Hormone Profiles and Treatments in the Late Pregnant Mare

Plasma relaxin, estrogens and progestogens concentration in coldblooded and hot-blood mares in the second half of gestation

Monitoring estrogens, progestogens, and relaxin plasma concentration can be important for determining pregnancies at risk of failure in mares. However, significant breed-related differences in values of reproductive hormones are known, and data concerning coldblooded (CB) mares are missing. The aim of the study was to determine and compare serum relaxin, estrone sulphate (E1S), estradiol-17β (E2), and progestogens concentration in pregnant CB and hot-blood (HB) mares during the second half of gestation. Blood samples obtained from 94 healthy mares in the second half of gestation with known mating dates were analyzed. Samples were collected from 36 CB mares aged from 3 to 16 years and 58 HB mares aged from 4 to 17 years. The hormone concentrations were measured using immunoenzymatic equine species-specific commercial kits. The serum relaxin concentration was almost three times lower in CB, whereas E1S and E2 almost twice as low, as compared to HB mares (P < 0.05). In conclusion, the extremely low concentration of relaxin in CB mares could be one reason for the increased amounts of difficult parturition requiring veterinary intervention noted in these breeds.

Outcomes of pregnant broodmares treated for colic at a tertiary care facility

OBJECTIVE

To evaluate, following colic admission during pregnancy, (1) broodmare survival; (2) the frequency of recurrent colic in broodmares and its associated variables, and (3) pregnancy outcome and the variables associated with a negative pregnancy outcome.

STUDY DESIGN

Ambidirectional observational cohort study.

ANIMALS

One hundred and four client-owned broodmare admissions.

METHODS

Admissions of pregnant mares from June 2010 until October 2016 were included. Data were collected until November 2017. Cox proportional hazards regression analysis was performed to evaluate variables associated with broodmare survival. Logistic regression analysis was used to examine the variables associated with recurrent colic and pregnancy outcome.

RESULTS

Broodmares from 73/104 (70.2%) admissions were discharged alive. Lesion category, admission hyperlactatemia (hazard ratio (HR) 3.24, 95%, CI 1.28-8.22, P = .013), and admission high packed cell volume (HR 2.89, 95% CI 1.29-6.47, P = .010) were associated with reduced survival. Recurrent colic was observed in broodmares from 33/70 admissions (47.1%). The final multivariable model for recurrent colic included Thoroughbred breed (OR 5.09, 95% CI 1.58-16.4, P = .006) and age (OR .876, 95% CI .747-1.03, P = .105). Overall, negative pregnancy outcome was 14/65 (21.5%). Lesion category, evidence of systemic inflammatory response syndrome (SIRS) in hospital (OR 31.2, 95% CI 2.09-466.5, P = .013), and diarrhea in hospital (OR 379.3, 95% CI 97.1-1482.0, P < .001) were associated with increased negative pregnancy outcome. Altrenogest administration was inversely associated with negative pregnancy outcome (OR 0.029, 95% CI .004-.222, P = .001).

CONCLUSION

Pregnant broodmares admitted for colic had lower survival than anticipated and were at risk of recurrent colic. Markers of broodmare disease severity were associated with pregnancy outcome.

CLINICAL SIGNIFICANCE

Lesion category, hematologic variables (packed cell volume and l-lactate concentration), evidence of SIRS, and diarrhea were useful for predicting broodmare and pregnancy outcomes.

Managing Reproduction Emergencies in the Field: Part 1: Injuries in Stallions; Injury of the External Portion of the Reproductive Tract and Gestational Conditions in the Mare

Selected emergency conditions of male and female reproductive tracts in horses are described, including injuries affecting the external genitalia of male horses and emergent conditions arising during gestation in mares. Conditions affecting male horses are discussed in the context of breeding stallions, but kicks or other mechanisms of trauma in the groin can also affect geldings. Priapism, paraphimosis, trauma to the scrotum and testicles, and penile injury are discussed. In mares, traumatic vestibular injury, placentitis, hydropsic conditions, prepubic tendon and abdominal wall compromise, and uterine torsion are included. Clinical recognition of the problem, diagnostic procedures, and treatments are summarized.

