Currently, painful husbandry procedures are routinely carried out in many sheep farming systems. Pain is an unpleasant sensory and emotional experience associated with tissue damage [1]. Any husbandry procedure that results in damage to living tissue should be assumed to cause pain and approached accordingly. Thus, all sheep farmers should aim to identify and adopt humane husbandry and management practices that do not cause pain, suffering or distress to animals. In the interim, best practice pain relief should be used.
Overview of husbandry practices
Routine husbandry practices carried out on sheep include shearing, application of chemicals to prevent or treat external parasite infestations, oral administration of anthelmintics to treat internal parasite infestations, foot inspections and vaccination. These procedures may cause stress in sheep, but they are unlikely to be significantly painful (unless rough handling or injury occurs).
Procedures considered to cause pain include tail docking, castration, and mulesing, which are generally carried out on lambs. Later in life, some ewes may be surgically artificially inseminated or undergo embryo transfer for reproductive purposes. Sheep undergoing these procedures will often display behaviours indicative of pain [2]. Pain-related behaviours in sheep vary depending on where the painful area is located, but may include head turning, foot stamping, lying on their side, rolling and writhing, restlessness, reluctance to move and bleating. Similar to other prey species, sheep may hide signs of pain in the presence of predators, including humans [2,3]. This is thought to be an evolutionary adaptation to reduce the risk of predation [2].
Prior to performing a painful procedure on farm, proper consideration must be given to the following:
- Removal: If the procedure is not justified, stop using the procedure
- Alternatives: Replace the procedure with a painless or less painful alternative
- Breeding/genetics: Where possible, rear animals that no longer require the use of such procedures (e.g. breeding for sheep that are resistant to flystrike so that mulesing is not needed)
- Modify: Improve the procedure in order to minimise pain intensity and/or duration
- Treatment: Pain reduction or prevention using anaesthesia and analgesia (pain relief). [4]
Painful husbandry procedures
Tail docking
The main reason that sheep are tail docked is to reduce the risk of flystrike (being infested by blowflies) by reducing the opportunity for urine and faeces to soil the hindquarters. However, evidence on whether tail docking does in fact reliably reduce flystrike risk is sparse and contradictory [5,6]. Alternatives to tail docking are to breed selectively for shorter tails (although heritability of this trait varies depending on sheep breed), or to reduce the flystrike risk of sheep with intact tails when needed, such as with crutching (shearing wool around the tail and hind legs) and pesticide usage [7,8].
Tail docking is routinely performed on young lambs using either a rubber ring, sharp knife, or hot docking iron. Lambs that are killed at an early age, e.g., for meat production, should not be tail docked. If the procedure is performed, it should be done on young lambs (less than 3 months of age) and accompanied by an effective local anaesthetic and a long-acting analgesic. Although all tail docking methods cause pain, research indicates that hot iron cauterisation is the least painful method. The length of the docked tail should at least cover the vulva in female lambs and an equivalent length in male lambs, as very short tails can increase the risk of flystrike, cancer and surgical complications [9].
Mulesing
Mulesing involves the use of shears to cut away wool-bearing skin from part of the tail and hindquarters of Merino sheep used mainly for wool production, to reduce the incidence of flystrike in the hindquarters. The main reason for mulesing is that Merino sheep have been bred to have highly wrinkled skin to increase wool production, but this leads to a significant risk of flystrike. It is unacceptable to continue to breed sheep that are susceptible to flystrike and therefore require mulesing or other painful procedures to manage flystrike risk. For more information and RSPCA’s position on mulesing sheep, read here.
Castration
Male lambs are routinely castrated to prevent unwanted breeding, reduce aggression and sexual behaviour, as well as minimise the risk of injuries to the animal, other animals and animal handlers. Castrated males may also produce preferred meat and carcass quality traits compared to non-castrated males [8].
The most common methods of castration include using a rubber ring or cutting using a knife or blade. Fertility control of sheep using a hormone-based vaccine program may be a viable option in the future [10]. All castration methods that are currently used cause signs of pain in sheep [8] so, regardless of the method used, local anaesthetic and a longer acting analgesic (pain relieving drug) should be given at a minimum.
Laparoscopic artificial insemination and embryo transfer
Artificial insemination via laparoscopy (‘keyhole’ surgery) is a surgical breeding procedure performed on sheep and goats. It is mainly carried out to facilitate the use of frozen semen [11].
The procedure involves penetration of the abdomen with a laparoscope (a surgical instrument with a small camera on the end), and injection of semen directly into the uterus of the ewe. Gas is also infused into the abdominal cavity so that the person performing the procedure can better view the reproductive tract. The procedure can result in high pregnancy rates and efficient semen use, however it requires specialised equipment and surgical expertise. Non-surgical insemination methods are challenging in sheep and goats due to the shape of their reproductive tract. Surgical artificial insemination is associated with signs of pain in sheep [2], and the restraint required for the procedure is likely to be stressful.
