Use of electroimmobilisation on animals

Purpose

  1. To provide guidance to veterinarians and other users on the use of electroimmobilisation on animals in Australia.
  2. To advocate for the regulation of sale and access to electroimmobilisation devices in Australia.
  3. To advocate for the regulation of users of electroimmobiliser devices on animals in Australia.
  4. To advocate for the use of humane alternatives for animal restraint.
Definitions and scope of policy:

Electroimmobilisation is the use of a pulsed, low-voltage electrical current to restrain conscious animals by causing paralysis via tetanic contracture of skeletal muscles.

The following procedures are not considered to be electroimmobilisation because they are (i) not a method of restraint, and (ii) do not act by causing paralysis:

Policy

  1. The AVA is opposed to the use of electroimmobilisation on animals, except under very limited and defined circumstances in beef cattle. These are:
  • Limited use by suitably experienced veterinarians for safety purposes, and only when other forms of restraint are not available or suitable;
  • Limited use by trained lay operators in emergency situations where a veterinarian is unavailable, and animal or human safety would be at risk without rapid intervention;
  • In all cases, use must be at the lowest voltage and for the shortest duration possible to achieve the desired outcome.
  1. Electroimmobilisation must not be used on beef cattle under any other circumstances than those described above. It must never be used on dairy cattle or sheep, or any other livestock species.
  2. Electroimmobilisation must never be used to perform routine husbandry procedures in any species, including beef cattle: neither as a substitute for effective holding and restraining facilities, nor as a replacement for low-stress stock handling techniques.
  3. Supply of electroimmobilisation devices must be restricted under legislation to veterinarians and veterinary-certified operators only.
  4. Further independent research must be done to establish the animal welfare implications of rectal immobilisers. Until such time that they can be demonstrated to be humane, their use must be strictly regulated.
  5. State animal welfare regulatory authorities must effectively enforce their relevant legislation.

 

Background

There are two types of electroimmobilisers available commercially in Australia:

  • the traditional whole-of-body immobiliser, where electrodes are applied to the head and tail region, and the electric current flows along the animal’s body. The current induces spastic contraction of the muscles throughout the body, preventing voluntary movement.
  • the rectal immobiliser, which uses a rectal probe to deliver a more localised immobilisation of the hind quarters; though according to the marketing material, if moved “deeper into the animal” (presumably more cranially into the colon) it can induce contraction of the forelimb musculature and restrain the head as well.[1]

Both types of devices are currently used under varying field situations in Australia to immobilise livestock such as cattle and sheep, in order to perform certain procedures. These situations range from genuine emergencies where there is no other safe means of restraint available, through to performing routine husbandry procedures such as castration, branding, earmarking, dehorning, spaying and even in the assistance of restraint to milk dairy cows. The AVA does not support use of electroimmobilisation for these routine purposes.

Animal welfare considerations
  1. The effect of the electroimmobilisation device.

Studies conducted on the whole-of-body device demonstrated that the application of electroimmobilisation is aversive and produces greater avoidance behaviour than other forms of mechanical restraint (Carter et al., 1983; Lambooy, 1985; Grandin, 1986; Rushen, 1986; Rushen and Congdon, 1986; Pascoe and McDonell 1986; Petherick et al, 2013; FAWAC, 2005, Whiting 2016). The procedure results in a fully conscious animal experiencing loss of motor control, sustained overstraining of muscles and laboured or suspended respiration (AVMA, 2008). In severe cases when used incorrectly it can cause death from respiratory paralysis and cardiac effects (Cattle Standards and Guidelines Writing Group, 2013).

There are no published studies on the mechanism of action nor animal welfare implications of rectal immobilisers. One unpublished study derived from a manufacturer’s website suggests that the more localised effect may result in a less aversive outcome compared with the whole-of-body model (Webb, undated), but no evidence is provided to back up this statement.  It is likely, based on first principles and the studies of other electroimmobilisation devices, that causing paralysis using a rectal probe will be perceived by cattle as aversive, and is likely to cause pain and distress akin to other electroimmobilisation techniques.

