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Topic:Infertility
Infertility in horses refers to the inability of a mare or stallion to reproduce successfully. This condition can arise from a variety of factors, including anatomical, physiological, genetic, or environmental influences. In mares, infertility may be linked to issues such as ovarian dysfunction, uterine infections, or hormonal imbalances. Stallions may experience infertility due to low sperm quality, testicular abnormalities, or reproductive tract infections. Diagnosing infertility involves a combination of physical examinations, laboratory tests, and imaging techniques to identify underlying causes. This page compiles peer-reviewed research studies and scholarly articles that explore the causes, diagnostic approaches, and management strategies for infertility in equine populations.
[The problem mare part 1: pathogenesis and clinical investigation]. A review is given of treatment for 'problem' mares that do not become pregnant. To determine the best therapy, it is necessary to understand the defence mechanisms of the uterus and the pathogenesis of not getting in foal. A thorough clinical examination is absolutely necessary to come to a correct diagnosis. This examination will be explained in a practical way. In the second article the different therapies for treating problem mares are discussed. The therapeutic possibilities vary widely. They can be classified in: anatomical corrections, anti-infectious therapy, and treatment to enhance th...
Clinical, bacteriologic, serologic, and pathologic features of infections with atypical Taylorella equigenitalis in mares. To characterize clinical, serologic, bacteriologic, cytologic, and pathologic endometrial responses of mares to 2 donkey-origin atypical bacterial isolates resembling Taylorella equigenitalis. Methods: Prospective in vivo study. Methods: 10 healthy mares. Methods: Mares in estrus (2/group) were inoculated by intrauterine infusion with 2 isolates of classic T equigenitalis or 2 isolates of atypical Taylorella sp or were sham-inoculated. Bacteriologic, serologic, clinical, uterine, cytologic, and pathologic endometrial responses were assessed 4, 11, 21, 35, and 63 days after inoculation and on d...
Pituitary response to steroid replacement therapy in fertile, subfertile and infertile stallions after castration. Recent studies in our laboratory investigating plasma gonadotrophin concentrations before and after castration indicate that the hypothalamic-pituitary axis is not the original site of dysfunction in stallions with idiopathic infertility. In the present study, fertile, subfertile and infertile stallions were subjected to replacement therapy with oestradiol and testosterone 1 year after castration to investigate hypothalamic-pituitary axis function further. Fertile (n=5), subfertile (n=3) and infertile (n=2) castrated stallions of Light horse breeds, aged 11-23 years, were given either oestradi...
Pregnancies produced from fertile and infertile stallions by intracytoplasmic sperm injection (ICSI) of single frozen-thawed spermatozoa into in vivo matured mare oocytes. The use of intracytoplasmic sperm injection (ICSI) for in vitro fertilization of equine oocytes and the developmental potential of these oocytes after transfer to the Fallopian tubes of synchronized mares were examined. Oocytes were aspirated from mature follicles 39 h after injection of a GnRH analogue and transported 190 km at 39 degrees C. Semen from a fertile and an infertile stallion was frozen and prepared for injection. Successfully injected oocytes were transferred surgically into the ampulla of the Fallopian tube either: (i) 4-8 h after semen injection; or (ii) after 24-48 h culture b...
Functional disturbances in the endometrium of barren mares: a histological and immunohistological study. Different types of endometrial maldifferentiation were investigated by histopathological (haematoxylin-eosin (HE), periodic acid Schiff-alcian blue and picro-sirius red staining) and immunohistological (oestrogen and progesterone receptors, Ki-67 antigen, intermediate filaments and laminin) analysis of endometrial biopsy specimens from mares (n=34), most of which had been barren for at least 1 year. Two major features were observed: (i) unequal differentiation, in which two functional stages are visible within a single biopsy sample: areas which are differentiated in accordance with the stage ...
