
different from the farm and its needs.
The welfare audit demands an understanding of animal husbandry – a
subject which is generally lacking depth in modern veterinary curriculums.
The basis of animal welfare is
the 5 freedoms based on the Bramble code instigated in the 1960’s:
Farming inherently abhors any
farm which fails to provide freedoms 1,2,3 and 5. However, freedom to express its normal
repertoire of behaviours can only be achieved if those behaviours are
understood by the stockpeople and the veterinarian assessor. Achieving normal behaviours should be the
focus of an animal welfare “audit”.
To provide an environment
suitable for pig’s its daily behaviour can be considered in eight broad
categories:
Play; social interaction with
other pigs; feeding behaviour; reproductive behaviour; behaviour at rest; its defecation behaviour; the pig’s ability
to adapt to inadequate environments and finally its interaction with man.
Each of these areas will be
examined with examples from various parts of the farm.
Who are pigs?
Before we investigate behaviour we
should introduce the central customer - the pig.
The suborder suina includes a
range of species spread around the whole world represented by the Peccary (3
species) in North and
All modern farmed pig belongs to
the species Sus scrofa.
The pig is not naturally
represented in
The major limiting factor to the
spread of the pig around the world is the snow line. The pig otherwise has adapted to temperate
and tropical forests, open savanna and desert areas.
Sus scrofa (the European Wild
Boar) evolved in the dense temperate forests of
Knowing the pig’s evolved
environment is the basis for providing a suitable framework within which to
farm.
Pigs at Play
Any stockperson watching a group
of pigs will soon be amused to observe their play activities. Play prepares them for situations and trains
survival skills.
Pigs are extremely intelligent
animals with a degree of complex behaviours that match and if not surpass a
domestic dog. Unlike cattle and sheep,
pigs exhibit a greater inquisitive and individualist behaviour patterns. This can be practically demonstrated when
moving a group of pigs. In many ways
pigs are more like people than they would wish to admit.
Providing an environment where
pigs can explore their play behaviour can help relieve stress and allow the pig
to cope better if their environment is temporarily adverse.
Company
Pigs will gain comfort and support
from other pigs and/or other animals.
Pigs should not be kept in isolation.
There may be obvious exceptions when the pig is under treatment for
meningitis or a severe lameness.
However, once the pig is over the critical stage of the condition it
should be housed with other pigs of a similar weight and age.
Environmental enrichment
Adult pigs
Adult pigs, similar to adult
humans generally have a lower requirement to play with items placed in their
pen. However, playing music to adult
sows can have a calming effect and has been used to reduce savaging of piglets
by gilts. Farrowing sows can be
provided with chopped paper, straw and hay to allow them to act out their
nesting behavioural requirements. Adult
sows can be provided with some chopped straw even while being housed in stall
accommodation. Note that the bedding
materials can cause disturbance to the slurry system which if blocked would
lead to significant other problems.
Wean to finish pigs
All wean to finish pigs should be
provided with toys within the pen.
The simplest toys are often the
most effective. Pigs love to play with
chains, rattles, large plastic bottles, rubber belting, old boots and
feedbags. Large balls became popular in
the 1990’s and while these can be useful, pigs can also become bored with
them. In addition they can be placed in
feeders and block feed access. Car
tires should be avoided as they have metal supports which can be swallowed
resulting in intestinal rupture.
Pen layout
Pen layout can encourage play
behaviour. However, note that in pens
which are long and narrow this can result in a running game with large numbers
of pigs running at high speeds. As the
pigs attempt to turn at the end of the pens, individuals may slip and become
injured – including long bone fractures.
When designing the pen ensure that this running behaviour is catered for
by providing chicanes which will slow the pigs down.
Social behaviour
Pigs are extremely social
animals. Their family group is
matricidal based on a small family group of breeding females with their piglets
and weaners. The boars are
solitary. Sus scrofa live in
groups of 20-40 individuals. In modern
farming we expect pigs to adapt to larger grouping. The wrong group size can lead to excessive
fighting and evidence of vice. The
major grouping time occurs at weaning.
Groups should be formed at weaning from which new animals will not be
added. The group can be subdivided as
the animals grow towards finishing and are moved to new housing. However, mixing and creating a new group will
reduce growth rates by a week. Wean to
finish operations avoid this need to moving and potentially mix groups of pigs.
Weaning can be an extremely
stressful time for the pig where we see a change in behaviour from a group
litter to more individualistic within a new group of pigs. This change is not immediately at weaning but
takes a number of days. It is therefore,
imperative that the veterinarian assists this transition time. However, the veterinarian needs to first
understand the basic challenges of weaning.