There are no practical pharmacological ways to mitigate the acute effects of electroimmobilisation – this is because the pain caused by electroimmobilisation is ischaemic in nature, mediated mainly by release of ATP and hydrogen ions.  Non-steroidal anti-inflammatory drugs (NSAIDs), for example, do not have a role in alleviating acute ischaemic muscle pain (Mense, 2008). Nor would NSAIDs be expected to have a role in reducing any distress the animal may experience.

A review of the animal welfare aspects of electroimmobilisation use in 2018 concluded that, based on the current limited literature, further research is needed to establish the impacts of the various devices, and that stronger regulation is likely to be necessary due to consumer concerns about humane animal handling (Grobler & Bath, 2018).

  1. Masking of pain and distress

During electroimmobilisation, the animal remains fully conscious and is aware of sensation but is unable to move. This is purposive and allows a procedure to be conducted swiftly, efficiently and safely.  However, electroimmobilisation prevents animals from being able to respond to painful stimuli, and the masking of these responses may act as a disincentive for use of analgesics by operators. AVA policy on Use of analgesia for routine husbandry procedures mandates use of appropriate and effective analgesia during all potentially painful livestock husbandry procedures.

  1. No provision of analgesia

Despite some marketing claims, there is no evidence in the published literature to suggest that any form of electroimmobilisation induces analgesia (Carter et al 1983; Lambooy 1985; Rushen and Congdon 1987; AVMA 2008; Grobler, 2018).

Published literature makes clear distinctions between electroimmobilisation and TENS (transcutaneous neural stimulation) and does not support the suggestion that similarities exist between the modalities in terms of analgesia provided. TENS does not induce paralysis, even at its highest settings, and whether it provides analgesia is also equivocal (AVMA, 2008; Hynd 2017). 

Regulation

Electroimmobilisation devices are banned in the UK and New Zealand but remain available and largely unregulated in Australia. Under the Australian Animal Welfare Standards and Guidelines (S5.8), only trained operators — or those supervised by a veterinarian or trained person — may use them. They can only be used if other restraint methods are inadequate and must never replace pain relief. However, the Cattle Standards have not been consistently adopted nor enforced by the various Australian jurisdictions. 

Under animal welfare legislation, in NSW and Tasmania, use of electroimmobilisation is restricted to veterinarians; in South Australia, users must be certified if they acquired the device after 11 July 1996; and in Victoria, electroimmobilisation is not permitted.  Anecdotal evidence suggests that there are many cases where these legal provisions are not policed or enforced.

 Recommendations

  1. Electroimmobilisation must not be used as a substitute for effective restraining facilities, or poor stockmanship.
  2. It must never be used to perform routine husbandry procedures such as castration, dehorning or spaying of cattle, and never be used in dairy cattle or any species other than beef cattle in the limited situations described.
  3. It is the responsibility of livestock owners to ensure they have appropriate yards, crushes and milking facilities to suit their requirements. Producers should also be encouraged to select for good temperament in their livestock breeding programs and to adopt low-stress stock handling techniques. Where there is risk to the safety of the handler or animal(s), forms of restraint other than electroimmobilisation should always be used in preference.
  4. Electroimmobilisation for veterinary interventions should only be used for animal restraint where there is no feasible alternative.
  5. In remote locations, where immediate access to veterinary services is unavailable, there are some limited scenarios where skilled use of electroimmobilisation by trained operators may allow for treatment of an animal in an emergency situation and therefore avoid the need for euthanasia where this might otherwise not be necessary. For example, on remote northern Australian extensive beef properties, cattle can become caught in wire or other structures and the ability to briefly and temporarily restrain an individual may allow for its safe release. In such situations, where any delay is likely to prolong the animal’s suffering, use of electroimmobilisation for as short a duration as possible may be justified.
  6. A certification program should be developed and implemented by industry for lay operators in those jurisdictions where lay use is permitted. Training should be overseen by suitably experienced veterinarians who certify operator competency on completion of the training and at annual audits.
  7. Only veterinarians, or operators who have been trained and certified as above, should be permitted to use EI, and only where there is no feasible alternative. Non-veterinary operators’ credentials should be audited annually by their supervising veterinarian and updated as required.
  8. Sales of electroimmobilisation devices directly to producers and the public must be banned so that supply is limited to certified operators. Electroimmobilisation devices should only be purchased through the supervising veterinarian who trains, certifies and audits the operator.
  9. Regulators should enforce their respective state legal provisions regarding use of electroimmobilisation.

