Ovarian Teratoma in a Mare

During a routine trip to a horse slaughterhouse, we found bilateral ovarian teratoma. Macroscopic findings were confirmed by the presence of hair, bones, and cartilage. Under microscopy, these tumors had mature foreign tissues as stratified squamous and respiratory epithelia, sebaceous and sweat glands, as well as follicular endocrine cells, inflammatory cells, hepatocytes, and hyaline cartilage.     

The Problem Mare: Management Philosophy,Diagnostic Procedures,and Therapeutic Options

Problem mares are a commonly encountered challenge in brood mare practice. The first step in management of a mare with a reproductive issue is to obtain an accurate diagnosis. Components of a systematic diagnostic evaluation are discussed. The optimal treatment strategy should be based on results of the diagnostic tests. Successful interactions with problem mares are usually contingent upon a committed and detail-oriented approach to diagnostics, therapeutics, and breeding management.     

Common Peripartum Problems in the Mare

Reproductive problems in the perinatal period can adversely affect a mare's future fertility or, worse, may be life threatening to her or her foal. A number of abnormalities can occur, including uterine torsion, uterine artery or uterine hemorrhage, retained fetal membranes, metritis, rectovaginal injuries, and necrotic vaginitis. Because hemorrhage, retained placenta, metritis, and necrotic vaginitis can happen after a normal delivery or after dystocia, all mares should be monitored closely in the first days after parturition for signs of lethargy, depression, colic, sore feet, or anorexia. Methods for diagnosing, managing, and treating these conditions and the possible complications are discussed.     

Treating the Mare with Placentitis: A Clinical Approach

Placentitis is a challenging condition in the mare to both diagnose and treat. The identification of clinical signs, use of ultrasonography, and interpretation of laboratory values (serum progestin and mammary secretion electrolytes) will be described. Current therapies for treating placental infections will be discussed. In addition, recommendations for managing the postpartum mare and neonate will be provided.     

Comparison of the Cytology Brush and Cotton Swab in the Cytological Evaluation of the Endometrium in Mares with Regard to Fertility

The aim of this study was to compare the cytology brush (CB) and cotton swab (CS) in the cytological evaluation of the endometrium in mares with regard to fertility. The study was conducted on 26 mares displaying spontaneous estrus. Samples for cytological evaluation were taken from each mare by using commercially available CS and CB. After sample collection, all mares were mated in the same estrus, and pregnancy diagnosis was performed 14-18 days after last mating. No vaginal cells were found in smears, and the CB technique yielded significantly more cells/high-power field (HPF) than the CS technique. Additionally, more cases of endometritis were diagnosed using the CB than the CS. It was also shown that the degree of inflammation is more important in diagnosis of infertility in the mare than the mere presence or absence of inflammation. In conclusion, further studies are needed to establish more precise criteria for the interpretation of inflammation, especially if samples are collected using the CB.     

中药子宫灌注剂治疗奶牛不孕症研究进展

中药子宫灌注剂在奶牛子宫内膜炎和卵巢疾病等繁殖疾病的防治中发挥着巨大的作用,临床用于防治奶牛主要繁殖障碍疾病的子宫灌注剂主要有溶液型、混悬型和乳浊型3种。本文对这3种剂型的组方、疗效及作用机理等的研究概况进行综述,以期为新型中药子宫灌注剂的研制及其在临床上的应用提供参考。     

Supplemental l-Arginine Shortens Gestation Length and Increases Mare Uterine Blood Flow before and after Parturition

