August 1, 2008

Getting rid of dags and worms - Part II

Part 2. Starting a "Dag-Free & Worm-Free" flock

Focus on the target - dags and worms (in that order), and it has to be done with minimal cost. All you need is raddle, some tags, your eyes and a finger.

Don't worry about other traits. You can ignore them for a while, as they won't decline genetically or disappear if you go flat out on dags and worms for a couple of generations.

The rams already on the farm
  • Get your rams in that are on the property now and stick your finger up their bums! They should not have been drenched for at least two months to be drug free. Here's what you feel for and score:

* Marbles (FCS 1) – you'll feel definite marbles.

* Hand grenades (FCS 2) – feel an empty chamber from which a hand grenade has been voided.

* Plops (FCS 3) – small green stain on finger end.

* Slops (FCS 4) – larger wet green stain on finger end.

* Scour (FCS 5) – finger covered in green runny faeces.

  • Only keep those with FCS 1, (or FCS 2 if there are not enough marblers). Cull the rest or use them as terminal sires so their progeny don't get back into the flock.
  • Take a faecal sample and send it to a recognised lab for a FEC. The target ideally should be zero but under 500 eggs/gm may have to be accepted, but certainly not above 1000 epg.

Next season's rams

  • Contact your stud breeder and tell him/her that what you want next year. You need rams that have been drug-free for at least two months and with FCS of 1 before you go to inspect them. You also want a FEC (done at a recognised lab) of less than 500 epg.
  • Can you imagine what kind of reception you'll get? BUT things have got to change and are changing, and this will hasten the changes needed. If breeders are not asked, why should they go to all the bother?
  • If you can't get the rams you need from the current sources, then when you get down the track a bit, consider breeding your own.
Next year's lambs
  • Don't drench any lambs at docking – that's the worst thing you can do!
  • If tapeworms are knocking the lambs, then drench based on your experience of benefits and not the drench adverts. Getting rid of any scour can reduce blowfly problems.
  • Base any drench at weaning on FEC and the chances of Barber's Pole.
  • From weaning on, only "crisis drench", and mark all daggy ewe lambs that need drenching.
  • Never use long-acting drenches on lambs.
Ewe hoggets
  • Drench only on the basis of FEC and the risk of a crisis, e.g. Barber's Pole.
  • Never use a long-acting drench on ewe hoggets.
  • Put a special mark on those that are always clean, regardless of the feed. These will be your replacements and mark persistently dirty sheep as potential culls.
  • Make the final selection on FCS, keeping only "marblers" and "hand grenaders".
  • Never use long-acting drenches no matter how good the promotional giveaways.
  • At all times of year, mark ewes that are persistently daggy and put them on the cull list.
  • At mating, mate your top marbling rams to groups of marbling ewes. Any ewes with sloppy faeces (FCS 3, 4 or 5), mate to a terminal sire and don't let any of their progeny back into the flock.
  • This exercise will form a "nucleus" of elite ewes. They are so important that they need a special tag.
  • You can strengthen this nucleus by making "scanning twins" an extra entry qualification after being Dag-Free & Worm-Free.
  • This nucleus will then become your "genetic engine" to breed replacements, and it will grow as better and better females qualify to go into it.
  • Pay special attention to the 5-year-old Cast-for-Age ewes, as they have stood the test of time and the best of them based on records (if you have any) or health, FCS and FEC should be viewed as potential ram mothers.

What will all this achieve?
It will put maximum selection pressure on parents that have genes to get rid of dags, and that have a natural genetic resistance to worms. The secret is to keep the selection pressure hard on, and not be concerned about other traits till you get dags and worms cleaned up.

Contact me with your comments or questions
See my book for details
D.C.Dalton (2007). "Internal parasites of sheep and their control – now and in the future". 3rd Edition with cartoons by David Henshaw.
Book available from

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