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Close-up of pig looking through window like opening of truck with mud or fecal matter on her snout and face.

The journey to the slaughterhouse

An animal’s journey to the slaughterhouse is a very stressful process and can lead to her death during transit. While one could argue that death is inevitable because animals will die in the slaughterhouse anyway, the fact that they are so vulnerable to perishing en route gives us an idea of how terrible the conditions of the trip are and what they go through on the trip.

Some fatalities during transport occur due to the heat or to falls, but in many cases animals suffer fatal heart attacks brought on by the high level of stress as a result of the transport conditions.

In addition to the stress of an unfamiliar environment, animals face unique challenges during this time, including:

  • Weather conditions: heat, sun, cold and wind. The lack of ventilation can cause overheating of their enclosures;
  • A lack of food and water, which can lead to exhaustion, weakness, and dehydration;
  • Being forced to stay on foot for long periods of time, which can lead to great tiredness and fatigue;
  • Wounds and other physical harm from fights that can occur between the animals, due to the highly stressful situation;
  • Jostling associated with road travel, including potholes, traffic, the speed of the vehicle, and roundabouts;
  • Slips, bangs, and falls against the walls of the truck or the crates in which the animals are transported, which can cause wounds, internal hemorrhages, and broken bones;
  • Overcrowding of the animals, which can cause suffocation.

 

Birds

Birds (chickens, hens, turkeys, geese, ducks) are grouped together and put in crates where they have barely any room to move. The crates are piled on top of each other, so the animals that are in the lower and central parts of the truck suffer from much worse ventilation and from extensive overheating. Those who occupy the upper part will suffer more from being exposed to harsh weather conditions.

Breaks in leg, hip and wing bones are usually more frequent during transportation, principally during loading and unloading. Teams responsible for capturing and loading birds onto the truck are usually required to load about 1,000-1,500 animals per hour. The animals are usually caught by the limbs and rapidly put, sometimes thrown, in transportation crates, which often causes bone fractures and internal hemorrhages.1 The animals must continue their already painful journey despite these injuries.2 The extremities of the birds can also be damaged if they get trapped in an awkward position in the crates, causing injury and overall discomfort.

Egg-laying birds, principally those raised in battery cages, are the most likely to suffer from broken bones during transport.3 This is because they spend their entire lives confined in cages without the possibility of moving their wings or exercising their muscles, causing their bones to become weak and brittle.4 The poor living conditions results in a 26% death rate among hens5 and 15% among male chickens.6

The sheer quantity of animals dying during transport gives us an idea of what the experience during the journey to the slaughterhouse must be like. Stress is the biggest factor in the deaths of these animals during their journey. An estimated 47% of animal mortality cases are the result of cardiac failure and heart attack. Thirty-five per cent of cases can be attributed to trauma, including breaking or dislocating hips (76%), liver hemorrhages (11%), and blows to the head (8%).7 Various studies have noted the presence of high levels of stress hormones during the transport of the birds to their deaths.8

 

Sheeps

The loading and unloading and the initial moments of the journey are the most stressful part for sheeps.9 Loading requires close proximity with humans and this can scare the animals, who are not used to this kind of human contact.

As with birds, sheeps can be injured during the loading and unloading process due to the need to get the animals on and off the trucks quickly. Sheeps are often afraid during the process and will resist being loaded or unloaded. Sheeps are sometimes hit with electric prods, especially in sensitive areas, like the eyes, the mouth, the abdomen, or the genitals, to force them to move. Workers still sometimes catch hold of sheeps by their wool fleece in order to push them, which causes them pain and stress.10

It has been found that physical changes indicating stress during the journey occur mostly in the first few hours.11 This can be seen in the rhythm of an animal’s heartbeats. When under stress, a sheep’s heart rhythm can rise and remain elevated for a long time.12 The heart rate rises from 100 to 160 beats per minute when a sheep is loaded in a vehicle, and stays at that rate for at least 15 minutes. During transport, a heightened heart rate is maintained for at least 9 hours.13

Additionally, during long journeys, sheeps suffer from the effects of rapid weight loss due to not having the food and water they need and due to situational stress. After travelling for 15 hours, for example, sheeps lose between 5.5 and 6% of their body weight,11 and after 24 hours of traveling, 7 or 8%.14

 

Pigs

Like most animals, pigs are usually brought to the slaughterhouse in trucks. A medium sized truck can transport 230 pigs, but each pig has only half a square meter on average. This creates a highly stressful situation due to lack of space, leading to conflicts and aggressive behavior between animals due to the mixing of different families in tight conditions.15

