**9. Using farm animals for experimental purposes**

In many countries, laboratory animals (mainly rodents) but also farm animals (mainly horses, cattle, sheep and goats) are used in research, testing and teaching.

Experiments conducted on farm animals may cause pain which ought to be eliminated or reduced to minimum for ethical and scientific reasons.

The suffering associated with surgical procedures may be prevented with the use of local anaesthetics. Most of them, if injected or inhalated, have an effect on physiological functions of animal body which may distort the results of an experiment, but this is also true for the pain which triggers stress reaction. The experiments may be performed without anaesthesia only in exceptional cases, when it is necessary from the scientific point of view.

Reliable results of experiments on farm animals are largely dependent on the standardisation of the factors affecting physiological reactions of these animals and on the broad idea of their wellbeing. The main factors influencing the quality of experiments conducted on farm animals include: their biological status (sex, age, body mass); health condition; nutrition; maintenance conditions; animal headquarters (ventilation, temperature, humidity, lighting, noise); exposure to stressogenic stimuli; proper care; the choice of appropriate experimental techniques. Meeting these requirements allows to obtain repeatable, reliable results of experiments and to create proper living conditions.

Experiments conducted on animals often require blood sampling. It is important to safeguard the welfare of farm animals from which blood is harvested for research purposes. Contemporary animal welfare requirements are more stringent than they have been in the past, and it is appropriate that there should be guidelines to protect the welfare of animals used in blood harvesting operations.

For the research purposes, blood harvesting usually implicates the removal of a relatively large volume of blood over a short period of time, i.e. more than would usually be required or routine diagnostic tests.

It is in the interests of good science as well as the welfare of the animals used that stress on the animals is kept to a minimum. If the process of harvesting is stressful for the animal because of handling, pain or discomfort, physiological changes occur which may compromise the quality of the scientific result obtained.