It is
important to try and mimic the pig’s pre-weaning environment in the immediate
post-weaning period.
Pre-weaning
each piglet has:
A drinker
each. A feeder each. Minimal
competition at eating/drinking. Eat and drink
warm liquid feed. Eat and drink
as a group/litter. Eat and drink
once every 1-2 hours. Sows in crates
lactate once every hour. Loose housed
sows by 24 days lactate once every 2 hours. Mother
determines the time to eat – the piglet does not. It is not an instinctive drinker, it is
behaviour driven. Sleep as a
group. Clearly
defined sleeping area. Clearly
defined defecation area. |
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The piglet may not even recognise itself as an
individual, only recognise the group
Environment immediately post-weaning
How many of these environmental features are
catered for after weaning? In addition, note that the pig would normally be weaned over a 12 week lactation period
rather than the 3-4 weeks currently practiced in farmed pigs.
Water supply
It is
essential to train the newly weaned pigs where their water supply is
positioned.
The water supply needs to provide more than
500 mls/min. Less than this flow, pigs
will not spend enough time to get their daily water supply. In the first week post-weaning there is
little diurnal variation in water intake – unlike after a week where water
consumption becomes associated with feed.
Insufficient water supply leads to fighting and ultimately variation in
the group. Consider adding a sweetener
or citric acid to the water if it encourages intake.
Air/ventilation
Assess
whether the pigs are comfortable by looking at the pigs when they are asleep and
look where and how they are laying see lying behaviour discussed later. It is essential to provide a sleeping area
which is draught free and with an initial air temperature of 30oC. Avoid gases moving from the slurry pits into
the pig’s building. Enter pens quietly
to assess weaner lying patterns. Noisy
stockpeople will miss clear evidence of draughts The provisions of windows looking into the
nursery can greatly help the stockperson monitor the wellbeing of the pig’s
under their care. Keep the lights with
50-100 lux lit for the first 3 days so the pigs can find the equipment, before
weaning they probably had 24 hours of light.
Floor
The
floor needs to be non abrasive. Having
steps to feeders can cause damage to the knees and legs, particularly important
in future breeding stock. The stocking
rate is important and you need to avoid both under- and over-stocking. This can only be achieved through good pig
flow. Pigs to 20 kg require 0.2 m2;
to 30 kg they require 0.3 m2.
All-in/all-out and adequate pressure washing/disinfecting is essential
to prevent cross over of infection from one group to the next.
Stock the pig’s themselves
To
manage the pigs adequately it is essential to maximise the weaning weight. Provide alternative systems designed to
provide more ideal environments to assist the smaller weaned pigs. One possibility is by streaming. These smaller more compromised pigs should be
provided with wet creep feed for longer than the rest of the group. Never introduce compromised pigs back into
newly weaned pigs at 7 kg, the immune system of the 7 kg pigs is grossly
inadequate to cope and never move weaned pigs back into the farrowing area.
Feed
Feed behaviour in the 1st five days
impacts social interactions.
Palatability Feed
at this stage is a high quality, high cost milk diet. The feed will sour quickly. It is essential not to store the feed at
above 18oC. Ensure the feed
bag is closed at all times.
How many times to feed Prior
to weaning pigs eat every 1-2 hours (12-24 times a day) depending on the
management system. The mother determines
feed times, the piglet does not.
Manually feed weaned pigs 6-4x a day with the stockperson acting as
‘mum’. This is continued for 3 to 4
days post-weaning. Ensure all weaners
eat. While this seems extreme, if the
feed intake in the first week can be optimised this can be worth 10 days to
finish and the reduction in treatments easily compensates for the extra labour
effort.
Type of feed The piglet thrives on liquid/porridge
type feed. Provide a creep/water
mix. Aim to get the pigs to ‘beg’ for
the feed, this makes identification of any poor feed intake pig much easier,
but does require a feeding system where all pigs can eat together. Any weaner that misses two eating episodes
should be taken to the trough and force fed/watered.
Type of feeder It is vitally important in the first week that all pigs can eat together and therefore a trough is required. The neck space for a pig at 7-10 kg is 70-100 mm. The use of long feed troughs can provide sufficient space. Once the pigs are eating well move to dry feeding through the normal pen trough.
Feeding behaviour
Feeding is an important event in the pig’s life. For example in the last section it was discussed how feeding can impact social interactions. Understanding the behavioural characteristics of feeding is vital for the stockperson to understand and observe. A change in a pig’s feeding behaviour can be an important key to indicate poor wellbeing and therefore, the need for enhanced stockmanship. The use of remote sensors in monitoring feed auger turns or feed bin weight changes can provide essential real-time information on pig health and wellbeing.
