Pain relief

From 1 July 2020, Victorian producers are required to administer a registered pain relief product if mulesing sheep.

The new regulation, under the Prevention of Cruelty to Animals Regulations 2019, makes it an offence to mules sheep without using pain relief. So what pain relief products are available, how do they work, and what provides the best pain relief, considering that mulesing is usually performed in conjunction with tail docking and castration?

From 1 July 2020, you must use a pain relief product registered by the Australian Pesticides and Veterinary Medicines Authority (APVMA) for pain relief in sheep when mulesing. The APVMA website lists numerous products registered for pain relief in sheep. Some of these products are controlled substances or gaseous anaesthetics so, in practice, your choice is down to two different types of pain relief products:

• local anaesthetic in the form of Tri-Solfen® or Numnuts®
• systemic anti-inflammatories or nonsteroidal anti-inflammatory drugs (NSAIDs) – two products (Buccalgesic® and Metacam 20®) that contain the active ingredient meloxicam.

Local anaesthetics

If you have been to the dentist and had a filling, you know what a local anaesthetic is. They take a few minutes to work and provide very good pain control for four to six hours. There are two ways of administering these products:

• topical application – that is, the local anaesthetic is applied directly to a wound (Tri-Solfen®)
• local injection of the anaesthetic (Numnuts®).

Tri-Solfen® contains two local anaesthetics (bupivicaine and lignocaine), adrenaline to reduce blood loss and an antiseptic (cetrimide). It is suitable only for open wounds – for example, following mulesing and open-knife castration. It can be purchased from your rural merchandise store.

The cost of Tri-Solfen® for a 15 kg animal is $1.15 for mulesing only. The meat withholding period (WHP) is 90 days, and export slaughter interval (ESI) is 90 days.

Numnuts® is a system for applying elastrator rings and at the same time delivering local anaesthetic precisely where it is required. It uses the local anaesthetic Numocaine® (lignocaine) and is a ‘veterinarian only’ (Schedule 4) product. It is both safe and easy to use. It is specifically designed, and is only suitable for ring application on tails and scrotums.

The cost of Numocaine® is $0.67/dose for scrotum and $0.67/dose for tail. Meat WHP is 0 days, and ESI has not been established.

In summary, local anaesthetics provide very quick and highly effective but short-term (four to six hours) pain relief.

Systemic anti-inflammatories

If you have taken an ibuprofen tablet, you know what an NSAID is. The most useful of this class of drugs in sheep is long-acting potent meloxicam, which comes as:

• an injectable solution – Metacam 20® (there are also numerous generic brands)
• an oral dose absorbed across the mucous membrane lining the mouth – Buccalgesic®.

There is nothing to separate the two with respect to pain relief. The choice will be based on your preference of injectable or oral and your set-up at marking. Both these products work within 10 to 15 minutes and are effective for 48 to 72 hours. They work by decreasing inflammation and pain at the wound site.

These products can only be supplied by your vet and cannot be purchased over the counter.

The cost for a 15 kg animal is $0.70. Metacam 20® meat WHP is 11 days, and ESI is 11 days. Buccalgesic® meat WHP is 10 days, and ESI is 10 days.

In summary, products containing meloxicam appear to be slower acting but provide a longer period of pain relief than local anaesthetic.

Using two forms of pain relief

For a procedure such as mulesing, there are advantages in using two different pain relief products at the same time. Using a local anaesthetic such as Tri-Solfen® and an anti-inflammatory such as meloxicam provides more immediate and greater pain relief for a longer period than either product used alone, as they act on two different pain pathways and are complementary.

Sourcing vet-only products

Numnuts®, Metacam® and Buccalgesic® are all vet-only products – that is, they need to be dispensed by a vet, and you have to have a bona fide vet–client relationship. If you haven’t used your vet for a while, they may not be able to legitimately prescribe these products, so talk to your vet a few weeks out from marking.

In summary, the choice of pain relief (see Table 2) will depend on your set-up, the number of animals, the meat WHP or ESI, and the procedures you are carrying out. Remember – if you are mulesing, you must use a registered form of pain relief, so think about the other procedures you are carrying out at the same time and determine what is the best fit overall.

Table 2 Suggested pain relief approach

Source: Dr Andrew Whale, Livestock Logic, Hamilton

More information

For more information about pain relief in livestock, listen to Dr Andrew Whale’s webinar on pain relief, at the Victorian Farmers Federation YouTube channel.