Comparison of semen samples collected from wild and captive jaguars (Panthera onca) by urethral catheterization after pharmacological induction

Pharmacological semen collection in domestic and wild canids and felids: literature review

Semen collection methods vary greatly and rely on the practitioner's expertise, available materials, and the specific behavioral traits of the male animals involved. When it comes to domestic cats, wild felids, and canids, semen collection is particularly challenging. Thus, given the difficulty of semen collection in these species, pharmacological semen collection (PSC) stands out since it is a quick and straightforward method that does not require specific equipment. The PSC consists of administering α2-adrenergic receptor agonist drugs, mainly medetomidine, and dexmedetomidine, aiming semen release into the urethra with posterior urethral catheterization and sperm recovery. This technique was primarily described in domestic cats and wild felids, and despite the decreased seminal volume, the retrieved semen is highly concentrated and presents good quality. However, further studies are required to optimize semen collection in domestic dogs and wild canids. Therefore, the purpose of this review is to provide a comprehensive overview of the research developed on pharmacological semen collection (PSC) in the past few decades. The objective is to equip professionals with the essential knowledge required for the efficient application of this technique in both domestic and wild canids and felids and to make a valuable contribution to conservation efforts and the preservation of biodiversity, aligning with the principles of One Conservation.

Comparison of two pharmacological semen collection times with α2-adrenergic agonist in domestic cats

The use of α2-adrenergic agonists in association with urethral catheterization has been used as a technique for pharmacological semen collection in cats. The mechanism of action of this drug is the stimulation of adrenoreceptors in the vas deferens, which results in ejaculation. While medetomidine is the α2-agonist most commonly used in studies, ejaculation with the use of dexmedetomidine associated with ketamine has been effective, but with variable results. Therefore, further studies regarding the methodology of use are required to obtain better seminal quality. This study aimed to compare two pharmacological semen collection times after the association of dexmedetomidine (30 μg/kg, IM; Dormitor®, Zoetis), ketamine (5 mg/kg, IM; ketamine, Vetnil) and urethral catheterization using a tomcat probe (0.8 mm × 1.00 mm × 11 cm). The collections were divided into two experimental groups: G10 (N = 8; urethral catheterization after 10 min of anaesthesia) and G15 (N = 8; urethral catheterization after 15 min of anaesthesia). The ejaculates were evaluated for ejaculate volume, sperm concentration, morphology and kinetics using the CASA system. To compare the groups, the t-test and the Mann-Whitney U-test were used with a significance level of 5%. It was identified that ejaculate volume (G10: 22.62 ± 2.13 vs. G15: 26.81 ± 1.55; p < .001) and sperm concentration (G10: 48.10 × 106  ± 17.84 vs. G15: 90.18 × 106  ± 19.35; p < .001) was higher in G15 than in G10 and had a lower percentage of minor defects than G10 (G10: 3.12 ± 2.41 vs. G15: 1.00 ± 1.19; p = .043). Regarding the kinetic parameters, the results of G15 were better for total motility-TM (G10: 67.00 ± 10.33 vs. G15: 81.87 ± 7.99; p = .006) and faster cells-RAPID: (G10: 55.00 ± 16.63 vs. G15: 74.25 ± 11.94; p = .019); whereas a higher proportion of cells with slow speed-SLOW were seen in G10 (G10: 31.00 ± 12.07 vs. 17.12 ± 7.53; p = .015). Based on these findings, we suggest that collection via urethral catheterization should be performed 15 min after the application of ketamine-associated dexmedetomidine to obtain a better-quality ejaculate.

Sperm Cooling as an Assisted Reproduction Tool for Wildlife: An Underrated Technology

The search for assisted reproduction techniques applied to the conservation and even the genetic improvement of wild species is becoming increasingly common. Regarding conservation of male gametes from wild animals, although current advances are focused on cryopreservation, the development of protocols for sperm refrigeration seems to be underrated, despite its various advantages and applications. Therefore, this review aims to highlight the importance of short-term conservation of sperm from wild mammals, report the development of state-of-the-art refrigeration protocols for both ejaculated and epididymal sperm, and evaluate the challenges and prospects of their application.

