Surgical resection of a dysgerminoma in a mare

A mare was referred for further evaluation of a mass found in the left caudal abdomen during a routine postpartum reproductive palpation. The mare was clinically normal with no history of health problems. Ultrasonographic examination of the mass confirmed its presence, but the origin of the mass could not be accurately determined. Routine haematology and serum biochemistry results were within normal limits. The mare was initially treated conservatively with antibiotics, but the mass continued to increase in size, so it was surgically excised. The mass involved the left ovary. The mare showed transient abdominal pain after surgery, but developed no other complications and was in foal 7 months later. On histology, the mass was diagnosed as a dysgerminoma, a rare ovarian tumour of germ cell origin.     

Abortion due to Bacillus safensis in a mare

A 16-year-old Westphalian mare aborted a dead fetus at 7 months of gestation without prodromal signs. The chorioallantois was diffusely thickened and discoloured, with fibrinous plaques, congestion and haemorrhage. Small colonies of 1-μm, Gram-positive bacilli were scattered throughout the exudate overlying the chorionic epithelium, and within macrophages. Bacillus safensis was isolated from the fetal lungs and from a swab sample of the mare's uterus. This strain represents the first case of a B. safensis-associated equine abortion and the first case of any infection caused by this bacterium.     

The uterus and early pregnancy failure in the mare

The environment the equine conceptus finds itself in when it arrives in the uterus some 6 days after ovulation will determine if it will thrive or die. The uterus will be its home for approximately the next 11 months and as such it needs to both coordinate the growth of the placenta and ensure there is enough nourishment passing to this organ for the fetus to develop normally. The trophoblast, endometrium, maternal ovaries and, later in pregnancy, the fetal gonads, all play roles in the hormonal changes that orchestrate these events. Although failures of these processes later in pregnancy can have catastrophic effects for the fetus, it is in early gestation that the foundations for a successful pregnancy are laid. This paper therefore concentrates on some of the noninfectious influences the uterus may have on survival of the young conceptus.     

Uterine B cell lymphoma in a mare

In this report, we describe the diagnostic findings and outcome of a uterine B cell lymphoma in a mare. A well circumscribed uterine mass with significant peripheral vascularisation was identified by transrectal ultrasonography during the reproductive examination of an 8‐year‐old Thoroughbred mare. Subsequent hysteroscopy revealed that the uterine mass was located intramurally and contained a protruding polyp‐like structure. A diagnosis of uterine B cell lymphoma was established by histopathological examination of a hysteroscopically‐obtained tissue sample. Additional diagnostics demonstrated that the uterus was a site of metastasis. Due to her deteriorating condition, extensiveness of the tumour and poor prognosis, the owner decided that the mare should be subjected to euthanasia.     

Hand-assisted laparoscopic ovariohysterectomy in the mare

OBJECTIVE: To develop a minimally invasive, hand-assisted laparoscopic ovariohysterectomy (HALS-OHE) technique in the mare and to evaluate safety and any associated complications. STUDY DESIGN: Experimental study. ANIMALS: Eight, 11-24-year-old mares with anatomically normal urogenital tracts. METHODS: The surgical technique was developed in 2 non-survival mares and subsequently evaluated in 6 survival procedures. Food was withheld for 48 hours, then mares were anesthetized and positioned in dorsal recumbency for laparoscopic surgery. A hand access device (Omniport) was placed followed by 4 laparoscopic portals. Transection of the ovarian pedicles and broad ligaments was achieved using a combination of a laparoscopic stapling instrument (Endo GIA II), an ultrasonically activated instrument (Harmonic Scalpel), and endoscopic clips (Endo Clip II ML). The genital tract was exteriorized through the laparotomy, and the uterus transected and sutured in a conventional pattern. Horses were evaluated through postoperative day 14 when a necropsy was performed. RESULTS: Four mares recuperated well after surgery, 1 mare was euthanatized because of bilateral femur fracture during anesthetic recovery, and another developed severe pleuropneumonia. At necropsy all but 1 abdominal incision was healing routinely. One mare had abscessed along the celiotomy incision and developed visceral adhesions. Uncomplicated healing of transected mesovarial, mesometrial, and uterine remnants was observed. CONCLUSIONS: Ovariohysterectomy in horses can be accomplished using HALS technique. CLINICAL RELEVANCE: HALS-OHE technique represents a minimally invasive and technically feasible alternative for conventional OHE. Careful patient selection and preparation may reduce the complications observed. The HALS technique may be useful in other laparoscopic surgical procedures.     

