Mark Purdey animal feed dates back to at least 1926. In the 1970s attention was directed within MAFF to the danger that this practice would result in the spread of infectious diseases. The diseases considered were those caused by conventional viral and bacterial organisms. No consideration appears to have been given to the risk that scrapie might be recycled in sheep, or even transmitted to other farm animals. This may seem surprising. The answer probably lies in the fact that half a century had elapsed without any indication that animal feed containing ovine protein was infecting sheep or any other animal." Purdey
Alternatives to animal testing test dummies, complete with internal sensors and video, have replaced live animal trauma testing for automobile crash testing. The first of these was "Sierra Sam" built in 1949 by Alderson Research Labs (ARL) Sierra Engineering. These dummies continue to be refined. Prior to this, live pigs were used as test subjects for crash testing. Computer models have been constructed to model human metabolism, to study plaque build-up and cardiovascular risk, and to evaluate toxicity of drugs, tasks for which animals are also used. In 2007, US researchers using the world's fastest computer at the time, BlueGene L, modeled half a