Possible role of autoimmunity to spermatozoa in idiopathic infertility of stallions. Testicular degeneration is a major cause of subfertility in stallions, although an aetiological diagnosis cannot be made in most cases. In the present study, autoimmune testicular degeneration was induced and evaluated in stallions by immunizing stallions with their own spermatozoa mixed with an adjuvant. The factors evaluated included changes in semen quality and testicular histology. A large decrease in sperm number and quality was observed in response to sperm autoantigens. An ELISA test specific for antisperm antibodies was developed which enabled antibody titres in serum, seminal plasma a...
Hyperkalaemic periodic paralysis in homozygous and heterozygous horses: a co-dominant genetic condition. Historical, clinical and experimental data were collected from 9 horses homozygous for HYPP (H/H). All showed episodes of respiratory stertor, described as a rattling or honking sound, usually within the first week post partum. Five horses had one or more episodes of dysphagia, in 3 horses this was accompanied by drooling and in 3 by weight loss. In comparison, only one of 35 contemporaneous half siblings (of which approximately half would be expected to be of the H/N genotype and half N/N) was observed to have respiratory stertor prior to weaning and none had problems with dysphagia. One matu...
Neoplasia of the male reproductive tract. Genital neoplasms in the male horse are relatively uncommon. Squamous cell carcinomas and squamous papillomas are the most commonly diagnosed neoplasms of the penis and prepuce. Geldings appear to be overrepresented for these types of neoplasms, and accumulation of smegma may be a contributing factor. Early diagnosis and treatment are essential for salvaging these organs before lesions become excessively large and invasive or are allowed to metastasize. Newer treatment modalities such as 5-fluorouracil appear to be promising alternatives to surgical excision. Although generally considered to b...
Incidence and morphology of endometrial angiopathies in mares in relationship to age and parity. The morphology of endometrial blood vessels in uterine biopsy specimens from mares of varying age and reproductive status was examined by light (n = 117) and electron microscopy (n = 13), and additionally after elastase digestion (n = 86). Inflammatory vascular alterations were observed in 20.5% of the specimens. Smaller and larger arterial and venous vessels demonstrated mild to severe degenerative lesions. Unaltered vessels were detected only in maiden mares. Vessels in older maiden mares were frequently affected by angiosclerotic changes, characterized by mild to moderate perivascular and i...
Morphometric analysis of endometrial periglandular fibrosis in mares. To develop an objective, quantifiable assay for endometrial periglandular fibrosis (EPF) and correlate assay results with histologic and ultrastructural changes in equine endometrial biopsy specimens. Methods: Endometrial biopsy specimens from 70 mares from 3 to 27 years old in estrus. Methods: In a double-blinded study design, endometrial biopsy specimens were graded histologically (modified Kenney classification) for EPF and inflammation. Endometrial periglandular collagen volume fraction (%EPCVF) was determined by light microscopic image analysis of picrosirius red-stained sections. Specime...
Regression of subcutaneous lymphoma following removal of an ovarian granulosatheca cell tumor in a horse. A 9-year-old Arabian mare was admitted for evaluation of multiple subcutaneous nodules and infertility. Fine-needle aspiration of one of the subcutaneous nodules resulted in a cytologic diagnosis of histiolymphocytic lymphoma. Palpation per rectum and transrectal ultrasonography revealed a mass associated with the left ovary. Excision of the ovarian tumor was performed, and a histopathologic diagnosis of granulosa-theca cell tumor was made. After removal of the granulosa-theca cell tumor, subcutaneous nodules regressed. The referring veterinarian reported that the nodules had also disappeared ...
Effects of age, season, and fertility status on plasma and intratesticular immunoreactive (IR) inhibin concentrations in stallions. The nature of the relationship between inhibin and reproductive function in the stallion is yet to be elucidated. Blood and testes from 51 light horse stallions ranging in age from 2 mo to 25 years were collected during the breeding and nonbreeding seasons to study the effects of testicular maturation, aging, season, and fertility status on peripheral and intratesticular concentrations of Ir inhibin and other reproductive hormones. Of the 51 stallions, 12 age-matched stallions (6 fertile, 3 subfertile, and 3 infertile) were used in the fertility study. Blood samples were taken before castratio...
