Comparison of the GnRH-stimulation test and a semiquantitative quick test for LH to diagnose presence of ovaries in the female domestic cat

[Diagnostic utility of the anti-Mullerian hormone in companion animals]

The anti-Mullerian hormone is a glycoprotein secreted by Sertoli cells in males and granulosa cells in females. The initial identification of this hormone in canine and feline serum was achieved in 2011. Meanwhile, a variety of studies have demonstrated its clinical significance as a tool in the endocrine diagnosis. This review summarizes the current knowledge about anti-Mullerian hormone in small animal reproduction and describes future opportunities for its diagnostic usage.

Infertility In Queens: Clinical approach, experiences and challenges

CLINICAL CHALLENGES

It is not easy for a veterinarian to determine the cause of infertility in a queen. The simplest method is to start by investigating the most common causes and then progress by successive elimination to the less common causes. For example, mating problems are commonly responsible for reproductive failure, and owners should be particularly vigilant in checking that the mating is progressing satisfactorily. Frequently, a veterinarian may have to determine, among other things, if there is a uterine or hormonal disorder or if an infectious pathology may be involved. In the case of a queen that is not cycling, it is important to differentiate a lack of onset of puberty in a young queen from a lack of cyclicity in an adult queen.

AIM

This review sets out a practical, step-by-step approach that veterinarians can follow, starting with the most common causes of infertility in queens and moving towards more rare or specific causes.

EQUIPMENT AND TECHNICAL SKILLS

Simple techniques such as vaginal smears are essential to determine if a queen that is ready to be mated is in full oestrus, if a queen is cycling or not and to diagnose inflammation of the genital tract. Veterinarians should be familiar with the peculiarities of the swabbing technique in cats, as well as the interpretation of feline vaginal cytology. Progesterone assays are useful on many occasions in the diagnosis pathway. A laboratory capable of performing karyotypes should ideally be available. Finally, it is important to be able to perform an ultrasound examination of the ovaries and uterus in a queen.

EVIDENCE BASE

Although it appears that infertility is a problem among purebred queens, there is a lack of knowledge in this area and too few published studies. Some causes of feline infertility remain poorly investigated.

Anti-Müllerian hormone as a diagnostic tool to identify queens with ovarian remnant syndrome

OBJECTIVES

Ovarian remnant syndrome (ORS) is suspected when heat signs occur in spayed individuals, but further diagnostic procedures are necessary to exclude other possible oestrogen sources, such as the adrenal gland or exogenous supplementation. Anti-Müllerian hormone (AMH), secreted by granulosa cells or Sertoli cells, serves to differentiate sexually intact from gonadectomised animals and has been described in dogs as a tool for diagnosing ORS. The aim of this study was to evaluate if AMH determination can be used to diagnose ORS in cats.

METHODS

AMH was measured with a chemiluminescence immunoassay in serum samples of 15 sexually intact, 9 spayed and 16 cats with a history of heat signs after spaying. Abdominal ultrasound (n = 13), vaginal smears (n = 7), progesterone measurement (n = 5) and laparotomy (n = 14) were used to determine the presence of ovarian tissue. After surgery, a histological examination of the obtained tissue was performed in the cats with suspected ORS.

RESULTS

In 15 cats with ORS the AMH serum concentrations were significantly higher than in spayed cats (n = 10; P = 0.025) and significantly lower than in sexually intact cats (n = 15; P = 0.001). Among the cats with ORS, the highest AMH serum concentrations were measured in the queens with cystic ovarian alterations and in one cat from which a whole ovary was obtained. The cat with the lowest AMH serum concentration had a simultaneous high progesterone serum concentration. Cats with ORS did not show any heat signs after surgical removal of the ovarian tissue.

CONCLUSIONS AND RELEVANCE

A single determination of AMH in blood serum is a useful diagnostic tool for the diagnosis of ORS in cats, regardless of the hormonal activity of the remnant ovarian tissue.

Long-term effect of neutering on plasma luteinising hormone concentration in cats

OBJECTIVES

The objectives of this study were to validate a commercially available luteinising hormone (LH) cat ELISA, to determine whether the increases in plasma LH concentration that occur after neutering are maintained throughout cats' lives and if other factors such as calendar seasons in both intact and neutered cats, and neutering age in neutered cats, influence plasma LH concentrations.

METHODS

Stored plasma samples from client-owned cats were used for the measurement of LH concentrations. Clinical data, including age, sex, age at neutering and medical history, were reviewed. Two populations were included in this study: (1) a senior and geriatric cat population (⩾9 years old), including 18 intact and 18 neutered cats matched for age, sex and month of sample collection; and (2) an adult cat population (2-8 years old), including 45 neutered cats. LH concentrations were measured using a commercially available feline ELISA.

