Biotelemetry

Biotelemetry is the remote detection and measurement of biological data about animal function, activity or condition. Biotelemetry has long been used for environmental research to study animal populations (e.g. radio tracking). Over the past few decades, telemetry systems have been increasingly applied in drug research and development for measurement of physiological and bioelectrical variables (e.g. blood pressure, heart rate, ECG). The absence of tethering, handling and restraint during measurement provides a unique opportunity to study laboratory animals with reduced stress and physiological disturbance during a longer period of time in their normal housing.

Telemetry can enable reductions in animal numbers. Firstly, because telemetry systems are stable for months (and possibly even years), animals can be used as their own controls, reducing data variance and consequently the number of animals needed per treatment group. Secondly, telemetry provides an ability to continuously record a number of variables so that there is a significant increase in the amount of data that can be obtained from a give number of animals, compared to the use of conventional methods. Thirdly, in the absence of potential stressors, such as restraint or externalised catheters, the quality of data obtained is improved. Telemetry systems can also provide indicators of animal wellbeing to help implement earlier, more humane endpoints. Telemetry is, therefore, widely regarded as benefiting science and animal welfare.

However, use of telemetry does not represent a true refinement unless due regard is paid to the impact that it has on individual animals. For example, internally- or externally-mounted telemetry devices for transmitting or storing (logging) physiological data from experimental animals require specialist implantation surgery and/or attachment procedures which can cause suffering to animals in the short and long-term if appropriate refinements are not implemented. Therefore, it is important that potential areas of suffering within telemetry projects are identified and positive steps taken to prevent or minimise them. Considerations include:

• Experimental design, e.g. data sampling and physical arrangement of hardware
• Choice and designing of device, including the potential for device impact due to its mass, shape, dimensions and location
• Deciding whether to use total implants, externally attached devices (e.g. backpack systems) or internal devices with exterior components such as skin buttons
• Refinements in surgical implantation, including training, anaesthesia, pain management and post-operative care
• Husbandry issues, e.g. selection of individuals of suitable health and temperament, habituation of animals to experimental conditions, means of avoiding single-housing, safe re-establishment of groups following surgery, long-term housing
• Re-use of animals
• Removal of implanted devices and the potential for rehoming or releasing animals

The BVA(AWF)/FRAME/RSPCA/UFAW Joint Working Group on Refinement has produced guidance on refinements in telemetry procedures, and husbandry refinements for rats, mice, dogs and non-human primates used in telemetry procedures (see the panel on the right). The Working Group has also produced short guidance on the legal issues associated with biotelemetry.

Other non-invasive means of measuring physiological and behavioural parameters include:

• Video monitoring
• Non-contact thermometry
• LABORAS