Mares and horses are integral components of equine studies, focusing on the reproductive and behavioral aspects of equine biology. Mares, or adult female horses, play a significant role in breeding programs and are often studied for their reproductive physiology, gestation, and maternal behaviors. Horses, as a broader category, encompass both sexes and all age groups, providing a comprehensive view of equine anatomy, physiology, and behavior. Research in this area often investigates the differences and similarities between mares and other horses in terms of hormonal cycles, reproductive health, and social interactions. This page compiles peer-reviewed studies and scholarly articles that explore the biological and behavioral characteristics of mares and horses, offering insights into their roles in equine science and management.
Urschel KL, Escobar J, McCutcheon LJ, Geor RJ.The objective of this study was to determine whether the rate of insulin infusion during isoglycemic hyperinsulinemic clamp procedures affected measures of insulin action, including glucose disposal and plasma non-esterified fatty acid, endothelin-1, and nitric oxide concentrations, in mature, healthy horses. Eight thoroughbred mares were studied during a 2-h hyperinsulinemic clamp procedure, conducted at each of 4 rates of insulin infusion: 0 (CON), 1.2 (LOWINS), 3 (MEDINS), and 6 (HIGHINS) mU · kg(-1) · min(-1). The infusion rate of a dextrose solution was adjusted throughout the clamp pro...
Urschel KL, Escobar J, McCutcheon LJ, Geor RJ.Little is known about the role insulin plays in regulating whole-body and muscle protein metabolism in horses. The objective of this study was to determine the effects of graded rates of insulin infusion on plasma amino acid concentrations and the activation of factors in the mechanistic target of rapamycin signaling pathway in the skeletal muscle of horses. Isoglycemic, hyperinsulinemic clamp procedures were conducted in 8 mature, thoroughbred mares receiving 4 rates of insulin infusion: 0 mU · kg(-1) · min(-1) (CON), 1.2 mU · kg(-1) · min(-1) (LOWINS), 3 mU · kg(-1) · min(-1) (MEDINS),...
Panarace M, Pellegrini RO, Basualdo MO, Belé M, Ursino DA, Cisterna R, Desimone G, Rodríguez E, Medina MJ.Flow cytometry sex-sorting technology was developed in 1989. However, it is only the bovine species in which offspring of the desired sex are obtained at a commercial level. The aim of the present work was to evaluate efficiency parameters when using fresh sexed semen in a large-scale equine commercial embryo transfer program. During the 2009, 2010 and 2011 breeding seasons, 938 synchronized cycles were artificially inseminated. One hundred (10.6%) mares failed to ovulate, and for the remaining 838 useable cycles, 887 doses of sexed semen were used, representing 1.06 doses per cycle. In genera...
Mariella J, Pirrone A, Gentilini F, Castagnetti C.The purposes of this study were to determine physiological changes occurring in hematologic and biochemical parameters in mares between the last month of gestation and the first week after parturition. If a significant change was observed with respect to the reference interval of an adult horse, a further aim of the study was to establish different reference intervals. Blood samples were collected from 62 healthy pregnant Standardbred mares. Seventeen nonpregnant and nonlactating mares were used as a control group. In pregnant mares, blood sampling was conducted every three days from 1 month b...
Pivoto FL, de Macêdo AG, da Silva MV, Ferreira FB, Silva DA, Pompermayer E, Sangioni LA, Mineo TW, Vogel FS.Protozoa from the family Sarcocystidae are agents of reproductive and neurological disorders in horses. The transmission of these protozoa may occur via horizontal or vertical means, and the frequency and potential of the later is not fully elucidated in horses. Thus, the aim of study was to correlation levels of antibodies in mares with pre colostral foals seropositive and assess the level and distribution of antibodies against Neospora spp., Sarcocystis neurona and Toxoplasma gondii, in mares and pre colostral foals at the parturition. The blood samples were collected from mares immediately ...
Sloet van Oldruitenborgh-Oosterbaan MM, Grinwis GC.Equine sarcoidosis seems to be an emerging problem. As more horses are referred for dermatologic disease, equine sarcoidosis should be considered in any case of exfoliative and/or nodular skin disease with or without systemic involvement, including generalized granulomatous disease affecting most internal organs. Multiple breeds are affected with mares being predisposed. Affected horses are typically 3 years or older. The prognosis for generalized granulomatous disease is generally poor, whereas the prognosis for the localized cutaneous form is favorable but may require lifelong treatment.
