Error in parentage of one-fifth of animals
The reliance of livestock breeders on genotyping for pedigree validation of animals has been undermined by the scale of "incorrect" parentage which has been found in a major scientific assessment.
The Teagasc study found that one or both parents has been incorrect in an average of one in five pedigrees after almost 18,000 genotypes of pedigree sheep were analysed.
The findings, which were revealed by Teagasc Moorepark scientist Noirin McHugh at the Sheep Ireland Stakeholder meeting at All Mellows College, Athenry were described as "an eye-opener" by breed society representatives attending the meeting.
Pedigree societies raised concerns over the potential serious legal implications for breeders.
"Something has to happen very, very quickly by the breed societies, once we are aware of these errors, because it is putting them in an awkward spot," one representative told the meeting.
Dr McHugh told the meeting: "Overall we are saying that in terms of parentage of the 18,000 animals that were genotyped, the parentage could not be verified for about 20pc where either the sire or dam or both were incorrect."
Of the sheep genotyped, 2pc failed genotyping, about 14pc did not match the records on the sire database and on the dam side around 9pc could not be verified.
"When we looked at samples where we had data available on both the sire and dam sides, there were about 4pc where both parents could not be actually verified and where one parent could not be verified was about 13pc," she said.
The meeting was told that in the beef sector the scale of error was about 17.5pc, but that has now been reduced to about 7pc with the corrections which have been carried out on verification of pedigrees.
With more breeders showing preference for animals with higher Eurostar ratings, and paying higher prices for the animals with greater numbers of Eurostars, the implications can be very significant.
"In reality what this means is that a farmer buying (what he thinks is) a five-star animal, it could be a one star, or a one star could be a five star" when the error in the pedigree is corrected, she pointed out.
For a commercial farmer going out to buy a ram at a sale, irrespective of breed, because it is the same across all breeds, on average one in five are incorrect.
She pointed out if it was incorrect then the "Eurostar figures for him are completely wrong, his parentage is wrong, and straight away you are giving incorrect information to the commercial farmers on the selection tools for the ram".
Dr McHugh said that they are now proceeding to look at the implications in terms of genetic evaluation and how it affects the individual animal's performance.