Ultrasonography of the normal reproductive tract of the female domestic cat

Ultrasonographic appearance and histopathological findings of the genital tract in healthy nulliparous female rabbits (Oryctolagus cuniculus)

Female rabbits often exhibit reproductive tract disorders and accurate sonographic descriptions of the normal genital tract are lacking. The aims of our prospective, analytical, and reference interval study were to describe the ultrasonographic appearance of the genital tract of healthy female rabbits, provide reference values, and compare ultrasonographic findings with histopathological samples. Twenty-eight intact female rabbits presented for elective ovariohysterectomy were included. Ovaries, oviducts, uterine horns, cervixes, and vagina were imaged by ultrasound to assess their size, shape, location, margination, echogenicity, and echotexture. The genital tract of 12 rabbits was sent for histopathology. Genitals were visible in all rabbits using the linear probe. The ovaries were oval-shaped and hypoechoic with a variable pattern. The oviducts, uterine horns, and vagina appeared as tubular structures with a consistent distinct layering, and the cervix as two contiguous hypoechoic tubular structures with a variable layering. Incidental findings, including paraovarian cysts, mineralization foci, and luminal fluid were observed. The median values of the height of the left and right ovaries, oviducts, uterine horns, cervixes, and vagina were, respectively, equal to 3.52 3.37, 1.39, 1.39, 4.34, 4.36, 5.57, 5.15, and 2.40 mm. Significant correlations were observed among age, body condition score, and some of the measurements. Abnormalities of the reproductive tract were reported in 4 of 28 rabbits. This study supports the use of ultrasonography in the evaluation of the reproductive tract of healthy female rabbits and provides reference values for use in rabbits with genital disorders.

Scientific and technical assistance on welfare aspects related to housing and health of cats and dogs in commercial breeding establishments

This Scientific Report addresses a mandate from the European Commission according to Article 31 of Regulation (EC) No 178/2002 on the welfare of cats and dogs in commercial breeding establishments kept for sport, hunting and companion purposes. The aim was to scrutinise recent recommendations made by the EU Platform on Animal Welfare Voluntary Initiative on measures to assist the preparation of policy options for the legal framework of commercial breeding of cats and dogs. Specifically, the main question addressed was if there is scientific evidence to support the measures for protection of cats and dogs in commercial breeding related to housing, health considerations and painful procedures. Three judgements were carried out based on scientific literature reviews and, where possible a review of national regulations. The first judgement addressed housing and included: type of accommodation, outdoor access, exercise, social behaviour, housing temperature and light requirements. The second judgement addressed health and included: age at first and last breeding, and breeding frequency. Judgement 3 addressed painful procedures (mutilations or convenience surgeries) and included: ear cropping, tail docking and vocal cord resections in dogs and declawing in cats. For each of these judgements, considerations were provided indicating where scientific literature is available to support recommendations on providing or avoiding specific housing, health or painful surgical interventions. Areas where evidence is lacking are indicated.

Serum antimüllerian hormone concentrations in female cats. Relation with ovarian remnant syndrome, ovarian cysts and gonadectomy status

The aim of this study was to reveal (1) the determination of the serum antimüllerian hormone concentrations in cats with ovarian remnant syndrome and ovarian cyst, (2) the effectiveness of the serum antimüllerian hormone concentrations in detecting gonadectomy status, and (3) ovarian expression of the antimüllerian hormone in the ovarian cysts and ovarian remnant tissue. For this purpose, a total of 31 domestic cats older than 1 year, including ORS (n = 9), OC (n = 3), spayed (n = 8), and intact (n = 11), were used in the study. Serum and intrafollicular AMH concentrations were determined by the electrochemiluminescence immunoassay, and expression of the AMH was determined by the immunohistochemical method. The serum AMH concentration in the ORS group was 1.49 ± 1.24 ng/ml (0.10-3.63 ng/ml) whereas it was 1.78 ± 0.92 ng/ml (0.8-2.63 ng/ml) in the OC group. AMH concentration in the intrafollicular fluid was determined as 0.023 ng/ml in a cat with an ovarian cyst. While the serum AMH concentration was below 0.01 ng/ml in spayed cats, it was 5.80 ± 3.30 ng/ml (1.88-11.86 ng/ml) in the intact cats. There was a significant difference between the spayed and intact groups in terms of serum AMH concentration (p < 0.05). Moreover, in cats with ovarian cyst and ovarian remnant syndrome, no difference was found between the groups in terms of serum AMH concentration (p > 0.05). No difference was found between the ovarian remnant syndrome and intact cats in terms of serum AMH concentration (p > 0.05). In immunohistochemical staining, ovarian cysts were found to be negative for AMH while a moderate (+2) AMH positivity was observed in other follicles. Furthermore, in cats with ovarian remnant syndrome, severe (+3) AMH positivity was observed. As a result, it was determined that gonadectomy status can be accurately diagnosed by the AMH measurement. Ovarian remnant syndrome cannot be diagnosed accurately by AMH measurement. In addition, it was found that AMH did not seem to play a role in the pathogenesis of ovarian cysts in cats.

Ovarian and uterine two-dimensional and Doppler ultrasonographic changes in the feline peri-estrus period

OBJECTIVES

The aim of this study was to evaluate two-dimensional and Doppler ultrasonographic changes of the ovary and uterus during estrus and the early post-estrus period in domestic cats.

METHODS

Two-dimensional and Doppler ultrasonographic evaluations of the ovaries and uterus were performed in seven queens on days 1, 3 and 5 of estrus, and 5 days after estrus (AE5).

