Basic causes of animal welfare problems

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Basic Causes of Animal Welfare Problems

● Proper livestock handling is extremely important to meat packers for obvious ethical reasons. Once livestock

arrive at packing plants, proper handling procedures are not only important for the animal's well-being, but can also mean the difference between profits and losses due to meat quality or worker safety. The Humane Slaughter Act of 1978 dictates strict animal handling and slaughtering standards for packing plants. Those standards are monitored by some 7,000 federal meat inspectors nation-wide. The meat packing industry takes these standards very seriously.

● For the best results in animal handling, plant management must make proper handling and stunning a high priority. Top management must play an active role. Plants with the best handling and stunning practices have managers who closely monitor stunning and handling practices. Employees handling hundreds of animals day after day, sometimes need reminders from management that animals must always be handled carefully.

● Healthy animals, properly handled, keep the meat industry running safely, efficiently and profitably.

To correct an animal welfare problem, first determine the cause:

1.

Stressful Pre-Slaughter Handling

There have been numerous research studies on stunning methods, but until recently, stress and discomfort during a lairage and movement of the animals to the stunning point was neglected.

2.

Distractions that Impede Animal Movement

Animals will often balk and stop moving through a handling system if there are distractions such as sparkling reflections, air blowing towards the animals, movement or high pitched noise.

3.

Lack of Employee Training

Maintaining a high standard of welfare requires constant management attention and vigilance.

4.

Poor Equipment Maintenance

The two major maintenance problem areas that the author has observed are poor captive bolt stunner maintenance, and slick floors.

5.

Poor Condition of the Animals Arriving at the Plant

A recent survey of U.S. cow and bull slaughter plants indicated that 1% of the cull beef cows and 1.1% of the cull dairy cows arrive downed and unable to walk (Colorado State University, 1995). Most of these animals were in bad condition before they left the farm.

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Providing Less Stressful Pre-Slaughter Handling

Ron Kilgour from New Zealand was the first researcher to discuss that there was a need for greater emphasis on procedures that occur prior to stunning or slaughter (Kilgour, 1978).

Cattle and sheep will move quietly through single file races and ride quietly in a well designed conveyor restrainer system. Moving in single file is a natural behaviour for cattle. In the U.S., large stunning boxes which held more than one bovine have been replaced with conveyor restrainers.

● Center track double rail restrainer. This system is available for both sheep and cattle. Livestock are riding the conveyor in a

comfortable, upright position. This is a very humane method of restraint.

● The V conveyor restrainer was introduced for cattle in the 1970s (Schmidt, 1972; Willems and Markley, 1972). It was replaced in the l990's with the center track double rail restrainer (Giger et al., 1977; Grandin, 1988b; 1991). Cattle and sheep will remain calm in conveyors because they are touching the animal in front and back of them.

● V conveyors work well for round, fat pigs, but less well for lean pigs. The author has observed that slender, lean pigs are not supported properly and heavily muscled pigs are pinched on the hams, whereas round, fat pigs are held in a comfortable position. Lean pigs are properly supported on a center track restrainer.

● In England, head restraint devices are required by legislation to hold a bovine's head for captive bolt stunning. The purpose of the legislation was to improve stunning accuracy. In some circumstances, head restraint can increase stress. Ewbank et al. (1992) found that cortisol levels were higher in a head restraint compared to a conventional single animal stunning box. It

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took an average of 32 seconds to induce the cattle to put their heads in the poorly designed yoke used in this study.

● Stress can be minimal in a well designed head restraint where the animal is stunned immediately after the head is caught (Tume and Shaw,1992; Frank Shaw, personal communication). The author has observed electrical stunning of cattle in a head restraint in New Zealand. Each animal quietly entered the stunning box and was stunned within 2 seconds after the head was clamped. Information on the design of head restraint devices can be found in CSIRO (1989) and Grandin (1993; 1994).

● Stress caused by prolonged restraint will be a severe problem if live animals are subjected to intravenous injections shortly prior to slaughter. Payne and Young (1995) report that intravenous injections of lambs with antifreeze glycoproteins may improve the quality of frozen meat.

Design mistakes in races and forcing pens will cause stress.

Cattle move more easily through a curved ramp.

One of the most serious design mistakes is laying the race out so that its entrance appears to be a dead end. Cattle will move more easily through a curved race compared to a straight race, but it must be laid out correctly (Grandin, 1980; 1990; 1993). Practical experience has shown that an animal standing in the forcing pen must be able to see a minimum of two to three body lengths up the single file race before it curves. Bending the single file race too sharply where it joins the forcing pen will cause animals to balk.

View of a round crowd pen leading to the curved single file race. Note there must be a straight section where the crowd pen is attached to the races.

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Grandin, T. (Editor) 1993

Livestock Handling and Transport CAB International, Wallingford Oxon, United Kingdom

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Distractions That Impede Animal Movement

A survey of 33 Canadian, and 24 United States slaughter operations ranging from small to the very largest revealed that cattle and pigs often balk and have to be prodded excessively due to distractions that can be easily eliminated. Click here to read a current abstract on Factors that impede animal movement at slaughter plants.

Incidence of Distractions Which Impede the Movement of Livestock

Type of distraction Acceptable, move easily

Not acceptable, excessive balking Lighting problems (too dim or too bright) 28 (85%) 5 (15%) Ventilation air blowing towards approaching animals 30 (91%) 3 (9%)

Seeing movement or sparkling reflections 25 (76%) 8 (24%)

These distractions will ruin the performance of well designed restrainers and races because animals often have to be prodded when they refuse to move. Sometimes, adding more light or moving a light to eliminate sparkling reflections on floors or walls will improve the movement of pigs or cattle.

In two plants a new double rail conveyor system worked well when the plant was new, but balking at the restrainer entrance gradually worsened as the lamps over the restrainer grew dimmer with age.

Animals have a tendency to move from a darker place to a more brightly illuminated place (Grandin, 1980; Van Putten and Elshoff, 1978). The light must not shine directly in the eyes of approaching animals.

