Applying the 3Rs: A Case Study on Evidence and Perceptions Relating to Rat Cage Height in the UK

Abstract

This article investigates the barriers to implementing higher caging in animal research establishments in the UK. The use of animals in research and testing in the UK is regulated by the Animals (Scientific Procedures) Act 1986, which sets out how animal experiments must be licensed and regulated. Within this, the Code of Practice currently allows laboratory rats to be housed in cages that are 20 cm high, even though adults can rear up to 30 cm. Most adult rats therefore cannot stand upright in ‘standard’ cages. We found that the main factors hindering the implementation of higher caging were classified into five different groups; health and safety, financial, animal welfare, scientific, and ‘human’. Suggestions to overcome these barriers are provided, as well as alternative animal welfare changes that can be put into place. We conclude that much of the desired evidence for moving to higher cages is already available, and therefore the focus should be on education and improving access to the existing evidence, in order to encourage facilities to work around existing financial and health and safety concerns.

Environmental Enrichment for Rats and Mice Housed in Laboratories: A Metareview

“…Researchers sometimes call for further evidence even in cases where evidence exists. For example, research has shown that typical laboratory rat cages do not provide sufficient vertical space [ 11 , 133 ], but lab animal stakeholders interviewed about cage height were generally unreceptive to change, citing a lack of scientific evidence [ 134 ]. In this example, stakeholders were seemingly influenced by their own experiences, assumptions about rat behaviour, or a desire to generate their own data.…”

Thinking outside the lab: Can studies of pet rats inform pet and laboratory rat welfare?

“…This is also consistent with a study by that found that female laboratory rats will frequently climb and dig when given an opportunity to do so 36 . Additionally, there is evidence that providing rats with space to rear reduces anxiety-like behaviour and cages allowing sufficient room to rear and provision of foraging opportunities are recommended to enhance rat welfare [71][72][73] . While further research should be conducted to elucidate the full extent to which allowing rats to perform these common behaviours could be beneficial to welfare, the available evidence supports the use of large cages that allow rats to rear, climb, and bound, with both nesting material and a digging substrate provided for both pet and laboratory rats.…”

Developing guidelines for pet rat housing through expert consultation

“…However, it is nevertheless important to ask the question of whether and in what ways guidelines for the welfare of the same species should vary according to the purposes for which they are being kept. Indeed, this issue is just one part of the continuing progression of animal welfare regulation; for example, the need for laboratory rats to be able to rear fully in their cages and the use of playpens for enrichment have received growing attention 8,9,12,42,43 …”

“…Indeed, this issue is just one part of the continuing progression of animal welfare regulation; for example, the need for laboratory rats to be able to rear fully in their cages and the use of playpens for enrichment have received growing attention. 8,9,12,42,43 During the development of these guidelines, there were some areas of conflict. For example, there was much disagreement about how to rank the different aspects of rat housing.…”

“…The first challenge is that while much research has been conducted on the care of captive rats, the focus of this research has largely been on laboratory rats. The conditions under which these animals are kept are usually too standardised and lacking in space and variation to provide much useful information about what constitutes good housing in the more spacious and complex environments that are often provided for pet rats 8–10 . Indeed, housing specifically designed for pet rats has been used to provide and study enhancements to laboratory rat welfare 11,12 .…”