Indicators (also referred to as criteria) for assessing well-being can vary and can be divided into several groups: physiological, behavioural, health, production and others.
The physiological indicators used to assess welfare in animals are:
- heart rate, respiration, body temperature,
- blood pressure,
- ECG, EEG,
- haematological indicators,
- biochemical indicators (glucose, urea, enzymes, acute phase proteins),
- immunological indicators,
- hormone levels (catecholamines, cortisol).
Animal behaviour (behavioural indicators) is the most authoritative source of information on the degree of tolerance of environmental conditions. The evaluation here consists of observing the animals’ behaviour under specific environmental conditions or situations. The quantitative and qualitative assessment of deviations of behavioural responses from the norm provides an important indication of the need for change. The more individuals manifest advanced pathological states, the more urgent it is to make specific changes to the animal environment.
Behavioural reactions are often the only adaptive responses to the environment, but they often accompany stress reactions. Stress, depending on the stressor and the form of stress (acute, chronic), is also an important criterion for assessing animal welfare. An animal under stress has to adapt its physiological or behavioural responses in order to stay alive in a clash with adverse environmental conditions. The environment influences the animal’s behaviour, so it should be calm and not generate additional stress. Stress responses depend on the sensitivity of the species and the duration and intensity of the stress factor. Under conditions of high animal concentration in a confined space, lack of movement, removal of some animals and re-grouping – and above all the inability to express the behavioural traits of the species – the impact of such a condition not only on the quantity and quality of the product obtained, but also on the health of the animals, becomes apparent. Very often, the animals do not want to consume the feed, which leads to lower production and the occurrence of diseases, including infectious ones. It is therefore important to take care of the animals during all technological operations, to comply with zootechnical standards and sanitary requirements for animal hygiene.
Animal health is one of the criteria for assessing welfare and is assessed according to a set scale, i.e. from very good health to very poor health (presence of diseases). Poor health always implies inadequate welfare, whereas good health may be accompanied by a reduced level of welfare, which may one day result in a significant deterioration of health. In addition, the traumatisation and failure of equipment, the use of materials that are inhospitable to animal health or even toxic, as well as faulty functional solutions in livestock buildings, or negligence in prevention and prophylaxis, always pose a serious threat to animal welfare.
Production (zootechnical) welfare indicators are monitored in practice by breeders and producers. These include the appearance and condition as well as the performance and reproduction of the animals. Emaciation, poor condition of the skin, coat, plumage, lameness and mutilations are indicative of inadequate welfare, as are reduced fertility and prolificacy, or a decrease in the unit productivity of the animals. On the other hand, potentially very good condition may be the result of a lack of exercise and so will not always be evidence of full welfare.
The most commonly used production indicators are: body weight, daily weight gain, weaning weight, feed intake (FI), feed conversion ratio (FCR), length of life, etc. High performance can sometimes also be achieved with deteriorated welfare, which generally has a negative impact on the length of service life. Often, among the indicators related to productivity, the area for animals and the quality of bedding are taken into account. This is a very simple indicator for practical evaluation and at the same time gives objective information on animal welfare.