Air blowing through a stunning box entrance or down a race will make both pigs and cattle stop. Nine percent of the surveyed plants had serious balking problems caused by ventilation blowing air either out the entrance of the stunning area or down a race. Seeing people moving up ahead or jiggling gates will also impede livestock movement.

Cattle move more easily through the curved race system because they can not see people and other distractions ahead.

In one plant, cattle balked at a small chain jiggling in the race and in another, cattle balked at a shiny reflection on a vibrating metal wall. When animals are calm, they will stop and look directly at things that make them balk.

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In 24% of the plants visited, animals became visibly frightened by sudden air hissing noises or extremely high pitched noises. Observations by the author indicate that high pitched noise causes more agitation than a low pitched rumble of chains and gears. The ears of cattle are most sensitive at 8,000 Hz (Ames, 1974) and they can hear up to 21,000 Hz (Algers, 1984).

Clanging and banging noises will make animals flinch or jump. Sheep slaughtered in a noisy commercial abattoir had higher cortisol levels than sheep slaughtered in a quiet research abattoir (Pearson et al.,1977). Sudden noise of a door slamming and banging on a wall increased heart rate in deer (Price et al., 1993). In the eight plants that had balking caused by noise, five were due to air hissing and three were due to high pitched motor noise. At one plant, elimination of a high pitched hydraulic whine resulted in calmer cattle. Stunning box entrance doors had hissing air in three plants. In one plant, installation silencers to stop hissing air resulted in a dramatic reduction of excited cattle.

Distractions Which Caused Pigs to Balk in the Stunning Chute and Crowd Pen, Which Caused Increased Usage of Electric Prods

Type of Animal Description

of Distraction Rating Comments

Market Pigs None: Very quiet, low machinery noise. Excellent Animals moved easily through chutes.

Market Pigs None Excellent " "

Sows Seeing people moving and possible reflections Acceptable Caused some slowing of the animals.

Market Pigs Noise from ventilation fans increased as pigs

approached the stunner. Acceptable Caused some slowing of the animals.

Market Pigs Seeing people moving and chains hanging in

chutes. Not Acceptable Seeing movement caused pigs to stop. Market Pigs Shiny reflections Not Acceptable

Market Pigs

Shadows and reflections

The staging area was much brighter than the stunning chute. This caused the pigs to turn back towards the light.The problem was worse when bright sun was shining.

Serious Problem

Made quiet handling and reduction of electric prod use impossible, because the pigs kept turning back.

None of the plants had ventilation air blowing into the faces of approaching animals. This will

usually cause balking. Plants with no distractions had worked to eliminate them prior to being

surveyed. Ratings of nine pork plants for distractions were 44% excellent, 22% acceptable, 22% not

acceptable, and 11% a serious problem.

Distractions Which Caused Cattle and Calves to Balk in Stunning Chute and Crowd Pen, Which

Increased Use of Electric Prods

Type of Animal Description of Distraction Rating Comments

Fed Cattle None Excellent Animals moved easily through the chutes.

Fed Cattle None Excellent " "

Cows None Excellent " "

Fed Cattle None Excellent " "

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Fed Cattle Air hissing from control valve exhaust. Not Acceptable Made cattle balk.

Cows

Air hissing from control valve,

reflections, seeing movement under stun box door.

Not Acceptable Made cattle balk. Screeching from saw also caused agitation.

Fed Cattle

Bright sunlight caused shadows in the crowd pen. Air hissing from control valve, high pitched whistling from a pump.

Not Acceptable Made cattle balk.

Cows Air hissing from control valve, seeing

movement under stun box door. Serious Problem

Made cattle balk, impossible to lower prodding score.

None of the plants had ventilation air blowing into the faces of approaching animals. This will

usually cause animals to balk. All plants with no distractions had worked to eliminate them prior to

being surveyed. Ratings 60% excellent, 30% not acceptable, and 10% serious problem.

In two plants (9%) distractions were sufficiently severe so that handlers had to constantly prod animals that either balked or turned back. In one beef plant cattle refused to enter the stunning box because they could see people moving under the stun box door. This problem could be easily corrected by installing a rubber flap on the bottom of the door to block the animal's vision of the movement. In the pork plant pigs refused to enter the crowd pen because the staging area was in bright sunlight.. This facility worked well when it was cloudy but poorly when the sun was out. The problem was corrected by installing metal siding on a building which had open sides. Minor balking problems can often be fixed by moving a light to eliminate a sparkling reflection. Pig movement was improved in one plant by covering a portion of the top of the stunning chute to eliminate glistening reflections on the wet floor of the chute.

Air hissing from control valves caused balking in 4 (33%) of the surveyed beef plants. This problem can be easily fixed by piping control valve exhausts outside or installing inexpensive mufflers. The mufflers have to be replaced every few months when they stop working due to clogging with dirt. Elimination of air hissing will also greatly improve the working environment for plant employees.

Other distractions which can impede movement are shadows, drain grates and changes of fencing or flooring types.

Drains should be located outside of the areas where animals walk. A drain or a metal plate running across an alley will cause balking.

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Shadows will cause livestock to balk.

Condition of Floors in Slaughter Plants

Number of slaughter systems Percentage Flooring Condition

8 27% Excellent, non-slip floor

15 52% Acceptable floor

6 21% Slick floor, not acceptable

A good example of a non-slick surface for livestock.

R

eferences :

Grandin, T.(1996)

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Journal of the American Veterinary Medical Association 209 No.4 : 757 - 759

Grandin, T.(1995)

Little Things Do Matter In Debugging Animal Environments Paper No. 954542 American Society of Engineers 2950 Niles Road St.Joseph , Michigan , 49085 USA

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Lack of Employee Training

During twenty years of experience, I have observed that plants which have good animal welfare have a manager who trains and supervises his or her employees. Plants with lax management often have animal abuse (Grandin, 1988c; 1994a).

● Maintaining a high standard of welfare requires constant management attention and vigilance.

● A good manager constantly works on improving details of procedures. After the distractions and serious design mistakes are eliminated, employees can fully use behavioural principles to move animals easily and quietly (Grandin, 1993; Kilgour and Dalton, 1984).