Marenzoni ML, Stefanetti V, Papa P, Casagrande Proietti P, Bietta A, Coletti M, Passamonti F, Henning K.The role of the horse in Coxiella burnetii infection has not been defined. Accordingly, a twofold approach was taken to further our knowledge on this topic: (1) conduct a systematic review of the literature to establish available evidence of C. burnetii infection in the horse; (2) undertake a biomolecular investigation of 122 cases of equine abortion, stillbirth and neonatal foal death, for the presence of C. burnetii using a PCR test targeting the IS1111 gene of C. burnetii. A review of the literature turned up seven studies that identified C. burnetii DNA in equine specimens, especially abor...
Benhajali H, Ezzaouia M, Lunel C, Charfi F, Hausberger M.Discomfort in farm animals may be induced by inappropriate types or timing of food supplies. Thus, time restriction of meals and lack of roughage have been shown to be one source of emergence of oral stereotypies and abnormal behaviour in horses which have evolved to eat high-fibre diets in small amounts over long periods of time. This feeding pattern is often altered in domestic environment where horses are often fed low fibre meals that can be rapidly consumed. This study aimed at determining the effect of the temporal pattern of feeding on reproductive efficiency of breeding mares, One hund...
Toishi Y, Tsunoda N, Tagami M, Hashimoto H, Kato F, Suzuki T, Nagaoka K, Watanabe G, Tokuyama S, Okuda K, Taya K.Evaluation of a new chemiluminescent enzyme immunoassay, the PATHFAST assay system (PATHFAST), for measurement of circulating progesterone in mares was performed. Five mares at the mid-luteal stage were administrated a single i.m. injection of prostaglandin F2α analog (PGF2α; cloprostenol 250 μg/ml), and then blood samples were collected from the jugular vein at 0, 15, 30 and 45 min, at one-hour intervals until 24 and at 48 hr via a catheter in the jugular vein. To monitor the physiological changes in circulating progesterone in mares after induced luteolysis, concentrations of progesterone...
Ponthier J, Teague SR, Franck TY, de la Rebière G, Serteyn DD, Brinsko SP, Love CC, Blanchard TL, Varner DD, Deleuze SC.Myeloperoxidase (MPO) is a pro-oxidant enzyme contained in and released by neutrophils during degranulation or after lysis. Post-thaw semen contains MPO and its concentration is associated with decreased sperm motility. Recently, MPO concentration in post-thaw semen was shown to be associated with the presence of non-sperm cells (NSC). The objective of this study was to evaluate the effect of a single-layer colloidal centrifugation before cryopreservation on NSC and MPO concentrations in equine semen. The experimental design consisted of freezing semen with or without previous centrifugation t...
Hemberg E, Einarsson S, Jones B, Mikko S.The objective of this study was to investigate the presence and origin of polymorphonuclear leucocytes (PMNLs) in the amniotic fluid of mares giving birth to healthy foals. Material from 25 mares was included. Amniotic fluid was collected during parturition before breakage of the amniotic vesicle. Manual microscopic cytologic evaluation was made on cytospin preparations after staining. PMNLs were found in all amniotic samples examined. The genomic DNA was extracted from 12 of the amniotic fluid samples and was genotyped. The results indicate that the PMNLs originate from the foetus.
Andruskevich SM, Perry P, Houpt K, Houpt TR.The objectives were to measure changes in fluid balance of mares at parturition and relate those changes to the foals' acquisition of passive immunity. Twelve Thoroughbred mares and their foals were observed for suckling behavior for the first 12h post-partum. The mare's water intake, packed cell volume, plasma protein concentration, and plasma osmolality were measured pre- and post-partum. The foals' immunoglobulin concentrations were measured at birth and 24h later. The median increase from pre- to post-foaling in mares' packed cell volume was 4.0% (interquartile range=0.3-6.8). The median i...
de Ruijter-Villani M, van Boxtel PR, Stout TA.Uterine-derived growth factors and cytokines play essential roles in regulating preimplantation conceptus development. In several species, fibroblast growth factor-2 (FGF2) promotes embryogenesis, trophoblast cell migration, and adhesion. This study investigated mRNA expression for FGF2, its receptors (FGFR1-4), the activating factor FGF binding protein (FGF-BP) in equine endometrium and trophectoderm during early pregnancy and the estrous cycle, and localized FGF2 protein in both endometrium and conceptus tissues. FGF2, FGFRs1-4, and FGFBP mRNAs were expressed in endometrium throughout the es...
Donovan CE, Hazzard T, Schmidt A, LeMieux J, Hathaway F, Kutzler MA.We investigated the effect of immunization against gonadotropin releasing hormone (GnRH) using a commercial canine GnRH vaccine on estrus suppression and unwanted estrous behavior in mares. In experiment 1, mares were immunized (n = 6) twice with vaccine (5 mL) given intramuscularly 4 weeks apart or received a control diluent (n = 5). Transrectal ultrasonographic examination of the reproductive tracts was performed three days a week for 40 weeks after initial vaccination. Blood samples were collected weekly for GnRH antibody titer and progesterone concentration determination. In experiment 2, ...