Uterine torsion diagnosed in a mare at 515 days' gestation

A pregnant mare with a history of prolonged gestation (～515 days) and suspected diagnosis of fetal mummification was examined. Rectal palpation revealed that the left broad ligament of the uterus was dorsal and medial to the right uterine ligament and it was not possible to observe the cervix during vaginal examination. Transabdominal ultrasound revealed fluid in the uterus, fetal membranes and the uterine walls defined and thickened. Free fluid was not seen in the peritoneal cavity. Laboratory tests (blood cell count and clinical chemistry) were normal. Based on clinical history, physical examination and ultrasound findings, a chronic uterine torsion with fetal death was diagnosed and the mare was subjected to exploratory celiotomy. The uterus was strongly adhered to the peritoneum of the ventral abdominal wall and there were multiple adhesions to the colon. Hysterotomy was performed to remove the fetus and to permit repositioning of the uterus. When the fetus was removed, a large devitalised grey tissue area of the right ventral uterine horn was observed. Multiple adhesions prevented a rescue hysterectomy and euthanasia of the patient was performed. During the necropsy, a 180° cranial cervix clockwise uterine torsion was observed. This rare case of uterine torsion appears to be the most chronic case reported in the equine literature.     

A review of fungal endometritis in the mare

Fungal endometritis is a relatively rare cause of infertility in the mare, accounting for only 1–5% of all cases of endometritis. However, it remains a challenge to the clinician due to difficulties in diagnosing and effectively treating affected mares, resulting in a high rate of recurrence and a guarded prognosis for ongoing fertility. Often occurring as an opportunistic infection, the most common causes of fungal endometritis in the mare are yeasts (Candida spp.) and moulds with septated hyphae (Aspergillus spp.). Early detection and identification of the causative agent are vital when choosing appropriate treatment as sensitivities to commonly used antifungals vary significantly. Assessing in vitro sensitivity for each isolate is accordingly recommended. Treatment of mares with fungal endometritis is multifaceted and includes; correction of any anatomical defects, uterine lavage and systemic and/or intrauterine infusion of antifungals. Concurrent bacterial infection is common so anticipation and subsequent treatment of bacterial endometritis is also often required.     

Renal failure in a pregnant mare

Although chronic renal disease is uncommon in horses, guidelines for management of the broodmare with kidney disease are needed to ensure successful foaling. Herein, we present a case report of a broodmare with chronic renal disease that produced a live foal, and parturition was predicted by monitoring pH and electrolytes in the milk. A 15-year-old pregnant mare presented with a history of poor body condition and weight loss despite an excellent appetite. At presentation, the mare was bright, alert and responsive, with severe pitting ventral oedema and vital parameters within normal limits. Plasma biochemistry revealed azotaemia, hypercalcaemia and hypophosphataemia. Based on clinical ultrasonographic and biochemical parameters, the mare was diagnosed with renal failure. Pregnancy was assessed by transabdominal ultrasound, and the fetal parameters were within normal limits; however, an increased combined thickness of the uterus and placenta and oedematous fetal membranes were found. Monitoring of mammary secretions accurately predicted the onset of foaling at 326 days of gestation. A healthy filly was delivered, and the fetal membranes were passed in a timely manner without complications. Physical examination and haematological parameters were within the normal limits for a neonate foal, except for a mild elevation in blood urea nitrogen. Two weeks later, the mare was subjected to euthanasia due to worsening of her condition. At necropsy and on histopathological examination, the findings were consistent with chronic renal disease. This case demonstrates that a pregnant horse with chronic renal disease can be managed with supportive care and produce a viable foal. Fetal well-being and mare’s prefoaling milk electrolytes were similar to parameters measured in healthy pregnant mares, suggesting that the feto-placental unit may be spared of the dam’s systemic disease. Prepartum physiological changes in the milk may be unaltered with concurrent maternal renal disease and still be useful for foaling prediction.     

