Electroejaculation of Ruminants
May 1, 2019
The Canadian Veterinary Medical Association (CVMA) considers that the electroejaculation of ruminants is a veterinary procedure. Veterinary skills are required to examine the suitability of the animal prior to the procedure and to ensure optimal: analgesia, restraint of the animal, selection and operation of the equipment and monitoring of the responses of the animal to minimize any discomfort associated with electroejaculation.
- Compared with the alternatives electroejaculation is a convenient, quick and reliable method for the collection of semen
- Electroejaculation has the potential to cause discomfort, especially if the procedure is not conducted appropriately
- Whenever possible, less invasive procedures should be used for semen collection in preference to electroejaculation.
- Where there is no practical alternative to electroejaculation, the procedure must be undertaken in a manner that minimizes discomfort and whenever possible pain relief, sedatives or anaesthesia should be used.
- Electroejaculation is a procedure used to collect semen as part of a breeding soundness examination (1). A breeding soundness examination is undertaken to maintain the fertility of an individual or the herd/flock. Compared with the alternatives (use of an artificial vagina or transrectal massage of the ampullae), electroejaculation is a convenient, quick and reliable method for the collection of semen. It can be used outside of the breeding season, on animals that have not been trained and on those that are not used to handling. Compared with the use of an artificial vagina, no females are required for mounting, there is reduced risk of disease transmission (2), there is less risk of human injury from handling the animal, and it is easier to provide appropriate facilities for human safety. The electroejaculation procedure involves the insertion of a probe into the rectum and the application of short, low-voltage pulses of electrical current to the pelvic nerves that stimulate the smooth muscles of the ampullae and vas deferens to induce ejaculation.
- Electroejaculation has the potential to cause discomfort, especially if the procedure is not conducted appropriately (2,3). The NFACC Code of Practice for the Care and Handling of Sheep (4) states in its requirements that the electroejaculation of rams is a procedure that must only be performed by a veterinarian. Research studies have shown that electroejaculation is an aversive experience for rams (5) and have identified signs (vocalization, increased heart rate, increased respiration rate, increased serum cortisol concentration and increased serum creatine kinase activity) that indicate the potential for rams, bulls and bucks to experience discomfort, pain or distress associated with electroejaculation (6-10). These responses to electroejaculation are mainly due to electrical stimulation rather than a consequence of normal ejaculation (10), restraint or insertion of the rectal probe (6,9).
- Veterinarians intending to use electroejaculation should satisfy themselves that they have had sufficient training in the use of this procedure. Prior to electroejaculation, the animal must be examined to determine its suitability for the procedure and the requirements for analgesia and chemical restraint should be evaluated. The animal must be restrained in a manner that minimises the risks of stress and injury. Gentle handling, habituation to the collection area and positive reinforcement such as feeding can reduce stress (11). Care is required to ensure that the anus and rectum are prepared prior to insertion of an appropriately sized, lubricated and sanitized probe. The equipment used must be manufactured for that purpose and maintained in good working condition. The equipment must be operated in a manner that only uses the minimum electrical stimulation that is sufficient to produce an ejaculation (12). If after repeated electrical stimulation, the procedure fails to produce an ejaculate, or if the animal becomes distressed, or is at risk of injury, the procedure should be stopped, and the animal not reused for an appropriate period.
- Research studies on the use of analgesia either epidural lidocaine, epidural xylazine, intravenous xylazine, or intrarectal topical application of lidocaine have so far failed to demonstrate statistically significant reductions in some of the signs of potential discomfort, such as the serum cortisol concentration, or heart rate responses of bulls to electroejaculation (7,13,14). However, after the use of epidural xylazine in bulls, a reduction in the behavioural signs of discomfort during electroejaculation has been reported (15). Epidural anaesthesia does not interfere with semen collection (7,15).
- Some studies have shown that the electrical stimulation required to induce ejaculation can be reduced by the administration of oxytocin and a prostaglandin-F2alpha analogue, or transrectal massage of the accessory sex glands prior to electroejaculation (16-18).
- Whenever possible, a less invasive procedure e.g. an artificial vagina (that in many circumstances is able to produce similar or better results (19)) should be used for semen collection in preference to electroejaculation. Where there is no practical alternative to electroejaculation, the procedure must be undertaken in a manner that minimizes discomfort, and whenever possible, pain relief, sedatives or anaesthesia should be used. There is a need for research into the development of alternative methods for the efficient and safe collection of semen from ruminants that reduce or avoid the risk of discomfort associated with the current methods used for electroejaculation.
- Hopper RM, King EH. Evaluation of breeding soundness: Basic examination of the semen. Bovine Reproduction. Ames, Iowa, USA: John Wiley & Sons, Inc 2014:68-78. Available from: https://onlinelibrary.wiley.com/doi/abs/10.1002/9781118833971.ch8 Last accessed September 11, 2018.
- Palmer CW. Welfare aspects of theriogenology: Investigating alternatives to electroejaculation of bulls. Theriogenology 2005;64:469-479. Available from: https://www.ncbi.nlm.nih.gov/pubmed/15955553 Last accessed September 11, 2018.
- Stafford KJ. Electroejaculation: A welfare issue? Surveillance 1995;22:15-17. Available from: http://www.sciquest.org.nz/node/46839 Last accessed September 11, 2018.