Understanding flight zone behaviour and utilizing a few basic principles, moving animals in a calm and orderly fashion becomes very easy.

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● The author has observed that the most common mistake made by employees is attempting to move too many

animals at a time.

For all species, forcing pens should not be filled more than three-quarters full.

● Employees should also be taught how to time groups of animals. The next group should not be driven into the

forcing pen until there is space in the race for them to walk into. This procedure utilizes natural following behaviour.

Sheep in a crowd pen following each other into a single file race. Notice the handler's position. The animals do not need prodding.

● Most importantly, employees need to remain calm and avoid sudden, jerky movements and yelling.

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Poor Equipment Maintenance

The two major maintenance problem areas that the author has observed are:

1.

Slick Floors

2.

Poor Captive Bolt Stunner Maintenance

● The majority of slippery floor problems were due to either the rough finish wearing off a concrete floor or a slick

floor in a cattle stunning box.

A good example of a non-slip floor

● The author has conducted welfare surveys in plants in both the U.S. and Canada. Slick floors which caused animals to fall down were the number one equipment problem. Cockram Corley (1991) found that slipping increased stress and also noted that it is a problem area.

● A survey of slaughter plants indicated that 21% had slick floors.

Condition of Floors in Slaughter Plants

Number of slaughter systems Percentage Flooring Condition

8 27% Excellent, non-slip floor

15 52% Acceptable floor

6 21% Slick floor, not acceptable

● The author has observed that the second most common equipment maintenance problem in U.S. plants is poor

maintenance of pneumatic captive bolt stunner. Stunners require careful maintenance to maintain maximum hitting power.

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Animal's Condition At The Plant

Animals which arrive at the plant in bad condition often suffer.

● A recent survey of U.S. cow and bull slaughter plants indicated that 1% of the cull beef cows and 1.1% of the cull dairy cows arrive downed and unable to walk (Colorado State University, 1995).

● Most of these animals were in bad condition before they left the farm.

● Further information on death losses and metabolic stress can be found in Gregory (1994) and Grandin (1993).

● There have also been increasing problems with very excitable cattle and pigs which are more difficult to drive and more likely to become excited (Grandin, 1992; 1994b).

● The author has observed that the increase in excitable cattle and pigs appears to be in the leaner animals.

● This is an area that needs to be researched because the welfare of excitable animals is sometimes severely compromised.

R

eferences :

Grandin, T. (1995)

Downers Are A Problem Meat and Poultry April ( page 10 )

Grandin, T. (1995)

Handling Hyper Hogs Meat and Poultry June ( page 56 )

Grandin, T.(1994)

Methods to reduce PSE and bloodsplash

Allen D. Leman Swine Conference Volume 21 pages 206-209 College of Veterinary Medicine, University of Minnesota.

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Environmental Enrichment for Confinement Hogs

Livestock Conservation Institute Annual Meeting Proceedings pages 119-123 1910 Lyda Drive Bowling Green, Kentucky 42104-5809

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Livestock Handling and Transport, 3rd Edition

Edited by:

Temple Grandin, Department of Animal Science, Colorado State University, Fort Collins,

Colorado, U.S.A.

ISBN # 9781845932190

Published by

CABI International

Readership

Researchers in animal science, welfare, verterinary science, and animal behaviour; and those

involved in animal transportation and handling welfare. Veterinarians, livestock producers, and

regulatory bodies will find a wealth of information in this book.

Summary

Handling and transport present some of the most severe stresses that farmed animals are likely

to experience. A completely revised introductory chapter covers the animal welfare auditing

programs of large corporate meat buyers and the development of worldwide standards. All

aspects are covered including handling for veterinary and husbandry procedures, restraint

methods, transport systems, and design of facilities on fram and at slaughter plants. This book

covers both research and practical information on handling of cattle, sheep, pigs, horses, deer,

and poultry.

●

Temple Grandin and contributors are world authorities on animal handling,

transportation, and welfare.

●

Extensive revisions to many chapters include information on handling and transport in

South America and developing countries

●

Updated and revised to include the latest research, with three new authors and chapters

on sheep transport, biosecurity, and low stress methods or sorting and weaning cattle.

●

The best of the older material has been kept including the popular handling system

layouts and behavior diagrams.

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●

Over 25 new photos and figures.

Reviews of the first edition

"...a must for the libraries of research institutes and teaching establishments." Livestock

Production Science

"This book is a must for every library of veterinary medicine, animal science, and

animal behaviour." American Veterinary Medical Association

"For anyone involved in the animal transportation industry this is an essential reference

work." Animal Transportation Association

1. Introduction: Effect of Customer Requirements, International Standards, and Marketing

Structure on the Handling and Transport of Livestock and Poultry, T Grandin

2. General Principles of Stress and Well-being, P.B. Siegel and W.B. Gross

3. Causes of Poor Welfare and Welfare Assessment during Handling and Transport, D.M.

Broom

4. Behavioural Principles of Handling Cattle and Other Grazing Animals under Extensive

Conditions, T. Grandin

5. Low-stress Restraint, Handling and Weaning of Cattle, J.X. Stookey and J.X. Watts

6. Handling Cattle Raised In Close Association with People, R. Ewbank and M. Parker

7. Handling Facilities and Restraint of Range Cattle, T. Grandin

8. Dairy Cattle Behaviour, Facilities, Handling, Transport, Automation, and Well-being, J.

L. Albright and W.K. Fulwider

9. Cattle Transport, T. Grandin and C. Gallo

10. Behavioural Principles of Sheep Handling, G.D. Hutson

11. Design of Sheep Yards and Shearing Sheds, A. Barber and R.B. Freeman

12. Sheep Transport, M.S. Cockram

13. Dogs for Herding and Guarding Livestock, L. Coppinger and R. Coppinger

14. Behavioural Principles of Pig Handling, P.H. Hemsworth

15. Transport of Pigs, E. Lambooij

16. Handling and Transport of Horses, K.A. Houpt

17. Deer Handling and Transport, L.R. Matthews

18. Poultry Handling and Transport, C.A. Weeks

19. Stress Physiology of Animals During Transport, T.G. Knowles and P.D. Warriss

20. Handling and Welfare of Livestock in Slaughter Plants, T. Grandin

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Factors that impede animal movement at slaughter plants

Journal American Veterinary Medical Association 1996; volume 209:757-759

Temple Grandin, PhD Dept. of Animal Science Colorado State University Fort Collins, Colorado 80523 U.S.A.

