The private, nonprofit SVF Foundation, based in Newport, R.I., collects embryos, semen and blood samples from critically endangered cattle, sheep and goats in an effort to save them from extinction.

A breed is listed as critically endangered by the American Livestock Breeds Conservancy if fewer than 200 animals are born in United States each year and less than 2,000 exist worldwide.

Here's a look at some of the breeds the foundation is preserving:

Dutch Belted Cattle: P.T. Barnum brought Dutch Belted dairy cattle to the United States from Holland in 1840 for exhibition in his circus. The cows have a distinct belt of white around their middle that inspired the nickname, Oreo cow. Popular among American farmers until about 1940, the cows produce milk high in protein and fat that is well suited to making butter and cheese.

Milking Devon Cattle: Settlers in the Plymouth colony imported Milking Devon cows to the United States from Britain in 1623. The multipurpose animals produce milk and beef and can work the farm in the heat and cold. British farmers still breed the related Beef Devon, but the red Milking Devon is found only in the United States.

Gulf Coast Sheep: Spanish explorers brought the sheep to Florida in the 1500s, and they later spread along the Gulf Coast. The breed tolerates heat well and is notable for its natural resistance to the internal parasites that plague most sheep.

Santa Cruz Sheep: The sheep developed on Santa Cruz Island off the coast of California in the 1800s. They have little or no wool on their bellies, faces, legs and tails and shed the wool they do have, making them well-suited to warm climates.

San Clemente Goats: The small, feral goats developed from animals left by Spanish settlers on San Clemente Island off the California coast. Explorers returned periodically to hunt them, but the goats were left largely isolated for centuries. They grew into smart, tough animals able to survive on their own.

Kerry Cattle: Kerry Cattle may have been the first dairy breed. It developed in Ireland 2,000 years ago and is still found in the southwestern part of that country. Brought to the United States in 1818, the cattle may be most notable for their ability to produce significant amounts of milk on very little forage.

Tennessee Myotonic Goats: Rare, but no longer critically endangered, the Tennessee Myotonic Goat has a unique condition in which its legs and neck stiffen and cause it to fall over in a kind of faint. Imported from Nova Scotia, Canada, in the late 1800s, the goats quickly became popular among Tennessee farmers for their meat, fertility and inability to climb out of fenced pastures.