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Oxytocin is a hormone with functions in: reproduction, maternal bonding, milk ejection, and feeding/social behavior, and is reported to be present in a variety of tissues. Our goal is to characterize oxytocin and leucyl and cystinyl aminopeptidase (LNPEP/oxytocinase), a key regulator of oxytocin in mares. We measured serum and tissue LNPEP by ELISA from ovulation (D0) until D21-22 in non-pregnant (n = 5) and pregnant mares (n = 6); and in periparturient and postpartum mares (n = 18). Placenta (n = 7) and homogenized tissue of diestrus mares (n = 6) were evaluated using protein determinations and LNPEP ELISAs. Identification of LNPEP and OXT protein in tissues was also performed via western blot, immunohistochemistry and liquid chromatography-mass spectrometry (LC-MS/MS). Furthermore, in situ hybridization was performed for LNPEP and OXT on endometrium, myometrium, pituitary and corpus luteum (CL). Serum LNPEP concentration were similar. Placental LNPEP U/mg protein was highest in the body and pregnant horn. The highest to lowest LNPEP U/mg protein by tissue were: myometrium > follicle wall > endometrium > kidney > CL > liver. Oxytocin was identified in the equine pituitary, CL and placenta and is likely to act in autocrine or paracrine manner, while LNPEP may act systemically and locally to regulate the availability of OXT.

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Our objectives were to examine changes in endometrial and luteal gene expression during estrus, diestrus, pregnancy and treatments to induce luteolysis and putatively induce luteostasis. Groups were: Diestrus (DIEST), Estrus (ESTR), Pregnant (PREG), Oxytocin (OXY), Carbetocin (CARB), and Meclofenamic acid (MFA). Blood was obtained from day (D)12 to D15 for measurement of oxytocinase, also referred to as leucyl-cysteinyl aminopeptidase (LNPEP) and progesterone. Luteal biopsies were obtained on D12 and D15 and an endometrial biopsy on D15. Real-time RT-PCR was performed for the following genes: PGR, ESR1, OXTR,OXT, LNPEP, PTGS2, PTGFR, PLA2G2C, PTGES, SLC2A4, and SLC2A1. Regarding serum LNPEP, PREG and OXY (p-value<0.001) had higher concentrations than DIEST mares. Endometrial PTGES expression was higher (p-value <0.04) in DIEST, PREG and OXY than other groups. Endometrium from ESTR had increased expression of OXT (p-value < 0.02) compared to MFA and OXY mares. Carbetocin treatment: decreased serum progesterone and LNPEP; increased endometrial PLA2G2C; decreased endometrial PTGES; and decreased luteal aromatase and PTGES. Treatment with MFA: decreased endometrial PLA2G2C, increased endometrial PTGES; and resulted in less OXTR and OXT luteal abundance on D12 compared to D15. Endometrial and luteal expression of LNPEP is affected by physiologic stage and treatment and is involved in luteal function and pregnancy recognition pathways through effects on oxytocin and prostaglandin synthesis in the horse.

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Our understanding of the temporal changes in endometrial and luteal gene transcripts related to the actions of oxytocin and prostaglandin during early equine pregnancy is incomplete. Additionally, the role of oxytocinase, also known as Leucyl-cystinyl aminopeptidase (LNPEP), during early pregnancy in mares has not been previously investigated. Luteal and endometrial biopsies were obtained on Day (D)8, D10, D12 and D15 post-ovulation in pregnant (PREG) and diestrus (DIEST) mares for real-time qPCR. Differences in endometrial gene expression occurred over time in: SLC2A4, SLC2A1, PTGES, OXTR and LNPEP. PTGFR and PLA2G2C had lower relative abundance in PREG D15 endometrium compared to D10. OXT and OXTR were increased on D10 and 15 PREG, respectively. Regarding luteal mRNA relative abundance, ESR1, PTGS2, PTGFR, and PTGES had higher relative abundance in D12 of DIEST and PREG. Luteal expression of OXTR and OXT had higher relative abundance in D15 compared to D8, and LNPEP had higher relative abundance in D10 and 12. Endometrial and luteal PTGES had an increased mRNA abundance in both D12 DIEST and PREG mares, which may lead to additional luteoprotective prostaglandin E2 (PGE2) secretion. Furthermore, luteal SLC2A1 had higher relative abundance in pregnancy, and likely supports the high metabolic activity of luteal tissue by increasing glucose uptake. Oxytocinase is present in endometrial and luteal tissue and its role in oxytocin induced prostaglandin secretion is uncertain.