Klein CC, Wietstock S, Hoffmann M.Diagnosing reproduction processes is a main activity of veterinarians concerning farm animals. So it would be eligible to replace this physically demanding work by other procedures. Aim of the presented study was to in-vestigate, whether results of breath analysis are related to sexual hormone levels in equine females. Breath samples of 25 mares as well as regularly taken samples of ambient air were analysed using Ion Mobility Spectrometry (IMS). Peak heights of three clusters were found to correlate moderately strong to blood serum levels of equine chorionic gona...
Nuñez CM, Adelman JS, Rubenstein DI.Adoption of nongenetic offspring occurs in a variety of species but is rare in equids. We report a case of adoption by a free-ranging, feral mare Equus caballus and compare the maternal care received by her genetic offspring (born 1995) to that of her adopted offspring (born 1996) for the first 30 weeks of development. We compare five measures of care: (1) total time spent suckling, (2) mare aggression during suckling, (3) number of mare-terminated suckling bouts, (4) contact maintenance, and (5) mare-foal distance. For most behaviors, we detected no difference in the mare's treatment of the t...
Hamond C, Pinna A, Martins G, Lilenbaum W.Leptospirosis is a zoonotic disease of global importance and has a worldwide distribution. This infection displays clear seasonal nature in some regions of the tropics, where the rainy season is marked by high temperatures. Household and wild animals carry leptospires and contribute to their dissemination in nature. Transmission mainly occurs by contact with water contaminated with the urine of infected animals, and consequently, it is quite widespread especially in times of rain, since many areas are subject to flooding and have poor sanitation. Serological tests demonstrate that Leptospira s...
Kafarnik C, Donaldson D, Payne R, Holloway A.A 13-year-old cob mare was presented with exophthalmos and periocular swelling of the left eye. The diagnostic work-up included ocular ultrasound, sonographic examination through the thinned frontal bone, radiography, standing computed tomography of the skull and exploratory osteoplastic surgery. Histopathology was consistent with an organized hematoma. An intradiploic hematoma of the frontal bone was diagnosed 5 years after head trauma, with progressive expansion and deformation of the skull resulting in exophthalmos. Exophthalmos with facial bone deformation was the only clinical finding of ...
Santos VG, Beg MA, Bettencourt EM, Ginther OJ.The effects of inhibition of PGF2α synthesis on luteolysis in mares and on the incidence of prolonged luteal activity were studied in controls and in a group treated with flunixin meglumine (FM), a PGF2α inhibitor (n = 6/group). The FM was given every 8 hours (1.0 mg/kg) on each of Days 14.0 to 16.7. Concentration (pg/mL) of PGF2α metabolite averaged over 8 hours of hourly blood sampling at the beginning of each day, was lower in the FM group than in the controls on Day 14 after ovulation (6.7 ± 1.3 vs. 13.8 ± 2.9, P < 0.05), Day 15 (15.0 ± 3.9 vs. 35.2 ± 10.4, P < 0.10), and Day 16 (21...
Ball BA, Scoggin KE, Troedsson MH, Squires EL.Biological effects of prostaglandin E2 are mediated via one of four receptors designated EP1, EP2, EP3 and EP4 which are encoded by separate genes. In general, EP1 and EP3 induce smooth muscle contraction whereas EP2 and EP4 induce smooth muscle relaxation. The objective of the current study was to characterize the expression of the genes for PGE2 receptors (EP2 and EP4) in the horse oviduct based upon immunohistochemistry (IHC) and quantitative PCR (qPCR). Oviductal tissue was collected from mares at estrus (n=5), at 5 days post-ovulation (n=4), and from prepubertal mares (n=5). Isthmic and a...
Davies Morel MC, Lawlor O, Nash DM.Endometritis is an important cause of sub-fertility in mares. The critical indicator of reproductive success and financial return for commercial studs is live foaling rate. Endometrial bacteriology and/or cytology are used to diagnose endometritis and thus identify mares at risk of early embryonic death. However, mares with endometritis may conceive but then abort in late gestation. The aims of this study were to establish, as part of a standard breeding examination (1) whether a threshold percentage of uterine polymorphonuclear neutrophils (PMNs) exists above which a significant reduction in ...
