According to the American Livestock Breeds Conservancy, it is important to conserve rare and heritage breed livestock for their genetics, historic value, educational value, and usefulness among other things.  In the title published by the ALBC, A Conservation Breeding Handbook, it is written:

"These breeds were carefully crafted by dedicated breeders  to fit a wide range of conditions, tasks, and needs.  Their beauty, dignity, and usefulness were all celebrated and they were partners in both agriculture and culture."

"What if these animals become extinct?  The Earth will have lost a unique segment of its biodiversity.  Agriculture will have lost the genetic resources critical for adaptation to changing conditions and methods of production."

"Unlike wild species, domestic breeds must be conserved by human beings.  Domestic animals share habitat with humans, that habitat known as agriculture.  It is the use and reproduction of rare breeds in agriculture settings that is essential for their conservation  and best reflects our long interaction".