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Leucyl and cystinyl aminopeptidase (LNPEP/oxytocinase) is an enzyme that metabolizes oxytocin in serum and tissues. The presence of oxytocin/neurophysin I (OXT), oxytocin and LNPEP and their relationship to other genes is unknown in the equine conceptus. Our objective was to characterize gene expression of LNPEP and OXT on D8, 10, 12, 14, 15, 16 and 21 conceptuses in relationship to other genes. Immunohistochemistry, western blot and liquid chromatography with tandem mass spectrometry (LC-MS/MS) were used for identification of oxytocin and LNPEP in D15, 16 and 18 conceptuses. LNPEP was increased at D15 compared to D10, was immunolocalized in the equine trophectoderm and endoderm, and protein was confirmed by LC-MS/MS. Maximal abundance of OXT was at D21, and lowest on D12 and D14, but no protein was identified. OXTR abundance was highest on D14 and D21. LNPEP was correlated with PTGFR and PTGES on D12 and D14-D15, and high expression of PTGES, PTGS2 was found on D14, D15 and D21; PTGFR was found on D8 and D12-21. LNPEP may have a role in prostaglandin regulation and conceptus fixation by decreasing the availability of oxytocin. Further investigation on the role embryonic LNPEP during pregnancy is warranted.

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Exposure to plants containing glucosinolates (GSLs) affects thyroid function in many species, in horses is implicated in the birth of foals with congenital hypothyroidism. The present study was performed to determine the effect of feeding a GSL (sinigrin) in combination with a low-iodine diet for 12 weeks on thyroid hormones and serum iodine concentrations in nonpregnant mares. Nineteen mares aged 2-14 years were divided into control (n = 6), low (20 mmol/day) (n = 7) and high GSL (35 mmol/day) (n = 6) groups. Thyrotropin-releasing hormone (TRH) stimulation tests and serum iodine measurements were performed at 0 and 12 weeks. Total triiodothyronine (TT3), total thyroxine (TT4), and thyroid-stimulating hormone (TSH) concentrations were measured at the baseline and in post-TRH samples. The post-TRH value minus the basal value (Delta Δ) and fold change (FC) were calculated for TSH, TT3, and TT4. Data were analyzed at P < .05. Highlights included Delta Δ and FC TT4 and TT3 concentrations having a group and week interaction (P < .001) with week 12 control mares having higher values than mares in week 12 low and high GSL groups. TT4 FC values had a group (P < .001) and group by week interaction (P < .001) with week 12 control concentrations higher (P < .006) than all groups. Iodine concentrations decreased (P < .002) over time in GSL mares. In conclusion, feeding mares a low-iodine diet with 20 and 35 mmol sinigrin/day resulted in lower serum iodine concentrations.