Association between the Area of the Highest Flank Temperature and Concentrations of Reproductive Hormones during Pregnancy in Polish Konik Horses-A Preliminary Study

Determination of the pregnancy status is one of the most important factors for effective pregnancy management. Knowledge of the stage of pregnancy is important to interpret many of the reproductive hormones' concentrations, including progesterone (P4), estrone sulfate (E1S), 17-ß estradiol (E2), and relaxin (REL). However, it is limited in wildlife or captive equids that cannot be handled. Reproductive hormones affect regional blood flow, the proliferation of tissues, and local metabolism intensity. Therefore, this preliminary study aimed to assess changes in thermal features of the abdomen lateral surface and concentrations of reproductive hormones in Polish native pregnant mares. The study was carried out on 14 non-pregnant and 26 pregnant Polish Konik mares during eleven months of pregnancy. Infrared thermography was conducted to image the lateral surface of mares' abdomen (Px1) and flank area (Px2); P4, E1S, E2, and REL concentrations in serum were also determined. The evidence of the association between the area with the highest temperatures (Area of Tmax) and serum concentrations of P4 (the slope = 1.373; p = 0.9245) and REL (the slope = 1.342; p = 0.4324) were noted dependent across months of pregnancy. Measures of superficial body temperatures were found to change monthly, similarly to ambient temperatures, with no evidence of coincidence with changes in reproductive hormone concentrations. Individual thermal characteristics of the lateral surface of the abdomen differed between pregnant and non-pregnant mares in other periods. Differences in maximal and average temperature and Area of Tmax were observed from the sixth month of pregnancy, and those in minimal temperature were observed from the eighth month.

Dynamics of androgens in healthy and hospitalized newborn foals

Background

Information on steroids derived from the adrenal glands, gonads, or fetoplacental unit is minimal in newborn foals.

Objective

To measure androgen concentrations in serum and determine their association with disease severity and outcome in hospitalized foals.

Animals

Hospitalized (n = 145) and healthy (n = 80) foals.

Methods

Prospective, multicenter, cross‐sectional study. Foals of ≤3 days of age from 3 hospitals and horse farms were classified as healthy and hospitalized (septic, sick nonseptic, neonatal maladjustment syndrome [NMS]) based on physical exam, medical history, and laboratory findings. Serum androgen and plasma ACTH concentrations were measured with immunoassays. Data were analyzed by nonparametric methods and univariate analysis.

Results

Serum dehydroepiandrosterone (DHEA), androstenedione, testosterone, and dihydrotestosterone (DHT) concentrations were higher upon admission in hospitalized foals (P <  .05), were associated with nonsurvival, decreased to 4.9‐10.8%, 5.7‐31%, and 30.8‐62.8% admission values in healthy, SNS, and septic foals, respectively (P < .05), but remained unchanged or increased in nonsurviving foals. ACTH:androgen ratios were higher in septic and NMS foals (P < .05). Foals with decreased androgen clearance were more likely to die (odds ratio > 3; P < .05).

Conclusions and Clinical Importance

Similar to glucocorticoids, mineralocorticoids, and progestagens, increased serum concentrations of androgens are associated with disease severity and adverse outcome in hospitalized newborn foals. In healthy foals, androgens decrease over time, however, remain elevated longer in septic and nonsurviving foals. Androgens could play a role in or reflect a response to disorders such as sepsis or NMS in newborn foals.

