Ovine pulmonary adenocarcinoma as an animal model for human lung cancer, because OPA is histologically similar to human adenocarcinoma in situ of the lung. Dolly the sheep, the first mammal successfully cloned from an adult somatic cell, was euthanized after it was confirmed that she had OPA. Ovine pulmonary adenocarcinoma Ovine pulmonary adenocarcinoma (OPA), also known as ovine pulmonary adenomatosis, or jaagsiekte, is a chronic and contagious disease of the lungs of sheep and goats. OPA is caused by a retrovirus called jaagsiekte sheep retrovirus (JSRV). The disease has a long incubation period, and therefore signs usually occur in adult animals (over 2
Animal welfare in the United States Animal welfare in the United States Animal welfare in the United States relates to the treatment of non-human animals in fields such as agriculture, hunting, medical testing and the domestic ownership of animals. It is distinct from animal conservation. The first known animal welfare laws in North America were regulations against "Tirranny or Crueltie" toward domestic animals included in the 1641 Massachusetts Body of Liberties. Starting in the late 1820s, a number of states passed anti-cruelty statutes. Many of these exempted animals used in experiments, and only twice were they invoked on behalf of animals. The first Humane Societies and