It is generally known that the quality of semen after freezing is dependent upon how good the semen is immediately after collection and prior to freezing. In some cases, there is nothing one can do to improve the quality of the semen collected and therefore, one must deal with the cards he has been given. However, there have been several management factors identified that adversely affect the quality of collected semen.

The goal of every collector should be to carefully prepare the AV and collect the stallion on one mount. Each time a stallion mounts and enters the AV and does not ejaculate the pre-sperm is accumulated in the bottle. After each unsuccessful collection attempt the bottle should be replaced with a warm fresh bottle. If this does not occur, we know that the quality of the semen will decrease.

Preparation of the AV is extremely important. The water temperature placed in the AV should be monitored and the final temperature of the AV prior to collection should be in the 46-50 degree Celsius range. It is not enough to use one’s hand to feel the AV and say that it is OK, but the temperature should be determined by a thermometer that has been calibrated and known to be correct. If an AV is too hot, the sperm can be damaged. Also, the stallion may be reluctant to breed a hot AV or if he does and it burns him then he may be reluctant to breed again. However, it is more likely that the AV temperature is too low because the hot water tank is not turned up high enough. If this is the case, then the stallion will not work the AV and may not ejaculate on the first mount or even after several mounts.

The skill of the collector can also affect how quickly the ejaculate is collected and how many mounts are required. Holding the AV at the wrong angle can disturb the stallion and prevent him from ejaculating. Failing to drain the water out of the AV immediately after collection can trap the sperm in the hot part of the AV and damage the motility and morphology of the sperm. This may also cause latent damage. This is where the damage is not seen immediately but shows up after storage of the sperm such as with cooled semen.

The amount of lubricant used to prepare the AV is extremely important. One common mistake is that the technician uses a whole hand full of lubricant. This results in the lubricant being driven into the semen by the stallion’s penis and the sperm are severely damaged by the high osmotic pressure of the lubricant. One should use only a small amount to lubricate the front part of the AV.

In collaboration with the Gluck Center at the University of Kentucky, we examined data from stallions collected by SBS in Maryland and Texas to see what effect multiple mounts prior to ejaculation had on the initial semen after collection and what effect multiple mounts had on the quality of the semen after freezing. We also asked, “what is the relationship between the initial concentration after collection and the quality of semen after freezing and thawing?” Our thought being that the higher the concentration, the better the post-thaw motility.

Semen collection and freezing records were available from 761 stallions and a total of 12,397 ejaculates over the period of 1996-2012. The criteria were that

Initial measurements included total motility, progressive motility, and concentration of sperm upon collection, gel-free semen volume and the total number of sperm in the ejaculate.

Results – Objective #1

Results – Objective #2

The second objective of this study was to determine the relationship between the initial concentration of the sperm upon collection and the post thaw motility.

This information was presented orally at the 11th International Symposium on Equine Reproduction in Hamilton New Zealand on January 26-Feb 1, 2014. The senior author on the paper was a student, Julie Kalmar, who was working on a MS degree at the University of Kentucky.