Incompetent cervix and pneumouterus in a maiden mare

This case report describes an uncommon case of a congenitally incompetent cervix and a resulting pneumouterus in a 5‐year‐old maiden Quarter Horse mare. The mare was presented for artificial insemination at the Clinic for Animal Reproduction, Freie Universität Berlin, Germany. Routine vaginal and rectal examinations revealed a shortened cervix of 3 cm length and a dilated uterus filled with a considerable amount of air. During ultrasonographic examination, ovaries of normal size with regular cyclic activity were detected. Chromosomal analysis could not confirm any genetic anomalies such as an expected XO karyotype. The mare was excluded from breeding due to its anatomical constitution.     

Malignant fibrous histiocytoma of the mammary gland in a mare

Mammary tumours are uncommon in mares. Sarcomas of the breast account for less than 1% of all human primary malignancies and, among these types of tumours, malignant fibrous histiocytoma (MFH) is very rare. This report describes a 6‐year‐old uniparous Paint mare that was presented for investigation of right mammary gland enlargement of 3 weeks' duration. The clinical and histopathological findings in this mare with malignant fibrous histiocytoma of the mammary gland as well as complications of bilateral mastectomy are detailed. At one year follow‐up there were no clinical signs of recurrence.     

Ascending placentitis in the mare: A review

Ascending placentitis is a condition that occurs late in pregnancy when bacteria enter the sterile uterus from the lower reproductive tract. It leads to abortion or the birth of premature and weakened foals. Early detection and treatment of this condition is vital for ensuring the production of a viable foal.Mares with ascending placentitis often present in late term pregnancy with signs of premature udder development and premature lactation. There may be a vulvar discharge. Early detection of placental problems is possible using trans-abdominal or trans-rectal ultrasonography. Hormones such as progesterone and relaxin may be measured as indicators of foetal stress and placental failure. Postpartum foetal membranes may be thickened and contain a fibronecrotic exudate. The region most affected is the cervical star. Definitive diagnosis of ascending placentitis is by histopathological examination of the chorioallantoic membrane.Ideal treatment strategies are aimed at curing the infection and prolonging the pregnancy to as close to term as possible and consist of anti-microbials, anti-inflammatories and hormonal support.Swabs are taken from affected mares to determine antibiotic sensitivity and to aid in treatment of foals born from these mares which are at risk of becoming septic. If detected early enough, the chances of producing a viable foal are greatly increased.     

The influence of mare numbers, ejaculation frequency and month on the fertility of Thoroughbred stallions

Reason for performing the study: Although considerable variation in per cycle pregnancy rates exists between Thoroughbred (TB) stallions, there is little information on factors that may influence this figure. Objective: To assess the influence of month, mare numbers and mating frequency on the fertility of TB stallions standing on studfarms in East Anglia, England. Methods: The daily breeding records of 31 TB stallions mating 3034 mares on 4851 occasions during the 2010 season were surveyed and related to first scan pregnancy rates. The influences of mare book size, month, number of matings per day and mating frequency or abstinence on per mating pregnancy rates were analysed. Results: The overall per mating pregnancy rate for all the stallions was 59.6%, but for individual stallions the figures ranged from 19.0% to 80.1%. The first mating occurred on 9 February and the last on 24 July and the per mating pregnancy rate per month was significantly reduced in June and July. The number of mares mated by individual stallions ranged from 15 to 161, giving a mean overall workload of 160 matings per 100 mares. The per mating pregnancy rate was not related to book size, the number of matings in the season or the mating frequency per day. However, some stallions showed differences in per mating pregnancy rate related to month or the number of ejaculations in the preceding 3 days. Conclusions: The majority of TB stallions are able to maintain good fertility despite large books of mares. However, 5 of the 31 stallions surveyed showed a per mating pregnancy rate of ≤50%. Potential relevance: This survey has identified wide differences between the per mating pregnancy rate in TB stallions. Identification of the factors involved through more comprehensive surveys would provide useful information for mare and stallion owners.     

