Three Asian wild foals have been successfully bred at the Calgary Zoo's conservation centre. The new additions were born in the last month at the zoo's endangered breeding facility south of Calgary, said zoo officials on Thursday.

The two fillies and one colt bring the Calgary herd to 11 horses. "While these foals will not likely be reintroduced to the wild, they represent the next generation for an aging captive population," said Bob Peel, curator for the Devonian Wildlife Conservation Centre.

Asian wild horses, or Przewalski's horses, are considered critically endangered by the World Conservation Union. They have a short mane and short upper tail, which they shed once a year, unlike domestic horses.The stocky, strong animals roamed Germany to Mongolia and northern China until the 18th century when they went into catastrophic decline. Efforts to reintroduce the species started again in the 1990s through captive breeding programs based on about a dozen animals.

The last count in 2008 showed 1,872 Prezwalski's horses in the world. On the same day the last foal was born, the oldest mare in the herd — who was 26 years old — died of age-related health problems. "It is part of the cycle of life that as we welcome new births we must accept the reality of eventual death," said Peel.