Ejaculation training, seminal alkaline phosphatase and semen preservation through cooling in a milk-based extender in domestic cats

Infertility In Toms: Clinical approach, experiences and challenges

PRACTICAL RELEVANCE

An infertile tom used to be a relatively rare presentation in feline practice. However, as a result of breeding strategies targeting specific morphological/behavioural traits, and the influence of inbreeding (especially practised in rare breeds), among other factors, feline infertility has become a genuine clinical problem. Furthermore, increased interest among cat breeders and pet owners in diagnosing and treating an 'unsuccessful' tom (including using assisted reproductive techniques [ARTs]), has made such patients more commonplace in veterinary practice.

CLINICAL CHALLENGES

A definitive cause for male infertility is often difficult to identify. One of the biggest challenges is the lack of fertility-based reference values for semen quality and hormone levels. Moreover, the literature in this field is scant and many reproductive tract conditions described in other species have not been reported in cats. The establishment of diagnostic tools and algorithms is essential to facilitate a reliable assessment of fertility potential.

GLOBAL IMPORTANCE

There is a growing demand for appropriate veterinary care relating to feline reproduction. There is an expectation among breeders, particularly of pedigree cats of high breeding value, that the same options widely used for dogs (including ARTs) should also be available for cats.

EQUIPMENT AND TECHNICAL SKILLS

Equipment required for investigating male infertility includes a microscope and ultrasound machine; a blood analyser may also be useful, but samples can instead be sent to a laboratory. The skills required are often already performed by veterinarians; for example, catheterising the urethra, performing ultrasonography and blood sampling.

EVIDENCE BASE

There are some reports of fertility problems in male cats in the literature, but this area of feline reproduction is still relatively undeveloped. This review draws on the comprehensive knowledge developed and shared by specialists in this field, and is supported by the authors' own clinical experience.

Normal feline reproduction: The tom

PRACTICAL RELEVANCE

Understanding the normal reproductive anatomy and physiology of the male cat is important for successful breeding. Veterinarians may be called in to troubleshoot when fertility and pregnancy rates decrease in a cattery. By understanding the normal physical parameters, as well as breeding behavior, the veterinarian is better equipped to assess the infertility issue. Also, clients are increasingly requesting breeding soundness examinations prior to mating or purchase. Semen collection is more difficult in the cat than in the dog but can still be accomplished in a clinical setting and provides important information when confronted with breeding males.

AIM

The aim of this review is to provide a practical overview of the breeding male. The reader will receive information on time of puberty, normal reproductive anatomy (both external and internal), and breeding management practices to optimize fertility. The most up-to-date semen collection techniques are discussed, as are sedation/anesthesia options. Also, historical literature on the basic anatomy of the male reproductive system is reviewed, such as how the penile spines work and when they appear; this information is specific to the cat.

EVIDENCE BASE

The information in this article is based on the author's experience, as well as drawing on historical and current literature, and provides the most up-to-date review as possible.

Expression of oxytocin receptors and oxytocin assisted electroejaculation in the domestic cat (Felis catus)

Oxytocin is a peptide hormone that mainly functions to control the contractility of smooth muscles and sex related steroidogenesis in male reproductive tracts. However, specific information concerning this hormone in controlling the reproductive organs of cats is limited. This study aimed to investigate the expression of oxytocin receptors (OTRs) and their signal mediator via prostacyclin synthase (PTGIS) in reproductive structures following oxytocin assisted electroejaculation. In Experiment 1, the testis, cauda epididymis and vas deferens from five cats were examined by immunohistochemistry and quantitative polymerase chain reaction in order to study the responses of OTR and PTGIS mRNA to oxytocin injection. Experiment 2 examined the effect of oxytocin administration prior to electroejaculation on ejaculate characteristics and sperm quality in terms of motility, viability and fertilising ability. Immunohistochemistry revealed the expression of OTRs in Leydig's, peritubular myoid cells and some spermatogenic cells. The expression was found in the epithelium and smooth muscle of the epididymis and vas deferens. After oxytocin administration, the OTR mRNA was upregulated in the epididymis (p > 0.05) and vas deferens (p = 0.01). The expression level of PTGIS mRNA increased in the response to oxytocin treatment only for the vas deferens (p > 0.05). Oxytocin treatment before electroejaculation resulted in an approximately two-fold increase in sperm concentration and total sperm output/ejaculate, while this intervention did not significantly affect ejaculate volume, sperm quality or fertilising ability. This study concluded that the oxytocin cascade is locally present in the reproductive structures and plays a role in promoting sperm delivery during electroejaculation in cats.

Testicular effects of a postnatal GnRH antagonist in domestic cats

The aim of this study was to describe the histological effects of two high postnatal doses of the potent third-generation GnRH antagonist, acyline in the domestic cat testicle. Secondly, the physical, endocrine, and steroidogenic findings of this pharmaceutical protocol are also reported. Twelve postnatal littermate male kittens were administered acyline in a dose of 2.2 mg/100 g SC weekly for 2 weeks (ACY; n = 6), or placebo (PL; n = 6). All the animals were followed up until puberty when they were castrated. Serial faecal samples were collected until the age of 10 weeks for testosterone (T) measurement. The kittens achieved puberty without either age (236.5 ± 19.7 vs. 221.7 ± 23.7 days) or body weight (3.05 ± 0.15 vs. 2.78 ± 0.28 kg, P > 0.05) differences between ACY and PL, respectively. Acyline suppressed faecal T concentrations for 3 weeks (P < 0.01). From the fourth week on, both groups had low concentrations up to the end of the follow-up period (P > 0.05). Histological assessment of the testes showed that ACY cats presented a reduced height of the epithelium (P < 0.01) due to the diminished number of germinal cells accompanied by an enlarged luminal area (P < 0.01) with cellular debris (P < 0.01). The immunostaining of P450c17 also appeared partially diminished in ACY testes.