Various studies have shown that, as for sheeps, the most stressful period in the journey for pigs is loading and unloading.16 A pig’s heart rate increases significantly while being loaded, descends gradually as soon as she becomes accustomed to being on the vehicle, then skyrockets again during unloading, indicating that both the loading and unloading are stressful processes.17

These changes in heart rate are the result of both physical efforts when the pig is forced to climb into the vehicle, and the psychological effects of being taken out of the pen. When a pig is removed from his pen, he is being taken from the only place that he knows to be taken to new surroundings and mixed with unfamiliar individuals.

Pigs have particular difficulty in going up ramps. There have been studies that have shown a rise in heart rate by a factor of 1.65 when they are forced to climb up a ramp. Workers usually use cattle prods or hammers to force them up the ramp and into the truck. The use of prods causes an additional increase in heart rate.18

Due to cross breeding, there is a recessive gene in pigs called ‘halotano’ that increases their susceptibility to stress. The pigs who have this gene will be especially susceptible and will feel greater anxiety during transport.

It is estimated that 170,000 pigs die each year, and 420,000 end up disabled due to injury caused during transport in the United States alone.19

 

Cows

Cows are usually transported on trucks or trains. They can be transported in pairs or groups. In a study of one journey lasting 24 hours, it was observed that cows transported in pairs (in crates) tend to collapse on the floor more quickly than those in groups.20 The movement of the vehicle can result in blows against the crates or animals falling on top of each other, causing injuries to their feet, hips or knees.

Adult cows prefer to stay on foot during the journey21 but they can lose their balance. Due to this, falls especially affect those animals found in the upper part of the vehicle. Furthermore, it is probable that many fall due to fatigue. Studies of cows weighing between around 1250 to 1300 pounds (570-600 kilos) show that they start to fall between the 14th and 16th hours of the journey, if they have enough room;22 but often they do not even have the space.

Calves also become very stressed during their transport, especially when they have been raised in individual cages rather than in pens, because of the crowded conditions and close contact with animals they don’t know. The combination of stressors that occur in the transportation to the slaughterhouse are exacerbated in calves who have been weaned just before being transported, due to the absence of milk and maternal care.23 Calves raised in small individual cages also display difficulties in going up truck ramps because their muscles are so atrophied from lack of movement.

Mixing cows and calves from distinct groups can lead to fights between them, making an already bad situation even worse.24


1 Gregory, N. G. & Wilkins, L. J. (1992) “Skeletal damage and bone defects during catching and processing”, in Whitehead, C. C. (ed.) Bone biology and skeletal disorders in poultry, Abingdon: Carfax, pp. 313-328. Gregory, N. G. (1998) Animal welfare and meat science, Oxon: CABI Publishing.

2 Newberry, R. C.; Webster, A. B.; Lewis, N. J. & van Arnam, C. (1999) “Management of spent hens”, Journal of Applied Animal Welfare Science, 2, pp. 13-29.

3 Gregory, N.G. & Wilkins, L.J. (1989) “Broken bones in domestic fowl: handling and processing damage in end-of-lay battery hens”, British Poultry Science, 30, pp. 555-562.

4 Knowles, T. G.; Broom, D. M. (1990) “The handling and transport of broilers and spent hens”, Applied Animal Behaviour Science. 28, pp. 75-91.

5 Swarbrick, O. (1986). “The welfare during transport of broilers, old hens and replacement pullets”, in Gibson, T. E. (ed.) The welfare of animals in transit, London: British Veterinary Association Animal Welfare Association, pp. 82-97.

6 Warriss, P. D.; Bevis, E. A.; Brown, S. N. & Edwards, J. E. (1992) “Longer journeys to processing plants are associated with higher mortality in broiler chickens”, British Poultry Science, 33, pp. 201-206.

7 Gregory, N.G. & Austin, S. D. (1992) “Causes of trauma in broilers arriving death to poultry processing plants”, Veterinary Record, 131, pp. 501-503.

8 Mitchell M. (1992) “Indicators of physiological stress in broiler chickens during road transportation”, Animal Welfare, 1, pp. 91-103. Freeman, B. M.; Kettlewell, P. J.; Manning, A. C. & Berry, P. S. (1984) “Stress of transportation for broilers”, Veterinary Record, 114, pp. 286-287.