The challenge of assisted reproduction for conservation of wild felids - A reality check

Threats to the Earth's biodiversity are increasing exponentially, driven by human population growth and resource consumption. As many as one million wildlife species may disappear within the next few decades due to this human-induced extinction event. This represents our current reality and has profound implications for wildlife conservation. Within this context, application of assisted reproductive technology (ART) to conservation management is unlikely to mitigate broad-scale species loss, but for select species, such as wild cats, ART may determine if populations survive or disappear. In North American and European zoos, 20 of the world's 38 wild felid species are managed within structured breeding programs, but most are not sustainable with natural breeding alone. Zoo-based breeding programs are facing tenuous futures due to triage-based responses to this growing sustainability crisis. Theoretically, ART could benefit conservation management, but only by recognizing and addressing its present challenges. The application of ART to wildlife has been rarely successful, with only 62 mammal species (including 15 cat species) ever propagated by AI, and just 35 of these species (6 cats) reproduced following frozen semen AI. Even this most basic form of ART has a minimal impact on wildlife sustainability. The drivers of this deficit include lack of species-specific reproductive knowledge and limited access to animals for study, but also is exacerbated by a science-conservation disconnect that attempts to apply advanced reproductive technologies to species in which basic ART remains unproven. For a few felid species, these scientific challenges have been overcome and AI with frozen semen is becoming feasible as a practical management tool; for other felids, further research is needed. Non-scientific issues also impair our ability to use ART to implement global management plans. Political dysfunction, regulatory barriers and societal indifference create inertia that interferes with achieving meaningful progress in applying ART to wildlife. Collectively, these challenges may seem insurmountable but human resiliency is essential if we are to resolve these issues in a systematic manner. It will require expanding collaborative efforts substantially and intensifying efforts to conserve wildlife species that are literally running out of time. Our goal is to create a new reality that includes a sustainable future for wild felids and other imperiled wildlife species.

Cryopreservation of jaguar (Panthera onca) sperm cells using different cryoprotectants and different thawing temperatures

The cryopreservation of jaguar semen must be improved to produce high-quality biobanking doses. Until now, the rare studies of semen freezing in the species have only evaluated glycerol, always with a significant reduction in sperm quality in thawed semen. The purpose of this study was to assess the efficacy of three cryoprotectants, dimethylsulfoxide (DMSO), glycerol (GLY), and methanol (MET), in the cryopreservation of jaguar semen in an LDL-based extender, as well as the effect of thawing temperature on dosage quality. Five mature males with a history of reproduction were used. On the males, an infrared thermal image (IRT) was captured, the spicules and testes were analyzed, and the CASA system was used to evaluate the quality of fresh and thawed sperm. The superficial IRT was 4.6 ± 1.2 °C cooler than the anal sphincter, and the semen measured between 27.3 and 28.7 °C shortly after exiting the urethra. The total motility of fresh sperm was 55.3 ± 22.6%, and progressive motility was 36.3 ± 18%. The total motility of thawed sperm was 5.28 ± 2.51%, 4.49 ± %2.49, and 0.51 ± 0.62% for DMSO, GLY, and MET, respectively. DMSO and GLY performed better than MET, and there was no difference in thawing temperature (37°C 30 s vs. 50°C 12 s). All animals exhibit a considerable level of morphological changes in sperm. Low amounts of total and progressive motility were found in the thawed sperm. Males with a high level of sperm morphological changes were found to be fertile, but the lone male with normospermia was infertile. Thus, we contest the applicability of the commonly used morphological classification for bovines to felid species.

