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
Abolitionism (animal rights) forms of animal use, since they believe this undermines the movement to abolish all forms of animal use. The objective is to secure a moral and legal paradigm shift, whereby animals are no longer regarded as things to be owned and used. The American philosopher Tom Regan writes that abolitionists want empty cages, not bigger ones. This is contrasted with animal welfare, which seeks incremental reform, and animal protectionism, which seeks to combine the first principles of abolitionism with an incremental approach, but which is regarded by some abolitionists as another form of welfarism or "New Welfarism". The word relates