By Kara Stewart, Purdue University Department of Animal Science; Brad Belstra, Fast Genetics, Madison, Wis.; and W.L. Flowers, North Carolina State University Department of Animal Science
It has long been known that latex has negative effects on overall function of spermatozoa in many species. Therefore, the recommendation has always been to use vinyl gloves when collecting boars. Although vinyl gloves do not appear to have detrimental effects on sperm cells, they can be slippery and do not fit the contour of the hand well. This can make it more difficult to maintain a hold on the end of the boar’s penis during collection. Therefore, boar studs are continually looking for alternatives. As a result, a study was conducted to determine to what effect the material of collection gloves influenced sperm function.
Boars were collected using a bare hand for 10 weeks. Ten milliliters of raw semen was then added to 50 mL conical tubes containing one finger of the following types of gloves: none (control); vinyl (two different lot numbers); nitrile (six different lot numbers); latex; and polyethylene. After two, five, 10 and 15 minutes of exposure to the gloves, a 1 milliliter sample of the ejaculate was analyzed for motility using CASA. After 15 minutes, the sample was evaluated, all treatments were extended in BTS (3 x 109 cells per 80 milliliters) and placed in a storage unit at 17 degrees C. At 24-hours and 72-hours post collection, a 1 milliliter sample of the extended semen was warmed for 30 minutes to 37 degrees C and evaluated.
After two minutes of exposure motility and progressive motility were similar among the controls and all the glove materials except for latex gloves which caused a significant reduction (Figure 1). After five minutes, latex gloves and most of the nitrile gloves (four out of six lots) had lower motility estimates compared with the other treatments. Motility and progressive motility were reduced at 24 and 72 hours for sperm exposed to latex, nitrile and one lot of vinyl gloves compared with the controls and those exposed to polyethylene and a second lot of vinyl gloves.
The results of this study indicate that latex, nitrile and some vinyl gloves can impair spermatozoa motility with as little as five to 15 minutes of exposure. The amount of time that the semen is in contact with the gloved hand during collection can vary as well as the actual technique itself. Some technicians do not completely cover the glans penis allowing the semen to pass freely into the collection vessel with minimal contact with the glove, while others completely cover the glans penis and the entire ejaculate usually comes into contact with the gloved hand.
If semen is exposed to the glove for less than two minutes, then it is reasonable to speculate that the material of which the collection glove is made would have minimal effects on its subsequent quality as long as it is not latex. However, increased periods of exposure are likely to cause significant reductions in motility even after it is extended. Overall, a prudent approach would be to completely avoid latex and nitrile gloves when collecting semen and routinely test different brands and batches of other types of gloves within the same brand in order to characterize any potential detrimental effect on viability of sperm cells.