Schauer SN, Sontakke SD, Watson ED, Esteves CL, Donadeu FX.Previous evidence from in vitro studies suggests specific roles for a subset of miRNAs, including miR-21, miR-23a, miR-145, miR-503, miR-224, miR-383, miR-378, miR-132, and miR-212, in regulating ovarian follicle development. The objective of this study was to determine changes in the levels of these miRNAs in relation to follicle selection, maturation, and ovulation in the monovular equine ovary. In Experiment 1, follicular fluid was aspirated during ovulatory cycles from the dominant (DO) and largest subordinate (S) follicles of an ovulatory wave and the dominant (DA) follicle of a mid-cycle...
Donadeu FX, Schauer SN.Relatively little is known about the physiological roles of microRNAs (miRNAs) during follicular development. Previous evidence from in vitro studies suggests specific roles for a subset of miRNAs, including miR-21, miR-23a, miR-145, miR-503, miR-224, miR-383, miR-378, miR-132, and miR-212, in regulating ovarian follicle development. The objective of this study was to gain insight on the involvement of these miRNAs during follicle maturation. Follicular fluid was aspirated from dominant follicles (>32 mm) during the ovulatory season (July to October) and the anovulatory season (January to M...
Serafini R, Longobardi V, Spadetta M, Neri D, Ariota B, Gasparrini B, Di Palo R.Aim of this study was to test the reliability of Trypan blue/Giemsa staining to evaluate sperm membrane integrity, acrosomal intactness and morphology in stallion to verify whether it could be applied in vitro as useful tool for sperm fertilizing ability. Fertility data on inseminated mares were collected to evaluate the relationship of sperm quality to pregnancy rates. Forty-one ejaculates were collected from 3 stallions of Salernitano Horse Breed and evaluated for gross appearance, volume, visual motility and membrane integrity with Trypan blue/Giemsa staining and thirty-five mares were inse...
Leary JM, Rodgerson D, Spirito M, Gomez J.To (1) describe a surgical technique for repair of lacerations of the ventral aspect of the cervix in anesthetized mares in Trendelenburg position; and (2) report conception rates and foaling after repair. Methods: Case series. Methods: Mares (n = 18). Methods: Cervical lacerations were repaired in 2 layers with anesthetized mares in Trendelenburg position. The cervix was retracted caudally with stay-sutures, and after excision of the healed margin of the laceration, the internal cervical mucosa and fibromuscular tissue were sutured in 1 layer with a continuous Lembert pattern. The externa...
Canisso IF, Ball BA, Troedsson MH, Silva ES, Davolli GM.The objectives of this study were to determine pH of the mammary gland secretions and the corresponding electrolyte concentrations in prefoaling mares. Pregnant mares (seven primiparous and seven multiparous) were monitored daily from 310-320 days of gestation until parturition. Prefoaling mammary gland secretions were collected, and pH was immediately determined with a pH meter and pH strip test. An aliquot of prefoaling mammary secretions was frozen and stored until further analyses. After parturition, samples from day -4 to 0 (day of foaling) were thawed and electrolyte concentrations (ie, ...
Meliani S, Benallou B, Halbouche M, Haddouche Z.To enhance effectiveness of reproduction management in Arabian mares, factors influencing the time of foaling were investigated in this study. Methods: Data were collected at the National Haras of Tiaret in Algeria from 2003 to 2010. The foaling time of 255 Arabian pure bred mares, aged from 3 to 20 years were used for this study. Results: A total of 78.07% of foaling happens between 7 pm and 6 am. Conclusions: The influence of the month of foaling and the sex of the foal, on the time of foaling was statically significant.
Ferreira-Dias G, Botelho M, Zagrajczuk A, Rebordão MR, Galvão AM, Bravo PP, Piotrowska-Tomala K, Szóstek AZ, Wiczkowski W, Piskula M, Fradinho MJ....Phytoestrogens exist in plants that are present in forages fed to horses. They may compete with 17-β estradiol and influence the estrous cycle. Therefore, the objective was to determine whether coumestrol from clover-mixed pastures is present in mare's plasma after their ingestion (experiment I), and when this phytoestrogen was present in mare's plasma after ingestion (experiment II). The effect of a long-term ingestion of phytoestrogens on estrous cycle disruption was assessed (experiment III; clinical case). Experiment I was carried out in nonpregnant anestrous and cyclic Lusitano mares (n ...
Winsco KN, Coverdale JA, Wickersham TA, Lucia JL, Hammer CJ.Thirty pregnant mares (538 to 695 kg BW; 4 to 19 yr of age) were used to evaluate the effects of plane of nutrition on DMI of hay and mare performance (BW, BCS, and rump fat) during the last third of pregnancy. Mares were divided into 4 blocks by their expected foaling date and randomly assigned within block to either a hay or concentrate plus hay diet (concentrate fed at 0.75% BW, as-fed basis) with 15 mares per treatment. Treatments began 110 d before expected foaling date (230 d of gestation) and terminated at parturition. Mares were housed by block and allowed ad libitum access to coastal ...
