Urethral catheterization and sperm vitrification for simplified semen banking in felids

Abstract

ContentsSemen banking of domestic cats and wild felids represents a vital resource for their long-term conservation, but current methods require access to advanced training and specialized equipment. A newer method of semen collection, urethral catheterization of medetomidine-treated cats, allows recovery of high sperm numbers, but it is unclear if this approach permits maximal sperm recovery or is feasible using less expensive alpha-2 agonists. Similarly, a newer sperm preservation approach, vitrification, offers advantages of simplicity and minimal equipment needs, but its efficacy in combination with urethral catheterization has not been investigated. Our specific objectives were to (i) evaluate sequential semen recovery with urethral catheterization and electroejaculation in domestic cats, (ii) assess the effectiveness of a weak (xylazine) versus strong (dexmedetomidine) alpha-2 agonist for inducing sperm release, and (iii) compare post-thaw sperm motility, acrosome status and fertilizing capacity of catheter-recovered samples after vitrification or straw freezing. Results indicated that electroejaculation following repeated catheterization allowed recovery of additional spermatozoa (range, 11-32 × 10 6 sperm/male) and that xylazine was ineffective for inducing meaningful sperm release (range, 0-0.4 × 10 6 sperm/male). Post-thaw motility and acrosome status of vitrified catheter samples did not differ (p > .05) from that of straw frozen samples. Preliminary results indicated that in vitro fertilization success (9/30, 30%) of vitrified catheter sperm did not differ (p > .05) from that observed with straw frozen samples (17/30, 57%). In conclusion, urethral catheterization of dexmedetomidine-treated cats allows recovery of substantial sperm numbers but electroejaculation still may be warranted for maximal sperm recovery. Xylazine is not suitable as an inexpensive alternative to dexmedetomidine for catheterization.Vitrification of catheter samples results in comparable post-thaw parameters to straw freezing and may be adequate for use with oviductal insemination procedures.

The Comparison of Semen Collection in Electroejaculation, Rectal Massage and Combination of Both Methods in the Critically Endangered Malayan Pangolin, Manis javanica

“…The findings were similar in the use of anesthesia in other wild mammals, using the xylazine combination under general anesthesia, in which the semen can sometimes be collected readily on the penile tip with the manipulation and positioning of the electroejaculator probe as an effect of immobilization [48]. However, it was found that medetomidine has 10 times more specificity towards the alpha-2-receptors than xylazine, indicating medetomidine as the better drug for spermatozoa recovery [49]. Digital massage of the rectal for semen collection in the sedated animals was also observed in other wildlife, together with the aid of gravitational pull through the positioning of the animal on a raised platform [50].…”

Vitrification Using Soy Lecithin and Sucrose: A New Way to Store the Sperm for the Preservation of Canine Reproductive Function

“…Despite these efforts, sperm vitrification has not gained popularity so far, and encouraging results have not yet been established in most species studied [5]. Effective vitrification methods have only been developed in felids, and the successful nature of this procedure is evidenced by litters having been produced in captive exotic and domestic cats [6,12].…”

Vitrification in straws conserves motility features better than spheres in donkey sperm

“…In this paper, a fixed sucrose concentration has been employed, but it is known carbohydrate requirements seems to be different regarding animal species (Caturla‐Sánchez et al., ; Merino et al., ; Pradiee et al., ; Swanson et al., ). In this sense, it would be necessary to carry on further studies including different sucrose concentrations in the extenders as well as different volume and concentration of the sperm suspension required for each vitrification technique.…”

“…It has showed a strong cryoprotective effect and has been achieved in two different ways: dropping sperm directly in LN 2 , obtaining spheres; or in filled straws and then immersed in LN 2 . The sphere method has shown to protect sperm parameters after vitrification and warming in human (Isachenko et al, ), dog (Sánchez et al., ), fish (Merino et al., ), wild goat (Pradiee et al., ) and cat (Swanson et al, ). Likewise, vitrification in straws has obtained good results in human (Sanchez et al., ), domestic goat (Daramola et al., ) and donkeys (Diaz‐Jimenez et al., ).…”