Frequently asked questions

Numnuts is entirely unique. Nothing else exists that can provide targeted pain relief to lambs during tail docking and castration. Here are some of the questions we’ve been asked during the past 8 years.

Numnuts and NumOcaine are now available in Australia.

Numnuts devices and spare parts can be bought directly from our online store.

NumOcaine is an S4 drug and must be bought from a registered vet. Please speak to your usual vet to arrange your NumOcaine supply, or get in touch with us for advice.

We hope to make the Numnuts system available in the UK and NZ in 2020. We are actively seeking UK Vet practices who wish to partner. 


Marking lambs usually involves both tail docking and castration. Numnuts has been especially developed for the combined procedure of docking the tail of male and female lambs as well as castrating male lambs with rubber ring. 

Numnuts is available on a ‘cost per procedure basis’ and is competitively priced against current pain relief products.  

If you are based in Australia, you can find our how much it will cost you by trying our cost estimator tool:  

There are two components to Numnuts: the ring applicator tool and the local anaesthetic, called NumOcaine®.

The ring applicator tool will last for many seasons.

The local anaesthetic comes in an injector cartridge, called a Quick Change Cartridge (QCC), that locks on top of the ring applicator tool, and is replaced every 65 shots.  This procedure ensures there is a sterile bottle of pain relief drug ready to use in each new cartridge.

The packaging has been carefully designed for operator convenience, and for operator and lamb safety. Using a new needle with every other injector cartridge helps minimise the risk  of infection to the lamb, and ensures that the needle remains sharp. This innovation is more humane than the common practice of using a single needle for 100s of animal injections, for instance during vaccination and some worm treatments.

In Australia, NumOcaine® is classified as an S4 drug and must be bought from a registered veterinarian. Regulations controlling the supply of the NumOcaine® injector module will vary between countries. Further details will be provided on this website when country-specific details become available.

Yes. The Numnuts system has been designed to utilise traditional rubber rings — a bloodless and highly effective, farmer-friendly method for castration and tail docking lambs that is used in many countries.

Numnuts has been designed for use on lambs held in the type of marking cradle commonly used in Australia and New Zealand, however Numnuts can also be used without a lamb marking cradle.

When lambs more than 7 days of age are marked, a cradle improves the ease with which lambs are held for marking. When lamb marking is carried out at 2-8 weeks of age an animal handling system like a lamb marking cradle is recommended.

A trained operator can apply Numnuts in 2-3 seconds

We believe the marginal additional time taken to push the local anaesthetic injection plunger on the Numnuts device is offset by the improved ergonomics and reduced RSI associated with using our unique innovative tool for applying rings to the tail and scrotum at marking.

Numnuts engineers worked alongside veterinarians, stockpersons, shepherds and farmers to ensure that Numnuts is safe, fast and practical to use by animal handlers familiar with marking lambs.

Numnuts does not alleviate all the pain a lamb experiences during castration and tail docking. Numnuts reduces the pain lambs experience substantially when they are marked. 

For a lamb, marking may be similar to the human experience of visiting a dentist. For a human, having a filling or a tooth extraction after an injection of local anaesthetic is usually not without some pain. Similarly at present, pain relief provide by Numnuts does not abolish all the pain associated with marking.

Numnuts has been developed in collaboration with veterinarians and animal behavioural scientists at two world leading animal health and animal welfare research organisations; Moredun Research Institute and CSIRO with the goal of reducing the pain experienced by lambs at marking.
Local Anaesthetic (LA) is the ideal class of drug for reducing acute pain. NumOcaine®, the LA in Numnuts, is a powerful drug that quickly blocks the transmission of pain signals by nerves.

NumOcaine® is injected directly where the ring is applied to the tail and scrotum. The marking ring disrupts blood flow to the tail and testicles, and the pain of ring castration and ring tail docking commences at these sites. Pain develops around 2 – 5 minutes after band application from loss of oxygen supply, and the acute pain associated with the procedure lasts 60-90 minutes. LA reduces the conduction of pain by nerves for a similar time frame.

Local anaesthetics are therefore an excellent choice for reducing the acute pain when lambs are marked with a rubber ring.

In contrast, non-steroidal anti-inflammatory drugs (NSAIDs) have a slower onset than local anaesthetics. They act by a different pathway to reduce the production of chemicals that provoke tissue inflammation and pain, called prostaglandins. NSAIDs are a good choice for reducing dull and chronic pain, once the immediate and most intense phases of pain have passed.
The withholding period for NumOcaine®  in Australia is 0 days.  

We have shown a significant improvement in the time it takes lambs to find their mothers and start suckling after having had NumOcaine administered with rubber ring. Numerous farmers have also reported that Numnuts lambs muster better, and can be herded back to the paddocks/ fields faster, with less dog intervention and less misadventure.

Most experts in this field feel it is unlikely that benefits from pain management at lamb marking will ever be measurable in terms of improved end production or profitability. Whatever temporary productivity setback a lamb might suffer without pain relief will have been compensated for by the time it (or its wool) goes to market. That compensation is likely to come at the cost of poorer feed conversion, but, under extensive production conditions, we simply do not have the instruments with which to measure this accurately.

The profitability the farmer will see is the knowledge that they are doing the right thing for their animals during necessary husbandry procedures, while sustaining continued access to a sheep-meat-eating and wool-producing consumer market that is showing an increased interest in the welfare of the animals that produce the meat and wool that they consume.

Regulations controlling marking practices varies between countries. In Australia, animal husbandry practice guidelines recommend marking lambs between 2 to 8 weeks of age, whereas government regulations indicate that marking should, where possible, occur between 2 and 12 weeks of age. Numnuts is designed to be used on lambs up to 12 weeks of age.


Lambs over 7 days old must be given a local anaesthetic prior to castration, which is exactly what Numnuts delivers.

However, lambs more than 3 months old may only be castrated by a vet (Veterinary Surgeons Act, 1966)

Numnuts is designed for castrating and tail docking lambs using rubber rings. However ‘Ring and Remove’ is an option: a ring can be placed on the tail using the Numnuts device and NumOcaine administered, and then tail removed on the distal side of the ring. Efficacy of ‘Ring and Remove’ has not yet been evaluated.

This article provides information on tail length best practice guidelines:

Numnuts is designed for marking lambs. NumOcaine is approved for calves – they will likely need more than one dose. No efficacy data currently exists. A future Numnuts device for calves is in future development pipeline.

Tail docking reduces soiling of wool with urine and faeces. This reduces the risk of sheep contracting the painful, and potentially fatal, disease ‘fly-strike’, and reduces the risk of carcass contamination in the abattoir.

Castration reduces fighting between males, improves meat and wool quality, and enables the farmer to selectively breed sheep for beneficial traits by use of superior sires.