The classic feeding behaviour repertoire is demonstrated by nursing pig and the following outline illustrates the typical pattern exhibited by mother and her piglets.
Nursing
Patterns
What attracts new born piglets? |
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Vocalisation of sows. Dark
areas. Afterbirth and birth fluids. Movement along hair patterns. |
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Suckling after birth |
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1 |
Piglets contact the udder as
quickly as 3 minutes, but average 15 minutes and 30 minutes to contact the
teat |
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2 |
Milk is continuously available
for several hours post-farrowing and there is little aggression as pigs
sample multiple teats |
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3 |
Cyclic milk ejection,
approximately hourly, results in more aggression until the piglets select
their preferred teat. |
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Cyclic nursing and suckling
(approximately once every hour) |
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Sow’s behaviour |
Piglet’s behaviour |
Slow grunting |
Assemble at udder |
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Increase grunt rate |
Nosing and teat location |
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Rapid increase in grunt rate |
Slow suckling |
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Milk flow (15 sec) |
Rapid suckling |
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Grunting declines |
Slow suckling or nosing |
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Sleep or change position |
Fall sleep |
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Teat Order |
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1 |
Established within 3 days |
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2 |
Consistence often over 90% |
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3 |
Less stable in large litters |
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4 |
About 10% of piglets use more
than one teat |
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5 |
Multiple teats more common in
small litters |
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6 |
Unused teats regress |
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7 |
When sow turns over, so does
the piglet teat order, it is teat specific |
Consequences of a teat order |
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1 |
Stable teat orders lead to more
uniform growth |
2 |
Relative weight gain within
litters depends on competition for teats |
3 |
Evening out litters by weights
(first 3 days) or selective teeth
clipping reduces small piglets |
4 |
Unused teats produce less milk
in subsequent lactation |
5 |
Mixing after day 9 piglets find
it difficult to re-make teat order. It
may take 2 days to restore order. Thus
the group weaning weight is reduced. |
In with natural state a sow would introduce her piglets to other
sow's piglets around day 10. After day
14 the group of piglets join the main group. |
Poor housing before and after
farrowing can significantly interfere with this nursing behaviour resulting in
poor colostrum intake. This can be
disastrous for piglet survival. If poor
feed intake is chronic, reduce an individual pig’s access to milk resulting in
reduced and variable weaning weights.
Facial necrosis may be seen in the affected piglets. Understanding nursing behaviour and providing
suitable environments minimize fighting during suckling. If the piglet is provided with adequate milk
supply it would not be necessary to teeth clip piglets within the first week of
life. This is demonstrated by outdoor
farrowed pigs.
Reproductive
behaviours
Providing an environment
sympathetic to the pig’s reproduction needs is essential to the maintenance of
pig flow and production. Even pig flow
is a key component to reducing variation within batches – eliminating
overstocking and understocking a major cause of poor pig health and wellbeing.
The behaviours exhibited at
courtship are used as an example.
Courtship
sequence in pigs
SNIFFING |
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hEAD TO HEAD |
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nOSING NUDGING |
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mOUNTING ATTEMPTS |
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sTANDING
- MATING |
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Have the assistance of a boar, preferably a mature boar that is
producing a large amount of pheromones (scents) that stimulate the
female. He must be trained in the
layout of the dry sow house/gestation area, but must not become too
accustomed to the work, or he will only detect the sows which waste their
feed. |
House sows and gilts no closer than 10 metre from the
boars. Ideally the sow and gilts
should not be able to see the boars until the time to mate/detect oestrus. |
Oestrus detection should start three days after weaning and
continue daily until served and daily for the entire duration of pregnancy. |
The boar should be presented to the head of the sow or
gilt. However, note that this is only
stage one of the courtship sequence. |
It is essential to have at least 20 minutes a day boar exposure
in gilts to induce oestrus. Constant
exposure can be detrimental to the length of oestrus exhibited. |
The boar needs to be within 1 metre of the sow/gilt face to
stimulate oestrus. The stimulatory
pheromones are in the boar’s saliva. |
Signs of oestrus should be exhibited within 30 seconds of boar
contract. |
Heat detection is easier if sows and gilts do not have boar
stimuli (sight, sound or smell) for one hour prior to checking for
oestrus. Gilts only exhibit intense
oestrus signs for periods of 7-10 minutes and may take 45 minutes before
being able to re-exhibit oestrus. |
Use another unfamiliar boar if sows or gilts exhibit some of the
signs of oestrus, but will not mate.