Perryman LE, McGuire TC, Torbeck RL.The capacity of cells from thymus, liver, spleen, mesenteric lymph nodes, peripheral blood, and bone marrow to respond to in vitro phytolectin and allogeneic lymphocyte-stimulation was determined in 16 pony fetuses 61 to 200 days old (gestational age). Phytolectin-responsive cells were detected in the thymus at the 80th gestational day, peripheral blood at 120 days, lymph node at 160 days, and spleen at 200 days. Mixed lymphocyte culture-responsive cells were detected in thymus at 100 days and in the spleen at 200 days (gestational age). Immunoglobulins (Ig) M and IgG were quantitated by radio...
Gerstenberg C, Allen WR, Stewart F.Placentation involves considerable growth and reorganization of both maternal and fetal tissues. In this investigation, immunohistochemical localization of the proliferation marker Ki-67 antigen was used to monitor cell division during placentation in mares. Endometrial biopsies were obtained from eight mares between day 14 and day 26 of pregnancy and from eight anoestrous mares that had been treated with various combinations of progesterone and oestrogen. Samples of endometrium and fetal membranes were obtained from 19 mares carrying normal horse conceptuses between day 30 and day 250 of gest...
Brinsko SP.This manuscript presents a brief historical review of investigations related to equine artificial insemination. The origin of recommended insemination doses for use fresh, cooled and frozen semen will be reviewed. Over 30 years ago, an insemination dose of 500 x 10(6) progressively motile sperm (PMS) was recommended to maximize pregnancy rates when mares were bred with fresh semen under less than ideal conditions. Since that time, 500 x 10(6) progressively motile sperm has been almost universally accepted as a standard insemination dose, regardless of a stallion's fertility or the refinements ...
Schulman M, Becker A, Ganswindt S, Guthrie A, Stout T, Ganswindt A.Validation of a method for the minimally-invasive measurement of physiological stress will help understanding of risk factors that may contribute to stress-associated events including recrudescence of Equid herpesvirus (EHV), which is anecdotally associated with sales consignment of pregnant Thoroughbred mares. In this study we compared two similar groups of late-gestation Thoroughbred broodmares on the same farm: a consigned Sales group (N = 8) and a non-consigned Control group (N = 6). The Sales mares were separated from their paddock companions and grouped prior to their preparation...
Lofstedt RM, Patel JH.In our experience, altrenogest has not always been able to exert predictable control over the estrous cycle of the mare. Therefore, we examined 12 mares that were treated with altrenogest to identify reasons for its failure to control the estrous cycle. The mares were fed altrenogest for 15 to 20 days and were examined for follicle development, ovulation, and corpus luteum formation during treatment. Through the use of real-time ultrasonography and radioimmunoassay for progesterone, we concluded that altrenogest was unable to suppress the growth of follicles to preovulatory size in some mares,...
Cadario ME, Thatcher WW, Klapstein E, Merrit AM, Archbald LF, Thatcher MJ, LeBlanc MM.Two experiments were performed to investigate relationships between oxytocin, prostaglandin release, uterine emptying and fluid accumulation in the uterus. In Experiment 1, the effect of oxytocin on the pattern of prostaglandin release during uterine clearance of radiocolloid was measured in 5 normal mares and 5 mares with delayed uterine clearance. Uterine clearance was measured during estrus by scintigraphy at 0, 60 and 120 min after colloid infusion. After the 120-min reading, 20 IU, i.v., oxytocin were given, and the amount of colloid cleared was measured at 135, 150 and 180 min. Plasma wa...
Donadeu FX, Ginther OJ.Follicular waves and associated circulating hormone concentrations were studied during the anovulatory season in pony mares (n=8). Follicles were monitored by ultrasonography and a blood sample was taken daily from 29 January until ovulation (mean, 28 April). A mid-anovulatory period (largest follicle, 16.0+/-0.5 mm in diameter) and transitional period (largest follicle, 22.4+/-0.5 mm) were distinctive in each mare. The two periods were delineated by an increase in the diameter of the largest follicle to >/=21.0 mm. Follicular waves, identified by significant increases in the mean diameter ...
Watson E, Davis A, Splan R, Porr CAS.With increasing public scrutiny on animal welfare, it behooves those involved in the equine industry to revisit best management practices to ensure these support healthy horses. There is little published research on how horses are used in the equine industry, particularly in therapeutic horseback riding (THR) programs. Although there is a large amount of information on the benefits of THR programs to the participants, there is little published information available about the horses. Therefore, the objective of this survey was to gather data regarding horse use and care in Professional Associat...