Summary: Factors that impede animal movement in slaughter plants and that are likely to cause excitement, stress, or bruises are major mistakes in the design of chutes and stockyard pens; lack of training or poor supervision of employees; distractions that impede animal movement, such as sparkling reflections on a wet floor, air hissing, highpitched noise, or air drafts blowing down the chute toward approaching animals; poor maintenance of facilities, such as worn out or slick floors that cause animals to fall; and animals from genetic lines that have an excitable temperament.

Veterinarians need to be aware of these factors because such factors can cause animals to balk and become excited, which may result in excessive prodding. When a handling system is being evaluated, one must be careful to discriminate between a major design mistake and small distractions that can be easily corrected, but that can ruin the performance of the best systems.

A survey of 29 Canadian slaughter plants revealed that

● 21% (6 plants) had slick floors that would cause animals to slip and fall, and

● 27% (8 plants) had highpitched motor noise or hissing air that caused animals to balk.

● Air drafts blowing down the chutes, which will often impede animal movement, were a problem in 10 % (3) of the plants.

Simple modifications of lighting and elimination of air drafts and hissing will often greatly improve animal movement.

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Methods to reduce PSE and bloodsplash

Temple Grandin, Ph.D.

(Updated October 2000)

Allen D. Leman Swine Conference Volume 21 1994, pages 206-209 College of Veterinary Medicine, University of Minnesota.

Published by: Veterinary Outreach Programs, UNIVERSITY OF MINNESOTA.

Observations by the author at slaughter plants and farms all over the United States, Canada, Europe, and Australia indicate that producers are responsible for about 50% of the pale, soft, and exudative (PSE) pork on the market, and packers are responsible for the other 50%. Surveys conducted in slaughter plants in two different countries indicated that PSE levels varied over 100% between different producers.

Genetics is probably the single most important factor contributing to the prevalence of PSE pork today. Some pork-grading systems motivate producers to breed pigs that carry the stress gene. These animals have maximum lean and weight gain (Aalhus et

al .,1991). Unfortunately, they also have high levels of PSE. Some of the highest levels of PSE were recorded in hybrid pigs, which had been selected for leanness and rapid growth. The breeding companies have recognized the problem and have taken steps to produce lines that will have lower levels of PSE. DNA testing methods will enable the PSS (porcine stress syndrome) gene to be eliminated (Sellers, 1993).

At one plant, a certain line of commercially available hybrid pigs constituted 10% of the pigs received each day. Ninety percent of the pigs that were dead on arrival or died in the yards came from these hybrids. Genetics has a large effect on death losses (Murray et al., 1998). Genetics is not the sole explanation for differences between producers. A survey conducted at a vertically integrated operation indicated that PSE levels varied 5-10 percentage points among producers who raised identical pigs in identical buildings. Handling, management, and transport also had an effect. Several surveys have shown that pigs transported a short distance will have more PSE compared to pigs transported a longer distance. Observations by the author have indicated that pigs hauled very short distances for under 30 minutes are often more stubborn and difficult to drive at the plant compared to pigs hauled longer distances (Grandin, 1993a). Pigs hauled long distances are more likely to have DFD (dark firm dry) meat because glycogen stores become depleted.

PSE can be reduced by fasting pigs 12 to 24 hours prior to slaughter (Warris and Bevis, 1987; Eikelenboom et al.,1990). Pigs should have access to water at all times. To reduce the possibility of carcass weight loss, a shorter fasting period of 12 hours prior to stunning and slaughter is recommended (Grandin, 1993).

Excitable pigs

There are problems with excitable pigs. The leanest animals with large muscles often have the worst excitability problems. Shea-Moore (1998) found that high lean pigs were more fearful. These pigs often have the worst meat quality problems. Pork from stress gene pigs which are grown to heavy weights is tougher and drier than pork from pigs which are stress gene free (Monin et al., 1999). Excitable pigs are very difficult to handle at the slaughter plant. This creates both meat quality and welfare problems. Handling excitable pigs at 1000 per hour in a single file race is difficult to do quietly. Some plants have installed two stunners to improve handling. Fortunately some of the vertically integrated companies have removed the stress gene from their herds. This has resulted in calmer pigs which are easier to handle. They are now breeding pigs for quality instead of quantity.

Handling of pigs can also be improved by installing a system which eliminates the single file races. The Danes have developed a CO2 stunning system where pigs are stunned in groups. Cattle move very easily through a single file race because their natural

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pig excitability increased, problems with single file races increased. When pig excitability is reduced single file races will have fewer problems.

Many excitable pigs are animals that have been raised in confinement (Grandin, 1993). Genetics is a major factor. Observations by the author in identical pig confinement buildings and in the same slaughter plant indicated that changing genetics improved handling. Pigs with a calmer temperament were easier to handle and PSE was reduced. There is a definite need for breeding companies to select pigs for temperament. This is especially important for pigs raised in confinement.

In confinement buildings, producers must provide pigs with more environmental stimulation. Providing confinement pigs with additional environmental enrichment, such as toys and people entering the pens, produced calmer pigs that were easier to drive (Grandin,1989; Pederen,1993). Producers need to eliminate practices such as keeping pigs in darkened rooms. Playing a radio in the building can help get pigs accustomed to sounds. Pigs that have been finished in a pen with a radio playing at a reasonable volume are less likely to be startled by sudden noises.