This is particularly important in a group of gilts where one is
detected by one boar but several others in oestrus are missed by the
stockperson’s enthusiasm for the sow/gilt which exhibit’s first. |
Apply
all the principles of stockmanship Ears
to detect a calling sow Eyes
to detect the restless, nervous sow, which is off her food, has a swollen
vulva, which is slightly red. Touch
to exhibit back pressure test in the presence of the boar The
commonsense to be quietly patient in observing animals. |
Using this understanding of
courtship behaviour allows for efficient effective breeding systems to be
designed. These systems can both speed
up breeding programmes - reducing stockpeople boredom while maintaining or even
increasing farrowing rates and litter size.
Behaviour at
rest
To provide an environment which
will help maintain the wellbeing of pigs in a group, it is essential that all
members of the health team recognized the signs of comfort. The behaviour of the pig at rest can be a
useful real time indicator of comfort.
Lying pattern as a real time indicator of comfort
Too cold |
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A cold pig lies on the floor with their legs tucked under their body to
reduce floor contact. Lie huddles with
other pigs. Lie close to a wall Pigs may shiver, The pigs may
become hairy With larger pigs they seen unable to adopt this tucked position for
very long and tend to lie semi-recumbent with their legs tucked into their
body. |
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Comfortable |
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Within a group of pigs there will be a selection of lying patterns. The
main group of pigs will sleep together in a pile, however, other pigs will be
lying spread out but with maximum contact with the floor. These separated
pigs will be the more dominant pigs. The lower order pigs will lie on the
edge of the main group. Comfortable pigs sleep with legs stretched out from
the body. A hot pig may chose to lie
in a wallow to make itself comfortable |
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Too hot |
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Pigs will be panting > 40 per minute Pigs are generally dirty. Lie away from other pigs, sometimes against a cold wall. They do not pile Lie in any wet/cooler area Pigs will dig into earth/bedded floors. |
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The stockperson needs to understand
the effect of adverse environments on the thermal-comfort requirements.
Environmental conditions which
may change the thermoneutral zone of pigs
Condition |
Change ◦C |
Straw bedding |
-4 |
Deep straw |
-6 |
Slight draught |
+5 |
Draught |
+10 |
Very cold and draughty |
+15 |
Pig housed on its own |
+8 |
Wet floor |
+4 |
Wet bedding |
+4 |
Fully slatted floor |
+2 |
Showers |
+4 |
Poor lying area |
+8 |
Restrict feeding |
+4 |
Note that in general it is more difficult
to provide a cooled environment for pigs.
Cold pigs can be relatively easily warmed. Stockpeople will often run buildings to make
themselves comfortable rather than their pigs.
This is particularly seen in farrowing houses where the environment is
complex – the mother (sow/gilt) requires an air temperature of 16-18°C whereas
the offspring require 28-32°C ambient air temperature. Note the lying behaviour of the mother and
offspring allows the stockperson to maintain the wellbeing of both groups.
Defecation
behaviour
Pigs are inherently clean animals
and avoid lying in feaces. From a few
days of age pigs will become toilet trained to defecation in a specific area of
the environment.
Pig’s defection area can be
expected to be either: Where the pen is
coolest Where the pen has a
draught Where the pen is
wettest Where the pen is
darkest Where the pen is
most private |
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The defecation pattern of the
pen provides a good long term indicator of comfort. The veterinarian can see the area even
without the pig’s presence. Abnormal
defecation patterns indicate a chronic reduction in optimal environment. |
Hot pigs will specifically choose
to wallow in feaces and slurry to assist cooling. Sometimes, this is unavoidable, but its
occurrence should be minimised. Once
pigs become ‘dirty’ they can be extremely difficult to retrain – even when
provided with ‘ideal’ environments.
Abnormal defecation patterns can
also limit other pen resources creating additional stressors – for example when
pigs defecate into feeders, waters or over lying areas.
Adaptation to
inadequate environments
The pig is able to accommodate a
range of environments and cope with temporarily inadequate environments. Big pen and large group situations allow the
pig to choose the most suitable environment.
In particular the pig will select the best area to sleep and
defecate. However, a suitable sized area
needs to be available for the pigs to find.
The pig demonstrates a
predictable range of behaviours. All
members of the health team should be aware of the visual signs of vice and be
willing to immediately investigate and change the environment.
When there are any evidence of
vice the stockperson should immediately check the following stressors:
Check stocking density.