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.

Infertility in purebred cats - A review of the potential causes

Although purebred cat breeding is growing in popularity in European countries, most research and publications concern dog reproduction. Infertility in queens has been poorly studied. It may not come as a surprise as common domestic shorthair cats are well known for their excellent fertility. However, even in the latter, the infertility rate is around 20%. Only recently, published articles have analyzed the reproductive performances in different breeds, for example in UK, Sweden, France and Italy, and found similar figures. In cats, infertility may arise from many factors such as mismating, prolonged anestrus or silent heats, hormonal, nutritional, genetical or chromosomal causes. Also, infectious diseases, probably frequent in breeding facilities, include pathological agents that are well recognized as having a negative effect on pregnancy or other pathogens for which the involvement in fertility problems is unclear. However, analyzing the literature, it appears that the most prevalent causes of infertility in pedigree cats may well be, in females, uterine pathology (sub-clinical endometritis, cystic endometrial hyperplasia, or mucometra), and in males, teratospermia, which may be "permanent" and linked to reduced heterozygosity or "transient" in tomcats that present normal quantitative spermatogenic parameters. The influence of the breed is unknown. There is an urgent need to study the origin of infertility in purebred cats in order to improve the diagnosis and to develop treatments that may restore normal fertility in subfertile or infertile animals.

Physical, histological, endocrinological and steroidogenical evaluation of male cats postnatally exposed to sexual steroids

To test the hypothesis that postnatal sexual steroids induce an impairment of domestic male cat reproductive function, this study describes the physical, endocrine, steroidogenical and histological effects of a single, high dose of a postnatal sexual steroid in this species. Twenty male kittens were randomly assigned within the first 24 h of birth to: Testosterone enanthate 12.5 mg sc (TE; n = 8), medroxyprogesterone acetate 10 mg sc (MA; n = 6), or Placebo sc (PL; n = 6). The cats were followed until puberty when they were castrated. Kittens achieved puberty without age differences among groups (P > 0.05). Two MA cats presented abnormal testicular descent. Histological evaluation of the MA (P < 0.01), but not of TE testes revealed decreased diameter (P < 0.01) and epithelial height (P < 0.01) of the seminiferous tubules. Leydig cell nuclear area was also reduced in this group. Conversely, tubular/intertubular ratio was increased in TE animals (P < 0.01). Quantitative real-time PCR analysis of mRNA expression of testicular tissue revealed no significant differences among groups for StAR, CYP17A1 and androgen receptors. TE animals showed decreased CYP19A1 mRNA expression (P < 0.05). In the first 4 postnatal weeks, fecal testosterone (T) values were high, basal and intermediate in TE, MA and PL (P < 0.05), respectively. These differences progressively diminished and the three groups presented basal T concentrations from the 7th week on (P > 0.05). It was concluded that the postnatal progestagen initially suppressed the gonadal axis and caused an impairment of spermatogenesis and testicular descent at puberty. Androgen treatment caused downregulation of the final steroidogenic cascade.

Effect of the indenopyridine RTI-4587-073 (l) on feline testicle

The aim of this study was to describe the seminal, histomorphological and hormonal effects of the oral indenopyridine RTI-4587-073(l) on feline testicle. Clinical side effects were also recorded. Sixty testicles of 30 adult cats that had been treated (d 0) with RTI-4587-073(l) 12.5 mg/kg PO and randomly hemiorchiectomized twice on: day -14 (n = 8), 6 h (n = 6), 12 h (n = 8), 24 h (n = 6), day 7 (n = 8), day 14 (n = 6), day 21 (n = 6), day 35 (n = 6) or day 42 (n = 6) were studied. Before each hemiorchiectomy, fecal samples for testosterone (T) measurement were collected and the testes were grossly and ultrasound examined. This indenopyridine did not cause changes in testicular weight (P > 0.1), volume (P > 0.1), echostructure, gonadosomatic index (P > 0.1), fecal T concentrations (P > 0.1), nor clinical side effects. A severe disorganization of the cytoarchitecture of the seminiferous epithelium, sloughed cells and fluid, were observed in the 6 h samples up to a maximum at 24 h. Tubular diameter (P < 0.01) increased twice, during the first 24 h and on d 35. Germinal epithelium achieved its minimum height on d 14 to rapidly recover thereafter. This treatment caused a significant decrease in the volume of all the seminiferous cell components, except spermatogonias. All histotological parameters normalized by the end of the study. It was concluded that RTI-4587-073(l) severely disrupted spermatogenesis during the first 24 h after treatment returning to normality in approximately one spermatic cycle without clinical side effects.