Producers should walk in the finishing pens every day to get the pigs accustomed to handling. The person should quielty walk through each pen in a different random direction each day to teach the pigs to quietly flow around them. The person should not stand in the pen and allow pigs to chew on their clothes. This trains the pigs to approach and chew instead of driving. Geverink et al (1998) reported that confinement pigs which have been driven in the aisle during finishing were easier to handle. Moving pigs out of their finishing pen one month prior to slaughter improved their willingness to move (Abbott et al., 1997)

Observations by the author have also indicated that raising finishing pigs on plastic or metal floors produces animals that are hard to drive because they do not know how to walk on concrete. Plastic or metal floors work well for young pigs, but during the final finishing phase, confinement pigs should be raised on a concrete surface. Producers must also avoid producing pigs with a high incidence of either hernias or spraddle legs. Both of these conditions have a strong genetic component.

Slaughter plant factors

After pigs arrive at the plant, handling and chilling practices will have a large effect on the incidence of PSE. I estimate that handling practices account for 10%-15% of the variation in PSE, and chilling practices account 20%-40%.

Improvements in handling practices have enabled several plants to ship 10% more pork to Japan. These handling procedures will reduce PSE:

● Schedule trucks to prevent delays during unloading. Heat builds up rapidly in a stationary truck. Do not overload trucks.

● Rest pigs for 2-4 hours prior to slaughter (Malmfors, 1982; Milligan et al., 1996). Trucks must be scheduled to allow

adequate resting time.

● Shower with cool water during hot weather (Smulders et al.,1983).

● Handle gently in the stunning chute. Rough handling during the last 5 minutes prior to slaughter increases PSE, because

pigs become overheated. Handlers must be taught behavioral principles of pig handling. Over-exertion and excitement shortly prior to stunning increases PSE in stress-resistant pigs that do not have the stress gene (Sayre, 1963; Barton-Gade, 1985).

● Reduce or eliminate electric prods in the stunning area. Stressful handling shortly before slaughter will damage meat quality (Warriss et al., 1990; D'Souza et al., 1998; Van der Wal, 1997).

● Reduced squealing in the stunning area will help reduce both PSE and bloodsplash. Squealing is associated with increased stress and lower meat quality (Warriss et al, 1994). The last five to ten minutes prior to stunning is most critical for reducing PSE.

● Fill the crowd (forcing) pen which leads up to the single file race only half full. Move small groups fo pigs. In group stunning systems the staging areas that leads into the stunning areas should be filled half full. Pigs need room to turn.

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● Replace electric prods with other driving aids such as flags, panels, or paddles.

● Eliminate distractions which make pigs balk and refuse to move such as air drafts blowing in their faces, sparkling

reflections on the floor, shadows or small moving objects such as chains. If pigs constantly back up, the distraction that is scaring them must be removed (Grandin, 2000, 1996). See the behavior section of this webpage.

Lower temperature

Gentle handling, rest, and showering helps lower body temperature. Pigs that are overheated are more likely to have PSE or DFD meat (Gariepy, 1989). Heat damages the meat, both in live pigs and shortly after slaughter, making proper chilling important. Sometimes carcasses are jammed together or there is insufficient refrigeration. Some managers make the mistake of maximizing pig numbers by overloading the cooler. They are saving a few pennies on numbers and throwing dollar bills away in carcass shrink losses. It is easier to quantify pigs per hour and person hours than shrink loss and customer dissatisfaction. The industry needs to change its mind set and eliminate the "ram and jam" mentality. To succeed in the marketplace of tomorrow, quality must come first and quantity second.

Segmented market

A segmented market causes losses to be passed from the producer to the next person in the marketing chain. A producer who sells pigs live-weight has no motivation to improve quality. Live-weight selling or a carcass marketing system that fails to reward quality are the major causes of quality problems. The producer gets the wrong economic incentives. Some grading systems reward lean, highly muscled pigs with high levels of PSE. The electronic probes currently being used by the packing plants measure fat thickness and the size of the loin, but there is no PSE measurement. This motivates the producer to select breeding stock for rapid gain, leanness, and muscle growth. These selection pressures have resulted in high levels of PSE because pigs carrying the stress gene are kept as breeding stock. The swine industry needs to use an accurate method for measuring PSE so that a PSE measurement can be added to the fat and loin eye size measurements. The producer must be financially rewarded for producing lean pigs with low levels of PSE. Changing the carcass measurement and payment system to include PSE measurement will motivate producers to reduce the incidence of the stress gene in their herds. The bottom line is that the producer has to be financially rewarded for producing quality pork instead of maximum tonnage.

Bloodsplash

Bloodsplash is damage to the meat caused by either small pinpoint haemorrhages or large blood clots in the meat. It is a severe cosmetic defect that affects the appearance of the meat. Haemorrhage problems are mainly caused by problems inside the plant, but nutritional factors such as low levels of selenium and vitamin E may possibly contribute to it by weakening capillary walls. Lean pigs often have more problems with bloodsplash.

These procedures have effectively reduced bloodsplash in many plants which use electric stunning:

● For electric stunning, use an amperage power supply where the amperage remains constant and voltage varies with pig

resistance. Old fashioned voltage-regulated stunners allow amperage spikes that damage the meat. Some plants have built their own electronic constant amperage power supplies. These units can lower bloodsplash over 100%. To ensure good animal welfare, a minimum of 1.25 amps must be used to reliably induce a grand mal seizure and produce instantaneous unconsciousness (Hoenderken, 1983). For large market pigs, a minimum of 300 volts should be used and slightly lower voltages can be used for lighter market pigs (Hoenderken, 1983; Gregory, 1988). Some plants have attempted to reduce bloodsplash by reducing amperage to 0.5 amps. This must never be permitted because scientific research has shown that low amperages or frequencies over 800 Hz fail to induce instantaneous unconsciousness.

● Bleeding a pig within 10 seconds after stunning will reduce bloodsplash. Prone sticking systems accomplish this, but older,

hanging sticking systems sometimes have intervals of over 30 seconds. Quick bleeding also improves animal welfare because it reduces the possibility of an animal reviving (Hoenderken, 1983; Blackmore and Newhook, 1981).

● The operator must be careful to avoid double stunning and causing the pig to contract more than once (Grandin, 1985/86).

Double stunning can be caused by allowing the stunning applicator to slide during the stun or turning on the electricity before the applicator is pressed firmly against the pig. The pig should not squeal when the stunner is applied.