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Iodine, thyroxine (T4) and triiodothyronine (T3) are required for normal fetal growth, maturation, and neonatal survival. There is a lack of robust information on iodine levels found in colostrum, milk, and serum of mares and foals after a healthy pregnancy. Our objective was to characterize colostrum, milk, and serum iodine levels in healthy postpartum mares and foals (n = 10) and explore relationships with thyroid hormone concentrations. Colostrum, milk, and jugular blood samples from draft breed mares and foals with an estimated average iodine daily intake of 39 mg per mare during pregnancy were obtained at Day 0 (foaling date) and/or 10 days later. Parameters studied were (1) mare basal concentrations of serum: TT3, TT4, and iodine; (2) iodine in colostrum at Day 0 and milk iodine (Day 10); and (3) foal basal: TT3, TT4, and serum iodine (Days 0 and 10). Median ± median error colostrum iodine levels (165 ± 15.1 µg/L) were higher than milk (48 ± 5.6 µg/L; P = .007) levels. Median ± median error foal serum iodine (268.5 ± 7.6 µg/L), TT4 (1,225 ± 47.8 nmol/L), and TT3 (14.2 ± 1.1 nmol/L) at foaling date were higher than at 10 days (serum iodine: 70 ± 3.6 µg/L; TT4: 69.6. ± 20.4 nmol/L; and TT3: 5.4 ± 0.3 nmol/L). In conclusion, equine mammary tissue concentrates iodine beyond plasma levels, making colostrum and milk a significant source of iodine. Foal serum iodine levels are high in the neonatal period and are positively correlated with TT4, which is important for neonatal adaptation.

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The ability to predict impending foaling is invaluable, as attending foaling improves mare and foal outcome during parturition; therefore, a comparison of foaling prediction technologies is warranted. The purpose of this study was to compare technologies to predict foaling. Forty Standardbred mares were monitored daily for parturition. Prefoaling mammary secretion was collected daily and evaluated using a: calcium titration method (Ca titration), calcium and magnesium strip (Ca and Mg), handheld digital pH device (pH digital), pH strip, and refractometer (Brix). In addition, a birth monitoring system that was attached in the mare's vulva was studied and all positive alarms (foaling) and negative alarms (false alerts) were recorded. Analysis of variance, correlation, and logistic analysis were used to analyze the different technologies and their associations between parity and foal gender. Receiver operator characteristic analysis for cutoff value and subsequently sensitivity, specificity, positive, and negative predictive values for each technology were obtained. Maiden mares and mares carrying a colt had a longer gestational length. Multiparous and maiden mares had no difference in their prefoaling mammary secretion pH using the digital and pH strip technologies when predicting foaling; however, the calcium concentrations measured using the Ca titration technology were lower in multiparous than in maiden mares. The Ca titration technology was the single best technology to predict when the mare was not going to foal; and when the Ca titration and pH digital were used in combination, their prediction for foaling increased when compared with using each technology individually.

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An understanding of the One Health and EcoHealth concepts by students is dependent on medical pedagogy and veterinary medical pedagogy having similarities that allow a common discourse. Medical pedagogy includes a focus on the social, political, and economic forces that affect human health, while this discourse is largely absent from veterinary medical pedagogy. There is, however, a gradient in health that human and animal populations experience. This health gradient in human populations, which runs from low to high according to the World Health Organization, is largely explained by "the conditions in which people are born, grow, live, work, and age."1,2 Regarding the human health gradient, other authors have broadened the list of conditions to include access to health care systems used to prevent disease and treat illness, and the distribution of power, money, and resources, which are shaped by social, economic, and political forces.1,2 In human medicine, these conditions are collectively termed the social determinants of health (SDH). Veterinarians who work with the public encounter people and their animals at both the low and the high end of the health gradient. This article explores the concept of the parallel social determinants of animal health (SDAH) using examples within urban, rural, and remote communities in North America as well as abroad. We believe that in order to understand the One Health paradigm it is imperative that veterinary pedagogy include information on, and competence in, SDH and SDAH to ultimately achieve improvements in human, animal, and environmental health and wellbeing.

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Hydropsical conditions are exceedingly rare in the horse. However, when they occur, they are true emergencies due to the severe enlargement of the pregnant uterus, which can result in clinical signs, such as an enlarged round abdomen, dyspnea, reluctance to walk, and colic, and may lead to the development of abdominal wall disease. The pathogenesis of hydropsical conditions is not fully elucidated, but they have been associated with placentitis and fetal abnormalities. This report describes six cases of hydropsical conditions in mares with or without concurrent abdominal wall disease. Five out of six cases were hydrallantois, and of these five, two mares had abdominal wall disease; the remaining one out of six cases was hydramnios. All mares were treated by termination of the pregnancy through gradual fluid drainage transcervically over a number of hours, and their fetuses were delivered vaginally. All fetuses were euthanized immediately after vaginal delivery. Of the six mares, two had signs of placentitis, two were confirmed seropositive for leptospirosis, and two were euthanized (one because of a vaginal tear that communicated through the peritoneum and one mare that developed abdominal wall rupture and laminitis). The remaining 4 mares were available for follow-up; three mares were not rebred, and one mare became an embryo donor, with a successful embryo recovery. We reported the prevalence of leptospira involvement in two out of six cases of hydrallantois and also described the clinical outcome of the mares after treatment with slow fetal fluid drainage.