RESULTS

On day 1, 5.4 ± 0.5 follicles of 2.1 ± 0.1 mm were detected progressively increasing in number and size up to day 5 and then decreased on AE5 (P <0.05). A maximum follicular diameter of 4.1 ± 0.1 mm was achieved on day 5. Both during and after estrus, the uterus was generally hypoechoic compared with the surrounding tissues and delineated by a thin hyperechoic line corresponding to the serosa. In some animals, the uterine layers were distinguished during and after estrus. The blood flow waveforms of the intraovarian and uterine arteries were characterized by a systolic peak and diastolic flow extending throughout the remainder of the cardiac cycle to the next systole. In the uterine artery waveforms, the early diastolic notch was mild or absent during most estrous observations. The resistance index of the intraovarian arteries decreased up to day 5, and then increased on AE5 (P <0.05). The resistance index of the uterine arteries was lower during estrus than in the post-estrus period (P <0.05).

CONCLUSIONS AND RELEVANCE

It is concluded that in the domestic cat, follicular number and diameter as well as ovarian and uterine blood flow changed during and immediately after estrus. Doppler ultrasound proved suitable to evaluate the hemodynamic changes involved in the cyclic remodeling of ovarian and uterine tissues that occurs during and after follicular growth in domestic cats.

Morphological and Imaging Features of Male Pseudohermaphroditism in a Feral Cat

A one-year-old European shorthair feral cat with signs of heat was presented at the Veterinary Teaching Hospital of Las Palmas de Gran Canaria University. After the physical exam, histology, hormonal analysis, ultrasound and computed tomography (CT) studies were performed. Examination of the external genitalia revealed the absence of one of the testes in the scrotal sac and the presence of a structure whose appearance could suggest an enlarged penis-like clitoris with small spines. The ultrasound study showed compatible images with the left ovary and intra-abdominal testis and tubular structures, which closely resembled the uterine horns. Similar structures were confirmed in the CT study. Exploratory celiotomy revealed the presence of the uterus and undescended testis attached to the uterine horn. Histological examination revealed immature testicular tissue in both gonads and the presence of Persistent Müllerian Duct (PMD). Though a karyotype was not performed, it was presumed to be the standard 38 XY found in pseudohermaphrodites. To date, this type of disorder of sexual development (DSD) has been scarcely reported in cats. Further studies are on the way to knowing the genetic mechanism of this disease.

Normal feline reproduction: The queen

PRACTICAL RELEVANCE

Cats are seasonally polyestrous, meaning they exhibit multiple estrous cycles within a season, followed by a period of non-cyclicity. Cats cycle when the day length is long but can be induced to cycle year-round with 14 h of continuous artificial lighting. The feline estrous cycle includes the following stages: proestrus, estrus, interestrus and, if ovulation occurs, diestrus. Cats are induced ovulators and ovulate in response to multiple natural matings. Successful breeding in a cattery requires knowledge of the female's reproductive cycle, behavior and management, and often improper management can be the sole cause of infertility.

AIM

The aim of this review is to provide readers with an overview of normal anatomy, cyclicity, management and behavior of the queen. It includes a series of questions veterinarians can ask to obtain a baseline knowledge of the management of the specific breeding set-up.

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.

Vaginal stimulation enhances ovulation of queen ovaries treated using a combination of eCG and hCG

Follicular changes throughout the oestrous phase have been poorly documented in queens because of the location and the small size of ovaries. We investigated follicular development in queens treated with a combination of equine chorionic gonadotropin (eCG) and human chorionic gonadotropin (hCG) and evaluated the effects of vaginal stimulation by a tomcat on ovulation induction. A hormonal treatment was administered using a simple crossover design. Four queens were administered 150 IU of eCG (day 1) and 250 IU of hCG on day 5 and 6. Half of the queens were mated with a vasectomised tomcat for 3 days after hCG injection. Ultrasound imaging of the ovaries clamped at a subcutaneous site was performed once a day from day 1 to 7, and on day 13, and the serum concentrations of oestradiol and progesterone were examined on day 1, 5, 7 and 13. The mean number of follicles gradually increased with the eCG treatment and decreased after hCG injection. The ovulation rate of follicles was significantly higher in the vaginal stimulation group (70.0%) than in the control group (42.6%). During the hormonal treatments, the serum concentration of oestradiol and progesterone did not differ between the two groups. Ultrasound imaging of the ovaries clamped at a subcutaneous site showed that eCG and hCG treatment promoted the follicular growth and corpus luteum formation, respectively. The combination of hCG injection with vaginal stimulation by a vasectomised tomcat enhanced the ovulation rate of follicles.

Endometrial receptivity and embryo implantation in carnivores-commonalities and differences with other mammalian species

Endometrial receptivity and embryo implantation processes are a major point of pregnancy failure in many mammalian species, including humans. Although reproductive biology in many carnivore species remains enigmatic, the few that have been studied so far are invaluable comparative models. The goals of this review are to (1) summarize current data on the mechanisms involved in uterine receptivity and embryo implantation in carnivores, including commonalities and differences with other mammalian species and (2) identify research priorities to better understand a key phenomenon in a critical group of mammals. Besides unique reproductive traits in some carnivores (induced vs. spontaneous ovulation in cats, ovulation at the germinal vesicle stage in dogs), preimplantation embryo development is comparable with other orders. However, the timing of implantation varies, especially in species having an embryonic diapause. Mechanisms involved in endometrial receptivity and decidualization still remain to be fully understood, but specific markers have already been identified. Importantly, the use of endogenous hormones to control the ovarian activity may impact endometrial receptivity and subsequent embryo implantation. Next, research efforts should take advantage of advanced technologies to further study embryo implantation in carnivores and to provide more relevant models to reproductive medicine or for the conservation of rare and endangered species.