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● Worn cords and switches should be replaced. Slight disruptions in electrical continuity will cause bloodsplash. Wet cords can also cause problems.

● Reduce electric prod usage. In a research trial, elimination of electric prods reduced bloodsplash (Calkins et al.,1980).

● CO2 stunning will reduce bloodsplash (Velarde et al., 1999). The disadvantage is that it is expensive to operate and it

requires well trained maintenance technicians.

Other Factors

Both PSE and bloodsplash will fluctuate with weather changes. Observations by the author indicate that PSE levels may double during the first 4 hot days of spring. Bloodsplash tends to worsen when temperatures fluctuate. It is very important to take weather into account when new methods for reducing PSE or bloodsplash are being tested. In one study, the amount of bloodsplash reduction benefit provided by new handling and stunning procedures greatly fluctuated, depending on the weather (Grandin, 1988). On some days, it provided great reductions in bloodsplash and on other days, almost no reduction. The procedures must be tested over a period of weeks to eliminate confounding effects of weather.

Bloodsplash can be reduced by the use of CO2 stunning (Velarde et al., 1999). Recent observations in a plant equipped with both state-of-the-art CO2 and constant amperage electrical stunning equipment indicated that PSE and bloodsplash levels were almost identical. CO2 definitely reduces bloodsplash compared to old-fashioned voltage regulated electrical stunning equipment. New CO2 stunning systems could provide handling advantages by eliminating the need to line pigs up in single-file chutes. However, there have been concerns about humaneness (Hoenderken, 1983). Some genetic lines of pigs react very well to CO2 and others may possibly be stressed. The Yorkshire breed reacts very well (Forslid, 1987), but stress-susceptible pigs may possibly be conscious during the initial excitation phase (Troeger and Waltersdorf, 1991). Therefore, CO2 may be an excellent method in a vertically integrated system where pig genetics could be controlled, but animal welfare may be poor for certain genetic types of pigs.

Conclusions

The biggest problem facing some segments of the industry is the emphasis on quantity rather than quality. Producers need to be provided with a marketing system that provides economic incentives to improve pork quality rather than just grow heavier pigs. In the 90's the "mind set" of a large segment of the United States pork industry was commodity based. The entire mind set of the industry needs to change from commodity-based to consumer-based. When this occurs, new procedures will be developed quickly. Fortunately, the industry has become more quality oriented and this has resulted in improvements in pig handling and changes in genetics.

Until this happens, nobody will be motivated to invest the time or the money to change systems.

References

Aalhus,J.L., Jones,S.D.M., Robertson,A.K.W., and Tong, Sather,A.P. (1991)

Growth characteristics and carcass composition of pigs with known genotypes for stress susceptibility over a weight range of 70 to 120 kg.

Animal Production 52: 347-353

Barton-Glade, P. (1985)

Developments in pre-slaughter handling of slaughter animals

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Blackmore,D.K., and Newhook,J.C. (1991)

Insensibility during slaughter of pigs in comparison with other domestic stock New Zealand Veterinary Journal 29: 219-222

Calkins,G.R., Davis,G.W., Cole,A.B., and Hutsell,D.A. (1980)

Incidence of bloodsplashed hams from hogs subjected to certain ante-mortem handling methods Journal of Animal Science (Suppl.1) 50:15 Abstract

Croft,P.S. (1952)

Problems with electrical stunning Veterinary Record 64: 255-258

Gariepy,C., Amiot,J., and Nadai,S. (1989)

Ante-mortem detection of PSE and DFD by infrared thermography of pigs before stunning

Meat Science 25: 37-41

Grandin,T. (1993)

Handling and welfare in slaughter plants

In: T.Grandin (Editor) Livestock Handling and Transport pages 289-311 CAB International, Wallingford, Oxon United Kingdom

Grandin, T.(no date)

PSE, the pork industry profit robber Livestock Conservation Institute Madison, Wisconsin

Grandin,T. (1993)

Environmental and genetic factors which contribute to handling problems in pork slaughter plants

Livestock Environment IV. American Society of Agricultural Engineers St.Joseph, Michigan pages 64-68

Grandin,T. (1989)

Effect of rearing environment enrichment on behavior and neural development of pigs

Doctoral Dissertation, University of Illinois Urbana/Champaign, Illinois

Grandin,T. (1988)

Effect of temperature fluctuation on petechial haemorrhages in pigs 34th International Congress of Meat Science and Technology CSIRO, Meat Research Laboratory, Cannon Hill, Queensland, Australia

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Grandin,T. (1985/86)

Cardiac arrest stunning of livestock and poultry

In: M.W.Fox and L.D. Mickley (Editors) Advances in Animal Welfare Science Martinus Nijhoff, Boston pages 1-30

Gregory,N.G.(1988)

Humane slaughter

34th International Congress of Meat Science and Technology Workshop on Stunning Livestock. CSIRO Meat Research Laboratory

Cannon Hill, Queensland, Australia

Hoenderken,R.(1983)

Electrical and carbon dioxide stunning of pigs for slaughter In: Eikelenboom,G.(Editor) Stunning of Animals for Slaughter

Martinus Nijhoff, Boston. pages 59-63

Forslid,A.(no date)

Transient neocortical, hippocampal and amygdaloid EEG silence by one minute inhalation of high concentration of CO2 in swine

Acta. Physiol. Scan. 130: 1-10

Malfors,G.(1982)

Studies of some factors affecting pig meat quality 28th European Meeting of Meat Research Workers

Madrid, Spain (pages 21-23)

Pederen,B.K., Curtis,S.E., Kelly,K.W., and Gonyou,H.W. (1993)

Wellbeing of growing finishing pigs: Environmental enrichment and pen space allowances

Livestock Environment IV.

