March 5, 2010

Breeding sheep to eliminate dags and worms. 5.

By Dr Clive Dalton


Two-tooth ewes from the A team nucleus
  • Now as two-tooths bred from the A team nucleus ewes, they should look a picture due to the intense selection pressure put on them up to now.
  • Apart from the odd sample to monitor progress, it’s not worth doing any more FECs, but keep on ruthlessly culling any that get daggy and don’t clear up quickly.
  • There would be no harm in doing a FCS now and again to check on any that are not measuring up, especially those getting daggy and not drying up fast.
  • Cull any that develop problems like footrot.

Planning the two-tooths’ mating
Decision needed: What rams are you going to join with these top two-tooths? They deserve very special consideration after all the work you’ve put into them.

Ram options

Option 1:

Stud breeders rams at pubic auction but few FEC records and no dag data.
  • Contact your nearest consultant from Sheep Improvement Ltd (SIL) by phoning 0800-745-435, or Email ""
  • Ask which breeders have rams for sale with WormFEC™ and Dag Score BVs.
  • Take care to check the records and ask the breeder how many rams have been tested and how this was done, as despite the SIL WormFEC™ protocol in the Breeders’ Manual (1994), some breeders have developed a few variations of their own.
  • FCS is not accepted by SIL as a correction for FEC. And in any case, the rams will all have been drenched regularly and recently, so you won’t be able to get a true ‘drug-free’ FCS assessment.
  • Beware that breeders may advertise that they are breeding for worm resistance or even worm resilience, but their programmes will need questioning.
Lab FEC raw data on rams at a sale - a very rare feature.
The FECs were not being used in an index.

Option 2:
  • Failing any success with SIL breeders, the next option is to look at any old sires you have on the farm purchased previously from SIL breeders.
  • This could surprise you or shock you - to see what you have spent money on (in all innocence) in previous seasons.
  • Their mature (genetic) immunity against dags and worms should have been fully developed – if they have any. It would be worthwhile having a look.
  • Make sure they have not been drenched for at least two months (preferably three) and first check their FCS. It’s not worth wasting $5 on a FEC if a ram is a scourer.
  • Any like this need to be used as terminal sires as you’ll be dagging their progeny for the next five years at least.
  • For the marblers or hand grenaders, get a FEC done.
  • Don’t contemplate using any animal with a FEC over 500 epg and zero should be a better target.

Option 3:
This is the obvious choice - to use your own rams, bred in the A team nucleus flock, and Pathway 2 describes this.

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