Vehicle Motion And The Welfare Of Animals During Transport
Animal transport is an issue gaining increasing attention from animal welfare advocates. Currently, a campaign against the live export of animals from Australia is gaining momentum, and The Save Movement has been looking at animal road transport for years. It’s an issue that we’ve covered on Faunalytics, and our library has numerous articles on the subject. However, for the most part, research and advocacy tends to focus on the subject from the angle of transport times, ambient temperature, and overt injuries.
This review article looks at the subject from a different angle, and examines previous research on motion sickness and its implications for farm animal welfare during ship and road transport. The number of animals raised globally for consumption and export per annum has increased substantially over the last five decades, from 2.6 to 36.5 million pigs, 6.5 to 15.2 million sheep, and so on. Researchers have tended to ignore motion sickness as a welfare issue for these animals: despite the scale of the issue, researchers have mainly been occupied with studying motion sickness in animals for human benefits, e.g. experiments with animals to study space motion sickness. However, motion sickness has been demonstrated in a range of species, including humans, pigs, fish, rats and birds. The only species believed to be incapable of experiencing it are some lower vertebrates.
Indicators to evaluate motion sickness’ impact on welfare
Human and non-human animals show similar gastrointestinal symptoms and clinical indicators associated with motion sickness, including hypersalivation, pica (craving for and consumption of non-nutritive substances) nausea, defecation and vomiting. In humans, researchers have used heart rate monitors to evaluate motion sickness, as it increases during nausea. However, all of the physiological responses listed above can also be used as indicators to evaluate motion sickness’ impact on animal welfare.
Sheep have been observed to show active coping behaviours during transport, such as teeth grinding and pawing at the ground, because they were stressed by vehicle movements and lack of food and water. Pigs has also exhibited motion sickness-related behaviours, including foaming, chomping, retching and vomiting. While these behaviours can also be the result of food withdrawal and negative emotions, such as anxiety and fear, they all have implications for animal welfare.
Postural balance and sea transportation
One theory of motion sickness, the postural instability theory, emphasizes that “environments that generate a prolonged postural instability will produce motion sickness.” When animals are transported, they are not always able to stop interactions with their environment. They experience uncontrolled movements, losses of balance and can’t maintain their posture, which cause them stress and, potentially, motion sickness. One study found that lambs transported on rough roads where more stressed (i.e. had higher blood cortisol concentrations and heart rates) than those transported on highways.
To avoid postural instability (and thereby motion sickness) during road transport, orientation and space allowance is important for the animals. However, researchers have not been able to identify an ideal space allowance to minimise loss of balance. In terms of sea transport, there has been little research on how it affects the animals, even though it produces body instability and could conceivably cause motion sickness, as much or more than road transport.
All in all, research establishes that motion sickness affects animals during road and sea transportation, and undeniably plays a role in their welfare. Still, little-to-no research has been carried out on the topic to avoid or lessen the impact it has on the animals. For animal advocates, this study serves as a call for action, to continue to advocate for reforms to animal transport that affect the welfare of millions of individuals every year. Though animal transport by road and sea may not be eliminated in the short-term, there are a variety of ways forward that can help animals immediately.