Supplementing diets with l-Arginine (Arg) improves female reproductive performance and reproductive blood flow in other species. The objectives of this study were to investigate uterine artery blood flow changes before and after parturition, and evaluate blood flow in Arg supplemented and control mares by Doppler ultrasonography. Sixteen light-horse mares began Doppler ultrasonography evaluation, 21 days before expected foaling date (EFD) and continued until day 7 postparturition. The mares under treatment (n = 8) were supplemented with 100 g Arg, once daily, beginning with 21 days before EFD. Blood flow measurements were calculated as pulsatility index (PI) and resistance index (RI) for both uterine arteries, either ipsilateral or contralateral; to uterine horn of established pregnancy; defined gravid uterine artery (GUA) and non-gravid uterine artery (NGUA), respectively. The mares under treatment had a shorter gestation length (337 ± 1.7 days) as compared to control (345 ± 2.1 days; P ≤ .05). No differences in gestation length were observed between groups when examined by age, parity, EFD, or sex of foal. Both GUA and NGUA uterine artery diameter decreased from the day before parturition to day 7 after parturition (P ≤ .001). During this time period, both PI and RI increased (P ≤ .01); indicating less blood flow. A treatment effect was observed with Arginine-treated mares having greater blood flow prepartum in the NGUA (P ≤ .001) and postpartum in the GUA (P ≤ .05), for both indices. The data demonstrated that supplementing mares with Arg shortened gestation length and increased uterine arterial blood flow before and after parturition.     

Problems After Breeding

Breeding induces an inflammatory response in the uterus. The inflammation is a physiological reaction with the purpose of clearing the uterus from excess spermatozoa, seminal plasma, and bacterial contamination. Breeding-induced endometritis is transient and most mares resolve the inflammation within 24 to 36 hours. If a mare fails to resolve the breeding-induced inflammation before an embryo enters the uterus, the pregnancy is likely to be lost. Susceptibility to persistent breeding-induced endometritis occurs in approximately 15% of a normal brood mare population.     

Effect of eFSH on Ovarian Cyclicity and Embryo Production of Mares in Spring Transitional Phase

The use of equine FSH (eFSH) for inducing follicular development and ovulation in transitional mares was evaluated. Twenty-seven mares, from 3 to 15 years of age, were examined during the months of August and September 2004, in Brazil. Ultrasound evaluations were performed during 2 weeks before the start of the experiment to confirm transitional characteristics (no follicles larger than 25 mm and no corpus luteum [CL] present). After this period, as the mares obtained a follicle of at least 25 mm, they were assigned to one of two groups: (1) control group, untreated; (2) treated with 12.5 mg eFSH, 2 times per day, until at least half of all follicles larger than 30 mm had reached 35 mm. Follicular activity of all mares was monitored. When most of the follicles from treated mares and a single follicle from control mares acquired a preovulatory size (≥35 mm), 2,500 IU human chorionic gonadotropin (hCG) was administered IV to induce ovulation. After hCG administration, the mares were inseminated with fresh semen every other day until ovulation. Ultrasound examinations continued until detection of the last ovulation, and embryo recovery was performed 7 to 8 days after ovulation. The mares of the treated group reached the first preovulatory follicle (4.1 ± 1.0 vs 14.9 ± 10.8 days) and ovulated before untreated mares (6.6 ± 1.2 vs 18.0 ± 11.1 days; P < .05). All mares were treated with prostaglandin F_2α (PGF_2α), on the day of embryo flushing. Three superovulated mares did not cycle immediately after PGF_2α treatment, and consequently had a longer interovulatory interval (22.4 vs 10.9 days, P < 0.05). The mean period of treatment was 4.79 ± 1.07 days and 85.71% of mares had multiple ovulations. The number of ovulations (5.6 vs 1.0) and embryos (2.0 vs 0.7) per mare were higher (P < 0.05) for treated mares than control mares. In conclusion, treatment with eFSH was effective in hastening the onset of the breeding season, inducing multiple ovulations, and increasing embryo production in transitional mares. This is the first report showing the use of FSH treatment to recover embryos from the first cycle of the year.     

