About Regulin®

Regulin® was developed in Australia by Professor Linton Staples at the Victorian Department of Agriculture in the 1980s. It was re-introduced to Australia 10 years ago, having been used successfully in European countries including Spain, France, Greece, Turkey and the UK.

How it works

Regulin comes as a subcutaneous implant of melatonin, a natural substance produced by animals. After insertion, the implant gradually delivers 18mg melatonin into the animal’s tissues mimicking the onset of Autumn, the natural joining season for sheep.

By ‘tricking’ the animal’s reproductive system, it enables earlier mating (spring and early summer) in seasonal breeds. In less seasonal breeds, Regulin creates a tighter lambing window and increases lambing percentages through more twins, fewer dry ewes and more lambs carried to term. (See the research).

 Good management results in better lamb growth.

Watch the video presentation above (also available on YouTube) in which Russ Davis from Ceva explains the science of seasonal reproduction in sheep and how melatonin improves performance.

Regulin implants are non-toxic, bio-compatible and completely biodegradable. The same sheep can be implanted annually. Regulin has no impact on subsequent joinings and there is no withholding period for meat or milk.

More than 540 stud, prime lamb and wool producers in Australia are already enjoying the benefits Regulin brings to their enterprises.

With Regulin® you can

  • Maximise your genetic gains and the genetic potential of your sheep
  • Improve reproductive performance in early joining and compress lambing periods
  • Realise the potential of your rams year round
  • Increase income per treated ewe
  • Get your lambs earlier to market with fewer lifts

How and when to use Regulin®

  • Regulin provides the maximum productive returns when used 40 days prior to ram introduction.
  • Using the specially designed implanter, administer one Regulin implant per ewe and three per ram beneath the skin (subcutaneously) near the base of the ear.
  • In order to maximise results from treated ewes, rams should be isolated from the ewes for at least 42 days prior to joining.
  • Regulin is recommended for use in Merinos and First Crosses to be joined in Spring and early Summer (October to January) for lambing in Autumn. Implantation is not recommended earlier than September, check with your Ceva Territory Manager if you wish to join earlier. 
  • Regulin is also effective in British breeds such as Border Leicester, Romney and others. However, there may be some variation in optimal timing for best results. Seek advice from your Ceva Territory Manager.

Precautions and contraindications

  • Use Regulin only in reproductively mature ewe lambs, maiden and older ewes.
  • Regulin will not replace good husbandry practices in achieving good reproductive performance – for good results, animals must be in healthy condition.
  • Regulin is contraindicated for use in reproductively immature animals or pregnant ewes.
  • Ewes to be joined should be treated with Regulin no more than 30-40 days prior to joining.

There is no withholding period for meat or milk from animals treated with Regulin.


Are you ready for Regulin?

Your answers to these eight questions will give you a good idea of the success you can expect to achieve with Regulin.

See what Regulin could do for your bottom line

Managing your program is easy with the Regulin APP


Download the Regulin APP to keep detailed information about your farm program, set calendar reminders and get access to handy resources.


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Regulin® is licensed for use in ewes and rams in Australia by:

Ceva Animal Health Pty Ltd.
11 Moores Road
Glenorie NSW 2157
ACN 002 692 426

T: +61 2 9652 7000
F: +61 2 9652 7001
Visit our WEBSITE


To request a call from one of our Regulin Repro Team members, please call 1300 6999 16 or use the contact form below.