RESULTS

Senior and geriatric neutered cats had higher plasma LH concentrations than age-matched intact cats (P <0.001). Calendar season did not influence plasma LH concentrations in the adult (P = 0.727) or senior/geriatric (P = 0.745) cats included in this study. No influence of age at neutering was observed on plasma LH concentrations (P = 0.296).

CONCLUSIONS AND RELEVANCE

Neutering causes a significant long-term increase in LH concentrations in cats and further studies are required to determine the consequences on feline health.

Retrospective study of aldosterone and progesterone secreting adrenal tumors in 10 cats

Background

Primary hyperaldosteronism caused by adrenal neoplasia has been well described in cats. Multiple corticosteroid abnormalities occur in a subset of affected cats, but characterizations of this syndrome are limited to several case reports.

Objectives

To describe a series of cats with adrenal tumors secreting aldosterone and additional corticosteroids.

Animals

Ten cats with multiple corticosteroid secreting adrenocortical tumors.

Methods

Retrospective case series. Medical records of cats with adrenal tumors secreting both aldosterone and progesterone were identified. Data concerning historical findings, clinicopathologic features, treatments, and outcomes were retrieved from medical records.

Results

All 10 cats had diabetes mellitus in addition to biochemical features of hyperaldosteronism such as hypokalemia. High corticosterone concentrations were observed in all 3 cats in which this corticosteroid was measured. Ultrasound examinations revealed unilateral adrenal tumors in all 10 cases, and the contralateral adrenal gland was either atrophied or not identified in 5 cats. Three of 4 cats developed hypoadrenocorticism after surgical adrenalectomy. Three cats achieved diabetic remission after adrenalectomy. Two cats treated with adrenalectomy survived >1 year, 1 cat survived 6.5 months, and 1 cat was alive 5.5 months after diagnosis. Survival >1 year occurred in 2 of 4 cats treated with medical management alone. Two cats were not treated.

Conclusions and Clinical Importance

The presence of multiple corticosteroid abnormalities should be considered in cats with aldosterone secreting adrenal tumors, especially those with concurrent diabetes mellitus. Both surgical and medical management can result in long‐term survival, although diabetic remission was documented only in cats undergoing adrenalectomy.

Case of Anorchia in a Mixed-Breed Dog

Anorchia is a rare and often poorly understood disorder of sexual development. In the present case report, we used a multidisciplinary approach to diagnose a case of anorchia in a 30-month old dog. The diagnostic process began with gathering the dog medical history followed by a clinical visit with the patient, which included a general wellness examination as well as an examination of the genital system. As suggested in the relevant literature, the dog underwent an ultrasound and then computed tomography (CT) of the genital system, which confirmed the diagnosis of testicular agenesis. Genetic testing confirmed the male XY karyotype. Hormone testing also supported the diagnosis: testosterone and anti-Müllerian hormone levels were below their reference ranges, and luteinizing hormone (LH) was above 1 ng/mL. Following the diagnostic procedures suggested in the relevant literature, the present study confirms anorchia in the dog and describes a case of testicular agenesis in the canine species.

Disappearance of signs of heat and induction of ovulation in oestrous queens with gonadorelin: a clinical study

OBJECTIVES

The objective of this study was to assess the efficacy of a single intramuscular administration of gonadorelin to induce ovulation in queens in oestrus.

METHODS

Twenty-seven queens presented in oestrus for elective ovariectomy were divided into a treatment (n = 19) and a placebo (n = 8) group. Treated queens received a 50 µg dose of gonadorelin, while placebo-treated queens were injected intramuscularly (IM) with an equal amount of saline solution. All treatments were performed between the second and fourth days of heat.

RESULTS

Two days later, signs of behavioural heat had disappeared in all gonadorelin-treated queens, while 5/8 placebo-treated queens were still in heat. Following ovariectomy, performed 4 days after drug administration, the ovaries of each queen were evaluated histologically and the number of corpora lutea were counted. Sixteen of 19 (84%) gonadorelin-treated queens had ovulated and developed five (range 2-9) corpora lutea, while 3/8 (37%) placebo-treated queens had ovulated and developed five (range 3-6) corpora lutea.

CONCLUSIONS AND RELEVANCE

This is the first study to document the efficacy of a 50 µg/cat gonadorelin dose to induce ovulation in oestrous queens when administered IM on days 2-4 following the onset of oestrus.

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.

Field study assessing the performance of a patient-side blood test to determine neuter status in female cats based on detection of luteinising hormone

OBJECTIVES

The aim of this study was to assess the performance of a patient-side blood test in determining neuter status in female cats.

METHODS

Residual blood samples from female cats of unknown neuter status that were admitted to four cat adoption centres in the UK were tested for luteinising hormone (LH) using the Witness LH test (Zoetis). A positive LH test result indicated that the cat was neutered. Cats were assessed for evidence of a surgical scar suggestive of prior neutering; if none was found, an exploratory laparotomy was performed to confirm neuter status. The LH test performance was assessed (sensitivity, specificity, negative and positive predictive value).

