How reliable are sheep pedigrees?

A.M. Crawford, M.L. Tate, J.C. McEwan, G. Kumaramanickavel, K.M. McEwan, K.G. Dodds, P.A. Swarbrick, P. Thomson

AgResearch Molecular Biology Unit, Biochemistry Department, Otago University, P O Box 56, Dunedin

Proceedings of the New Zealand Society of Animal Production. 1993, 53: 363-370

The advent of highly polymorphic genetic markers in sheep has enabled, for the first time, a retrospective study of the pedigree records of New Zealand sheep flocks. Three research flocks and one study flock have been analysed. The flocks were genotyped using a variety of microsatellite DNA markers and/or the polymorphic blood proteins transferrin, vitamin D binding protein, and ovine plasminogen antigen.

The first flocks analysed were the half-sib Booroola pedigrees from progeny tests of heterozygous Booroola rams and their daughters. Of 291 daughters of rams, 7 were shown to have an incorrect sire assignment. The remaining flocks consisted of full sire/dam/offspring pedigrees. The stud flock showed 2 instances in 45 pedigrees where the sire was incorrectly assigned. Of 53 Inverdale lambs tested 5 were shown to have an incorrectly assigned parent and in 387 pedigrees from a progeny test flock at Woodlands only two pedigree errors were detected.

These error rates are lower than previously estimated from field observations which give confidence in the use of these pedigrees for genetic selection. Simple flock management techniques are described which help achieve the low error rates reported.

Keywords: NZSAPAB; Pedigree auditing; Parentage testing; Microsatellites; Protein polymorphisms.

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Last Updated 25-01-1997