Todhunter KH, Muscatello G, Blishen AJ, Chicken C, Perkins NR, Gilkerson JR, Begg AP.A series of unusual abortions occurred in Thoroughbred and Quarterhorse mares in the Hunter Valley region of New South Wales from mid-March to November 2004. The initial link between early cases was the microbiological culture of atypical environmental coryneforms from the stomach contents and/or lungs of fetuses aborted on different properties. Methods: The unique pathologic lesions were described with a case definition and the term 'equine amnionitis and fetal loss' (EAFL) was established. Results: The causal factor was the ingestion of the processionary caterpillar (Ochrogaster lunifer). Ba...
Dobrinski I, Thomas PG, Ball BA.Two bioassays were used to evaluate the interaction of fresh and cryopreserved equine semen with oviductal epithelial cells (OEC) and with the zona pellucida (ZP). Split ejaculates were either stored at room temperature or frozen and thawed. In experiment 1, progressive motility and membrane integrity were evaluated for each treatment. Fluorescent labeled spermatozoa were cocultured with monolayers of OEC for 30 minutes, and the number of sperm attached to OEC was counted by fluorescence microscopy and analysis of digitized images. Motility of spermatozoa attached to OEC was observed at 0.5, 3...
Loux SC, Macías-Garcia B, González-Fernández L, Canesin HD, Varner DD, Hinrichs K.Equine in vitro fertilization is not yet successful because equine sperm do not effectively capacitate in vitro. Results of previous studies suggest that this may be due to failure of induction of hyperactivated motility in equine sperm under standard capacitating conditions. To evaluate factors directly affecting axonemal motility in equine sperm, we developed a demembranated sperm model and analyzed motility parameters in this model under different conditions using computer-assisted sperm analysis. Treatment of ejaculated equine sperm with 0.02% Triton X-100 for 30 sec maximized both permeab...
Berlin D, Aroch I.Magnesium (Mg) and calcium (Ca) are the main divalent cations in the body. The free ionized fraction is the physiologically active form of both Mg and Ca. As ion-selective-electrode (ISE) analyzers are becoming widely used in veterinary practice it will be useful to establish reference intervals for horses. In the present study, reference intervals were established for ionized, total and the ratio of the ionized to total Mg and Ca concentrations in four horse groups: adults, neonatal foals, and pregnant and lactating mares, as well as in three sample types, whole blood, plasma and serum, using...
Dufour P, Courtois J, Seynaeve Y, Peeters S, Le Goff C, Cavalier E, Ponthier J.Steroid concentrations in serum are fluctuating during pregnancy of many mammal species. The current knowledge about endocrinology of gestation is mainly based on immunoassays. However, the lack of specificity of these assays hampers the reliability of the results. In the present work, we developed and validated a methodology associating liquid chromatography (LC) and mass spectrometry (MS) to simultaneously quantify, with high specificity and accuracy, estrone-3-sulfate (E3S), progesterone (PRO), estrone (E1) and estradiol (E2) in serum of two different mammal species. The sample preparation ...
Jaeger LH, Moreno LZ, Kremer FS, Dellagostin OA, Moreno AM, Lilenbaum W.The genome of a Brazilian strain of Leptospira kirschneri serogroup Grippotyphosa isolated from a mare post-abortion was sequenced and analyzed. High symmetrical identity and few structural differences were found when compared with a European strain of the same serogroup, L. kirschneri serovar Valbuzzi strain 200702274. Genes associated with virulence and antimicrobial resistance were found. Knowledge of the virulence evolution of Leptospira remains limited, especially in diseases of the reproductive sphere. We highlight the importance of virulence studies in the sphere of genital leptospirosi...
Beckelmann J, Budik S, Bartel C, Aurich C.Until now, sex determination in equine embryos has been performed by detection of Y-chromosome-specific sequences only. In the present study, expression of a Barr-body-specific marker, the X-inactivated-specific transcript (Xist) gene, whose gene product consists of RNA which coats and thereby inactivates one of the X chromosomes, was investigated in equine embryos produced in vivo. Preattachment embryos at different times after ovulation (Day 8: n = 9; Day 10: n = 12; Day 12: n = 15) were analyzed for Xist RNA expression using quantitative and qualitative reverse transcription-polymerase chai...
