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Pre-lamb management

Pre-lamb: A crucial time in the Ewe’s production cycle

To set your farm up for a successful lambing, consider the following factors for your ewes:

Nutrition

Ewes should have access to adequate quantities of high quality feed (minimum 1200kgDM/Ha, >3.5cm pasture height).

Body condition

Ewes with BCS ≥3 in late pregnancy have better:

  • Lamb survival
  • Colostrum and milk production
  • Lamb growth rates and weaning weights
  • Ewe weaning weights

Disease prevention

Routinely vaccinate ewes against clostridial disease pre-lamb to:

  • Prevent death of ewes at lambing due to clostridial disease, and
  • Protect lambs for their first 6 to 8 weeks of life (via the ewes colostrum)

Parasite management

Selectively treating ewes for parasites based on feed cover, BCS and number of lambs scanned will:

  • Maximise ewe BCS, weight and milk production
  • Maximise lamb growth rate
  • Minimise dags
  • Minimise pasture contamination
  • Potentially reduce your animal health cost

Do you need to drench your ewes pre-lamb?

When a drench is appropriate for ewes on your farm, you can choose options with varying duration of activity.

Not all farms need to drench their ewes at pre-lamb. However, some ewes do benefit from treatment and if used on the right farms and the right ewes, this can be beneficial. As a general rule, the greater your pastures are contaminated with parasite larvae the more benefit you will get from treating your ewes pre-lamb.

The following series of questions will help you decide if your ewes could benefit from pre-lamb drench treatments and if you are likely to get a positive return on your investment.

A selective approach to treating ewes

When a drench is appropriate for ewes on your farm, you can choose options with varying duration of activity.

Generally, those ewes that are in the poorest condition and under the greatest nutritional or parasite challenge will benefit from drenches with the longest duration of activity. The following diagram is an example of how ewes could be treated selectively according to their need.

Figure 1: An example of a selective approach to drenching ewes at pre-lamb.

Figure 1: An example of a selective approach to drenching ewes at pre-lamb. For information on the above products please see our Drench and Vaccine Product pages

Use of long-acting drenches can increase the rate of drench resistance development and should be used with care. You can mitigate some of the risk with strategies such as the use of an Exit drench after using a long acting product. Ideally the Exit drench should be given towards the end of the duration of activity for the product and should be a short acting drench that is fully effective on the property.

If you have known or suspected resistance but ewes are still in need of additional support, a Primer drench is an additional tool to help remove adult worms that may not be removed by the long acting treatment. A Primer drench is an effective short acting drench that contains different actives to the long acting treatment. Given at the same time as the long acting treatment, the primer drench removes the adults, leaving just the incoming larvae to be controlled by the long acting drug. Larvae are generally easier to kill, so may still be controlled by the product even as drug levels decline. However, the more resistant genes the worms have, the shorter the time this persistent control will last.

Monitoring

Drench efficacy should be monitored using fecal egg counts (FECs). This can be done around 14 days after treatment to assess initial product efficacy/drench resistance or during the payout period of longer acting products to assess persistent efficacy. It can also be assessed at the end of the payout e.g. for Cydectin LA this would be ~Day 100 to see if an Exit treatment is required at tailing, pre-weaning or weaning (depending when the product was administered). Speak to your vet for more information about the best time to do a FEC post treatment.

The information given here is aligned with Wormwise (Wormwise.co.nz), New Zealand’s leading source of parasite management advice. This information is a general guidance only and not a substitute for veterinary advice. Please speak to your vet for further information specific to your farm.

  • Zoetis New Zealand Limited Tel: 0800 963 847, www.zoetis.co.nz. Cydectin is a registered trademark of Zoetis. ACVM Nos. A9926.

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