In the design of a research protocolResearch protocol A description of the design of the study., thought must be given to the implementation of humane endpointsHumane endpoint The moment in the experiment at which pain and/or distress experienced by the investigational animal is ended or alleviated by either killing the animal humanely or by discontinuing the procedure.. Information pertaining to this issue should be laid down in the protocol and should include the following points of consideration:

• the clinical course, including any critical aspects thereof, and any anticipated discomfortDiscomfort A state of pain and distress in laboratory animals./painPain The negative sensory or emotional experience that indicates awareness in the animal of injury or the threat of injury to the body. This negative experience induces changes in an animal’s behavior and physiology, intended to limit the effect of, or avoid the injury, to reduce the chances of repeated injury and to promote recovery.;
• observation frequency and registration of findings;
• the humane endpointHumane endpoint The moment in the experiment at which pain and/or distress experienced by the investigational animal is ended or alleviated by either killing the animal humanely or by discontinuing the procedure. and the parameters underlying the establishment of this humane endpoint;
• the responsibilities with respect to observation and treatment/euthanasiaEuthanasia Killing by applying methods that rapidly lead to unconsciousness and death without pain or discomfort to the animal. Methods for euthanasia can be divided into mechanical and physical.;
• the type of treatment/euthanasia;
• autopsyAutopsy The examination of an animal’s internal and external organs after death. For a quality autopsy, the animal must be examined shortly after its demise or it has to be well-preserved up to examination..

Should there be any doubt as to the (clinical) progression of the illness or about the parameters for determining the humane endpoint, then conducting a pilot studyPilot study A small-scale experiment that is carried out in advance of the main investigation to test experimental methods and determine an animal’s responses, such as dose response, or adverse effects. Also called: pilot experiment / pilot test/ pilot. with a limited number of animals is recommended.

Responsibility

Prior to the start of an animal experiment, all staff directly involved need to be accurately informed about the critical periods in the experiment. In this matter, the initiative lies with the principal investigator. All personnel must be knowledgeable about the following aspects:

• normal behavior and physiology of the animal;
• anticipated deviations from the norm in the proposed procedure;
• the moment at which a humane endpoint will be decided;
• awareness of their role and responsibility;
• the consultant in the event of unanticipated clinical effects;
• facilities and options for postmortem examination to establish the cause of death;
• a scoring system to facilitate decision making.

In case of uncertainty, expert advice must be obtained, either from the designated veterinarian, a laboratory animal specialist or a pathologist. It is important that all responsible personnel be reachable at all times for consultation, should questions arise concerning the implementation of a humane endpoint for an animal.

Pilot studies

Pilot studies are carried out prior to the main experiment to allow definition of various elements or parameters of the study. Pilot studies for setting humane endpoints in an experiment are needed when:

• the effects of the treatment are unknown, so that morbidityMorbidity 1. susceptibility to disease; 2. the number of sick individuals in a population., time course of effects, and appropriate observation frequency still have to be more narrowly defined;
• identification of humane endpoints may be possible on the basis of specific parameters (e.g. telemetrically obtained data);
• the pathological changes observed in an animal will later be used to set humane endpoints.