How Can We Introduce ART into Wild Felid Conservation in Practice? Joint Experience in Semen Collection from Captive Wild Felids in Europe

Simple Summary

Artificial reproductive techniques (ART), such as cryopreservation of sperm cells and artificial insemination, are useful tools for species conservation. However, there is relatively little information published about their introduction into clinical practice for wild felids. The aim of this paper was to describe how those techniques were applied by three European teams in various species of wild felids. In total, this article presents 22 semen collection attempts in 12 species of wild felids, 15 of which were successful and resulted in the collection of at least one million spermatozoa. The failures in obtaining spermatozoa were most probably due to (1) male infertility, (2) wrong age/non-breeding season, or (3) recent multiple copulations. The cases presented in the article confirm that although ART have been introduced into clinical practice, they are mostly used in cases of infertility, not as routine breeding tools. Greater involvement of zoological gardens and private breeders is required, as many chances for preservation of valuable material are lost.

Abstract

Although artificial reproductive techniques (ART) are considered to be a valuable tool for species conservation, information about their introduction into clinical practice for wild felids is limited. The aim of this paper was to jointly describe cases of non-experimental sperm collection from males of various species of wild felids, performed by three European centers focused on feline reproduction. In total, the article presents 22 attempts of semen collection in 12 species of wild felids. The reasons for semen collection were: fertility assessment (10 cases), artificial insemination (5 cases), sperm rescue (postmortem collection for cryopreservation, 5 cases), and sperm banking (in vivo collection for cryopreservation, 2 cases). Semen collection was successful (defined as at least 1 × 10⁶ spermatozoa) in 15 cases. The failures in obtaining spermatozoa were most probably due to (1) male infertility, (2) wrong age/non-breeding season, or (3) recent multiple copulations. The cases presented here confirm that although ART have been introduced into clinical practice, they are mostly used in cases of infertility, not as routine breeding tools. Higher involvement of zoological gardens and private breeders is required, as many chances for preservation of valuable material are lost.

Semen collection by urethral catheterization and electro-ejaculation with different voltages, and the effect of holding temperature and cooling rate before cryopreservation on semen quality in the Japanese macaque (Macaca fuscata)

In the Japanese macaque, semen has been collected by electro-ejaculation (EE), using the higher voltage stimuli compared to other species including genus Macaca. Semen coagulate immediately after ejaculation, which makes difficult to produce high-quality semen for artificial insemination. Recently, semen collection using urethral catheterization (UC) has been reported in carnivore and this technique may allow semen collection without coagulation in a less invasive manner. Further, the temporal preservation temperature and cooling rate of semen during cryopreservation affect post thawing sperm quality. In this study, to improve semen quality and quantity, as well as the animal welfare, semen collection was performed by EE with high (5-15 V) or low (3-6 V) voltage, UC and a combination of the two (EE-UC). It has been suggested that a high voltage is necessary for semen collection, but 10 V stimulation was effective enough and 15 V is for additional sperm collection. Also, liquid semen was collected by EE-UC and this could increase the total number of sperm. Further, to improve the post thawing sperm motility, semen was kept at four temperatures (4, 15, 25 and 37˚C) for 60 min, and processed with two cooling procedures (slow cooling before second dilution and fast cooling after second dilution). Holding semen at 25˚C and fast cooling after the second dilution maintained progressive motile sperm rate. The present results will contribute to the improvement of semen collection and animal welfare of Japanese macaques.

Quality of domestic cat semen collected by urethral catheterization after the use of different alpha 2-adrenergic agonists

OBJECTIVES

We compared the effects of two alpha (α)2-adrenergic agonists on semen traits.

METHODS

In this study, 13 adult domestic cats were divided into two experimental groups, according to the chemical ejaculation protocol used: the first group received medetomidine hydrochloride (100 µg/kg) and ketamine (5000 µg/kg); the second group received dexmedetomidine hydrochloride (25 µg/kg) and ketamine (5000 µg/kg), both by the intramuscular route.

