The 2020 Five Domains Model

The Five Domains Model is a comprehensive, systematic framework for assessing the welfare of animals. It was developed by Emeritus Professor David Mellor over three decades, in collaboration with other academics and animal welfare researchers.

Emeritus Professor David Mellor began thinking differently about animals and their welfare while studying a Bachelor of Science at the University of New England, Australia. His unique and integrative approach was recognised with a First Class Honours, and the 1966 University Medal.

Prof. Mellor went on to obtain a PhD in perinatal physiology (perinatal being the time immediately before and after birth) at the University of Edinburgh, and has dedicated his career to understanding scientifically, the experiences of animals under different conditions. This was revolutionary at the time and eventually, led to the development of the Five Domains Model.

From its first formal appearance in 1994 as a Model for predicting the impact of procedures on animals used in research, to being adopted worldwide as the most comprehensive and applicable animal welfare assessment and monitoring framework, the Five Domains Model has undergone many revisions and updates; it has evolved as the scientific knowledge has improved.

The Mellorater was developed to apply the most up-to-date version: The 2020 Five Domains Model for Animal Welfare Assessment and Monitoring.

The Five Domains refer to five areas of an animal’s life that are known to influence their physical and mental welfare.

• In Domain 1 we consider the animal's nutrition and hydration; what they eat and drink, how they do so, and the experiences that are associated with feeding and drinking.

• Domain 2 is for the (external or physical) environmental conditions and the experiences associated to the physical environment.

• Domain 3 is for the experiences associated with the animal's state of health and fitness.

Domain 4 prompts us to focus on how the animal interacts with their surroundings and other animals, including humans, and includes three categories (a, b, c):

• Domain 4a refers to how the animal interacts with and uses the spaces available to them.

• Domain 4b considers how the animal interacts with other non-human animals, whether they are of the same or different species.

• Domain 4c is dedicated to evaluating the welfare impacts of their interactions with humans.

The subdivision of Domain 4 was the main focus of the 2020 review of the Five Domains Model. It helps drill down to the animal's behavioural interactions in much more detail.

Domain 5 is the crucial one, mental state. It is meant to capture whether the conditions the animal is in and their interactions with their life-world are giving rise to negative or positive experiences. The mental or affective state is used to determine the horse’s welfare state - on a spectrum between poor and good.

As a rule of thumb, when an animal cannot resolve negative experiences in a timely manner (before they intensify and become debilitating or chronic) they will tend to be in a negative mental state, which is considered a state of poor or compromised welfare. In this state, they may be unable to benefit from any enhanced welfare opportunities.

In contrast, when the animal can avoid or resolve negative experiences in a timely manner, and they are benefiting from a very wide range of positive experiences, they will tend to be in a positive mental state, which is considered a state of good or enhanced welfare.