Diagnosis of Endometritis in the Mare Based on Bacteriological and Cytological Examinations of the Endometrium: Comparison of Results Obtained by Swabs and Biopsies

The objective of this study was to compare results from endometrial cytological and bacteriological examinations obtained by two different laboratories. One laboratory used endometrial swabs and the other endometrial biopsies for the examinations. A higher proportion of sterile, cytology positive cases were found in the laboratory using swabs (148/401 [37%] vs 12/237 [5%], P < .0001). In both laboratories it was found that positive cytology was less likely to occur when Escherichia coli was isolated than if other species were isolated. This tendency was significant in both laboratories (P < .05 vs P < .0001).     

Feasibility and Safety of Endometrial Injection of Autologous Bone Marrow Mesenchymal Stem Cells in Mares

​Chronic degenerative endometritis (CDE) is an important cause of fertility problems in older mares. It is estimated that 30% of mares breeding are over 18 years old and the high value of their progeny encourages the use of these animals in assisted reproduction procedures. Currently, cell-based therapies are broadly used in human and veterinary regenerative medicine and have been showed a good effect on the treatment of liver fibrosis. Thus, the present study aimed to evaluate the feasibility and safety of endometrial injection of autologous bone marrow MSCs in mares. Mares were examined by transrectal ultrasound and the endometrial stem cells injections performed during diestrous, using injection needles coupled to a teflon catheter through the biopsy channel of a flexible endoscope. After treatment clinical evaluations (heart reat, respiratory rate, staining of the mucosa, capillary refill time, body temperature and lameness score) were performed daily during seven days. The intrauterine fluid and endometrial edema was evaluated before, 24 and 48 hours after the procedure by ultrasonographic exams and the inflammatory infiltrate (polymorphonuclear cells and mononuclear cells) and degree of fibrosis by histological evaluations before (D0) and 15 (D15), 30 (D30) and 60 (D60) days after endometrial injections. The results were evaluated by Kolmogorov-Smirnov and Kruskal-Wallis test followed by Dunn test and for fertility rates was used Chi-square, considering a 5% significance level. Neither clinical alteration was observed in mares after treatment, as well as, intrauterine fluid and endometrial edema were not detected in any mare before and after cell therapy. After cell therapy, significantly more PMNs were found in D15 biopsies, however, these cells were not observed in D30 and D60 biopsies. No worsening on the histological architecture after treatment was observed in any mare. In conclusion, the results of this study showed that endometrial hysteroscopic injections of stem cells in mares is a safe procedure.     

Development and Comparison of Sampling Techniques for a Broad Range,Semiquantitative Polymerase Chain Reaction Assay for Detection of Bacterial DNA in the Equine Uterus

Microbial culture from a double-guarded culture swab is commonly used to diagnose infectious endometritis. The objective of this study was to develop a quantitative polymerase chain reaction (qPCR) assay to detect a broad range of bacteria from equine uterine samples. Twenty-seven mares with a clinical history of endometritis had a double-guarded culture swab collected for analysis by qPCR and microbial cultures. An additional 12 mares had a uterine biopsy sample collected for qPCR analysis, microbial culture, and histopathology. Subsequently, a double-guarded culture swab for microbial culture and a cytology brush sample were also collected. The qPCR assay detected bacterial DNA in nine of 27 mares from a double-guarded swab and six of 12 mares from an endometrial biopsy. Positive microbial growth was detected in nine of 27 mares and four of 12 mares from a double-guarded culture swab. Bacterial DNA was detected in two of 27 mares and two of 12 mares without subsequent microbial growth. The simple presence of an organism's DNA allows for detection by nonculture-based systems, both live and dead organisms can be identified. In conclusion, the qPCR assay was determined to be a sensitive diagnostic technique for identifying pathogens associated with infectious endometritis. The primary application of the qPCR assay is detection of potential pathogenic bacteria in the uterus of a mare suspected of having infectious endometritis when a traditional microbial culture is negative. Further work is warranted to determine if mares positive for bacterial DNA and negative for microbial culture are affected clinically.     