9 Knowles, T. G. (1998) “A review of road transport of slaughter sheep”, Veterinary Record, 143, pp. 212-219.

10 Farm Animal Welfare Council (1994) Report on the welfare of sheep, London: MAFF Publications. Knowles, T. G.; Maunder, D. H. & Warriss, P. D. (1994) “Factors affecting the incidence of bruising in lambs arriving at one slaughterhouse”, Veterinary Record, 134, pp. 44-45.

11 Broom, D. M.; Goode, J. A.; Hall, S. J. G.; Lloyd, D. M. & Parrott, R. F. (1996) “Hormonal and physiological effects of a 15 hour road journey in sheep: comparison with the responses to loading, handling and penning in the absence of transport”, British Veterinary Journal, 152, pp. 593-604.

12 Parrott, R.F.; Hall, S. J. G. & Lloyd, D. M. (1998) “Heart rate and stress hormone responses of sheep to road transport following two different loading responses”, Animal Welfare, 7, pp. 257-267.

13 Parrott, R. F.; Hall, S. J. G.; Lloyd, D. M.; Goode, J. A. & Broom, D. M. (1998) “Effects of a maximum permissible journey time (31 h) on physiological responses of fleeced and shorn sheep to transport, with observations on behaviour during a short (1 h) rest-stop”, Animal Science, 66, pp. 197-207.

14 Knowles, T. G.; Brown, S.N.; Warriss, P. D.; Phillips, A. J.; Doland, S. K.; Hunt, P.; Ford, J. E.; Edwards, J. E. & Watkins, P. E. (1995). “Effects on sheep of transport by road for up to 24 hours”, Veterinary Record 136, pp. 431-438.

15 Shenton, S. L. T.; Shackleton, D. M. (1990) “Effects of mixing unfamiliar individuals and of azaperone on the social behaviour of finishing pigs”, Applied Animal Behaviour Science, 26, pp. 157-68.

16 Hall, S. J. G. & Bradshaw, R. H. (1998) “Welfare aspects of transport by road of sheep and pigs”, Journal Applied Animal Welfare Science, 1, pp. 235-54.

17 Bradshaw, R. H.; Parrott, R. F.; Forsling, M. L.; Goode, J. A.; Lloyd, D. M.; Rodway, R. G. & Broom, D. M. (1996) “Stress and travel sickness in pigs: effects of road transport on plasma concentrations of cortisol, beta-endorphin and lysine vasopressin”, Animal Science, 63, pp. 507-516. Christensen, L., Barton-Gade, P. (1996) “Design of experimental vehicle for transport of pigs and some preliminary results of environmental measurements”, Proceedings EU-seminar: New information on welfare and meat quality of pigs as related to handling, transport and lairage conditions, Mariensee, 29-30 June, pp. 47-67.

18 van Putten, G. & Elshof, W. J. (1978). “Observations on the effect of transport on the well being and lean quality of slaughter pigs”, Animal Regulation Studies, 1, pp. 247-271.

19 Vansickle, J. (2002) “Quality assurance program paunched”, NationalHogFarmer.com, Feb. 15 [accessed on 9 September 2012].

20 Lambooy E. and Hulsegge, B. (1988) “Long distance transport of pregnant heifers by truck”, Applied Animal Behaviour Science, 20, pp. 249-258.

21 Knowles, T. G. (1999) “A review of the road transport of cattle”, Veterinary Record 144, pp. 197-201

22 Tarrant, P. V.; Kenny, F. J.; Harrington, D. & Murphy, M. (1992) “Long distance transportation of steers to slaughter: Effect of stocking density on physiology, behaviour and carcass quality”, Livestock Production Science, 30, pp. 223-238; Knowles, G.; Warriss, P. D.; Brown, S. N. & Edwards, J. E. (1999) “Effects on cattle of transportation by road for up to 31 hours”, Veterinary Record, 145, pp. 575-582.

23 Trunkfield, H. R.; Broom, D. M.; Maatje, K.; Wierenga, H. K.; Lambooy, E. & Kooijman, J. (1991) “Effects of housing on responses of veal calves to handling and transport”, in Metz, J. H. M. & Groenestein, C. M. (eds.) New trends in veal calf production, Wageningen: Pudoc, pp. 40-43.

24 Mench, J. A.; Swanson, J. C. & Stricklin, W. R. (1990) “Social stress and dominance among group members after mixing beef cows”, Canadian Journal of Animal Science, 70, pp. 345-354.

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