New rules for animal experiments?

The Government has announced that a new body will be set up to oversee the use of animals in scientific experiments. How can we further reduce the number of animals used in experiments, and make sure that when animals are used, they suffer as little as possible?

Rules should take into account all the circumstances. I know of a scientist who used to use rabbits to produce antibodies to proteins he was working on. We haven't yet been able to work out how to get a wide selection of different antibodies from cells cultured in the lab. He would inject the (harmless) protein into the rabbit, whose immune system would react to this foreign body to produce a varied selection of antibodies. He would then draw out a couple of millilitres of blood and purify the antibodies for use in his experiments. The only thing the rabbit suffered was a couple of injections. Its job done, the rabbit would be retired. He would take them home and keep them as pets in his back garden, with a hutch and grass -- a pretty good life in return for a couple of injections.

He can't do that any more. The rules were changed a few years ago. Now, once the experiment is finished, the animal must be destroyed. So now he uses mice instead. They are so small that taking out enough blood to use in the experiments kills them. And as they'd have to be killed anyway...

Now, I think I understand what they were trying to do: make sure that animals whose usefulness is over don't languish in lab cages forever. But surely in this case, the rules have missed the point? We have here a problem of over-generalisation. We always need to be careful to ensure that rules meant to safeguard the welfare of animals don't end up acting against the very thing they are trying to protect.