Parentage being changed & Scrapie genotyping available

Parentage being changed & Scrapie genotyping available

Noirin McHugh presented an update on parentage predictions and scrapie at the Sheep Ireland Industry Meeting held on Monday 29th April 2019 in Tullamore Court Hotel, County Offaly. The synopsis of Noirin’s presentation on the day are outlined below. View Noirins’s full presentation from the day here.

Genetic indexes rely on accurate parentage in order to produce the most accurate predictions, therefor it is highly important from a breed improvement point of view that parentage is accurate. It is also important for flockbooks have accurate parentage for the breed flockbook integrity.

The breakdown of parentage errors

There is now almost 22,000 animals genotyped in the Sheep Ireland database (Commercial and Pedigree), of which half had a parent genotyped also. The current sire error rate of all the genotyped animals is 8.3% and 5.6% for dams. These figures would be expected, as there are lots of occasions where genuine mistakes can be made from

  • Recording mating groups (Which ram bred with which ewe)
  • Multiple ewes lambing in a group pen and lambs getting mixed up
  • Lambs being fostered and not recorded
  • Recording the wrong tag number at lambing time
  • Admin error when recording the data onto the database

The good news is that thanks to some new work done by Sheep Ireland, when an incorrect parent has been identified, in 40% of cases the correct parent can be identified via screening the other genotypes in the database. The parentage will then be updated to reflect this, however if a new parent can’t be identified then this will mean the animal shall have it incorrect parentage removed, as wrong information is worse than no information.


The Impact of Parentage errors

Some of the animals that have their parentage changed as a result of the parentage correction process could drop/gain as much as €4.96/€7.98 on the Replacement index, leading to a significant change in their EuroStar rating. These changes will not only effect the animals with a direct sire/dam error, but it could have a knock on affect throughout the bloodline.

Parentage errors have the largest effect on animals with no or small numbers of progeny. This is because the more progeny an animal has, the less it relies on its ancestry for the formulation of it stars, and the more it relies on its own progeny’s performance.


Scrapie  genotyping now available

Both Teagasc and Sheep Ireland have been working for some time now to validate the test for scrapie using this new genotyping technology. We have encountered some difficulties in the past, but these have now been overcome. Any sample ordered from today forward will also receive a scrapie status. This scrapie status is not DAFM approved, but the next step is to work with DAFM to try and make this happen.

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