RESULTS

The animals responded positively (P >0.05) to chemical collection. Seminal parameters evaluated included volume, sperm vigor, total motility, progressive motility, sperm concentration, and the structural and functional integrity of the plasma membrane; sperm morphology values did not differ between groups (P >0.05).

CONCLUSIONS AND RELEVANCE

The results indicated that dexmedetomidine is a more viable and economical alternative to medetomidine in domestic cats submitted to semen collection by urethral catheterization. Semen collection by urethral catheterization after using α2-adrenergic agonists is a recently developed technique in feline species that is considered to be quick and highly applicable to assisted reproduction programs in felids.

Can detomidine replace medetomidine for pharmacological semen collection in domestic cats?

Among the different methods used for semen collection from domestic cats, the pharmacological collection by urethral catheterization becomes disruptive. Medetomidine is the elected α²-adrenoceptor agonist for that, but in several countries, it is not commercially available. This study aimed to evaluate the efficacy of detomidine compared to medetomidine in collecting semen by urethral catheterization in domestic cats. Urethral catheterization was performed on 13 mongrel cats using a disposable semi-rigid tomcat urinary catheter. Of the 19 semen collections performed with medetomidine induction, 94.7% were successful, while with detomidine induction, only 56.3% of 16 were successful. The values semen samples variables were as follows for volume - 10.56 ± 0.4 vs 8.88 ± 0.5 mL, motility - 171.67 ± 0.79 vs 49.77 ± 3.45%, vigor - 4.1 ± 0.03 vs 3.10 ± 0.1 and concentration - 3.24 ± 0.19 vs 2.15 ± 0.13 ×10⁹ sperm/mL respectively for medetomidine and detomidine group. The failure in semen collections with detomidine was mainly due to azoospermic samples, poor urethral relaxation, insufficient volume, or contamination of urine. The sperm concentration was also lower in the detomidine group (P <0.05) when compared to medetomidine. However, when the volume of semen collected was compared, we found no statistical differences. Despite its low performance in collecting semen from cats, detomidine may be an alternative when medetomidine is not accessible.

Spermatic profile of captive giant anteaters (Myrmecophaga tridactyla): Knowing more to preserve better

The giant anteater (Myrmecophaga tridactyla) is being threatened by natural habitat destruction and fragmentation, illegal hunting and road kills. In this context, the generation of basic information on the reproductive parameters of this species is vital, aiming to improve reproductive management via, amongst others, assisted reproductive technologies. This study aimed to describe the morphological and functional features of semen collected from captive giant anteaters. Electroejaculation was performed in 13 animals housed in zoos located in São Paulo state, Brazil. Semen samples were collected from 13 animals in 16 procedures. Samples were evaluated for volume, motility, vigor, pH, concentration, sperm morphology, and functional tests. The following mean values were obtained: volume 1.28 ± 0.27 mL; motility 28.3 ± 6.2%; vigor 2.4 ± 0.25; concentration 129.4 ± 36.1 × 10⁶ sperm/mL; pH 7.4 ± 0.2. Total acrosome, head, midpiece, and tail sperm abnormalities were 3.2 ± 0.8%, 25.4 ± 3.6%, 20.7 ± 3.2%, and 14.7 ± 2.6%, respectively. Intact acrosome was found in 83.7 ± 3.1% and intact membrane in 81.1 ± 4.0% of all samples collected. Mitochondrial activity was 66.4 ± 6.0% (Class I), 18.7 ± 2.9% (Class II), 8.0 ± 2.0% (Class III), 3.9 ± 1.0% (Class IV), and 3.0 ± 0.9% (Class V). Sperm DNA fragmentation rate was 13.2 ± 3.7%. These results indicated that electroejaculation is a feasible method for semen collection in giant anteaters, allowing a more detailed description of the semen in this species.