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CASE DESCRIPTION 5 mares were evaluated because of reproductive complications following long-term (> 1 year) use of intrauterine glass marbles for estrus suppression. CLINICAL FINDINGS 3 mares had 1 intrauterine glass marble, and 2 mares had 2 intrauterine glass marbles. On examination, 2 mares had signs of chronic endometritis, and 3 had signs of pyometra. Marbles or glass shards adhered to the endometrium were identified by means of hysteroscopy in 3 of 5 mares. Five of 7 marbles had surface imperfections or were broken. TREATMENT AND OUTCOME All patients were treated with uterine lavage and intrauterine and systemic administration of antimicrobials chosen on the basis of results of bacterial culture and susceptibility testing. Two of 5 mares were treated with intrauterine Tris-EDTA. One mare underwent 3 unsuccessful embryo transfer procedures and was subsequently lost to follow-up. One mare was euthanized because of severe vaginal and cervical adhesions and chronic vaginal discharge. Three mares had no apparent signs of reproductive disease at the time of follow-up but were not rebred. CLINICAL RELEVANCE Results of the present small case series suggested that use of intrauterine glass marbles should be discouraged because of the potential for severe reproductive consequences.

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Intrauterine plant oil infusion, including fractionated coconut oil, has been previously found to be a safe, inexpensive, and reversible method of prolonging the luteal phase in mares when administered on Day 10 of the estrous cycle. Our objective was to understand the uteroovarian response to the administration of fractionated coconut oil infusion in the uterus of diestrous mares. We hypothesized that intrauterine coconut oil administration on Day 10 would prolong luteal life span in a dose-dependent fashion and would result in higher serum progesterone levels than untreated mares at the expected time of luteolysis. Light-horse mares (n = 18) were examined using transrectal palpation and ultrasonography to determine if they had a normal interovulatory interval and were then examined daily in estrus until the day of ovulation (Day 0) and then every other day during an estrous cycle. Jugular blood was drawn on Day 11, Day 13, Day 15, and Day 17, centrifuged, and serum stored until assayed for progesterone (P4; Siemens Coat-a-Count Progesterone RIA, Los Angeles, CA, USA). Mares were randomly assigned to treatment and studied over one to two estrous cycles with a rest cycle after each treatment cycle. Groups were: control (n = 5), fractionated coconut oil 1.0 mL (Miglyol 810; Sasol Oil, Witten, Germany) infused in the uterus with an artificial insemination pipette on Day 10 (Group 1; n = 5) and fractionated coconut oil 0.5 mL infused in the uterus with an embryo transfer gun, on Day 10 (Group 2; n = 5). All statistical analyses were performed using analytical software (Stata SE, version 13.1, College Station, TX, USA) at P < 0.05. Data were first evaluated using the Shapiro-Wilk test for normality. Differences between groups in days to luteolysis (DTL) were examined using analysis of variance and Bonferroni, and the effect of day and treatment on P4 levels were examined using the Kruskal-Wallis and Dunn's all pairwise test. There was a significant difference in DTL between the groups (P = 0.0083), with fewer DTL in Group 1 compared to control (P = 0.011) and to Group 2 (P = 0.034). There was a significant effect of day (P < 0.0001) on P4 levels with Day 11 P4 levels higher than Day 15 and Day 17 and Day 13 P4 levels higher than Day 15 or Day 17 (P < 0.03). There was a significant effect of treatment group (P = 0.0098) on P4 levels with control and Group 2 levels higher than Group 1 mares (P = 0.0012, P = 0.0495, respectively). We concluded that intrauterine administration of 1 mL of fractionated coconut oil lowered P4 levels in diestrus in a dose-dependent fashion and did not prolonged the luteal phase of the mares.

