DNA parent­age test­ing can pick out finest of the flock

The Press and Journal (Inverness, Highlands, and Islands) - - NEWS - BY DAVY McCRACKEN

With lamb­ing over, our thoughts turn to which of our tups are pro­duc­ing more, higher value lambs?

We do not have the fa­cil­ity to bring down all our ewes into fields for mat­ing or to tag and record lambs as they are born.

In our Auchter­tyre high­hill flock we use mul­ti­ple­sire mat­ing groups, where four or five tups are put out with each larger group of ewes in dif­fer­ent ar­eas of the hill. We also put out chaser tups to try catch any ewe not mated first time around.

For the past few years we have been us­ing DNA test­ing to try to get close to 100% ac­cu­rate as­sign­ment of both pa­ter­nity and ma­ter­nity.

At the start of the process in 2014, all of our ewes and tups on Auchter­tyre were DNA-sam­pled us­ing an Allflex “punch­gun”, which takes a tis­sue sam­ple from the ear and stores it in a small tube.

Once these sam­ples are col­lected, we only need to take tis­sue sam­ples from the lambs born each year when brought in for mark­ing, and from any new tups in­tro­duced into the flock. The tis­sue sam­ples are sent off to Zoetis for “Shep­herd-Plus” parent­age test­ing, where they seek to match the DNA-pro­file of each lamb with the ewes and tups al­ready on file.

Of the lamb sam­ples sent in 2017, 96% were matched with both a sire and a dam in the flock and only 13 lambs had a da­monly match, suggesting neigh­bours’ tups got to their moth­ers first.

Each year the DNA data usu­ally shows marked dif­fer­ences in the per­for­mance of in­di­vid­ual tups within the mul­ti­ple­sire mat­ing groups.

At best an in­di­vid­ual tup will be shown to have fa­thered the ma­jor­ity of the lambs in a group, and at worst an­other will have fa­thered few or no lambs.

Although DNA-test­ing is an ad­di­tional ex­pense, it is the only prac­ti­cal way to ob­tain parent­age in­for­ma­tion which can al­low us to make in­formed de­ci­sions when select­ing tups for use in fu­ture years and lambs to use as re­place­ments into the flock.

l Davy McCracken heads up SRUC’s hill and moun­tain re­search cen­tre at Kirk­ton and Auchter­tyre.

“In our hill flock we use mul­ti­ple sire mat­ing”

TEST­ING TIME: DNA anal­y­sis helps to in­form the breed­ing per­for­mance of tups and ewes

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