Absence of Any Specific Diurnal Pattern in the Time of Ovulation in the Mare

This study investigates a long-held belief that mares tend to ovulate during the night. If this were so, a strategic examination regimen might replace multiple daily examinations when the time of ovulation needs to be known to within a few hours. Over 500 mares were examined at least three times daily to determine the time, to within ±4.25 hours, of 896 ovulations. The time of ovulation was determined as midway between the pre-ovulatory and post-ovulatory examinations. Three broad peaks of incidence of ovulation occurred at 5:00 am, 2:00 pm, and 10:00 pm. The interval between peaks was 9, 8, and 7 hours. during which 34.2% (5:00 am to 2:00 pm), 44.3% (2:00 pm to 10:00 pm), and 21.3% (10:00 pm to 5:00 am) of ovulations occurred. The percentage of ovulations occurring in the period 2:00 pm to 10:00 pm was significantly higher (P < .001) than in the period 10:00 pm to 5:00 am and significantly higher (P < .01) than in the period 5:00 am to 2:00 pm. The data showed that mares ovulated at all times of the day and night, with some increased incidence between 2:00 pm and 10:00 pm. Therefore, no strategic examination regimen was possible.     

A Case of Bronchioloalveolar Carcinoma in a Mare

A case of pulmonary carcinoma in a 23-year-old Quarterhorse mare is described. On physical examination, depression, poor body condition, tachypnea, bilateral serosanguineous nasal discharge and a wide area of reduced breath sounds in association with the right hemithorax were detected. Laboratory evaluation showed leukocytosis with neutrophilia and lymphopenia, hyperfibrinogenemia, hyperprotidemia, hypoalbuminemia, increased beta 2 and gamma globulin fractions, hypoxemia, and normocapnia. Radiography and thoracic ultrasonography revealed a large rounded mass extending from the 9th to the 14th right intercostal space, where neither bronchial nor vascular structures were detectable. Endoscopy showed a large amount of serosanguineous fluid within the tracheal lumen and a mass of reddish soft tissue completely obliterating the right caudal lobar bronchus. Histopathology of the endobronchial mass and of the transthoracic ultrasound-guided biopsy samples was consistent with a primary pulmonary epithelial tumor. Due to worsening of the clinical condition, the mare was euthanized. Postmortem examination confirmed the presence of a large 30-cm mass located in the right caudal pulmonary lobe, characterized by epithelial cells arranged in papillary projections and alveolar structures, findings consistent with bronchioloalveolar carcinoma.     

Effect of Follicle Size and Follicle-Stimulating Hormone on Ovulation Induction and Embryo Recovery in the Mare

The timing of ovulation is an important component to many equine breeding strategies. The action of luteinizing hormone on ovulation induction has been recognized; however, potential effects of follicle-stimulating hormone (FSH) have been less defined. Objectives of this study were to determine whether (1) mares could be induced to ovulate follicles ≤30 mm; (2) equine FSH (eFSH) has a positive effect on ovulation induction, and (3) ovulation of small follicles would affect embryo recovery. Light-horse mares (n = 12) between 4 and 10 years of age were assigned to treatments when they had a dominant growing follicle with a mean diameter of 24, 28, or 35 ± 2 mm and endometrial edema. Treatments were (1) H35, human chorionic gonadotropin (hCG) at 35 ± 2 mm; (2) F35, eFSH at 35 ± 2 mm; (3) H28, hCG at 28 ± 2 mm; (4) FH28, eFSH and hCG at 28 ± 2 mm; (5) D28, deslorelin (gonadotropin-releasing hormone [GnRH] analog) at 28 ± 2 mm; (6) FH24/H24, hCG or eFSH and hCG at 24 ± 2 mm. Mares’ reproductive tracts were scanned at 24 ± 2-hour intervals after treatment to detect ovulation. Mares were inseminated, and embryos were collected. Numbers of mares that ovulated within 48 ± 2 hours after treatment were: H35, 8/8 (100%); F35, 8/14 (57%); H28, 7/12 (58%); FH28, 9/12 (75%); D28, 3/7 (43%) and FH/H24, 4/14 (29%). The number of mares that ovulated in 48 ± 2 hours for H35 was not different from that for FH28 but was higher (P < .05) than all other groups. Embryo recovery rates, diameters, developmental stages, and morphology scores were not different for mares ovulating 48 hours or less versus more than 48 hours after treatment or among treatment groups. Results of this study demonstrate that follicles ≤30 mm can be induced to ovulate with no effect on embryo recovery or quality, as assessed by stereomicroscopy.     