Thorson JF, Karren BJ, Bauer ML, Cavinder CA, Coverdale JA, Hammer CJ.To investigate the maternal plane of nutrition and role of Se yeast on foaling variables and passive transfer of IgG, 28 Quarter Horse mares were used in a study with a randomized complete block design. Mares were blocked by expected foaling date and assigned randomly within block to dietary treatments. Dietary treatments were arranged as a 2 x 2 factorial with 2 planes of nutrition, pasture or pasture + grain mix (fed at 0.75% of BW on an as-fed basis) and 2 concentrations of Se yeast (0 or 0.3 mg/kg of DMI). This resulted in 4 treatments: pasture (PA), pasture + Se (PS), pasture + grain mix ...
Papich MG, Van Camp SD, Cole JA, Whitacre MD.Enrofloxacin was administered i.v. to five adult mares at a dose of 5 mg/kg. After administration, blood and endometrial biopsy samples were collected at regular intervals for 24 h. The plasma and tissue samples were analyzed for enrofloxacin and the metabolite ciprofloxacin by high-pressure liquid chromatography. In plasma, enrofloxacin had a terminal half-life (t(1/2)), volume of distribution (area method), and systemic clearance of 6.7 +/- 2.9 h, 1.9 +/- 0.4 L/kg, and 3.7 +/- 1.4 mL/kg/min, respectively. Ciprofloxacin had a maximum plasma concentration (Cmax) of 0.28 +/- 0.09 microg/mL. In ...
Santos MM, Maia LL, Nobre DM, Oliveira Neto JF, Garcia TR, Lage MC, de Melo MI, Viana WS, Palhares MS, da Silva Filho JM, Santos RL, Valle GR.The aim of this study was to determine the influence of parental age on the sex ratio of offspring in horses. Two trials were performed. In the first trial, the data from a randomly obtained population with a 1:1 sex ratio of 59,950 Mangalarga Marchador horses born in Brazil from 1990 to 2011 were analyzed. The sex ratios of the offspring were compared among groups according to the mare and the stallion ages (from 3 to 25 years). In the first step of the analysis, the mares and stallions were grouped according to age in 5-year intervals. In the second step, the groups were based on the parenta...
Mantovani R, Sartori C, Pigozzi G.This study investigated some aspects of breeding management in the Italian Heavy Draught Horse breed, aiming at improving its efficiency at stud farm level. A first aim was to evaluate the risk of unsuccessful reproduction in mares after an early (3 years) or normal (4 years) age at first foaling, in interaction with different stud rearing systems. A second objective was the examination of the mean time length in which young 2-year-old stallions maintain a genetic superiority on older proven stallions, identifying a 'genetic lifespan' in which young stallions can be safely used for reducing th...
Sessions-Bresnahan DR, Carnevale EM.Age-related changes in follicle paracrine signalling are not defined, and follicular gene transcript abundance could predict oocyte viability. Granulosa cells from preovulatory follicles of mares considered Young (n=12; 4-14 years), Mid-aged (n=9; 15-19 years) and Old (n=14; 20-27 years) were evaluated for transcript abundance related to systemic and follicle-specific pathways. Gene transcript abundance for receptors of insulin, adiponectin and peroxisome proliferating factor-γ were higher or tended to be higher in Mid-aged or Old than Young mares. Transcript abundance for interleukin (IL)-6 ...
Güvenc K, Reilas T, Katila T.It is unclear whether AI of mares deep into the uterine horn causes more or less inflammation of the endometrium than conventional AI. Thus, we compared uterine inflammatory reactions of mares inseminated with two different doses of frozen-thawed semen into the tip of the uterine horn (UH) ipsilateral to the preovulatory follicle with those of mares inseminated into the uterine body (UB). Thirty-two mares were assigned to one of four groups (eight mares/group): UB20=AI into UB, 20 x 10(6)sperm/0.5 mL; UB200=AI into UB, 200 x 10(6)sperm/0.5 mL; UH20=AI into UH, 20 x 10(6)sperm/0.5 mL; UH200=AI ...
Satué K, Muñoz A, Blanco O.In order to investigate the effect of pregnancy on equine hematological profile, venous blood samples were taken from 44 Carthusian broodmares every two weeks during pregnancy, divided into three periods: I (conception to 110 days), II (111-220 days) and III (222 days to delivery). Routine hematological analysis was performed. Packed cell volume (PCV) increased in period II probably as a consequence of the climatic conditions or as a result of physical stress of lactation during period I. After that, a reduction in PCV was found but this was not matched with a similar decrease in total serum p...