Evaluation of different skin regions derived from a postmortem jaguar, Panthera onca (Linnaeus, 1758), after vitrification for development of cryobanks from captive animals

Biological resource banks represent valuable tools for the conservation of species vulnerable to extinction, such as the jaguar. Cryobanks of skins have the potential to safeguard rare genotypes, allowing the potential exploitation of biological samples in animal multiplication technologies and the study of genetic variability. Determination of the most suitable skin regions for tissue conservation can help increase the efficiency of cryobanks and the storage of biological samples. To this end, we evaluated the effects of vitrification of skin tissues from the ear, caudal, and femoral regions of a post-mortem jaguar belonging to a zoo in Brazil. Non-vitrified and vitrified samples were evaluated and compared using quantitative methods, focusing on skin thickness, cell quantification, number of perinuclear halos, collagen and elastic density, and proliferative activity. No differences were observed in skin thickness, number of perinuclear halos, elastic density, and proliferative activity between non-vitrified and vitrified tissues in skin from any region. However, vitrified tissues derived from femoral skin showed a reduction in the number of fibroblasts, epidermal cells and collagen density compared to non-vitrified tissues. In summary, the ear and caudal regions provided the best conservation of somatic tissues derived from jaguars, and skin samples from these regions are therefore the most suitable for the formation of cryobanks.

Training tom cats for semen collection using an artificial vagina: a retrospective study

OBJECTIVES

Owing to the lack of literature on training cats to use an artificial vagina (AV), we performed a retrospective study on the success of training tom cats for semen collection using an AV.

METHODS

Records from training 20 cats (2009 until 2019) for semen collection using AVs were analyzed. Sexual preferences, behavior towards humans, queens and other tom cats, as well as libido, number of training sessions and rate of success were observed. Data are presented as percentages and the results are described subjectively.

RESULTS

In 85% of tom cats, collection using an AV was performed successfully. Training was unsuccessful when libido was low or absent. Behavior towards humans did not interfere with the success rate, while libido did.

CONCLUSIONS AND RELEVANCE

Most tom cats can be successfully trained to have semen collected using an AV; the number of training sessions required depends on the male's libido and the technician's experience.

Cryptorchidism in free-living jaguar (Panthera onca): first case report

Cryptorchidism is a genital alteration wherein one or both testicles fail to descend into the scrotum and has multifactorial causes. A free-range adult male was captured twice in the Pantanal of Nhecolândia to put a GPS collar and semen collection. Pharmacological semen collection, andrological examination and semen analysis were performed. At the first capture and during the andrological examination only the left testis was found, and the male qualified as cryptorchid. The penis had no penile spines at either procedure. The semen volume obtained at first and second capture was 435 and 160 μL, respectively, with a concentration of 618 and 100 x 10⁶ sperm/mL, progressive motility of ~ 5% and ~ 1% and total morphological sperm abnormalities of 74% and 86%. The male was monitored by a GPS collar, but the signal was lost, making it difficult to re-captures and perform new seminal and ultrasound evaluations to discard monorchidism - exceedingly rare in felids. Genetic studies to assess the individual's homozygosity are necessary to verify whether cryptorchidism in this individual has a genetic factor.

Medetomidine may cause heart murmur in Cougars and Jaguars: case report

We report heart murmur in Jaguars and Cougars found during reproductive procedures for semen and oocyte collection.  Two male Cougars (n=2) and three female Jaguars (n=3) were examined.  Anesthesia was performed with ketamine and medetomidine in males.  Females also received propofol and were maintained with isoflurane.  The animals were evaluated during anesthetic monitoring with multiparameter monitor alongside clinical examination, ambulatory electrocardiogram and echocardiogram.  All animals presented mitral valve regurgitation under anesthesia, but without morphological changes in the cardiac structure or hemodynamic changes.  Medetomidine may cause transitory heart murmur in healthy Jaguars and Cougars.   

Can amides be alternative cryoprotectors for the preservation of feline semen?

