There are many different definitions of the concept of animal welfare. However, it is widely accepted that animal welfare includes both the physical and the mental health of animals. The so-called "Five Freedoms" provide a useful framework to assess animal welfare and has been widely used in a variety of animals, including dogs and cats.¹ According to the principle of the "Five Freedoms", animal welfare is satisfactory when the following five requirements are met: freedom from prolonged hunger, thirst and malnutrition; freedom from pain, injury and disease; freedom from thermal and physical discomfort; freedom to express most normal patterns of behaviour, and freedom from fear or distress. One of the problems with the principle of the "Five Freedoms", however, is that it does not mention positive emotions and these are a clearly important aspect of animal welfare. Indeed, long-term animal welfare should be seen as the balance between positive and negative emotions. This is reflected in the concept of "Quality of Life", which refers to how an animal feels about its life.^2,3,4

Animal welfare should be assessed using a combination of different indicators and these can be conveniently divided into animal-based and resource-based indicators. Although each of these two categories has its own advantages and disadvantages, animal-based indicators provide direct information on the state of the animals and are therefore preferred by most animal welfare scientists. Animal-based indicators include body condition, health records, physiological parameters and, most importantly, behavioural measures. Although physiological parameters are commonly used in research, they are not very useful in practice and will not be covered here.

Obesity, which is a prevalent problem in both dogs and cats,⁵ is a good indicator of poor welfare as it increases heat intolerance and the risk of several diseases, including osteoarthritis, which is a major cause of pain in dogs and cats. In fact, several studies carried out in different species including dogs and cats have shown that a restriction in food intake increases life span and delays the onset of different chronic diseases.⁶

Although all diseases can be considered a welfare issues, those that cause pain or other negative emotional states, those that interfere with normal behaviour and those that are more likely when animals are in a negative emotional state are particularly relevant in terms of welfare assessment. Pain is indeed one of the main welfare problems in dogs and cats, chronic pain being particularly important. Pain assessment should be based primarily on behavioural changes. Behavioural signs of pain include decreased ambulation and general activity, decreased appetite, changes in the time spent grooming, aggression, fear reactions, inappropriate elimination, vocalization, decreased interaction with other pets or with family members, altered facial expression and posture, restlessness, apathy and hiding. A detailed knowledge of the behaviour of each individual animal is necessary to assess pain and owner assessment may be very useful, particularly to assess chronic pan.

Behavioural indicators of welfare which are not directly related to pain include, among many others, aggressive behaviours, fear or anxiety-elated behaviours and repetitive behaviours. Aggressive behaviour is very often related to a negative emotional state such as pain, fear or stress. Moreover, aggression disrupts the human-animal bond, which may decrease animal welfare even further.

Fear and anxiety are negative emotional states and therefore all fear and anxiety-related behavioural problems should be considered as indicators of poor welfare. Separation anxiety is particularly important from an animal welfare standpoint, not only because of its high prevalence, but also because a vast majority of owners of dogs with separation related behaviours do not seek professional advice. Dogs with separation anxiety have been shown to have a negative cognitive bias, which adds to the detrimental effects of separation anxiety on dog welfare.

Repetitive behaviours can be caused by a variety of causes but it is thought that chronic stress and behavioural restriction (i.e., the inability to perform important, highly motivated behaviours) play an important role in the development of these behaviours. Additionally, animals that have been exposed to stressful environments early in life may be more predisposed to develop repetitive behaviours when adults.

Several strategies can be used to increase the welfare of companion animals, environmental enrichment being one of them. One of the aims of environmental enrichment is to increase the animal's perception of control over their environment. These can be achieved by increasing the predictability of aversive stimuli and providing hiding places to increase the animal's perception of control over its environment.^7,8 Another objective of environmental enrichment is to allow animals to express their natural behaviour, particularly those behaviour patterns with a strong motivation or with positive effects on the animals' emotional state. Therefore, a detailed knowledge of the biology of the species and the motivational basis of behaviour are needed when planning an environmental enrichment program.

Some behaviours are positive welfare indicators as they reflect a positive emotional state. Although there is a need for further research on the positive emotions of animals, it is widely accepted that play and affiliative behaviours are likely to be good indicators of positive welfare.

References

1.  Farm Animal Welfare Council. FAWC updates the Five Freedoms. Vet Rec. 1997;17:357.

2.  Dawkins MS. Through animal eyes: what behaviour tells us. Appl Anim Behav Sci. 2006;100:4–10.

3.  Boissy A, Manteuffel G, Jensen MB, et al. Assessment of positive emotions in animals to improve their welfare. Physiol Behav. 2007;92:375–397.

4.  Webster J. Animal Welfare: Limping Towards Eden. Oxford, UK: Blakwell; 2005.

5.  Lusby A, Kirk AC. Obesity. In: Bonagura JD, Twedt DC, eds. Kirk's Current Veterinary Therapy XIV. St Louis, MO: Saunders Elsevier; 2009:191–195.

6.  Kealy RD, Lawler DF, Ballam JM, et al. Effects of diet restriction on life span and age-related changes in dogs. J Am Vet Med Assoc. 2002;220(9):1315–1320.

7.  Fontayne R, Vervliet B, Hermans D, Baeyens F, Vansteenwegen D. Reducing chronic anxiety by making the threatening event predictable: An experimental approach. Behav Res Ther. 2009;47:830–839.

8.  Grillon C, Baas JP, Lissek S, Smith K, Milstein J. Anxious responses to predictable and unpredictable aversive events. Behav Neurosci. 2004;118(5):916–924.