HCG binding to the testicular LH receptor is similar in fertile, subfertile, and infertile stallions. Recent evidence in our laboratory suggests that the cause of idiopathic subfertility/infertility in breeding stallions may originate in the testes at the luteinizing hormone (LH) receptor or postreceptor level. The objective of this research was to determine if LH receptor binding activity is altered in subfertile and infertile stallions. Six fertile, three subfertile, and three infertile stallions, ages 11-23 years, were classified according to normal semen parameters and pregnancy rates and then castrated in the breeding season. Blood was collected prior to castration, and plasma was stored ...
Characterization of polypeptides synthesized and secreted by oviductal epithelial cell explants obtained from young, fertile and aged, subfertile mares. To compare the electrophoretic patterns of proteins synthesized and secreted by oviductal epithelial cell (OEC) explants obtained from young, fertile and aged, subfertile mares. Methods: Young, fertile (n = 5; 2 to 7 years old) and aged, subfertile (n = 5; 17 to 24 years old) mares. Methods: 2-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis and computerized densitometry. Results: Variation in the synthesis and secretion of polypeptides from young, fertile mare OEC (YOEC) and aged, subfertile mare OEC (AOEC) was evidenced by differences in the intensity of radiolabeled pol...
Contagious equine metritis. Contagious equine metritis (CEM) is a highly contagious venereal infection of equids caused by Taylorella equigenitalis, a bacterium with fastidious growth requirements. A disease of major international concern, CEM can be the cause of short-term infertility and, very rarely, abortion in mares. Unlike the mare, stallions exposed to T. equigenitalis do not develop clinical signs of disease. CEM is transmitted by direct or indirect venereal contact. The carrier state occurs in the mare and the stallion and carrier animals are frequently the source of infection for new outbreaks of the disease. T...
Influence of chronic degenerative endometritis (endometrosis) on placental development in the mare. Placentation between 80 and 220 days of gestation was studied by measurement of fetal dimensions and gross, light and transmission and scanning electron microscopic examinations of the allantochorion and endometrium from 4 fertile mares with no, or very mild, endometrial histopathology and 6 subfertile Thoroughbred mares suffering varying degrees of age-related chronic degenerative endometritis (endometrosis). Spontaneously occurring twin gestation was observed in 3 animals. Several of the subfertile mares had endometrial cysts which showed 2 distinct features during pregnancy: those located n...
Molecular analysis of an XY mare with gonadal dysgenesis. In this study, cytogenetic analysis of an infertile mare revealed a 64, XY karyotype. The XY sex-reversed animal had a female phenotype with gonadal dysgenesis. Using Southern blot analysis, we tested for the presence of two Y-specific genes SRY and ZFY by using DNA isolated from peripheral blood leukocytes. The results showed that at least the DNA-binding domain of the SRY gene was deleted from the Y chromosome of the XY mare but that the ZFY gene was present on this chromosome.
Successful pregnancy after partial hysterectomy in two mares. Infertility was associated with a uterine mass in 2 Thoroughbred mares. Both mares had produced live foals, but had been barren for 2 years, despite repeated breedings. Each mass was removed through a right ventral paramedian incision. Histologic examination of the masses revealed a leiomyoma and an ovarian abscess. In 1 mare, approximately 30% of 1 uterine horn was removed because of tumor attachment; in the other mare, approximately 50% of 1 uterine horn was removed because of adhesions to the ovarian abscess. Pregnancy information was available for both mares for the 3 years after surgery; ...
Microscopical characteristics of uterine wall arteries in barren aged mares. The morphology of the arteries in the uterine wall was studied in three multiparous aged mares that had suffered repeated pregnancy failure. The uterine wall arteries exhibited elastosis of the intima or adventitia, or both, resembling "physiological pregnancy sclerosis". In areas affected by elastosis, degeneration of the pre-existing elastic fibres and increased glycosaminoglycans were frequently observed. Newly formed elastic fibres were not evident. Delayed resorption due to disordered metabolic turnover of the elastin was thought to be an important factor in the pathogenesis of the arteri...