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Caregivers of HIV-positive children were interviewed in the Mbarara and Isingiro districts of Uganda to identify current trends in practices related to HIV testing and the disclosure of HIV status to the child. A total of 28 caregivers of at least one HIV-positive child participated in semi-structured interviews exploring when and why they tested the child for HIV, when the child was informed of their positive status, and what the caregiver did to prepare themselves and the child for status disclosure. For a majority (96%) of respondents, the decision to test the child for HIV was due to existing illness in either the child or a relative. Other common themes identified included the existence of stigma in the caregivers' communities and doubt that the children truly understood what was being explained to them when their status was disclosed. Most (65%) children were informed of their HIV status between the ages of 5 and 9, with the mean age of disclosure occurring at the age of 7. General provision of HIV information typically began at the same age as disclosure, and as many as two thirds (64%) of the caregivers sought advice from an HIV counsellor prior to disclosure. How a caregiver chose to prepare themselves and the child did not affect the caregiver's perception of whether the disclosure experience was beneficial or not. These findings suggest that the HIV disclosure experience in Mbarara and Isingiro districts differs from current guidelines, especially with respect to age of disclosure, how caregivers prepare themselves and the child, and approaching disclosure as an ongoing process. The doubts expressed by caregivers regarding the child's level of HIV understanding following the disclosure experience suggest the children may be insufficiently prepared at the time of the initial disclosure event. The findings also suggest that examining the content of pre-disclosure counselling and HIV education, and how health care professionals are trained to facilitate the disclosure process as important avenues for further research.

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Ultrasound-guided biopsies of corpora lutea have been previously used for research purposes in the mare and cow. However, the health effects and fertility after transvaginal luteal biopsies (TVLB) or transvaginal ovarian biopsies (TVOB) obtained for diagnostic purposes in cases of suspected ovarian tumors have not been previously evaluated in the horse. The aim of this study was to determine the effects on health and fertility of TVLB and TVOB in mares; 53 mares were included in the study (11 control non-biopsied mares, 37 TVLB mares biopsied on one or more of the following Days 8, 10, 12, 15, 21, and 5 TVOB mares with ovarian abnormalities), resulting in a total of 108 TVLB and TVOB cycles and 183 procedures. Mares were divided into Groups 1 to 3 by the number of TVLB per estrous cycle (mare in Group 1 had 1 TVLB procedure, mares in Group 2 had 2 TVLB procedures, and mares in Group 3 had 3 TVLB procedures). Group 4 comprised TVOB mare cycles with ovarian abnormalities (n = 5). Mares were examined to determine day of ovulation (Day 0) and the presence of a corpora lutea using transrectal ultrasonography. Mares were sedated, and an ultrasound-guided transvaginal biopsy was performed of luteal or ovarian tissue. Health effects of TVLB or TVOB were assessed by daily rectal temperatures, appetite, and general demeanor for 72 hours post-procedure, and 3 mares were examined at necropsy. Fertility was not significantly different in control and TVLB Groups 1 to 3 (P = 0.7648) and in the first or subsequent cycles where the ovulation was from an ovary that had a previous TVLB (P = 0.7147). A TVLB on Day 8 post-ovulation may induce an early return to estrus. In conclusion, the TVLB or TVOB procedure had no effect on health and fertility in this study if the procedure was correctly performed with good technique. Because of the low number of cycles (n = 37), the fertility data should be interpreted with caution. The TVOB may be applied in the diagnosis of mares with ovarian abnormalities, and no adverse health effects were associated with TVOB of mares with granulosa theca cell tumor.