Sperm cryopreservation is a tool for the conservation of the genetic material of animals of genetic importance or for species preservation. In the case of domestic cats, this can be used to generate information about seminal harvest, evaluation and preservation, which is especially important due to its applicability to wild felids. This study evaluated seminal samples harvested by urethral catheterisation from 13 adult domestic cats. Samples were cryopreserved with experimental groups of extenders were defined by the penetrating cryoprotectant: 6% glycerol (GLY6%), 3% dimethylacetamide (DMA3%) and 3% dimethylformamide (DMF3%). The samples were thawed and evaluated by conventional microscopy and by computer-assisted sperm analysis (CASA). The structural and functional membrane integrity was assessed by supravital tests (EOS), hypoosmotic swelling tests (HOST) and flow cytometry (FC). There was a correlation (P < 0.05) between total motility and EOS (r = 0.54), HOST and FC (r = -0.62) and total motility and flow cytometry (r = 0.63), indicating that these are complementary parameters that increase the accuracy of the feline sperm quality evaluation post-thaw. The results regarding the structural and functional integrity of the sperm plasma membrane did not differ (P > 0.05) among groups. However, the DMA3% group had a lower (P < 0.05) percentage of morphological changes in the sperm tail compared to samples cryopreserved with GLY6% and DMF3%. Additionally, DMA3% provided lower values of immobile sperm post-thaw when compared to DMF3%. DMA is an interesting alternative to GLY and superior to DMF for the cryopreservation of feline semen at the studied concentrations.

Sperm evaluation and morphological description of male genitalia of meerkats (Suricata suricatta)

In ex situ conditions, little is known about the reproductive biology of meerkats. The aim of present study was to describe the morphological aspects of male genital organs and accessory glands using macroscopic evaluation, ultrasonography, and radiography, as well as describing semen characteristics post-electroejaculation. The results indicated anatomical characteristics of meerkats are very similar to those of cats, having a prostate, accessory bulbourethral glands, and an elongated and radiopaque structure in the penis, which is indicative of there being a baculum. The testicular volume was 0.81 cm³ (± 0.10) and the relative testis weight was 1.37 cm³/kg (± 0.15). Both testicles are present in the scrotum, which has an ellipsoidal shape, homogeneous texture, hypoechoic parenchyma and are encased in a hyperechoic tunica albuginea. Electroejaculation was effectively induced in all animals for semen collection with utilization of medetomidine and ketamine. The values semen samples variables were as follows for volume - 0.125 ± 0.193 mL, motility - 19.8 ± 18.6 %, vigor - 1.9 ± 1.0, concentration - 40.5 ± 25.2 × 10⁶ sperm/mL and morphologically normal sperm - 10.8 ± 6.6 %. This is the first study in which there is a description of morphological and imaging aspects of the male reproductive tracts of meerkats, as well as the seminal characteristics after using electroejaculation for semen collection. Knowledge of anatomical and seminal characteristics is essential for implementation of assisted reproduction programs, as well as reproductive management in the species.

Coleta de sêmen em Leopardus guttulus pelo método do cateterismo uretral

RESUMO Considerando a realidade conservacionista dos animais mantidos em cativeiro, em especial os pequenos felídeos silvestres, objetivou-se, com este estudo, descrever o método de coleta de sêmen por cateterismo uretral em Leopardus guttulus cativos, anestesiados com cetamina-dexmedetomidina. Inicialmente foram utilizados 13 animais para coleta de sêmen por cateterismo mediante o uso de diferentes doses de cetamina-dexmedetomidina. Após determinação da dose anestésica ideal para coleta de sêmen nessa espécie, cinco L. guttulus machos foram submetidos a coletas seriadas de sêmen pelo método do cateterismo. A dose ideal para coleta de sêmen foi de 0,008mg/kg de dexmedetomidina e 10mg/kg de cetamina. Os valores médios para volume e concentração foram de 35,9µL e 552,8x106sptz/mL. Com média de 71% de motilidade e 3,1 de vigor, 68% dos espermatozoides apresentaram vitalidade (integridade de membrana) e 77% integridade acrossomal. Sobre as patologias espermáticas, obteve-se uma média de 28% de espermatozoides com defeitos maiores, 6% com defeitos menores e 67% normais. As vantagens do método, como a facilidade e o baixo custo, fazem recomendar sua utilização em L. guttulus, pois foram apresentados bons resultados quanto à concentração espermática, à motilidade, ao vigor, à viabilidade espermática e à integridade acrossomal, sendo uma técnica promissora para utilização em felinos selvagens.

