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Breeding Values & Genetic Ties

A genetic tie implies that a specific ram born in one flock produces offspring in two flocks. Only under such circumstances can accurate between flock – and between year – breeding values be claimed. E.g. a flock which is not genetically linked to other flocks within the breed, are regarded as a separate ‘genetic island’ of which the breeding values are biased and not comparable to the rest of flocks within the breed.

Accurate unbiased breeding values are dependent on all breeders complying with the following set of rules:

  1. In each flock, at least one ram (breeding sire) has to produce offspring in two consecutive lambing seasons. As far as practically possible at least 20 offspring must be produced in each lambing season.
  2. Each flock must ensure that all breeding sires produce sufficient numbers of offspring within each contemporary group. E.g. it is of no use if a contemporary group consists of only two progeny of one sire and 15 progeny of another sire.
  3. In order to link every flock to the current generation of registered Dohne Merinos, it is recommended that each flock purchase at least one proven sire (with at least 20 progeny) from another flock every five years. It must be ensured that the purchased proven sire produces at least 20 progeny in your own flock. More links over each five year period will increase both the accuracy and comparability of breeding values.
  4. A link also exists when a breeder sells a proven sire in his flock (with at least 20 progeny) to another breeder and the sire produces at least 20 progeny in the buyers flock.

Potential clients and breeders: Please note that the reference point of the Dohne Merino data base changed from 1992 to the year 2000. The implication is that genetic ties date back to the year 2000 and not 1992 as in the previous year. This change to facilitate multiple trait analysis including weaning weight has an influence on the colour code classification of our breeders. Breeders are urged to plan their future matings to strengthen their genetic ties and reliability of breeding values!

Information pertaining to genetic links supplied by Dr JJ Olivier, Wes Kaap Dept Landbou

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