Other relevant policies and position statements

Pain and analgesia: https://www.ava.com.au/policy-advocacy/policies/surgical-medical-and-other-veterinary-procedures-general/pain-and-analgesia/

Use of analgesia for routine husbandry procedures (ava.com.au): https://www.ava.com.au/policy-advocacy/policies/surgical-medical-and-other-veterinary-procedures-general/use-of-analgesia-for-routine-husbandry-procedures/

References

AVMA 2008: electroimmobilization_bgnd.pdf (avma.org)

Carter PD, Johnston NE, Corner LA et al (1983) Observations on the effect of electro-immobilisation on the dehorning of cattle. Australian Veterinary Journal 60(1):17–19.

Cattle Standards and Guidelines Writing Committee (2013). Cattle Standards and Guidelines Electro-immobilisation Discussion Paper. Prepared February 2013.

FAWAC (2005). Sub-Committee to the Scientific Advisory Committee on Animal Health and Welfare.  The use of electro-immobilisation on live farm animals in Ireland: http://www.fawac.ie/media/fawac/content/publications/scientificreports/ElectroImmobilisationDefinitivereport240505.pdf

Grandin T (1986). Electro-immobilization is NOT a humane method of restraint. (accessed on 3 Feb, 2024): https://www.grandin.com/humane/electro.html

Grandin T, Curtis SE, Widowski TM, Thurmon JC (1986). Electro-immobilization versus mechanical restraint in an avoid-avoid choice test for ewes. J Anim Sci 1986:62;1469-1480: http://www.grandin.com/references/UI-grandin.html

Grobler M and Bath G (2018). Systematic literature review on the animal welfare aspects of the use of electro-immobilisation in livestock: https://doi.org/10.1071/AN15195

Hynd P. I. (2017) Electro-analgesia for sheep husbandry practices: a review. Animal Production Science 57, 801-810.

Lambooy E (1985). Electroanaesthesia or electroimmobilisation of calves, sheep and pigs by the Feenix Stockstill. Veterinary Quarterly 7(2):120–126.

Mense S (2008). Muscle Pain: Mechanisms and Clinical Significance. Dtsch Arztebl Int 2008; 105(12): 214–9.  DOI: 10.3238/artzebl.2008.0214

Pascoe PJ, McDonell WN. (1986) The noxious effects of electroimmobilization in adult Holstein cows: a pilot study. Can J Vet Res. 50(2):275-279.

Petherick JC, McCosker K, Mayer DG, Letchford P, and McGowan M (2013). Evaluation of the impacts of spaying by either the dropped ovary technique or ovariectomy via flank laparotomy on the welfare of Bos indicus beef heifers and cows. J ANIM SCI, 91:382-394. http://www.journalofanimalscience.org/content/91/1/382

Rushen J (1986) Aversion of sheep to electro-immobilization and physical restraint. Applied Animal Behaviour Science 15(4):315–324.

Rushen J, Congdon P, (1986) Sheep may be more averse to electro-immobilisation than to shearing. Australian Veterinary Journal 63(11):373–374.

Shrode RR, Hammack SP. Chute behavior of yearling beef cattle (Abstr.). J Anim Sci 1971;33:193.

Stricklin WR, Heisler CE, Wilson LL. Heritability of temperament in beef cattle (Abstr.). J Anim Sci 1980;51(Suppl 1):109.

VKM (2017). A review on the use of electric devices to modify animal behaviour and the impact on animal welfare. Opinion of the Panel on Animal health and welfare of the Norwegian Scientific Committee for Food and Environment.

Webb S, (undated, unpublished). Electronic neural stimulation for physical restraint in bos taurus – Aversiveness and Humaneness Contrasted with Squeeze Chute Methodology

Whiting T 2016. Pain in human and non-human animals caused by electricity. CVJ/VOL57/ August 2016

 

 

[1]   The rectal probe manufacturer claims that whole body immobilisation to the level of and including the head can be achieved by inserting the rectal probe “deeper” into the animal (https://www.raueasy.com/immobilizer-faq).