Semen collection and evaluation is an extremely important aspect of artificial insemination. Without proper collection of good quality semen, AI is a useless technique. Semen collection can be accomplished in two different yet similar ways, either by manual stimulation or through use of an artificial vagina. In either case, it is useful to have a teaser bitch to aid in the collection. A teaser can either be a female in heat or a female with a pheromone extract rubbed near the base of the tail to simulate heat odor (Lofstedt, 2001). Studies have shown that having a teaser female present can greatly assist in collecting the dog and improve the quality of semen collected. Without a teaser animal obtaining an ejaculate can be difficult or in some cases impossible (, 2006).

     If a teaser is present when performing manual stimulation, the dog will be allowed to mount the bitch and then the collector will firmly grasp the penis and begin rapid massage. If a teaser is not present, the collector simply grasps the penis and begins manual stimulation. Once the dog achieves erection and the prepuce slips behind the bulbus glandis, massage is stopped and the collector will grasp the bulbus glandis firmly until ejaculation is completed (, 2006).

     If an artificial vagina (AV) is used to collect a dog, the dog is allowed to mount the teaser female and the penis is grasped and inserted into the AV. When the penis is inserted into the AV it is likely to see pelvic thrusting on part of the dog and the beginning of ejaculation. Once again the collector will firmly grasp the bulbis glandis until ejaculation is complete (, 2006).

     In both methods, any warm receptacle, often a plastic bag, can be used to collect the semen. Often, during ejaculation the dog will lift his hind leg trying to step over the collector’s arm. This should be allowed as this is the natural position for the continuation of ejaculation in the dog. The ejaculate consists of three different parts. The first amount (1-3 ml) is a clear fluid which does not contain any semen. The second portion (.1 to 6 ml) is a cloudy, sperm rich section. Lastly, a portion containing only fluid from the prostate is ejaculated (1 to 50 ml). On average, ejaculation in the dog usually takes about fifteen minutes. When ejaculation is complete, the dog should be observed to ensure that the bulbis glandis retreats back into the prepuce with the loss of erection (Lofstedt, 2001).

     The semen should be collected into a warm container and kept between 35 to 37 degrees Celsius until sperm motility has been analyzed, at which time the ejaculate can be allowed to cool to room temperature. When evaluating sperm, several different features are examined to determine the quality of the ejaculate. The color of the semen should be a milky white, with the prostatic fluid being a clear supernatant. Total volume of semen collected can vary greatly, anywhere from 1ml to 60ml. Motile sperm should make up 60 to 90 percent of all sperm, and 70 to 90 percent of sperm should be morphologically normal. An average ejaculate should be contain anywhere from 200 to 3000 * 10^6 sperm. Lastly, it is useful to note that bacteria are plentiful in semen, with more than 10,000 per ml on average (Lofstedt, 2001). By using these criteria to evaluate canine semen, good ejaculates can be separated from those with low viability or high contamination.

Components of a normal canine ejaculate (Lofstedt, 2001).
Characteristic Description
Color Opalescent to milky white, clear prostatic supernatant or homogeneous greyish white
Volume Pre sperm fraction: 0.1 to 3 ml,
Sperm-rich fraction: 0.1 to 6 ml,
Prostatic fraction: one to 50 ml,
Total volume: one to 60 ml
Motile sperm (%) 60 to 90%
Morphologically normal sperm (%) 70 to 90%
Sperm per ejaculate (x10^6) 200 to 3000
Bacterial content >10,000/ml

     Collected semen can be used fresh, fresh-extended, or frozen. For semen that is to be inseminated directly after collection, it need not be extended, and the entire amount of semen collected can be inseminated into the female at once (Lofstedt, 2001). Samples that will not be used immediately but will be used within 24 hours of collection should have an extender added to nourishe and protect the sperm. These fresh-extended samples must be cooled until ready for use when they are warmed back to 37 to 39 degrees Celsius. For shipping semen or semen that is to be split into multiple breeding doses, freezing is the most common method (, 2006). Studies have shown that frozen sperm have decreased viability, so a larger dose of sperm is required to achieve fertilization (Pe?, 2003). However, as previously mentioned, freezing semen allows it to be shipped world-wide and it can be stored for long periods of time if frozen properly. Also, viability of frozen semen can be increased by adding the proper extender, buffer, and cryoprotectant, as well as cooling or thawing semen at the proper rate. Dilution of post-thaw semen has also shown beneficial affects on sperm viability (Farstad, 1996). While there are some conflicting reports to the actual conception rate when using frozen semen, 50 to 70 percent conception is usually obtained with slightly higher rates of conception with fresh and fresh-extended semen. In general, the longer the time before semen is inseminated, the lower the conception rate of the female (Lofstedt, 2001).