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dog unit and home pen design

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Home pen design


The design of the home pen and animal room (the area which includes home pens, corridors and any indoor play areas) may be one of the most crucial Refinements for dog welfare. Dogs will spend the majority of the day in the home pen, so its design will have a considerable impact on welfare. EU legislation mandates a minimum pen size of 2.25m2 per dog (10-20kg) when group housed and 4.50m2 when singly-housed, while other legislation (e.g. United States Department of Agriculture, 2013) mandates significantly smaller minimums, e.g. 0.74m2 for dogs of a similar size. Many facilities are investing in a modern home pen design but much of the supporting evidence for the benefits of their implementation remains anecdotal. The impact of housing systems and home pen design is so significant that it should be considered part of the experimental protocol and weighed up in any cost-benefit analyses (Sherwin, 2007[1]).

Factors which are considered important for home pen design include visibility, choice of resting places or platforms, size, ease of entry for staff, ease of partitioning dogs, and use of noise reducing materials (Hubrecht et al., 1992[2]; Sales et al., 1997[3]; Prescott et al., 2004[4]). Lack of visibility or noise-reducing materials can cause allelomimetic barking which can lead to considerable noise (Prescott et al., 2004[4]).

A comparison of UK standard housing has elucidated the welfare impact of implenting modern dog facilties (Scullion Hall et al., 2017[5]). When compared to traditional UK housing (concrete floors, vertical metal bars), a modern home pen design, with features such as increased visibility, a choice of resting platforms and horizontal bars, leads to better welfare, as measured through improvements in welfare-indicating behaviours and an impact on mechanical threshold (sensitivity to physical pressure). The same research demonstrated that while replacing traditional housing with modern housing benefits welfare, overall facility design also has an impact on welfare. Dogs in the modern facility which had access to indoor play areas, a changing selection of effective environmental enrichment and regular training and staff contact had more positive welfare than dogs housed in modern pens in the traditional facility. This demonstrates that implementing a modern design at the overall unit level further benefits welfare.

The design of the dog facility and home pens has a significant impact on welfare. Together with the time spent in the home pen (the majority or all of the day, for many dogs), the design of dog housing must be considered fundamental to dog welfare. Given the benefits of implenting a modern faciltiy design, which also has benefits for staff by increasing the ease and efficiency of many tasks, we consider implementing modern facility design a critical Refinement.


Features of a modern design home pen and animal room


Filtering the light on the animal room door prevents disturbances to the animals while allowing staff to monitor them A number of entrances, exits and ledges within a pen allows dogs to choose their location and maintain space from pen mates Horizontal bars prevent paddling
Sliding pen doors makes entering and leaving pens more efficient and reduces the chance of dogs escaping Ledges at height allow dogs to calmly observe their surroundings Ledges at height allow dogs to interact calmly with staff at a comfortable height
Increased visibility greatly reduces barking and excitement Increased visibility benefits dogs and staff by allowing observation of the whole animal room Dogs are undisturbed by activities in the animal room
Dishes which can be fixed to hatches allow feeding and removal of dishes without entering the pen Drinkers allow free access to water without the risk of spills Ledges can be fixed at a variety of heights or removed for study needs
A separate area containing paper bedding which can be manipulated by dogs stimulates natural behaviours Sliding hatches can be access from outside the pen, increasing the efficiency of husbandry activities Dogs can be easily penned back without the need for handling


Metabolism cages


Dogs in regulatory toxicology or metabolism studies may be housed in metabolism cages as part of study protocols. The purpose of the metabolism cage is to capture all urine and faeces excreted in a given period of time. In the UK, this requires dogs to be singly-housed in cages smaller than the minimum home pen size, and it is recognised as a regulated procedure because of the potential negative impact on welfare.

The following good practice recommendations for housing in metabolism cages are made in Prescott et al. (2004)[4]:

• The dimensions of the cage should allow the dog to perform the following activities without being restricted: stand on all four legs, lie in a natural position and stretch out.
• A floor area of 1-1.2m2 is recommended.
• Food and water containers, shelves and bedding should not interfere with the ability to move or stretch out.
• Flooring materials such as grids should not cause damage to animals' paws.
• The duration should be minimised, should be specified in the research protocols, and balanced against other potential sources of stress and the objectives of the study.
• Dogs should be given two weeks to recover from every week held in metabolism cages.
• An upper limit of 15 days in the metabolism cage should be applied.
• Dogs should always be able to see at least one other dog.
• Dogs should be provided with additional contact from staff.
• Enrichment should always be provided.

1. Sherwin, C.M. (2004) The influences of standard laboratory cages on rodents and the validity of research data. Animal Welfare, 13, S9-15.

2. Hubrecht, R., Serpell, J. & Poole, T. (1992). Correlates of pen size and housing conditions on the behaviour of kennelled dogs. Applied Animal Behaviour Science, 34 (4), 365–383.

3. Sales, G., Hubrecht, R., Peyvandi, A., Milligan, S., & Shield, B. (1997). Noise in dog kennelling: is barking a welfare problem for dogs?. Applied Animal Behaviour Science, 52(3-4), 321-329.

4. Prescott, M., Morton, D. B., Anderson, D., Buckwell, A., Heath, S., Hubrecht, R., Jennings, M., Robb, D., Ruane, B., Swallow, J. & Thompson, P. (2004). Refining dog husbandry and care: Eighth report of the BVAAWF/FRAME/RSPCA/UFAW Joint Working Group on Refinement. Laboratory Animals, 38 (SUPPL. 1), S1:1-S1:94.

5. Scullion Hall, L. E. M., Robinson, S., Finch, J., & Buchanan-Smith, H. M. (2017). The influence of facility and home pen design on the welfare of the laboratory-housed dog. Journal of Pharmacological and Toxicological Methods, 83, 21-29.




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