Doppler indices of the equine fetal carotid artery throughout gestation

Assessment of pregnancy viability in the equine patient is currently based on gestational profiles of limited prognostic value. In recent years Doppler technology has been applied to uterine and umbilical arteries of pregnant mares to monitor fetal responsive haemodynamics, suggestive of compromise. To date, uterine artery Doppler indices failed to provide sufficient evidence of pregnancy viability and the umbilical cord of the equine fetus is inconsistently visualized past 250 days gestation. The objectives of this study were to: i) evaluate intracranial blood flow impedance by Doppler examination of the fetal carotid artery and ii) establish reference values for healthy, uncomplicated pregnancies. The middle cerebral artery (MCA), a branch of the carotid artery, is commonly employed to assess intracranial hemodynamics in the human fetus, exhibiting high resistance to circulation to the fetal brain in uncomplicated pregnancies. For the purpose of this study, 12 pregnant mares were examined at 2-3 weeks interval by B mode and Doppler ultrasonography until delivery and a novel technique was developed for Doppler evaluation of the carotid artery in the equine fetus, in order to provide objective evidence of the hemodynamic status of the equine fetus. Additional biophysical and biochemical parameters were collected to demonstrate appropriate pregnancy development. In this study Doppler waveform analysis of fetal intracranial vasculature demonstrated an elevated blood flow impedance, showing a significant correlation of carotid Doppler indices with gestational age. Results were comparable to human fetal trends for the middle cerebral artery (MCA) from mid gestation to term. Biochemical data showed expected patterns of uncomplicated pregnancies.

The oxytocin-prostaglandins pathways in the horse (Equus caballus) placenta during pregnancy, physiological parturition, and parturition with fetal membrane retention

Despite their importance in mammalian reproduction, substances in the oxytocin-prostaglandins pathways have not been investigated in the horse placenta during most of pregnancy and parturition. Therefore, we quantified placental content of oxytocin (OXT), oxytocin receptor (OXTR), and prostaglandin E2 and F2 alpha during days 90-240 of pregnancy (PREG), physiological parturition (PHYS), and parturition with fetal membrane retention (FMR) in heavy draft horses (PREG = 13, PHYS = 11, FMR = 10). We also quantified OXTR and prostaglandin endoperoxide synthase-2 (PTGS2) mRNA expression and determined the immunolocalization of OXT, OXTR, and PTGS2. For relative quantification of OXT and OXTR, we used western blotting with densitometry. To quantify the prostaglandins, we used enzyme immunoassays. For relative quantification of OXTR and PTGS2, we used RT-qPCR. For immunolocalization of OXT, OXTR, and PTGS2, we used immunohistochemistry. We found that OXT was present in cells of the allantochorion and endometrium in all groups. PTGS2 expression in the allantochorion was 14.7-fold lower in FMR than in PHYS (p = 0.007). These results suggest that OXT is synthesized in the horse placenta. As PTGS2 synthesis is induced by inflammation, they also suggest that FMR in heavy draft horses may be associated with dysregulation of inflammatory processes.

Changes in maternal pregnane concentrations in mares with experimentally-induced, ascending placentitis

