A Modification of the Crump Manual Semen Collection Method
as Used by the University of PA (New Bolton Center)
– Description of semen collection from a stallion without using an AV, but using a modified manual stimulation (“Crump”) technique.
By Jos Mottershead
A reprint of Jim and Julia Crump’s paper on the technique (Crump Jr. J, Crump J. 1989. Stallion Ejaculation Induced by Manual Stimulation of the Penis. Theriogenology31;2:341-346) can be found on their Roanoke AI Labs web site (requires Adobe Acrobat Reader). The following method is a modification of the method described therein.
After the stallion is washed (if desired) and teased to produce an erection, a plastic collection bag is secured around the penis by tape (don’t secure the tape directly to the penis, and don’t have the tape so tight as to interrupt circulation – remember the penis will become engorged just prior to and during ejaculation). A useful alternative to a regular plastic bag is a rectal palpation sleeve (glove), tying a knot at the distal end to close off the fingers. Once secured, hot compresses are applied initially to the glans of the penis, and after a thrusting response occurs, the upper portion of the shaft in the region of the preputial ridge. We have used compresses that were the thin (half-inch) man-made dishwashing “sponges” which measure about 8 inches by 10 inches. These are submersed in hot water (55 degrees Celsius – a good guide is “as hot as your hand will stand it”), and squeezed out immediately before application. The first is held in the “flat” of the left hand (if the technician is on the left – “near” – side of the horse), with the flat of the hand being applied against the end of the glans of the penis. The stallion should then drop his hindquarters slightly, and start a thrusting motion against your hand. Allow the hand to move with the thrusting, and at the same time use the other (right) hand to form a “U” of the thumb and index finger, with the second compress inside the “U”, and gently apply pressure with this hand on each side of the penis shaft at the upper end. This simulates the pressure applied naturally by the vulva, whereas the left hand is simulating the pressure applied when pushing against the cranial portion of the vagina (caudal cervix). No great amount of pressure is required, and in fact stallions will often resent excessive pressures. Be sure to follow the thrusting movement of the penis with one’s hands.
After a short period of this stimulation (it varies with stallion, but considerably less than a minute would be “normal”) the stallion will hopefully ejaculate, and the semen is collected in the bag. If manual dexterity is one of your strong points, you can fractionate the ejaculate by “pinching off” the collection bag after a couple of ejaculatory spurts, thereby separating out the gel fraction, which is presented in the tail-fraction of the ejaculate.
Not all stallions will respond to this method, but many will. Collections can be carried out on the ground, or on a breeding mount (or I suppose on a mare if so desired). A good stallion handler is an important part of the team, especially the first few times this is done, as it is possible that the stallion unused to such handling may kick. Obviously for the same reason, suitable positioning of the collector is important. Advantages of this method include reduction in equipment costs and also preparation time for collection. Disadvantages include the fact that not all stallions accept this degree of penile handling and that in cold weather it can be difficult to maintain adequately warm temperatures with the sponges and also the semen if ejaculation is achieved.
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