RESULTS

Two hundred and thirty-six cats had both LH test and exploratory laparotomy data. The specificity of the test in detecting neutered cats was 100% (95% confidence interval 96.2-99.9) and the sensitivity was 69% (95% confidence interval 59.3-76.8). The prevalence of neutered cats in this sample was 49%. The positive and negative predictive values were 1 and 0.77, respectively.

CONCLUSIONS AND RELEVANCE

The Witness LH test correctly detected all unneutered cats and thus there were no false-positive results that incorrectly indicated a cat was neutered. This study therefore suggests that positive LH test results avoid the need to perform surgery to confirm neuter status. This has significant welfare benefits for cats as it provides a lower risk, faster and less traumatic alternative to surgery and, in the shelter setting, it will have a positive impact on the cost, speed of assessment and time to rehoming of cats.

Accuracy of a point-of-care luteinizing hormone test for help in distinguishing between sexually intact and ovariectomized or castrated domestic cats

Objectives The aim of this study was to determine the accuracy of a commercial luteinizing hormone (LH) test as an aid in distinguishing between sexually intact and ovariectomized or castrated domestic cats. Methods Convenience serum samples collected from sexually intact female and male cats (n = 67) undergoing elective sterilization surgery and archived sera from ovariectomized and castrated cats (n = 54) were tested for LH using a commercial diagnostic assay. Test results were compared with the known reproductive status of the cats. Additionally, sera from sexually intact (n = 54) and ovariectomized (n = 94) queens were collected at specific times of the year to evaluate possible seasonal effects on test results. Results Overall test sensitivity was 89.3% (95% confidence interval [CI] 82.3-94.2%), specificity was 92.6% (95% CI 87.1-96.2%) and accuracy was 91.1%. Analysis of results of female cats (n = 216) - sexually intact (n = 87) and ovariectomized (n = 129) - yielded a test sensitivity of 90.8% (95% CI 82.7-96.0%), a specificity of 92.3% (95% CI 86.2-96.2%) and accuracy of 91.7%. Analysis of the results of male cats (n = 53) - sexually intact (n = 19) and neutered (n = 34) - yielded test a sensitivity of 85.3% (95% CI 68.9-95.1%), a specificity of 94.7% (95% CI 74.0-99.9%) and accuracy of 88.7%. The sera of 10 intact queens unexpectedly yielded positive LH results; two of these cats were in estrus, based on visual inspection at the time of ovariohysterectomy. Test accuracy was 94.6% for those 148 samples collected at specific times of the year, with two samples each over three, 3 month periods yielding false-positive results. Conclusions and relevance The commercial point-of-care LH test is a useful adjunct to historical and physical examination findings for determination of reproductive status in domestic cats. Repeat testing 24 h later should be considered for those female cats with signs of estrus and initial positive test results.

Concentrations of anti-Müllerian hormone in the domestic cat. Relation with spay or neuter status and serum estradiol

Female cats with unknown history can be diagnosed as spayed or intact with a GnRH-stimulation test or an LH test independent of the stage in the estrous cycle. However, although most females are correctly diagnosed with the LH test, the sensitivity and specificity are not 100%. The GnRH-stimulation test, although reliable, requires an injection of buserelin 2 hours before the blood sample is collected. Granulosa cells are the only cell type that produces anti-Müllerian hormone (AMH) in females, whereas Sertoli cells produce AMH in males. Anti-Müllerian hormone has been linked to spay status in dogs and cats and to ovarian and testicular pathology and fertility in different species. Our aim was to evaluate serum AMH concentrations in spayed female cats and in intact female cats of known age and reproductive stage (inactive ovaries or luteal phase). In addition, our aim was to compare serum AMH concentrations in intact and neutered male cats. We analyzed serum AMH concentrations in 15 spayed and 16 intact females and in 15 intact and 12 neutered male cats. Serum AMH was below the lowest standard point (<0.14 ng/mL) in all spayed females and neutered males, ranged between 1.3 and 19.0 ng/mL in the intact females and between 4.8 and 81.3 ng/mL in intact males. Thus, the AMH test had 100% sensitivity and specificity to diagnose the presence or absence of ovaries and testes in this study. In addition, in contrast to serum estradiol, serum AMH was not affected by buserelin stimulation (P = 0.459). Serum AMH was not correlated with serum estradiol before (rs = -0.188, P = 0.519) or after (rs = 0.335, P = 0.242) buserelin stimulation in the intact females. Four 6-month-old intact cats (two females and two males) had the highest AMH concentrations which in the females might represent a prepubertal peak previously described in other species and in males is likely due to high concentrations before puberty. In conclusion, we found that the AMH Gen II ELISA is reliable for diagnosing spay and neuter status of cats and that the domestic cat might be an interesting model for studies on AMH dynamics.