New Lab Rodent Recommendations Rile Researchers

Research using lab rats or mice funded by the NIH is regulated by a set of guidelines that have very recently been upgraded. Mother rats and mice with litters are now recommended to have more room than current guidelines require. The new guidelines are not hard and fast rules, but researchers are concerned that not following these guidelines would jeopardize funding, and it appears from my reading of them that the new cage size guidelines are minimum requirements that must be met.

The main difference that is causing some discussion about the new guidelines is that cages that hold females with litters would be larger, and thus potentially different from the other cages as well. In many labs, current rat cages that are all 140 square inches at the base would have to be replaced with larger cages that are 210 square inches at the base. This is not a huge difference in size, but since a large number of cages would no longer fit in whatever shelving or rackspace is set up, there would have to be a lot of changes. Also, researchers appear to be annoyed that while currently all the cages in a given facility may be the same size with variable number of rats or mice in them, the new standards would require either a lot of extra space for all cages or different size cages, which would be more difficult to manage.

NPR, reporting this story, gives Johns Hopkins as an example. They have a rat and mouse facility about one football field in size, with about 40,000 shoe box size cages that fit in special racks and that integrate with a ventilation and water supply system. The facility is paid for with an internal rent of 62.5 cents per cage per day. It would cost about $300,000 to buy new cages, and more space would have to be found.

The implementation of the regulations is somewhat negotiable, which is probably not a good thing for the researchers. It might be much better to have a required change implemented over a small number of years, and to have costs covered by future NIH funding, than to be uncertain as to whether or not one must change to retain funding, vs. this new rule simply going away. Also, in the long run, this is not as expensive as it sounds. Johns Hopkins received almost 700 million dollars in NIH research funding in 2010. Throwing a million bucks into the overall research budget one time and a few hundred thousand increase which will be covered by grants over the long term is not insignificant, but it is certainly doable.

Some "animal rights" groups want the rodents to have even more room. Some scientists have pointed out that there is no evidence that increasing room changes anything for the rodents, which is probably not a helpful thing to say at this point in time because if it it seems to imply that there has been no research into enclose size requirements for rodents. The new guidelines explicitly state that "Space recommendations were nominally expanded based on ... professional and expert opinion and on current housing methods," and "substantial guidance" is provided in the document to achieve the objectives of the new goal. Also, the guide attempts to distinguish between things that researchers must, vs. should, vs may do. I would assume that "shoulds" and "mays" are guidelines that under some conditions could be seen as potential future "musts." If I was in charge of an animal research facility, I'd be meeting with member of the NIH committee now and then to assess their future directions along these lines, so that the next time I speced out rat cages, I'd consider the "should" requirements if there was an expectation that "should" would someday become "must." The cage size increases appear to be in the "must" category but with exceptions. It is actually rather complicated, which is why the people who run these facilities are experts!

Here's a copy of the guidelines.