Observing and monitoring the welfareWelfare A complex and dynamic internal state that includes: successful biologic functioning, positive experiences, and absence of negative conditions. The animal adapts effectively to internal needs and external stimuli and maintains a good mental state. of each individual animal in the course of the experiment requires routine daily check-ups and an adequate assessment of all aspects of well-beingWell-being A complex and dynamic internal state that includes: successful biologic functioning, positive experiences, and absence of negative conditions. The animal adapts effectively to internal needs and external stimuli and maintains a good mental state., and a recording system.

Of particular importance are the critical phases in the experiment during which the animal’s welfare may be threatened. Ideally, these critical phases should have been identified at the start of the investigation. 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. may be helpful. Animals that can be expected to deteriorate, should be examined more frequently and more carefully. This check can consist of undisturbed observation, handlingHandling Manipulating the animal, picking it up, holding it, and restraining it., body condition scoringBody condition scoring A non-invasive method in rodents for assessing health and establishing endpoints for adults where body weight is not a viable monitoring tool, such as with tumor models, ascites production and pregnancy, or young growing animals., response to external stimuli, blood and urine assays, weighing, and special registration methods, but also by visual inspection of the environment. Score sheetsScore sheet Form for recording clinical signs to determine animal well-being and if appropriate the application of a humane or scientific endpoint. can be used to record the findings.

Undisturbed observation

Undisturbed observation means that animals are observed from a distance with the least possible disruption. Ideally, a camera is set up in the animal room and the images are viewed in another location. This is not always feasible. In that case, the observer should enter the animal room as quietly as possible and wait a while, before starting the observation (see movie 1).

Aspects to be evaluated

• Activity: Healthy mice and rats are active but they also have rest periods which become more frequent as the animal gets older. Mice and rats are nocturnal animals and their active phase is during hours of darkness. Aberrant behaviour will occur earlier and be more pronounced during the active phase. It is recommended to observe the animals in the dark if the active phase is relevant for the experiment. This can be done using infrared light.
• Social interactions: Are these normal (e.g. playing, determining dominanceDominance This term describes the ranking of animals. A dominant animal occupies the top position in the hierarchy of a group of animals., sleeping) or abnormal (e.g. fighting, isolation from the group, barberingBarbering Chewing away a cage mate’s or own fur.)? VocalisationVocalisation Sounds produced by animals that may or may not (ultrasound, infrasound) be audible to humans. The rat associates 20 kHz sounds with fear or pain and 50 kHz sounds with pleasant situations. (making sounds) is another aspect of rodent interaction.
• Alertness: An alert animal explores and evaluates its environment by behaviours such as rearing up and sniffing.
• GroomingGrooming The behavior animals engage in to keep clean. Grooming removes dirt from fur and body openings. Absence of this behavior indicates reduced well-being.: A healthy animal pays frequent attention to the care of its body.
• Abnormal behaviour such as restlessness, circlingCircling Continuously moving in circles. This is caused by a brain condition or by an infection of the inner ear (also: head tilt). (see movie 2), bizarre fightingBizarre fighting Abnormal fighting behavior. After dominance relationships have been established, the (bizarre) fighting does not stop, leading, in time, to (serious) injuries., stereotypic behaviourStereotypic behaviour A phenomenon that appears as a response to chronic stress. It is manifested as a set repeated pattern of seemingly purposeless activity. (see movie 3), lethargyLethargy 1. somnolence; 2. state of disinterest and inactivity., vocalizationVocalisation Sounds produced by animals that may or may not (ultrasound, infrasound) be audible to humans. The rat associates 20 kHz sounds with fear or pain and 50 kHz sounds with pleasant situations. (see movie 4).
• Abnormal physical appearance: The occurrence of malformations or abnormal development e.g. hydrocephalusHydrocephalus Abnormal volume of cerebrospinal fluid in the skull. In young animals resulting in an increase of cranium size. (see picture), tumorTumor Neoplasm, new growth. Is predicated upon autonomous growth of cells or tissues into benign or malignant tumors. (see picture), growth retardation (see picture).

Undisturbed observation should also include observation of the environment, e.g. the cage and bedding, for abnormal findings (e.g. fecesFeces Stool/droppings. Also called faeces., blood, etc.).

Prevent anthropomorphicAnthropomorphic Resembling a human characteristic/being. In the context of animals, projecting human characteristics on animals, particularly feelings. projection

The ability to recognize reduced well-being is strongly dependent on the knowledge and experience of the observer and should be devoid of any anthropomorphic projection. Since rats and mice are natural prey animals, they are known to suppress behaviour that signals 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. and disease, to reduce the chance of predation.