Electroejaculation of Bulls
Position
The Canadian Veterinary Medical Association (CVMA) believes that electroejaculation is acceptable as a portion of a breeding soundness examination of bulls.
Background
In recent years, lobbying efforts by animal welfare concerns has resulted in scrutiny of the practice of electroejaculation (EEJ) of bulls for diagnostic and reproductive purposes as animal behaviour at the time of EEJ is consistent with a somewhat painful or uncomfortable experience (1-3).
Nearly all electroejaculation is performed as part of breeding soundness examinations of bulls by veterinarians (4). A breeding soundness examination is a prudent measure undertaken to ensure the fertility of the individual and the herd. Attempts to use artificial vaginas as a replacement for EEJ have been relatively unsuccessful (resulting from reluctance of bulls to perform under observation and in a confined situation) (5,6). The use of cow condoms as a method of obtaining samples is experiencing similar difficulties and EEJ remains the most reliable method for obtaining semen samples (7). It should be noted that a satisfactory sample obtained by EEJ does not equate to breeding soundness and that some deficiencies will only be detected on close observation of the actual breeding performance.
The use of restrained cows for mating with artificial vaginas or cow condoms provides other animal welfare concerns.
Equipment used
Electroejaculation is accomplished by the electrical stimulation of the smooth muscles of the ampullae and vas deferens through the use of an intra-rectal probe and an electrical source with voltage control. This equipment has been in use for approximately 50 years, and has undergone numerous modifications to adapt it specifically for use in bulls (1,2).
The innovations of longitudinal electrodes (as opposed to ring electrodes), epidural aneasthesia, sedation, and programmed controls have shown promise in making EEJ a less distressful experience, based on plasma cortisol and aversion studies.
Animal welfare implications
Observations on bulls subjected to EEJ two or three times a week was consistent with bulls developing no aversion to the technique (10). Veterinarians are encouraged to keep abreast on ongoing research into the animal welfare implications and into the alternatives to electroejaculation.
References
1. Stafford, K. J. Electroejaculation; a welfare issue. Surveillance 1995; 22:15-17
2. Palmer CW. Welfare aspects of theriogenology: investigating alternatives to electroejaculation of bulls. Theriogenology 2005;64(3):469-479.
3. 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(8):504-6.
4. Chenoweth PJ. Rationale for using bull breeding soundness evaluations. Comp Cont Edu Pract Vet 2000;22(2):S48-S55
5. Falk, A. J. ; Effects of epidural lidocaine anesthesia on bulls during electro-ejaculation, Can Vet J 2001;42:116-120
6. 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(3):235-240
7. Palmer CW, Amundson SD, Brito LF, Waldner CL, Barth AD. Use of oxytocin and cloprostenol to facilitate semen collection by electroejaculation or transrectal massage in bulls. Anim Reprod Sci. 2004 Feb;80(3-4):213-223
8. Palmer CW, Brito LF, Arteaga AA, Soderquist L, Persson Y, Barth AD. Comparison of electroejaculation and transrectal massage for semen collection in range and yearling feedlot beef bulls. Anim Reprod Sci. 2005;87(1-2):25-31.
9. Falk AJ, Waldner CL, Cotter BS, Gudmundson J, Barth AD. Effects of epidural lidocaine anesthesia on bulls during electroejaculation. Can Vet J. 2001;42(2):116-120.
10. Barth AD, Bowman PA. The sequential appearance of sperm abnormalities after scrotal insulation or dexamethasone treatment in bulls. Can Vet J. 1994;35(2):93-102
(Adopted March 2006)