Animal welfare is the viewpoint that animals should not suffer unnecessarily, and basic needs should be met. The suffering and satisfaction of an animal cannot be measured directly, but the consequences of various causes of suffering and satisfaction can be compared in numerous ways. For example, welfare scientists discovered that it’s more physiologically stressful for a lamb to have its tail docked with a knife than with a rubber ring (Lester, Mellor, Holmes, Ward, Stafford 1996). There are three components of animal welfare. Welfare science considers human effects on animals from the animals’ point of view. Ethics concerns human actions towards animals. Legalization considers the treatment of animals from humans. There are three concepts of animal welfare. Physical status (fitness) suggests that when physiological systems cause survival or reproduction to be impaired, an animal has a poor state of welfare.
An experiment on pregnant pigs in individual cage stalls was carried out. The experiment showed the design of cage stalls could affect the welfare of pigs. Pigs housed in stalls comprised of horizontal bars showed evidence of chronic stress response of an enormity sufficient to adversely affect the welfare and active avoidance by neighbouring. Pigs housed in stalls comprised of vertical bars showed the highest levels of aggression (Barnett, Hemsworth, Cronin, Newman, McCallum 1991). Mental status suggests that neither health, lack of stress or fitness is sufficient to determine that an animal has good welfare. An animal’s feelings are a major factor. Naturalness suggests that welfare also considers nurturing and accomplishment of an animal’s nature. An experiment was carried out studying the behaviour of pigs in social family groups, in the natural environment of a Scottish woodland. An artificial pig park was created that provided sufficient environmental resources to allow the behaviour of pigs kept for farming purposes.
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The key aim was to fabricate an environment that allowed the pigs free expression of natural behaviour within the confines of a model farm (Stolba &Wood-Gush, 1989). A set of rules called the Five Freedoms were set to understand animal welfare and to put these understandings into practice. The five freedoms stated below form the basic philosophy of the UK Farm Animal Welfare Council (FAWC, 1993). The Five Freedoms are:
- Freedom from thirst hunger and thirst,
- Freedom from discomfort,
- Freedom from pain, injury and disease,
- Freedom to express normal behaviour,
- Freedom from fear and distress.
Need is a requirement, fundamental in the biology of the animal, to obtain a particular resource or respond to a particular environmental or body stimulus (Broom & Johnson, 1993). Therefore this suggests that physiology or behaviour can be affected if a need is not provided for. Some needs can be more significant than others. In terms of legalization, an owner of an animal should have sufficient experience and scientific knowledge of an animal under their care. The animal’s physiological and ethological (behaviour) needs should be taken into account. Death is relevant to welfare when considering the manner used. For example the importance of slaughter methods. Poor welfare conditions can be associated with high death rates, for example, poor husbandry conditions can lead to diseases.
A change in an animal’s welfare can cause a change in physiological responses. There are two types of responses, the Autonomic Nervous responses and the Neuroendocrine responses. The Autonomic Nervous System (ANS) consists of the Sympathetic Adrenal Medullary system (SAM) and the Parasympathetic Nervous system (PNS). In the SAM system, an increase in cardiac output leads to an increase in heart rate and cardiac muscle contraction. The intake of air will increase causing respiratory rate and bronchiole relaxation to increase. The PNS system regulates the SAM system. During this system, cardiac output reduces therefore so does the heart rate. The heart rate can indicate a change in welfare. The heart rate may increase due to an animal preparing an active response. The heart rate may decrease due to the animal becoming motionless. A change in blood pressure can also be a measure of physiological behaviour. The respiratory rate is a good observation of the present state as it can easily be observed, and is also closely linked with heart rate.
A change in welfare has an effect on three sub-divisions of the NS. The three sub-divisions are the Hypothalmic-Pituitary Adrenal Axis (HPA), Anterior Pituitary and Posterior Pituitary. The HPA is a major advocate of endocrine responses. The HPA increases immobilization of energy stores for a physical response and mediates responses to food arrival, stress and other factors. The HPA is not as instant as the SAM. It is a measure of acute welfare changes in the blood. An experiment was carried out on mixed pigs to see if it was better to slaughter the pigs as soon as they arrived at the abattoir, or to keep them in the lairage for 3 hours first. The cortisol and lactate levels were considerably higher when pigs were slaughtered straight away. Cortisol would have indicated generalized stress, it was concluded that during the period of rest the stress levels of the pigs reduced (Warriss, Brown, Nute, Knowles, Edwards, Perry, Johnson 1995). Another indicator of welfare can be seen by assessments of behaviour.
To avoid suffering and gain pleasure an animal is motivated to behave in a way to maintain a balance. Measurement of motivation can be seen through preference tests that provide information about the choice or preference of an animal. The amount of work carried out portrays how important a reward can be for them. The strength of motivation is a measure of how much the need for animals matters. A hen may be required to work more by possibly walking further and further to reach the desired target such as a nest box. It has been established that the motivation of hens to seek a nest box to lay their eggs is almost independent of the amount of work they must execute to achieve it (Webster 2005). Animal behaviour should be observed in their natural environment, and also in a restricted environment. An experiment carried out investigated the social preferences and separation stress in dairy calves.
They concluded that calves seem to prefer a familiar calf to an unfamiliar calf, and the presence and familiarity of a companion calf affects the calves’ reaction to separation (Faerevik, Jensen, Boe 2005). An animal spends time behaving constructively to avoid suffering and gain pleasure in a suitable environment. When the opportunity to control the environment is denied, suffering often occurs due to frustration. Stereotypical behaviour can be described as “Repetitive, invariant performance of an activity that is apparently purposeless because it is not directed towards any obvious reward” (Webster 2005). This type of behaviour is often seen as a mechanism to deal with frustration resulting from time spent in a barren environment. An experiment was used to measure the motivation of Clethrionomys glareolus in selecting an enriched environment in preference to a barren environment, following long-lasting confinement in barren cages. Some animals had developed stereotypic ‘looping’ behaviour, which is similar to turning somersaults as a result of confinement. These showed a decrease in motivation to seek environmental enrichment when it was offered (Cooper & Nichol 1991). This showed the relationship between the progression of stereotypic behaviour and the prolonged denial of environmental enrichment.
- Barnett, J.L., Cronin, G.M., Hemsworth, P.H., McCallan, T.H and Newman, E.A. (1991). Effects of design of individual cage stalls on the behavioural and physiological responses related to the welfare of pregnant pigs. Applied Animal Behaviour Science 32, 23-33.
- Boe, K.E., Faerevik, G., Jensen, M.B. (2005). Dairy calves social preferences and the significance of a companion animal during separation from the group. Applied Animal Behaviour Science 99, 205-221.
- Cooper, J.J. and Nichol, C.J. (1991) Stereotypic behaviour affects environmental preferences in bank voles Clethrionomys glareolus. Animal Behaviour, 41, 971-77
- Lester, S.J., Mellor, D.J., Holmes, R.J., Ward, R.N. and Stafford, K.J. (1996) Behavioural and cortisol responses of lambs to castration and tailing using different methods. New Zealand Veterinary Journal 44, 45-54.
- Stolba, A. and Wood-Gush, A.D.M. (1989) The behaviour of pigs in a semi-natural environment. Animal Production, 48, 419-25.
- Warriss, P.D., Brown, S.N., Nute, G.R., Knowles, T.G., Edwards, J.E., Perry, A.M. and Johnson, S.P. (1995) Potential interactions between the effects of preslaughter stress and post-mortem electrical stimulation of the carcasses on meat quality in pigs. Meat Science 41, 55-68.
- Webster, J. (2005). Animal Welfare limping towards Eden. Blackwell publishing.