Check tail length, in particular variability. Check feed particle size
(target> 500 µm). Check salt (NaCl) concentration in feed or water. Check
water supplies. Check for evidence of a draught at pig height (cold draught air
speed > 0.2 m/sec). Check air quality
(target - NH3 < 20
ppm H2S < 10 ppm and CO2
< 3000 ppm). Check humidity (target between 50 and 75%). Check light
intensity. Check water supplies. Check feeder space availability. Check 24
hour temperature fluctuations. Mixing
pigs. Moving pigs. Facial necrosis is associated with lactation
failure.
Areas of Vice
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Note that postmortem
findings can assist the veterinarian recognise that the pig was provided with a
suboptimal environment which may have reduced the wellbeing of the pigs.
Examples of pathology
indicative of suboptimal environments:
Injury to the skin –
as illustrated in the previous picture.
Pulmonary millary abscesses, vegetative endocarditis, bacteriaemia,
spinal abscessation and single or multiple discrete abscesses throughout the
body
When the pig fails to
adequately cope with its environment, the pig becomes compromised and
unwell. It often succumbs to pathogens
demonstrating a variety of clinical signs depending on the pathogen. The stockperson must have measures to cope
with all compromised pigs. Utilisation
of hospital accommodation, suitable treatments and humane euthanasia where
required. Poor welfare is unfortunately
often associated with stockpeople attempting to heal pigs that are too sick or
economically incurable.
Interaction with
man
When the veterinarian walks the
farm, observe the pig’s behaviour to the stockpeople and yourself. The pigs should come up to the fence line
while you are outside their pen. Enter
their pen. The pigs should move away
initially, but rapidly turn and face you.
Then several members of the group will approach gaining confidence. Within minutes the group will surround you
and may even start licking and nibbling on your legs and clothing. They can give you a particularly painful bite
behind your knee. These behaviours are
more positive in large groups of pigs; small groups tend to be more nervous and
reticent.
The
relationship between human and pigs can have significant effects on the farm’s
performance and wellbeing of the pig.
Handling studies have shown that pigs are very sensitive to brief
tactile interactions from humans.
Observe
the stockpersons reaction to the pig and look for positive behaviours and
provide retraining to eliminate all negative behaviours.
Positive behaviours of the
stockperson |
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Pats Hand
on the back Talking
to the pig Squatting
to the pig’s level |
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Negative behaviours of the
stockperson |
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Kicks not even forceful but also minor Hits with hand or baton Slaps Pushes Shouting Fast movements (Note:
The picture shown was staged) |
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It is
important to realise that negative behaviours are not only about physical interactions
but also body posture and general attitude.
If pigs
see other pigs being positively handled they will reduce their own fear
response. Interestingly however, it a
pig sees another pig being negatively handled it does not increase its fear response. Pigs which experience negative responses from
one stockperson will generally have fear responses to all people. Therefore, it is important for all members of
the team to have a positive attitude.
Permitted
use of negative interactions
At
times it is necessary to use negative interactions in the day to day husbandry
of a pig farm, for instance when it is necessary to get the animal to move out
of a pen. It is also essential after
utilising the negative action to enforce positive interactions once the animal
is up and moving. This way the long term effect of the negative action can be
nullified.
Summary
To audit a pig’s wellbeing, the
veterinarian needs to familarise her/himself with all the normal repetoir of
behaviour, expectations and characteristics of the pig at all the different
phases of its life.
There are numerous audits being developed around the world. Many of these programmes, while well meaning
fail to be taken up by the industry unless they are legally enforced and then
they are begrudged.
To ensure that environments are
provided which enhance the wellbeing of the pig the whole health team should
enthusiastically collaborate and not require enforcement. The provision of the suitable environment
should be natural. A veterinarian who
focuses on providing an environment sympathetic to the pig’s need is more
important than one who only measures the numbers of drinkers and then checks
the box off the list.
This paper provides one idea of a methodology to enhance the wellbeing to pigs
by attempting to provide the freedom to express normal behaviours. The method demands that the veterinarian
understand what are normal behaviours and then encourages the provision of an
environment which allows its expression.
Expression of a normal repertoire of behaviours will maintain a pig’s
wellbeing; enhance its welfare; provide an enjoyable environment for
stockpeople and therefore enhanced profit for owners and farmers. It is essential for successful and healthy
farming to achieve all of these components.
If the pigs are allowed the freedom to express their normal behaviours
and produce healthy meat with fewer medications, at a reasonable cost: the
average consumer of their meat and other products will be more satisfied that
the animal’s welfare is being satisfied.