Veterinarians, under pressure from their employers, have adopted practices which lead to the underreporting of animal diseases, especially as a consequence of factory farming methods and pressures to protect the financial investments therein. They have failed to investigate adequately the extent or nature of such hazards in the process of further increasing the yields of animal husbandry. Veterinarians have condoned the restrictive conditions under which animals are kept for such purposes or for entertainment (as in zoos, aquaria or circuses). They have also condoned the development of breeds which cannot survive without surgically assisted births (as in the case of certain breeds of dogs). Veterinarians are implicated in drugging of racehorses and other animals used for sporting events.