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A Navajo-Churro ram.
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Sheep
Conservation & challenges

One living story. Knowledge kept together.

A Navajo-Churro ram. · Just chaos · CC BY 2.0 · License terms

A future for a living population

What does this animal face?

Conservation depends on keeping a population able to continue, including its reproductive animals, families and the people who maintain it. Visible popularity can hide a narrow breeding base. A small herd in one location faces different pressures from a similarly sized population distributed across several herds.

This world currently contains 23 listed breed, strain or variety entries. That catalogue size is not a count of living animals. Open each population’s conservation chapter to see its category and the source-reported figures that have been verified.

Navajo-ChurroCritical →Florida CrackerCritical →Romeldale/CVMThreatened →St. CroixWatch →Santa CruzCritical →Hog IslandCritical →TunisWatch →Leicester LongwoolThreatened →OxfordWatch →Dorset HornThreatened →TeeswaterCritical →CotswoldCritical →Barbados BlackbellyThreatened →Karakul – AmericanThreatened →LincolnThreatened →Soay – BritishThreatened →Wiltshire HornWatch →Clun ForestThreatened →Gulf Coast or Gulf Coast NativeCritical →Black Welsh MountainThreatened →ShetlandRecovering →Jacob – AmericanThreatened →ShropshireWatch →

FAO’s DAD-IS keeps domestic breed information by country and maintains population-history tools. A useful statistic retains its date, geography and definition: breeding females, registrations, sampled animals and all living animals are different measures. A historical low point is meaningful history, but should not be presented as a current census.

The Livestock Conservancy: 2026 list · FAO: population-data framework · IUCN: species assessment questions

Interactive explanation · hypothetical animals

One hundred animals.
Different breeding foundations.

Compare the same total with different numbers of breeding males and females. This simplified model illustrates why a head count alone cannot describe a population’s genetic future.

Animals in this example100
Idealized effective population size19.0Nₑ = 4 × males × females ÷ total

These are teaching examples, not estimates for the breed on this page. The formula assumes an idealized breeding population. Relatedness, unequal offspring contributions, changing numbers and overlapping generations require more detailed analysis. It does not predict a specific mating’s inbreeding or recommend a breeding plan.

Model basis: FAO, monitoring animal genetic resources (1992), section 4.2. Further guidance: FAO, In vivo conservation of animal genetic resources (2013).

Sources for general species learning

Keep learning from official information.

These research portals help locate further material. A search link is a route for exploration; it is separate from the sources used for the article above. Domestic breed information, wild-species assessment, historical books and new research need their own context.