I have written a number of blog entries on the animal welfare research projects we are conducting through the Detroit Zoological Society’s Center for Zoo Animal Welfare, and how collaborations enable us to move forward with many of the initiatives we undertake. Let’s now go back to the basics and explore what animal welfare is, how we go about evaluating the welfare of individual animals, and why this is fundamentally important.
The Association of Zoos & Aquariums’ Animal Welfare Committee defines animal welfare as an animal’s collective physical, mental and emotional states over a period of time, and is measurable on a continuum from good to poor. Although there are a number of other definitions available, the main factors remain consistent: Welfare is measured at the level of the individual animal, it encompasses all aspects of an animal’s life, and it can change over the course of time. The goal for anyone working with and around animals is to ensure that they each experience good welfare.
Going back many decades, people have long been concerned with the welfare of animals. In the 1960s, the Five Freedoms model was developed, originally as a means to assess the welfare of farm animals. This model states that animals should experience freedom from thirst, hunger and malnutrition, freedom from discomfort, freedom from pain, injury and disease, freedom from fear and distress, and freedom to express normal behavior. Since its initial development, this model has been applied in a variety of settings, including in zoos. However, the Five Freedoms model can be improved upon, as it is focused on minimizing negative states rather than also promoting positive welfare. Additionally, some of what is stated can be counter-productive to an animal’s survival. For example, if an animal never experiences thirst, then it may never drink, and this would not be a good thing. Therefore, the absolute freedom from some of the experiences is not even feasible. Rather, the important factor is ensuring that the resources necessary to perform the associated behaviors are available.
More recently, the Five Domains model was created, which delineates how nutrition, physical health, behavior and the environment (both physical and social) feed into an animal’s emotional state. The outcome is the individual’s welfare status. For example, if an animal is hungry but does not have access to food, this will result in a feeling of hunger, which will be a negative factor in the overall welfare status of that animal. If an animal is able to express natural behaviors, he or she will experience satisfaction, which is a positive emotion and contributes to positive welfare. All physical influences are taken into consideration as well as how they impact the internal, emotional state of the animal, in order to assess overall well-being.
Assessing welfare is a complex process that requires an understanding of the needs of a species and an individual as well as experience with scientific methods. It also typically includes multiple types of measures such as behavioral and physiological indicators. One can begin by evaluating what is made available to an animal, such as the physical space, the type of food presented and the social opportunities provided. This kind of assessment is known as a resource-based assessment, as it focuses on what we provide to the animals. To truly understand how an animal is faring, however, we also need to understand how they respond to their environment, and as such, conduct animal-based assessments. In our case, we usually observe how animals are interacting with their physical environment, with one another if they are a social species, and we utilize various physiological measures such as body condition, overall health and even hormone levels.
In order to ensure animals living in zoos are thriving, we need to understand what matters to them and that requires us to figure out how to “ask” them. Using existing methods and developing new ones to assess welfare is critical if we are to make evidence-based decisions for caring for animals. By letting animals tell us what is working and what needs to be improved, we are making their welfare a priority, and this is the ultimate responsibility we have to each and every animal living in the care of humans.
– Dr. Stephanie Allard is the director of animal welfare for the Detroit Zoological Society and oversees the Center for Zoo Animal Welfare.