An organic farmer in the UK observed that immediately after the government started requiring most farmers to use a pesticide to try to eradicate a parasitic fly, the outbreak of mad cow occurred, while his own exempted herds remained free of the disease. Despite lack of government funding, he launched his own scientific investigation, which confirmed that mad cow is caused by an overconsumption of "organophosphates" present in the pesticides. Since I lack the biological or chemical knowledge, I'm not even going to try to explain the details. Despite his successes, governments lobbied by big chemical companies have refused to launch any of their own studies to confirm or repudiate his claims.