Breeding the mare with frozen semen

Breeding with frozen semen has become more commonplace. For a successful outcome, it is important to select fertile mares and to use quality frozen semen. The method/timing of insemination will be determined primarily by the number of semen doses available per cycle. Direct insemination of semen straws is preferred as this technique results in less loss of spermatozoa in insemination equipment. Ovulatory agents are crucial to help with timing of ovulation with respect to insemination. A post breeding examination should be performed to confirm ovulation and to examine the mare for possible complications such as post mating induced endometritis. With attention to details, frozen semen can be used with very good results.     

Gastric and small intestinal ileus as a cause of acute colic in the post parturient mare

REASONS FOR PERFORMING STUDY: Ileus (functional obstruction of aboral gastrointestinal transit) is an uncommon cause of gastrointestinal dysfunction and colic in the horse. A number of specific conditions have been previously reported in association with ileus. This report describes the recognition of primary gastric and small intestinal ileus of undetermined cause in a series of post parturient mares. OBJECTIVES: To describe the clinical features, treatment and outcome of a series of episodes of primary gastric and small intestinal ileus. METHODS: A retrospective study was performed of colic episodes seen in an equine practice in Newmarket, UK over a 6 year period (2002-2007). RESULTS: Seventeen episodes of gastric and small intestinal ileus were identified, which occurred in 15 horses. All episodes occurred in post parturient mares. No previously reported cause of ileus was identified in any of the episodes. Fifteen of the 17 episodes received medical treatment (medical support and nasogastric decompression) and, in addition, surgical decompression was performed in 9 episodes. Two mares were subjected to euthanasia before treatment due to the presence of gastric rupture and the remaining 13 mares survived with a follow-up period of at least 10 months. Two mares suffered a further episode of gastric and small intestinal ileus, one 4 days and the other 2 years after the initial episode. CONCLUSIONS: Gastric and small intestinal ileus of, as yet, unknown aetiology appears to be a potential cause of acute colic in the post parturient mare. The outcome following treatment by decompression is good.     

Prepubic tendon rupture in the mare

The following article discusses the clinical appearance, diagnosis, management and prognosis of abdominal wall tearing and prepubic tendon (PPT) ruptures of mares.     

Surgical treatment of a mammary gland comedocarcinoma in an Arabian mare: Post-operative management,and histopathological and immunohistochemical features

A lactating 20-year-old, brown, Arabian mare, weighing about 300 kg, presented for bleeding from one teat and severe swelling of the entire mammary gland. The mare had untreated mastitis 10 months before. Consequently, a gangrenous teat developed after chronic bloody and purulent discharges. The teat was removed surgically by the field veterinarian. At that time, the mammary gland increased in size. Bloody and purulent discharges restarted 10 days previously. Under general anaesthesia, the entire mammary gland was removed. Comedocarcinoma was diagnosed by histopathological assessment. Immunohistochemical staining was performed for pan-cytokeratin and vimentin. Microscopic examination of immunohistochemical stained slides revealed expression of pan-cytokeratin. In conclusion, this report describes clinical, macroscopic, histopathological and immunohistochemical characteristics of comedocarcinoma that did not metastasise to regional lymph nodes. Reports in the field of equine oncology contribute to improved general knowledge in equine medicine, contributing to better diagnosis and treatment.     

The effects of endometrial damage on placental and fetal development in a mare

A 13-year-old ex-polo pony maiden mare with an extensively damaged endometrium was initially used as an embryo donor in a research herd. Embryos recovered from the mare were of normal morphology and size. Subsequently, the mare was inseminated and left pregnant. Early conceptus development was normal and she foaled a small (22 kg) but healthy filly after a gestation of 360 days. Examination of the placenta showed that development of the microcotyledons accurately reflected the damage to the uterus. Plasma progestagen profiles throughout gestation also provided evidence for placental pathology and fetal stress.     

Haemoperitoneum in a pregnant mare with an ovarian haematoma

Haemoperitoneum is a rarely reported but life‐threatening complication of a multitude of disease processes that can affect horses. This report describes an unusual case of haemoperitoneum in a pregnant mare attributed to a unilateral ovarian haematoma during early gestation. The mare was treated with supportive care and discharged 8 days after initial presentation. Following discharge, the mare maintained her pregnancy to term and delivered a live colt at 321 days of gestation.