Surgical artificial insemination should only be performed if it is likely to significantly benefit the welfare of future generations of sheep, for example by introducing genetics that would negate the need for painful husbandry procedures. It should only be undertaken by veterinarians, with appropriate analgesia, anaesthesia and sedation. Minimising pain, discomfort and stress should be a high priority.
An additional concern with the procedure is that it can involve the use of a hormone (equine chorionic gonadotropin, or eCG) to stimulate the ewe’s reproductive cycle. This hormone is produced from blood collected from pregnant horses farmed for this purpose. The condition and treatment of horses on these farms is a serious animal welfare concern [e.g., [12]] and the use of eCG should be urgently replaced with synthetic alternatives.
Embryo transfer is carried out as a means of producing a greater number of offspring from a favoured female than can be achieved through conventional breeding. The procedure involves the collection of embryos via laparoscopy from the uterus of a ewe with favoured genetic traits (the ‘donor’ ewe). Collected embryos are then deposited (‘transferred’) into the uterus of a recipient ewe, generally also via laparoscopy [11]. Given that surgical methods for embryo transfer involve penetration of the abdominal cavity, the welfare risks are similar to surgical artificial insemination. Welfare risks apply for both the donor and recipient ewes. Non-surgical methods exist but are difficult to perform due to sheep’s anatomy [11].
Competency and animal handling
All people handling sheep and/or performing painful procedures must be appropriately trained and able to competently undertake their required tasks. Sheep should be handled calmly and quietly, using principles of low-stress handling [3]. If young animals are separated from their mothers to perform a procedure, they should be returned as soon as possible to minimise stress. Before commencing a painful procedure, sheep should be restrained in a manner that is appropriate to the age and size of the animal, as well as to the procedure being performed. The restraint method should be as quick as possible, avoid pain and minimise stress to the animal. Personnel need to have the ability to recognise and address signs of pain, suffering or distress. Contingency plans should be in place and adhered to should euthanasia or emergency veterinary care be required.
One Welfare
Reducing the use of painful procedures and minimising sheep pain and stress where procedures are performed may contribute to a better working environment and greater job satisfaction for farm staff. Click here for more information on One Welfare.
What is the RSPCA’s view?
Before performing any painful procedure, proper consideration must be given to alternatives that could eliminate the need for the procedure. Where it is considered necessary to undertake a painful procedure, it must be done at the youngest possible age. All procedures must be performed by trained, highly skilled and competent operators. Pain relief using effective analgesics and anaesthetics must be provided, as well as sedation where appropriate. Current good practice pain relief for procedures such as castration, tail docking and mulesing involves the use of a local anaesthetic in combination with a non-steroidal anti-inflammatory drug. Research priorities should be aimed at progressing alternatives to painful invasive procedures (e.g., breeding for traits that remove the need for certain procedures to be undertaken) as well as urgent development of technologies that provide longer-lasting pain relief.
References
[1] International Association for the Study of Pain. IASP Announces Revised Definition of Pain [Internet]. 2020 [cited 2023 Aug 2].
[2] Small A, Fisher AD, Lee C, Colditz I. Analgesia for Sheep in Commercial Production: Where to Next? Animals. 2021;11:1127.
[3] Grandin T. The importance of stockmanship to maintain high standards of handling and transport of livestock and poultry. In: Grandin T, editor. Livestock handling and transport. 5th ed. Oxfordshire, UK: CABI; 2019. p. 1–11.
[4] Stafford K, Mellor D. Painful husbandry procedures in livestock and poultry. In: Grandin T, editor. Improving animal welfare: a practical approach. CABI; 2022. p. 88–114.
[5] Sutherland MA, Tucker CB. The long and short of it: A review of tail docking in farm animals. Appl Anim Behav Sci. 2011 [cited 2012 Mar 24];135:179–91.
[6] Orihuela A, Ungerfeld R. Tail docking in sheep (Ovis aries): A review on the arguments for and against the procedure, advantages/disadvantages, methods, and new evidence to revisit the topic. Livest Sci. 2019;230:103837.
[7] Webb-Ware J, Vizard A, Lean G. Effects of tail amputation and treatment with an albendazole controlled-release capsule on the health and productivity of prime lambs. Aust Vet J. 2000;78:838–42.
[8] Gascoigne E, Mouland C, Lovatt F. Considering the 3Rs for castration and tail docking in sheep. In Pract. 2021;43:152–62.
[9] Woodruff ME, Doyle R, Coleman G, Hemsworth L, Munoz C. Knowledge and attitudes are important factors in farmers’ choice of lamb tail docking length. Vet Rec. 2020;186:319–319.
[10] Needham T, Lambrechts H, Hoffman LC. Castration of male livestock and the potential of immunocastration to improve animal we. S Afr J Anim Sci. 2017;47:731.
[11] de Graaf S, Leahy T. Controlled breeding. In: Abbott K, editor. The Practice of Sheep Veterinary Medicine. 1st ed. University of Adelaide Press; 2019. p. 238–64.
[12] Vilanova XM, De Briyne N, Beaver B, Turner P V. Horse welfare during equine chorionic gonadotropin (eCG) production. Animals. 2019;9:1–10.