Serum levels of testosterone and oestrogens in normal and infertile stallions. The serum concentrations of testosterone and oestrogens were determined in stallions classified as geldings, normal (according to age) or infertile (azoospermic). There were significant differences in testosterone and oestrogen levels between the groups. Normal concentrations of testosterone and total oestrogens were attained after 16 months of age. Castrated and immature horses ( 4 years). The results suggest that serum levels of testosterone and total oestrogens may provide a sensitive index of the endocrine function of the testis in male horses.
Dose-response effects of gonadotropin-releasing hormone on plasma concentrations of gonadotropins and testosterone in fertile and subfertile stallions. Five fertile and five subfertile stallions were treated with a single intravenous injection of saline the first week followed by a single intravenous injection of varying doses of gonadotropin-releasing hormone (5, 10, 25, 100, 500 micrograms) given in a randomized fashion over the next 5 weeks during the nonbreeding season. Blood samples were collected periodically before and after treatment for analysis of luteinizing hormone, follicle stimulating hormone, and testosterone content by radioimmunoassay. Before treatment, semen samples were collected every other day for 3 weeks for analysis of ...
Videoendoscopic evaluation of the mare’s uterus: II. Findings in subfertile mares. Videoendoscopy of the reproductive tract was performed in 87 Thoroughbred mares with histories of reduced fertility. During hysteroscopy samples for cytological, microbiological and histological examinations were obtained under visual control. Common findings in these broodmares included: (a) endometrial degeneration, as assessed by an uneven distribution or atrophy of endometrial folds and/or a scarred appearance of the endometrium (49 mares, 56%); (b) endometrial cysts of various sizes and locations within the uterus with the most common location being at the base of the uterine horns (48 ma...
Testicular feminization syndrome in a mare. Testicular feminization syndrome was diagnosed in a mare with aggressive, stallion like behavior and a history of infertility. She was found to have a high baseline testosterone concentration suggesting that testicular tissue was present, and ovarian-like structures examined by use of transrectal ultrasonography had the appearance typical of testicular tissue. Although her external female genitalia appeared normal, her vagina ended in a blind sac, and no cervix or uterus were identified. Surgery was performed, and structures removed from the abdominal cavity were determined to be hypoplastic t...
Seasonal effects on seminal quality, plasma hormone concentrations, and GnRH-induced LH response in fertile and subfertile stallions. Seasonal effects on hormonal and seminal parameters in subfertile stallions have not been well documented and could provide information that is needed to understand the underlying endocrine mechanisms associated with testicular dysfunction. Such information may be useful in developing diagnostic tools to identify those stallions who are candidates for treatment. This investigation characterizes and compares the effects of season on endocrine function and seminal quality in fertile and subfertile stallions. Eight fertile and six subfertile stallions between the ages of 5 and 18 years were injec...
Spermatozoal head defect as a cause of infertility in a stallion. A 9-year-old Arabian stallion with a 3-year history of infertility was evaluated for breeding soundness. Both testes were small. Ultrasonography revealed a small amount of free fluid between the tunics of both testes. Results of cytologic examination of the fluid were unremarkable. On semen examination, progressive motility was 10%, and total number of spermatozoa in the ejaculate was 6.6 x 10(9), of which 92% were abnormal. Predominant abnormalities were head defects (75%): 57% of the heads had single or multiple vacuoles, and 60% also had midpiece swelling or bending.
Anomalies of centriolar derivatives manifest in spermatic flagella and respiratory cilia of the stallion. Anomalies of centriolar derivatives were identified in ejaculates and testicular and tracheal biopsies of a sterile stallion, using light, scanning, and transmission electron microscopy. LM revealed that over half the sperm population had only a vestigial or no tail, while the rest had tails of variable length and shape. The vestigial tail was represented by its anlage, which was implanted on the nucleus and differentiated up to capitulum and collum stage. The stunted tail had an axoneme and its derivatives, but was short in all tail segments. Regardless of the tail length or shape, virtually ...
