Loading and unloading pigs for transport is stressful, since this may be a novel situation for the pig (Grandin 1997). Pigs have evolved to treat novel situations as dangerous (Grandin 1997). Their reaction will also be influenced by previous experience and genetics (Grandin 1997). If pigs have not been exposed to regular human contact, attempts to load them will be met with resistance. The way to overcome this, is to gradually introduce pigs to the idea of being loaded and unloaded through consistent contact with barn personnel. Tame animals that are used to close contact with people are usually less stressed by handling (Grandin 1997).
Researchers from the Netherlands examined the effects of regular moving and handling during the finishing period on behaviour and meat quality (Geverink et al. 1998). One hundred and forty-four pigs in the study were exposed to one of three treatments (48 per treatment). Handling treatments were applied over 10 sessions, two times per week beginning when pigs were 15 weeks of age.
The Environment Treatment
This involved regular exposure to an environment other than their home pen, followed by transport in a box. Pigs were allowed to voluntarily exit their pen and spend some time in a new space (7x1 m). After eight minutes, pigs were gently moved, using boards, into a transport box on wheels. The box was driven for two minutes. After two minutes, the pigs were unloaded, again using boards. The critical point here is that at all times pigs were separated from the human handlers with boards there was no direct human to pig contact.
The Handling Treatment
This treatment involved extensive human-pig contact beginning at 15 weeks of age. Handlers spent time squatting in the pen, stroking and petting pigs when they approached the handler and initiated contact. Handlers walked through the pens for one minute and subsequently held each pig in a tight grip for about five seconds. These procedures were designed to represent both positive and negative (but not harmful) handling experiences.
No contact with humans apart from that received during routine husbandry, such as feeding and cleaning.
When the pigs were 25 weeks of age, they were transported to a commercial slaughterhouse. Pigs from the three treatments were observed during loading and the following data recorded:
- Latency time for each pig to leave the pen.
- Latency time for each pig to enter the transport box.
- Behaviour during transport (videotape).
The data indicated that during the treatment the "environment" pigs left the pen more quickly (Figure 1) and were quicker to load on the last day (Geverink et al. 1998). The researchers concluded that pigs that are exposed to this type of activity repeatedly are easier to load - making transportation easier for both the pig and the stockperson.
Figure 1. Mean latency time ± SEM to leave the pen voluntarily during the 10 sessions of the Environment treatment (adapted from Geverink et al. 1998).
The general trend of the graph shows a decrease in mean latency time ± SEM from session one through session ten.
Surprisingly, the pigs from the handling group took about as long to load as the control group, suggesting that the handling group pigs had become too tame to easily move (Geverink et al. 1998).
The challenge for producers is how to realistically accommodate "simulated" loading and unloading activity in your day to day operation. If you are a producer who has discovered a way to habituate pigs to transportation through regular moving, I would like to hear from you.
Geverink, N.A., Kappers, A., van de Burgwal, J.A., Lambooij, E., Blokhuis, H.J. and E.M. Wiegent. 1998. Effects of regular moving and handling on the behavioral and physiological responses of pigs to preslaughter treatment and consequences for subsequent meat quality. J.Anim. Sci. 76:2080-2085.
Grandin, T. 1997. Assessment of stress during handling and transport. J.Anim. Sci. 75:249-257.
By Penny Lawlis - Animal Care Specialist/OMAFRA
Government of Ontario Ministry of Agriculture, Food and Rural Affairs