Field friendly method for wild feline semen cryopreservation

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.

Colheita farmacológica de sêmen de onças-pardas (Puma concolor: Mammalia: Carnivora: Felidae)

RESUMO Objetivou-se, por meio do presente estudo, avaliar o método de colheita farmacológica de sêmen com sondagem uretral, em machos de onças-pardas (Puma concolor) mantidos em cativeiro. A técnica proposta (Cat; N=3) foi comparada com a eletroejaculação (EE; N=4). Para a colheita farmacológica, utilizou-se medetomidina para induzir a liberação de sêmen na uretra e sonda uretral para gatos, sem janela lateral, para colheita do sêmen por capilaridade. O método foi eficaz em todos os animais usados. Por meio dessa técnica, colheram-se amostras com menor volume (106,7±30,5aµL) e maior concentração (524,1±54,3b x 106 espermatozoides/mL) em relação à EE (450,0±0,1bµL e 205,0±141,8a x 106 espermatozoides/mL). As avaliações de vigor, motilidade e patologia espermática demonstraram que a técnica não afeta a qualidade do sêmen em relação à EE (P>0,05). Dessa forma, o método proposto consiste em uma técnica mais prática e eficiente para a colheita de sêmen com boa qualidade, dispensando o eletroejaculador.

Reproductive biology and biotechnologies in wild felids

Conservation strategies in natural habitats as well as in breeding centers are necessary for maintaining and reinforcing viable populations of wild felids. Among the fundamental knowledge that is required for conservation breeding, a solid understanding of reproductive biology is critical for improving natural breeding and enhance genetic diversity. Additionally, it offers the opportunity to develop assisted reproductive technologies (ARTs) in threatened and endangered species. Conservation breeding and reproductive biotechnologies of wild felids have advanced in the past decade. It has been clearly shown that female felids have species and individual patterns of reproductive cycles and respond differently to exogenous hormones. In males, several species still have poor semen quality often due to the loss of genetic diversity in small populations. To overcome the challenges of natural breeding (incompatibility between individuals or suboptimal environment) and mitigate inbreeding, artificial insemination, embryo production and embryo transfer have been further developed in 24 wild cat species. Major factors limiting ART success are inconsistent responses to ovarian stimulation, variable quality of gametes and embryos, and preparation of recipient females. Additional approaches including stem cell technologies have been explored for future medical applications. However, there still is a critical need for better knowledge of feline reproductive biology and improvement of ARTs efficiency to increase the genetic diversity and create sustainable populations of wild felids.

Semen Cryopreservation and Banking for the Conservation of Neotropical Carnivores

Neotropical carnivores include a large number of threatened and endangered species. It is critical to develop conservation efforts to ensure the sustainability of populations in situ and ex situ. The highest priorities are to protect natural habitats and better understand the biology of rare species. Conservation efforts also are directed toward the implementation of breeding programs and the development of reproductive biotechnologies in which the cryopreservation of male gametes plays a major role. It also is fundamental to create semen banks that contribute to maintaining genetic diversity in small and endangered populations. The present article aims at reviewing the state of the art in cryopreservation of semen from neotropical carnivores and discuss the development of systematic banking for the conservation of these understudied species.