Nielsen MK, Littman BA, Orzech SW, Ripley NE.Equine cyathostomins are ubiquitous in grazing horses around the world and a main target in parasite control programs. Anthelmintic resistance has been reported with increasing frequency in these parasites over the past decades, and recent findings of fulminant resistance to the macrocyclic lactone class have raised severe concerns. This study aimed to evaluate ivermectin efficacy in cohorts of yearlings and mares present on four different farms in Central Kentucky. Strongylid egg counts were determined with an automated egg counting system, and the percent fecal egg count reduction (FECR) was...
Misuno E, Clark CR, Anderson SL, Jenkins E, Wagner B, Dembek K, Petrie L.The goals of this study were to report the seasonal shedding patterns of strongyle and spp. eggs in repeated fecal samples for mares ( = 38) and foals ( = 39), and to evaluate the efficacy of ivermectin treatment in mares from 2 selected horse breeding farms in central Saskatchewan. Median strongyle fecal egg counts (FEC) peaked in July and August in adult horses. The farms differed significantly ( = 0.0005) in regard to strongyle shedding categories ( 500 eggs/g) over time, but for each individual horse (both farms combined) these categories did not differ over time ( = 0.13) on samples coll...
Meinert C, Silva JF, Kroetz I, Klug E, Trigg TE, Hoppen HO, Jöchle W.A small, biocompatible and short-term implant releasing 1.5 mg or 2.25 mg of the GnRH analogue deslorelin was evaluated in 140 Hanoverian (warm blooded) mares during the 1990 breeding season (Study I). Mares in oestrus and with a follicle 40 +/- 2 mm in diameter were assigned alternately to treatment (70) or remained as untreated controls. Implants were administered subcutaneously, and intervals to ovulation determined by rectal examination and ultrasound at 12-h intervals. Since results with both doses of deslorelin were similar, data were pooled. Deslorelin implantation resulted in ovulation...
Samper JC.Semen quality, mare status and mare management during estrus will have the greatest impact on pregnancy rates when breeding mares with frozen semen. If semen quality is not optimal, mare selection and reproductive management are crucial in determining the outcome. In addition to mare selection, client communication is a key factor in a frozen semen program. Old maiden mares and problem mares should be monitored for normal cyclicity and all, except young maidens, should have at least a uterine culture and cytology performed. Mares with positive bacterial cultures and cytologies should be treate...
Nagy P, Solti L, Kulcsár M, Reiczigel J, Huszenicza G, Abaváry K, Wölfling A.Several assay systems (3H radioimmunoassay (RIA) with and without extraction; microplate enzyme-linked immunoassay (ELISA); qualitative ELISA (tube test)] were used to measure plasma progesterone concentration in mare plasma. The direct RIA showed a close correlation (R = 0.94) with the extraction RIA. The direct RIA and the microplate ELISA were compared in two different studies. In the first study 1155 samples of postpartum mares were used for progesterone determination with both assays. The ELISA resulted in more elevated values both in oestrus and dioestrus (0.19+/-0.3 and 2.44+/-3.62 nmol...
Paulini F, Chaves SB, Rôlo JLJP, Azevedo RB, Lucci CM.Visualization and clear understanding of the ovarian structures are important in determining the stage of oestrus, helping to diagnose several pathologies and supporting advances in reproductive technologies. In this research, computerized microtomography (microCT) was used to explore and characterize the ovarian structure of seven mammalian species. Ovaries of rats, female dog, queens, cows, mares, sows and a female donkey were used. After microCT scanning, the same samples were prepared for histologic evaluation, used here as a validation criterion. It was possible to distinguish regions of ...
Chompoosan C, Pongthaisong P, Kenchaiwong W, Pontaema T, Lerdweeraphon W.Pregnancy affects maternal hemodynamics. The changes in autonomic nervous system activity for hemodynamics adaptation in pregnant horses are still unclear. Thus, this study aimed to examine the effect of pregnancy on electrocardiographic, vasovagal tonus index, and echocardiographic variables in horses. Unassigned: A total of 23 Thai native crossbred mares without any cardiac abnormalities were included in this study. The animals were assigned into two groups, a non-pregnant mare group (n =12) and a pregnant mare group (n = 11). Electrocardiogram recordings (paper speed = 25 mm/s and calibrati...
Köhne M, Hegger A, Tönissen A, Heusinger A, Hader C, Görgens A, Sieme H.Antimicrobial-resistant bacteria pose a serious threat to the wellbeing of animals and humans. In equine reproduction, endometritis caused by facultative microbial pathogens is a condition, which is usually treated with antibiotics. Data from Germany on prevalence of facultative pathogenic microorganisms cultured in samples from the equine uterus and the frequency of multi-drug resistant (MDR) bacteria is lacking. The aim of the study was to provide representative numbers for both. Microbiological culture results (n = 28,887) of endometrial samples submitted to a large veterinary diagnostic ...