The objectives of this study were to compare via liquid chromatography-tandem mass spectrometry (LC-MS/MS) progesterone (P4), 5α-dihydroprogesterone (DHP), allopregnanolone, 3β-hydroxy-5α-pregnan-20-one (3β5P), 20α-hydroxy-5α-pregnan-3-one (20α5P), 5α-pregnan-3β,20α-diol (βα-diol), and 5α-pregnan-3β,20β-diol (ββ-diol) concentrations in plasma of mares with experimentally-induced, ascending placentitis compared to gestationally age-matched control mares. Placentitis was induced via intracervical inoculation of Streptococcus equi spp. zooepidemicus between 260 and 280 days of gestation. Placentitis mares were subdivided into those which aborted in less than eight days (n = 6; acute) and those that aborted at ≥ 8 days after inoculation (n = 9; chronic). Ten pregnant mares at similar gestational ages served as healthy controls. Pregnanes were measured for days (-8), -6, -4, -3, -2, -1, and 0 days preceding abortion in the treated mares, and for the matched days of gestation in the control mares by LC-MS/MS and by immunoassay for immunoreactive (ir) P4. In mares with chronic placentitis, concentrations of DHP and its downstream metabolites (allopregnanolone, 3β5P, 20α5P, βα-diol) increased at 2-8 days prior to abortion compared to control mares. Of these pregnanes, 20α5P and βα-diol increased at eight days prior to abortion and demonstrated the largest increase (approximately 3 to 4×) in mares with chronic placentitis compared to control mares. Concentrations of P4 determined by LC-MS/MS were at or below the limit of detection (0.5 ng/mL) for control mares and did not increase significantly in mares with chronic placentitis. Immunoreactive-P4 was increased at two days prior to abortion in mares with chronic placentitis but was not different from controls in mares with acute placentitis. In mares with acute placentitis, concentrations of DHP, allopregnanolone, 3β5P, 20α5P, and βα-diol decreased within 0-3 days prior to abortion. In mares with chronic placentitis, the patterns of increased pregnanes metabolized by the placenta was similar to changes in maternal pregnanes noted in normal mares beyond Day 300 of gestation and likely represent the effects of fetal stress and adrenal activation on pregnane metabolism by the fetus and placenta. Decreases in these same pregnanes in mares with acute cases likely reflect extreme fetal or placental compromise.

Evaluation of neonatal vitality and blood glucose, lactate and cortisol concentrations in foals of the Paint Horse breed

ABSTRACT: Clinical evaluations of newborns, as well as defining the therapeutic decision, represent significant challenges to the veterinarian. This study aimed to evaluate neonatal vitality using the modified Apgar score and blood glucose, lactate, and cortisol concentrations in newborn equines. Twenty foals of the Paint Horse breed born by normal delivery were evaluated during the first 48 hours of life. The modified Apgar score was determined at birth and 10 minutes later, with values ranging from 0 to 10. Blood samples for the laboratory tests were collected at birth and at 4, 8, 12, 16, 20, 24, 36, and 48 hours. The mean Apgar score was significantly lower at birth than at 10 minutes (p < 0.001). Blood glucose concentrations increased significantly between birth (98.90 ± 35.97 mg/dL) and 8 hours (127.90 ± 27.15 mg/dL), stabilizing after the first 12 hours (148.95 ± 29.59 mg/dL). Serum lactate concentrations showed a significant decrease across the time points tested, with the highest value occurring at birth (5.48 ± 2.17 mmol/L) and stabilizing after 24 hours (2.76 ± 1.31 mmol/L). Cortisol concentrations significantly decreased (p < 0.01) between 4 (10.46 ± 7.46 μg/dL) and 48 hours (5.21 ± 3.35 μg/dL), with the highest value occurring 4 hours after birth. The common occurrence of laboratory abnormalities in healthy newborn foals reinforces the need to conduct regular clinical examinations and to develop laboratory reference values for different breeds and ages.

A clinical case of equine fungal placentitis with reference to hormone profiles and ultrasonography

Fungal placentitis is an infectious disease inducing abortion in pregnant mares. In the present report, we describe a field case of abortion caused by fungal placentitis with consecutive examinations. The progesterone level and combined thickness of the uterus and placenta (CTUP) were abnormal before the onset of clinical signs. Additionally, the estradiol level started to change before the appearance of clinical signs. Abnormal serum amyloid A values and an abnormal fetal heart rate were observed after the onset of clinical signs. The present report demonstrates that the progesterone level and CTUP may be adequate as early diagnostic markers of fungal placentitis and bacterial infection. Endocrinological evaluation based on cutoff values or serial measurements were also useful for early diagnosis.