American Society of Agricultural Engineers, St.Joseph, Michigan

Sayre,R.N., Briskey,E.J., and Hoekstra,W.G.(1963)

Effect of excitement, fasting and sucrose feeding on porcine muscle phosphorylase and postmordem glycolysis Journal of Food Science 28: 472-477

Sellers,H.I.(1993)

Porcine stress syndrome

Large Animal Veterinarian November/December (pages 6-8)

Smulders,F.J.M., Romme,A.M.T.S., Woolthuis,C.H.J.,et al.(1983)

Pre-stunning treatment during lairage and pork quality In: Eikelenboom,G.(Editor) Stunning of Animals for Slaughter

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Martinus Nijhoff, Boston (pages 90-95)

Troeger,K. and Waltersdorf,W.(1991)

Gas anesthesia of slaughter pigs Fleischwirtschaft International, 4: 43-49

Warriss,P.D. and Bevis,E.A. (1987)

Liver glycogen slaughtered pigs and estimated time of fasting before slaughter British Veterinary Journal 143: 254-260

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References Added October 2000 Update

D'Souza, D.N., R.D. Warner, F.R. Dunshea, B.J. Leury. 1998.

Effect of on-farm and preslaughter handling of pigs on meat quality. Aust. J. Agric. Res. 49:1021-1025.

Geverink, N.A., A. Kappers, E. Van de Burgwal, E. Labmooij, J.H. Blokhuis, and V.M. Wiegant. 1998.

Effects of regular moving and handling on the behavioral and physiological responses of pigs to pre-slaughter treatment and consequences for meat quality.

J. Anim. Sci. 76:2080-2085.

Grandin, T. (editor). 2000.

Livestock handling and transport, 2nd edition. CAB International, WAllingford, Oxon, UK.

Milligan, S.D., C.B. Ramsey, M.F. Miller, C.S., Caster, and L.D. Thompson. 1996.

Resting pigs, hot fat trimming and accelerated chilling of carcasses to improve pork quality. J. Anim. Sci. 76:74-86.

Monin, G., C. Larzul, P. LeRoy, J. Culioli, J. Mourot, S. Rousset-Akrim, A. Talmant, C. Touraille, and P.

Sellier. 1999.

Effects of halothane genotype and the slaughter weight on texture of pork. Journal of Animal Science, 77:408-415.

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Importance of halothane gene on muscle quality and preslaughter death in western Canadian pigs. Canadian Journal of Animal Science, 78:543-548.

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J. Anim. Sci., 74(supl. 1), p. 100.

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Causes of variation in pork quality. Meat Sci., 46:319-327.

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The effect of stunning method on the incidence of PSE and hemorrhages in pork carcasses. Meat Sci., 55:309-314.

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Livestock Handling Committee

Chairman: Temple Grandin, Grandin Livestock Systems

Livestock Conservation Institute

Proceedings of the 1988 Annual Meeting, Kansas City, Missouri

Environmental Enrichment for Confinement pigs

Livestock Conservation Institute 1988 Annual Meeting Proceedings

pages 119-123 1910 Lyda Drive

Bowling Green, Kentucky 42104-5809

Temple Grandin

Grandin Livestock Handling Systems Colorado State University

Fort Collins, Colorado 80526

Producers have been giving pigs toys for many years to prevent boredom, reduce vices such as tail biting, and help prevent aggression when pigs are mixed. Providing pigs with additional stimulation will make them calmer and less excitable. Pigs raised in a barn with a radio playing are less likely to startle when they hear a sound such as a door slamming. Calmer pigs are more likely to have better meat quality because they will be less likely to become excited on a high speed slaughter line. A series of experiments were conducted at the University of Illinois by the author, Stan Curtis, and Ian Taylor to learn more about the effects of environmental stimulation on pig behavior.

Toy Preferences

Pigs have definite toy preferences. If a ball rolls into the manure they will no longer play with it. This is why we used toys suspended from the ceiling. Then the young pigs are given a choice between hanging chains, cloth strips, and rubber hoses, the animals prefer the cloth strips and the hose over the chain. In a short term initial preference test, the cloth strip was preferred. In a week long preference test the hose was the preferred toy.

Soft pliable objects were definitely preferred over the hard chain. There were two different behaviors the pigs performed with the toys. The behaviors were chewing or jerking and shaking. They shook the toy like a dog tugging on a towel. The pigs seldom jerked or shook the chain. It probably hurt their mouths. Pigs will play with chains, but they prefer to play with pliable objects when they are given a choice. The pigs performed a wider variety of behaviors with the pliable objects.

Excitability

The purpose of the next series of experiments was to determine the effect of different environmental enrichments on behavior and handling of confinement reared, finishing pigs. All pigs were reared in a closed, environmentally controlled house. Landrace sired crossbred pigs were subjected to four different treatments during the last five weeks of finishing.

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The treatments were:

● Control -

People never entered the pens, but the pigs could see people in the aisle and in adjacent pens.

● Mingle -

a person entered the pens and gently petted the pigs for five to ten minutes once a week for five weeks.

● Drive - The pigs were driven in the aisle once a week.

● Toy - The animals were provided with continuous access to rubber hoses suspended from the ceiling for the last five weeks of finishing.

Some pens of pigs were subjected to combinations of the treatments.

In Trial 3, two different types of mingle treatment were used, an Assertive Mingle and a Gentle Mingle. In Assertive Mingle, the person petted every pig, even if it attempted to avoid the person. In Gentle Mingle, only pigs which approached were petted. The Gentle Mingle method was used in Trials 1 and 2.

All environmental enrichment treatments definitely reduced excitability. Animals that had a combination of two or more treatments were rated less excitable then animals with a single treatment. Excitability was measured on a 1 to 4 rating scale. Two raters entered each pig pen at the end of the trial. The rating was blind. The raters did not know which

treatments the pigs had been on. The higher the rating the more excitable the pigs. Pigs with a rating of 4 actively avoided the rater and piled up and squealed. Pigs with a rating of 1 were calm and often approached the rater.

