Declining breeds of domesticated animals

Endangered species of farm animals
As farming has become more industrialized and energy-intensive, a small number of breeds have become dominant - specialized animals that respond well to high-energy diets, confined living conditions and intense medical treatment. This specialization develops narrow gene pools which may be susceptible to diseases.
In Canada, Holstein cow stands in 95% of the dairy stalls and there are only six commercial poultry breeds. In UK this century at least 20 breeds of British farm animals have died out.
Special breeding for rate-of-gain production rates and narrow gene pool may hurt the people if consumers' taste, climatic patterns and diseases change in the future.
(D) Detailed problems