Sperm quality after collection with three different UrCaPI (Urethral Catheterization after Pharmacological Induction) protocols

The urethral catheterization after the medetomidine pharmacological effect (UrCaPI) is the most practical technique to obtain a good cat ejaculate because not requires a specific equipment, as the electroejaculation (EE), or a trained tomcat, as the sperm collection with artificial vagina. As reported in literature the sperm collected by UrCaPI or by EE could be used for cryopreservation or for in vitro fertilization with the same results. The aim of this study is to evaluate if different protocols used for UrCaPI collection permits to obtain significative differences in sperm quality.In this experiment were enrolled male cats referred, between January and May 2009, to Animal Reproduction Unit of Veterinary Clinical Department – University of Bologna, in order to be submitted to orchiectomy. A total of 59 adult (1-4 years), mixed-breed male cats, privately owned or belonging to a cat pound, clinically healthy with two palpably normal descended testicles were used for this experiment. Before starting the study, the cats were random assigned to one of three groups for sperm collection using different protocols of UrCaPI. The UrCaPI was performed as described by Zambelli et al., using a 3F by 11 cm long urinary tomcat catheter with the tip cutted. All the animals were intramuscularly injected with medetomidine (120 μg/kg of body weight) in order to perform sperm collection and then the anaesthesia was maintained with 1.5-2% isoflurane in oxygen in order to perform the orchiectomy. In 11/59 cats (group 1) the collection was performed immediately once medetomidine pharmacological effect was obtained, 23/59 cats (group 2) were collected three times every 5 minutes after the pharmacological effect, finally in 25/59 (group 3) UrCaPI was performed 20 minutes after pharmacological effect was reached. Semen was collected into a pre-warmed plastic 1,5 mL eppendorf tube. The volume was measured using a calibrated pipette. Successively, 2 µl of sperm was diluted with 18 µL of Tris-glucose-citrate in order to be correctly evaluated. The percent motility (0-100%) and progressive motility (scale 0-5) were immediately estimated using a phase-contrast microscope (X400) equipped with a warming plate. A Bürker chamber was used for measuring sperm concentration (x106/ml). Data from semen evaluation have been expressed as mean ± S.D. and analysed using a t-test for independent samples or a Wald-Wolfowitz runs test, depending on data distribution (Statistica for Windows, Stat Soft Inc., Tulsa, Oklahoma, USA). A value of p<0.01 was considered significant. Sperm quality did not significantly differ between the three method of collection (p>0.01). Conclusions. Quality of sperm collected using a single catheterization (Group 1) immediately after pharmacological medetomidine effect was statistically not different (p>0.01) in comparison with sperm quality obtained with the other two protocols. Moreover this method avoids the urethra traumatism that a multiple catheterization could induce.