Over the last decade, assisted reproduction and captive breeding have become more important for wildlife conservation. The Lynx lynx, one of Europe's largest predators, has bounced back from the brink of extinction in Europe, but it is still critically endangered as some subspecies in some areas. Refining and improving assisted reproduction techniques in this species is therefore essential for its effective conservation. In particular, the collection, evaluation, and conservation of spermatozoa would allow the development of sperm cryopreservation and artificial insemination, and the reproductive evaluation of captive or free-ranging males before the beginning of the breeding season. Urethral catheterization after pharmacological administration (Ur.Ca.P.I) is a recent technique for semen collection, successfully implemented in other feline species.1,4,6,7 The Ur.Ca.P.I technique uses an urethral catheter to collect sperm released in the urethra in response to medetomidine administration.
The aim of the present study was to evaluate the feasibility of semen collection in the Lynx species through Ur.Ca.P.I, and to assess semen characteristics.
Two seven years adult males of European lynx hosted at the Parco Safari delle Langhe (Italy) were examined prior to the breeding season. The animals were injected with intramuscular dose of dexmedetomidine (20 µg/kg), ketamine (4 mg/kg), and butorphanol (0.4 mg/kg), and the prostatic urethra of each male was examined by ultrasound to evaluate the level of urethral distension. At this time, a urinary tom cat catheter (1 mmx30.5 cm)a with the tip cut (as described by Zambelli et al.7) and with an appropriate length, was lubricated by a preheated 0.9% saline solution and inserted into the urethra. The catheter was left in situ for 40 s to allow semen collection inside the catheter. At catheter withdrawal, semen was placed in Eppendorf tubes and immediately evaluated for pH (using a litmus paper) and volume (using a micropipette). An aliquot of 30 µl was then examined to assess sperm concentration and the percentage of motile spermatozoa.
Semen pH were 6.6 and 6.3; ejaculates volumes were 300 and 400 µl, and sperm concentration were 0.4x06/ml and 0.8x06/ml, respectively. Both ejaculates had a general motility <50%.
The pH values appear lower than those registered in the Iberian lynx; discrepancies may be due to the different evaluation method, or to individual variability.2 The estimated volumes were in agreement with those reported for the Iberian lynx, and higher than those previously reported for the same period of the year in the European lynx.2-3 Nevertheless, in these latter studies, semen collection was performed through electroejaculation, and it can therefore be hypothesized that the Ur.Ca.P.I technique may lead to the collection of a greater volume of ejaculate in the male lynx. Sperm concentrations were lower compared to other studies, while general motility was similar to the mean motility reported for the same species; these low values of concentration and motility were probably due to the month of collection (December), since male lynxes are seasonal breeders with increasing testis size from February to May.2,3,5
The results of the present study show that the Ur.Ca.P.I can represent a valid and less invasive alternative to other methods for the collection of semen in the male lynx. Both animals were uneventful recovered, and the anesthetic protocol based on low dose of dexmedetomidine in combination with ketamine and butorphanol was considered safe and useful. Although further studies performed on a greater number of males are needed, the present data suggest that Ur.Ca.P.I technique may allow the collection of a larger volume of ejaculate in the lynx species.
The authors would like to thank the staff of Parco Safari delle Langhe for the assistance in the care of the animals, and all the colleagues who collaborated in the study.
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