Excitability Scores

Trial Control Mingle Drive Toy Mingle Drive Drive Toy Mingle Toy Mingle Drive Toy Trial #1 3.25 2.50 2.75 1.75 1.25 1.50 1.75 1.00 Trial #2 2.75 1.00 2.75 2.25 1.25 1.75 2.50 1.50

Trial Control Assertive Mingle Gentle Mingle Toy Assertive Mingle Toy Gentle Mingle Toy Trial #3 3.45 1.85 2.58 2.25 1.66 1.86

(Grandin, Curtis and Taylor, 1987)

Effect on Weight Gains

Some producers may be concerned that these treatments would stress the pigs and lower weight gains. This did not occur. None of the treatments had an effect on weight gains. It is of the utmost importance that the mingle and driving treatments are done gently. Our pigs appeared to "enjoy" the weekly walks in the aisle. They ran excitedly down the aisle. If animals

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feel threatened or intimidated weight gains will suffer. Australian scientist Paul Hemsworth found that inconsistent handling stressed pigs and reduced weight gains. If the handler occasionally slapped or shocked the pigs when he entered the pens, the animals became stressed each time he approached. Even if the handler is gentle and nice most of the time, the pigs learned that he is not to be trusted. How an animal perceives a situation during handling can have a big effect on stress levels. Procedures such as weekly weighing will usually have little effect on weight gain if the animals have learned that nothing bad is going to happen. Weekly weighing may have a detrimental effect on weight if the pigs see the "mean" man who shocked them with a prod. Most animals are smart enough to associate certain people with painful experiences. It is doubtful that baby piglets associate a particular person with castration. These animals are so young that the brain is probably too immature to store specific memory.

Stimuli which may initially frighten a pig can often become pleasurable. During pen washing the animals squealed and became excited the first few times. By the third or forth washing the animals appeared to eagerly anticipate pen washing. They approached and played in the water. Some turned broadside to get the full blast of the water.

Effect of Experience and Genetics

Some breeds or genetic lines within a breed will remain calmer in a barren environment than others. Both genetics and experience prior to finishing will effect how a specific finishing pig will react to enrichment. Hemsworth has also found that baby pigl ets which receive frequent gentle handling are still tamer weeks later. They are more likely to approach strange people.

The effect of toy, mingle and driving treatment on handling was tested on Landrace sired crossbred pigs. In the first trial, mingle and toy treatments reduced the force required to drive pigs through a chute. In the second trial, the controls were slightly easier to drive. The mingled pigs had become so tame that driving was difficult. The pigs used in the second trial were tame and calm before Trial 2 started. The pigs used in Trial 1 were more excitable than Trial 2 pigs at the beginning of the experiment. The animals in Trial 2 also received more frequent pen washing. This provided additional

environmental enrichment that commercial pigs do not receive.

There may be an optimal level of stimulation for animals that will be marketed for slaughter. You want a calm animal which will not panic and become excited, but on the other hand, you do not want an animal that is so tame that driving is difficult. This principle does not apply to breeding stock. Breeding stock benefit from lots of tender loving care. Tame sows and boars are easier to handle and have better productivity.

The amount of contact with people that will produce a calm, easy to drive market pig is going to vary. Genetic factors will interact with previous experiences. Pigs which are very excitable would require more contact with people in the pens than calm pigs. Most confinement reared finishing pigs would probably benefit from toys and a radio. Pigs differentiate between people in the aisle and people in the pen. For maximum effect the person must enter the pen.

Welfare Implications

Environmental enrichment procedures improve welfare. Many experiments have been conducted on the effect of sensory restriction on animal behavior and physiology. Dogs, rats, and other animals reared in a barren environment will become hyper-excitable. They will react strongly to small stimuli which would hardly be noticed by animals reared in a more enriched environment. Pigs raised in confinement buildings with little contact with people sometimes react in the same manner as the animals described in the sensory deprivation literature. I want to emphasize that only some confinement reared pigs have this problem, not all of them.

About thirty years ago, a number of sensory restriction, experiments were performed on young dogs by R. Melzack. The animals were placed in barren kennels. They could hear and smell other dogs. This was not total deprivation but a barren, restricted environment. The dogs became hyper-excitable, and they had abnormal brain waves. The brain waves were still abnormal six months after the dogs were returned to a household environment. Genetic factors also play a role. Some breeds or genetic lines within a br eed will become more excitable when subjected to sensory restriction than others. Simple environmental enrichment procedures will prevent pigs from showing the symptoms of sensory restriction.

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Playing a radio, with a variety of music and talk, in the barn will greatly reduce frenzied jumping about when a person enters the room.

Meat Quality

Environmental enrichment procedures have the potential of improving meat quality. Hot, excited pigs are more likely to have poor quality meat. Canadian research indicated that overheated pigs have a much higher incidence of DFD or PSE meat. Danish research and observations made by the author also indicate that gentle handling at the packing plant improves meat quality.

Observations at large slaughter plants indicate that some groups of confinement reared pigs are highly excitable and difficult to drive. Other groups of confinement reared pigs are easy to drive. Animals that are difficult to drive are more likely to be zapped with electric prods to keep them moving onto a high speed slaughter line.

Previous studies in Europe indicated that rearing environment had little effect on meat quality. The failure to find

differences is probably due to very gentle treatment at slaughter. In one experiment the pigs were slaughtered in groups of eight. If the pigs had been subjected to the stresses of a high speed line, there is a good possibility there may have been a difference. Paul Warris in England reported that confinement reared pigs were more excitable than the pigs reared outside, but the effect on m eat quality was minimal. Excitability will probably have little effect on meat quality if the pigs are slaughtered under optimal conditions, in a quiet meat laboratory or a small abattoir. Pigs slaughtered in commercial plans at 1000 per hour are subjecte d to rougher handling. Pigs which balk and refuse to move will receive more electric prodding.

There may also be an interaction between genetics and environment. Reducing excitability may have a greater effect on meat quality in some types of pigs compared to others. A. Fortin from Canada recently reported that the beneficial effects of rest prior to slaughter varies. Stress resistant pigs benefited more than the stress susceptible pigs. Overall, resting pigs for a few hours prior to slaughter will improve meat quality. The amount of improvement is going to vary greatly between different groups of pigs.

Conclusions

The development of simple economical environmental enrichment procedures can improve animal welfare and possibly improve meat quality by calming down excitable pigs.

Basic causes of animal welfare problems