Reproductive Disorders in Horses

Reproductive disease is relatively common in the horse, resulting in a variable, yet significant, economic impact on individual horsemen as well as the entire industry. Diverse expertise from the veterinary community ensures and improves individual and population health of the horse. From a pathology and diagnostics perspective, this review provides a comprehensive overview of pathology of the male and female equine reproductive tract. Recognition by clinical and gross features is emphasized, although some essential histologic parameters are included, as appropriate. Where relevant, discussion of ancillary diagnostic tests and approaches are included for some diseases and lesions.

Cortisol and progestin release, heart rate and heart rate variability in the pregnant and postpartum mare, fetus and newborn foal

The mechanisms leading to parturition in the horse in many aspects differ from those in other species. Pregnancy is maintained not by progesterone but by 5α-pregnanes and the progestin precursor pregnenolone originates from the fetus. As parturition approaches, the fetal adrenal switches from pregnenolone to cortisol synthesis but it is not known whether cortisol crosses the placenta. We hypothesized that in parallel to fetal cortisol release, cortisol in the maternal circulation increases before foaling and this increase can be determined in both saliva and plasma. In addition, maternal, fetal and neonatal heart rate and heart rate variability were measured. In 25 pregnant mares, saliva for cortisol analysis was collected 4 times daily from 15 days before to 5 days after foaling. In 13 mares, in addition, fetomaternal electrocardiogram (ECG) recordings were made and blood samples for progestin and cortisol analysis were collected once daily. Heart rate (HR) was recorded until 5 days after foaling. The heart rate variability (HRV) variables standard deviation of the beat-to-beat (RR) interval (SDRR) and root mean square of successive RR differences (RMSSD) were calculated. From Days 15 to 4 before parturition, progestin concentration increased (peak 267 ± 42 ng/mL) and decreased thereafter (P < 0.05, day of foaling 113 ± 18 ng/mL). A prepartum increase in maternal cortisol concentrations was evident in blood (P < 0.05) and saliva (P < 0.05) and paralleled the decrease in progestin concentrations. In mares, HR remained constant during the last days of pregnancy but decreased within one day after parturition (P < 0.05) while maternal HRV did not change. In the fetus and neonate, HR increased from before to after birth (P < 0.05) indicating increasing demands on the cardiovascular system with adaptation to extrauterine life.

Concentrations of 15-ketodihydro-PGF2alpha, cortisol, and progesterone in the plasma of healthy and pathologic newborn foals

Information regarding the plasma hormone profiles of prostaglandins (PGs), cortisol (C), and progesterone (P4) during pathologic processes in newborn foals is scarce. The aim of this study was to determine the plasma concentrations of these hormones in diseased foals (n=40) and healthy at-term foals (n=24) (Equus caballus) during the first 2 weeks of life. Blood samples were collected daily, before any treatment with nonsteroidal drugs in diseased foals, and plasma was analyzed by radioimmunoassay. 15-Ketodihydro-PGF(2alpha) (PGM) was consistently higher in diseased foals than in healthy foals, probably related to roles of PGs in completing organ maturation and/or the presence of oxidative stress or inflammation. Similar trends were observed for C and P4. In diseased newborns, only PGM was significantly higher in nonsurviving foals, although C showed a similar profile. When specific diseases were considered, the levels of PGM and C were lower in premature foals at 12h of life, whereas the concentration of P4 was higher than in controls. The results of this study demonstrate the differences in plasma hormone levels between healthy and pathologic newborn foals, particularly during the first 2 d of life, probably reflecting the inability of diseased foals to cope with the transition between fetal and neonatal life.

Primary unilateral fibroleiomyoma of the ovary in a pregnant mare: a case report

Fibroleiomyomas of the ovary are rare. This smooth muscle tumour may develop and increase in size during pregnancy. Diagnosis is based on histological and immunohistochemical analyses. Histologically, the ovarian fibroleiomyoma consists of non-invasive bundles of smooth muscle cells that synthesize collagen-like extracellular matrix. This case report describes an ovarian fibroleiomyoma in a pregnant multiparous broodmare with a history of intermittent signs of colic.