Field friendly method for wild feline semen cryopreservation

Abstract

The aim of this study was to develop a field-friendly method for free-living jaguar and cougar semen cryopreservation.  Six captive Jaguars Panthera onca and three captive Cougars Puma concolor were chemically restrained with a combination of medetomidine (0.08–0.1 mg/kg) and ketamine (5 mg/kg).  Semen was collected through a tomcat urinary catheter with an open end, diluted for a final concentration of 50 x 106 sperm/mL in a TRIS-egg yolk extender and packaged into 0.25 mL straws.  We compared two cooling methods: CoolA - in which straws were placed in a glass tube that was placed in a glass bottle containing water (600mL at 38°C) and transferred to a polystyrene container (12L) containing an 11cm column of ice and water at room temperature; CoolB – where the glass bottle – straws kit was transferred to a 4.26L cooler containing nine blocks (81cm3) of Ice Foam recyclable ice, previously frozen in liquid nitrogen.  The sperm volume varied from 2 to 720 µl for the jaguars and from 80 to 140 µl for the cougars.  Sperm concentration varied from 224 to 5,115 x106 sperm/mL for the jaguars and from 485.7 to 562.5 x 106 sperm/mL for the cougars.  Concerning the cooling treatments, there was no difference in frozen-thawed sperm quality between the methods, in both species.  Thereby, the cooling method using recyclable ice frozen in liquid nitrogen can be used for semen cryopreservation in wild felines, eliminating the need for electric energy.