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Upgrading Guidelines


The American Teeswater Sheep Association (ATSA) supports the development of white Teeswater sheep from the crossing of specific longwool breeds of non-Teeswater ewes with purebred Teeswater rams. The first generation (50%) blood bred back to a purebred 100% Teeswater sires produces a 75% blood. A second generation (75% blood) female, bred to a purebred 100% Teeswater sire produces an 87.5% blood, the fourth generation produces 93.7%, and a fifth generation produces 96.8%.

The foundation animals used in the first cross matings with ATSA registered parents must be white and registered with the recognized U.S. breed associations or their UK counterparts, as determined by the Board per the requirements of Section 1. Rules of Registry, or qualified first generation cross-bred foundation animals recorded in the ATSA’s foundation registry. No other foundation breeds shall be recognized. The following foundation breed registries are recognized by the ATSA: Bluefaced Leicesters, Border Leicester, Cotswold, Leicester Longwool, Lincoln, North American Wensleydale.

There is a separation of record keeping for white and naturally colored animals registered. The ATSA will take all reasonable steps to track the presence of colored genetics in the Teeswater population and include such information on registrations certificates.


All applications for registration shall include parentage and fleece color. All white sires and dams producing colored offspring will have the designation of Color Factored (CF/White) added to their pedigree information.. White progeny of colored parents will have the designation CF/White added to their pedigree information.

All first cross lambs must be sired by use of 100% Teeswater semen from registered white Teeswater rams. Ewe lambs from this cross will be registered as 50% Teeswater. First cross male lambs will not be eligible for registration. All rams must be at least 75% Teeswater blood and test RR at codon 171 to be eligible for registration.

A sire must be registered as 75% Teeswater or higher before any progeny are eligible for registration when bred to registered Teeswater ewes.

Lambs will be registered with their blood percentage calculated from the use of two registered parents. i.e. 50% dam crossed with a 75% sire results in a 62.5% lamb. If this lamb is male, it is not eligible for registration.

The ATSA has set codon 171 standard for the use of imported semen, and beginning January 1, 2009, only semen from registered Teeswater rams testing RR at codon 171 will be eligible to sire registered animals.

Registered ewes that have met the UK Society’s requirements and are included in their Section 22 will be given the classification of Ewe of Merit. These ewes are suitable for producing lambs that may be registered in the UK Flock Book. *Refer to current UK Society Guidelines regarding their US Program.


The Ewe of Merit designation may also be granted to ewes meeting the specific guidelines set forth by the Board in the Ewe of Merit Qualification Guidelines for US Producers Policy.

Registered offspring of Ewes of Merit sired via AI by purebred UK registered rams who are registered in the UK Society’s Flock Book or have met the requirements set forth by the Board in the Elite Qualification Guidelines for US Producers Policy shall be given the classification of Elite. Elite animals that have met qualification criteria or are included in the UK Society’s Flock Book will be considered Purebred Teeswaters and will have the value of 100% assigned to all future offspring calculations.

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