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Reliable methods for regulating oestrus and superovulation in equine embryo transfer (ET) programs are desirable. The objective in this study was to compare two oestrus synchronization methods combined with equine follicle-stimulating hormone (eFSH) treatment in an ET program. In the progesterone and estradiol-17ß (P&E) group, mares (n=12) were given progesterone and estradiol-17ß, daily for 10 days, followed by prostaglandin (PG)F(2α) on the last day. In the PG group, mares (n=12) were given PGF(2α) 5 days post-ovulation. In both groups donor mares were allocated to eFSH therapy, and were subsequently bred. Embryo recovery and transfer were performed routinely. The interval to ovulation (mean ± SEM, range) was not statistically different between donor mares in the P&E group (10.2±0.3, 9-12 days) and donor mares in the PG group (8.7±0.7, 4-12 days). Among donor mares, the synchrony of ovulations was higher following the P&E regimen (P<0.05); however, there was a tendency (P<0.06) for fewer ovulations than in the PG group (1.5±0.3 vs. 2.5±0.4 ovulations, respectively). Embryo recovery (0.9±0.3 vs. 1.4±0.3 embryo/recovery) and recipient pregnancy rate per transferred embryo (4/9, 44% vs. 4/15, 27%) were similar. It was concluded that the P&E regimen was more reliable for synchronization of oestrus in eFSH-treated mares but the fewer ovulations may curtail any advantage of this regimen.

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The objective of this investigation was to clone and express the elk and horse common alpha-subunit and FSH beta-subunit cDNAs, and to produce recombinant FSH from both species in vitro. The RNAs extracted from elk and horse pituitary glands were reverse-transcribed and amplified by polymerase chain reaction. The cDNAs corresponding to both subunits of elk and horse were cloned into the expression vector pBudCE4.1 and transfected into CRL-9096 cells. Expression of both genes was determined in the transfected cells by Northern and Western blot analysis. Recombinant elk and horse FSH secreted in culture media were characterized by an in vitro bioassay and RIA. When the recombinant products were assessed as activity over mass of FSH measured by RIA, the horse product was 5.6 times more potent than the elk product. The recombinant products injected to immature female Wistar rats stimulated ovarian growth. The results suggest that the products obtained correspond to recombinant versions of the native elk and horse FSH. The availability of these recombinant products may aid in the development of more predictable and efficient techniques of ovarian stimulation in cervids, equids, and other species as well.

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The objective was to compare the reproductive performances associated with the first (Cycle-1), second (Cycle-2), and mid-season (MS-Cycle) ovulations of the breeding season in donor mares that were treated with equine-FSH (eFSH) in the early vernal transition. Mares (n=15) kept under ambient light were examined ultrasonographically per-rectum starting January 30. When an ovarian follicle > or =25mm in diameter was detected, twice daily eFSH treatments were initiated. The eFSH treatments ceased when a follicle > or =35mm was detected, and 36h later hCG was administered. Thereafter, mares were artificially inseminated every 48h until ovulation (Day 0). Trans-cervical embryo recovery attempts were performed on Day 8, and subsequently PGF2alpha was administered. Equine FSH was not administered in the subsequent estrous cycles. In Cycle-2 and in the MS-Cycle, hCG was administered when a follicle > or =35mm was detected; breeding, embryo recovery, and PGF2alpha administration, were similar to Cycle-1. Mares had an untreated estrous cycle (no treatment or breeding) between Cycle-2 and the MS-Cycle. All mares developed follicle(s) > or =35mm after 4.9+/-0.6 days of eFSH treatment, and subsequently ovulations occurred; mean (95% CI) interval from treatment initiation to ovulation was 7.9 (6.5-9.3) days. The number of preovulatory follicles (> or =30mm) at the time of hCG administration (Cycle-1: 2.2+/-0.3 compared with Cycle-2: 1.0+/-0 compared with MS-Cycle: 1.1+/-0.1 follicles), and the number of ovulations (2.5+/-0.4 compared with 1.0+/-0 compared with 1.1+/-0.1 ovulations) were greater (p<0.05) in Cycle-1. Nevertheless, mean embryo numbers did not differ among cycles (0.8+/-0.2 compared with 0.5+/-0.1 compared with 0.5+/-0.1 embryo/mare). On average, embryo morphology grade was less (p<0.05) in Cycle-1 as compared to non-eFSH cycles (combined Cycle-2 and MS-Cycle). This impaired embryo quality could be due to a seasonal effect, or negative effect of the eFSH treatment, which was possibly related to alterations in the hormonal environment (estradiol-17beta and progesterone). A prolonged IOI (>21 days) was recorded in 7 of 15 mares following the Cycle-1 ovulation, but not subsequently. In conclusion, eFSH treatment of vernal transitional donor mares stimulated ovulation within only few days of treatment, and the following embryo recovery rate was at least as good as in the subsequent estrous cycles; however, on average, embryos were morphologically impaired. In subsequent estrous cycles in the breeding season, ovulations, embryo recovery rates, and embryo variables did not appear to be negatively affected; however, the first inter-ovulatory interval of the breeding season was prolonged in approximately half of the mares.