- NFACC 2013 Code of Practice for the Care and Handling of Sheep. Available from: https://www.nfacc.ca/codes-of-practice/sheep Last accessed September 11, 2018.
- Stafford KJ, Spoorenberg J, West DM, Vermunt JJ, Petrie N, Lawoko CRO. The effect of electro-ejaculation on aversive behaviour and plasma cortisol concentration in rams. N Z Vet J 1996;44:95-98. Available from: https://www.ncbi.nlm.nih.gov/pubmed/16031903 Last accessed September 11, 2018.
- Orihuela A, Aguirre V, Hernandez C, Flores-Perez I, Vazquez R. Breaking down the effect of electro-ejaculation on the serum cortisol response, heart and respiratory rates in hair sheep (Ovis Aries). J Anim Vet Adv 2009;8:1968-1972. Available from: https://www.medwelljournals.com/abstract/?doi=javaa.2009.1968.1972 Last accessed September 11, 2018.
- Falk AJ, Waldner CL, Cotter BS, Gudmundson J, Barth AD. Effects of epidural lidocaine anesthesia on bulls during electroejaculation. Can Vet J 2001;42:116-120. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1476483/ Last accessed September 11, 2018.
- Damián JP, Ungerfeld R. The stress response of frequently electroejaculated rams to electroejaculation: Hormonal, physiological, biochemical, haematological and behavioural parameters. Reprod Domest Anim 2011;46:646-650. Available from: https://www.ncbi.nlm.nih.gov/pubmed/21092067 Last accessed September 11, 2018.
- Whitlock BK, Coffman EA, Coetzee JF, Daniel JA. Electroejaculation increased vocalization and plasma concentrations of cortisol and progesterone, but not substance P, in beef bulls. Theriogenology 2012;78:737-746. Available from: https://www.ncbi.nlm.nih.gov/pubmed/22537995 Last accessed September 11, 2018.
- Abril-Sánchez S, Freitas-de-Melo A, Damián JP, Giriboni J, Villagrá-García A, Ungerfeld R. Ejaculation does not contribute to the stress response to electroejaculation in sheep. Reprod Domest Anim 2017;52:403-408. Available from: https://www.ncbi.nlm.nih.gov/pubmed/28120512 Last accessed September 11, 2018.
- Hargreaves AL, Hutson GD. Handling systems for sheep. Livest Prod Sci 1997;49:121-138. Available from: https://www.sciencedirect.com/science/article/pii/S0301622697000092 Last accessed September 11, 2018.
- Cameron RDA. Semen collection and evaluation in the ram: The effect of method of stimulation on response to electroejaculation. Aust Vet J 1977;53:380-383. Available from: https://www.ncbi.nlm.nih.gov/pubmed/588166 Last accessed September 11, 2018.
- Mosure WL, Meyer RA, Gudmundson J, Barth AD. Evaluation of possible methods to reduce pain associated with electroejaculation in bulls. Can Vet J 1998;39:504-506. Available from: https://www.ncbi.nlm.nih.gov/pubmed/9711391 Last accessed September 11, 2018.
- Etson CJ, Waldner CL, Barth AD. Evaluation of a segmented rectal probe and caudal epidural anesthesia for electroejaculation of bulls. Can Vet J 2004;45:235-240. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC548610/ Last accessed September 11, 2018.
- Pagliosa RC, Derossi R, Costa DS, Faria FJC. Efficacy of caudal epidural injection of lidocaine, xylazine and xylazine plus hyaluronidase in reducing discomfort produced by electroejaculation in bulls. J Vet Med Sci 2015;77:1339-1345. Available from: https://www.ncbi.nlm.nih.gov/pubmed/26097016 Last accessed September 11, 2018.
- Palmer CW, Amundson SD, Brito LFC, Waldner CL, Barth AD. Use of oxytocin and cloprostenol to facilitate semen collection by electroejaculation or transrectal massage in bulls. Anim Reprod Sci 2004;80:213-223. Available from: https://www.ncbi.nlm.nih.gov/pubmed/15036498 Last accessed September 11, 2018.
- Abril-Sánchez S, Freitas-de-Melo A, Beracochea F, et al. Sperm collection by transrectal ultrasound-guided massage of the accessory sex glands is less stressful than electroejaculation without altering sperm characteristics in conscious goat bucks. Theriogenology 2017;98:82-87. Available from: https://www.sciencedirect.com/science/article/pii/S0093691X1730225X Last accessed September 11, 2018.
- Ungerfeld R, Casuriaga D, Giriboni J, Freitas-de-Melo A, Silveira P, Brandão FZ. Administration of cloprostenol and oxytocin before electroejaculation in goat bucks reduces the needed amount of electrical stimulation without affecting seminal quality. Theriogenology 2018;107:1-5. Available from: https://www.ncbi.nlm.nih.gov/pubmed/29120706 Last accessed September 11, 2018.
- Bopape M, Lehloenya K, Chokoe T, Nedambale, T. Comparison of electro ejaculator and artificial vagina on semen collection from South African indigenous goat following assessment by computer aided sperm analysis. Open J Anim Sci. 2015; 5:210-218. Available from: https://file.scirp.org/Html/15-1400324_55970.htm Last accessed September 11, 2018.
((Revised October 2018))