The Effect of Manual Removal of Placenta Immediately after Foaling on Subsequent Fertility Parameters in the Mare

Retained placenta is considered to be a common problem in postpartum mares. The incidence varies from 6% to 54% depending on the breed, with higher incidence in heavy draught mares than in light-weight mares. Retained placenta has been linked to lower postpartum oxytocin concentration, impaired uterine involution, and dystocia. The objective of this study was to assess the effect of early manual removal of placenta immediately postpartum on subsequent fertility parameters (development of free intrauterine fluid, inflammatory status of endometrium, and on pregnancy rates) and to compare them with mares with spontaneous expulsion of placenta. A total of 29 mares, mainly Irish draught, were closely monitored during foaling by closed circuit television and allocated to two groups: (1) mares that expelled the placenta spontaneously within 3 hours of foaling; and (2) mares that were cleansed manually immediately after foal delivery. All mares were examined and scanned 5 and 9 days postpartum, and free intrauterine fluid was recorded; endometrial swabs were taken 9 days postpartum for endometrial cytology and culture. None of the fertility parameters analyzed showed statistical difference between groups 1 and 2. Therefore, it can be concluded that early manual removal of placenta has no detrimental effects on subsequent fertility of mares and, therefore, can be recommended when a veterinarian attends a foaling.     

Exercising the Pregnant Mare from Day 16 to Day 80 of Gestation

Our previous research has demonstrated moderate exercise can be detrimental to early pregnancy in the mare, but little work has examined exercise after pregnancy has been detected. We exercised mares (n = 8) 6 days a week for 45 min from Day 16 until Day 80 of gestation. Color Doppler ultrasonography was used to evaluate embryonic vesicle size, fetal length, and uterine blood flow. Blood was sampled every other day to analyze cortisol and progesterone concentrations. Results indicated that exercising pregnant mares (n = 4) led to greater (P < .01) cortisol concentrations 30 min after the exercise period. No overall treatment effect could be detected in progesterone concentrations; however, following Day 60 of gestation, progesterone concentrations were lower (P < .05) in exercised mares. Additionally, progesterone concentrations peaked earlier in exercised mares at Day 52 of gestation compared to peak levels at Day 68 of gestation for control mares. No significant effects were detected in embryonic vesicle size. Fetal length tended (P = .06) to be longer in the conceptus of exercised mares. Uterine blood flow did not differ between groups but increased as pregnancy progressed (P < .001) in both groups. All mares in this study went on to deliver healthy foals and suffered no difficulties during parturition. These results indicated that moderate exercise was not detrimental to mare pregnancy.     

Surgical Management of Enterocutaneous Fistula in a Mare

Enterocutaneous fistulas are reported to be sequelae of congenital umbilical hernia or penetrating trauma to the equine patient's abdomen. An enterocutaneous fistula is considered to be the least common clinical presentation in a horse with incarcinated umbilical hernia, and may be life-threatening if not managed timely. This case report describes an enterocutaneous fistula in a mare as a sequela to congenital umblical hernia. The mare had an uneventful recovery after surgical repair and delivered a healthy foal on subsequent follow-up. The report highlights the need to repair congenital umbilical hernias (regardless of the size), if they do not resolve by the age of 6 to 12 months.