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Superovulatory treatment may potentially increase the embryo recovery rate and the per-cycle pregnancy rate in normal or subfertile mares that are managed properly. However, some studies suggest a possible negative effect of superovulatory treatment on ovarian follicular maturation and embryo viability. Objectives of the present study were to investigate the early effects of eFSH treatment in reproductively normal mares in terms of: folliculogenesis, pregnancy rate, early embryonic development, reproductive tract parameters (tone and edema), and serum estradiol-17beta and progesterone concentrations. Reproductively sound mares (n=26) were evaluated daily by transrectal palpation and ultrasonography. Five days after spontaneous ovulation, mares were randomly assigned to one of two treatment groups. In the eFSH group, mares (n=16 estrous cycles) were administered eFSH twice daily; beginning when a follicle > or =20mm was detected, and continuing until at least one follicle reached a diameter of > or =35 mm. PGF2alpha was administered 2 days following initiation of eFSH therapy, and hCG was administered approximately 36h after cessation of eFSH therapy. In the control group, mares (n=26 estrous cycles) were administered PGF2alpha 7 days after spontaneous ovulation, and hCG when a follicle > or =35 mm was detected. All mares were bred with fresh semen, monitored for ovulation (Day 0), and evaluated for pregnancy on Days 11-16. Serum estradiol-17beta and progesterone concentrations were analyzed using radioimmunoassay on the Day of hCG administration, and Days 8, 11 and 16. Mares treated with eFSH had more follicles > or =30 mm at the time of hCG administration (2.6+/-0.4 compared with 1.1+/-0.1; P<0.01), and more ovulations (2.3+/-0.5 compared with 1.1+/-0.3; P<0.01). However, pregnancy rates were not significantly different between groups (50%; 8/16 compared with 62%; 16/26). Mean overall daily growth rate of embryonic vesicles from Day 11 to 16 was not statistically different between the two groups (3.3+/-0.3 compared with 3.7+/-0.1 mm/day) (P=0.2); however, was more variable (P<0.01) in the eFSH group (95%CI: 2.6-3.8mm/day) than in the control group (95%CI: 3.5-3.9 mm/day). Administration of eFSH modified the reproductive tract variables and serum concentrations of progesterone and estradiol-17beta on the days that oocyte maturation, fertilization, and early embryonic development are expected to occur. These alterations may be related to the greater incidence of non-ovulatory follicles (25% compared with 0%), fewer embryos per ovulation rate (0.3+/-0.1 compared with 0.6+/-0.1), and the lesser than expected pregnancy rates in the eFSH-treated mares.

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Endometritis has been reported to be the third most common medical condition of horses. Timely diagnosis and treatment of endometritis in mares increases the chance of pregnancy. Exfoliative endometrial cytology is often used as a clinical tool to evaluate endometrial inflammation through detection of neutrophils. There is a lack of information on the time frame for changes in endometrial cytologic parameters following breeding. The main objectives of this article are to use current information to describe systematic analysis of endometrial cytology using standardized methods for sample collection and interpretation, and discuss how these parameters change in relationship to post-breeding interval and mare susceptibility.

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