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.
Jackson PS, Allen WR, Ricketts SW, Hall R.Uterine irrigation was carried out in eight Welsh pony mares using 50 ml of chlorhexidine gluconate solution diluted to give active ingredient concentrations of 0.25 per cent to 2 per cent. Treatment was repeated up to twice in mares showing no adverse effects and irritancy of treatment judged on clinical symptoms and uterine biopsy. Results indicated the inadvisability of using a higher concentration than 0.25 per cent. Three daily applications of a diluted surgical scub solution containing 2 per cent chlorhexidine gluconate to the penis of an arab stallion failed to produce symptoms or irrit...
Campbell DL, Douglas LW, Ramge JC.Siliconized rubber tubes were used to cannulate one oviduct in 7 mares, and secretions were collected in a polycarbonate container located externally, in the region of the left paralumbar fossa. Secretion rates were recorded daily during the estrous cycle. Concentrations of calcium, magnesium, sodium, potassium, inorganic phosphorus and glucose were determined in the oviduct fluids secreted throughout the estrous cycle. Secretion rates were greatest during estrus (days 1-9), with a significant decrease (P<.01) noted during nonestrus (days 10-21). Concentrations of all constitutents measured...
Foster JP, Evans MJ, Irvine CH.Mares at different stages of the oestrous cycle were given a single intravenous injection of 0.5 mg synthetic Gn-RH. The mean area of the induced LH peak was significantly less at mid-cycle (Day 10-11) than at any other time. The mean height of the LH peak above preinjection concentration was greater at late oestrus and early cycle (Day 5-6) than at mid-cycle and early oestrus. There were no significant different in mean FSH responses. The LH:FSH ratio for both height and area of induced peaks was significantly less at mid-cycle than at other times of injection. These results suggest that one ...
Taverne MA, van der Weyden GC, Fontijne P, Dieleman SJ, Pashen RL, Allen WR.Uterine electromyography was performed by means of chronically implanted surface electrodes in 3 Pony mares during spontaneous oestrous cycles and following luteolysis induced by a prostaglandin analogue (fluprostenol). Three distinct patterns were recognized during the oestrous cycle. (1) During oestrus well defined phases of activity with closely grouped high-amplitude spikes were separated by long periods (10-45 min) of complete inactivity. (2) During dioestrus more diffuse phases of activity with low-amplitude spikes were separated by variable periods of relative inactivity. (3) During lut...
Rutgers HC, Stibbe S, van den Ingh TS, Breukink HJ.The case of a 16-year-old mare with multiple dermal lymphosarcoma of the histiolymphocytic type is described. Leukaemic changes were not found to be present in the superficial and internal lymph nodes or in the visceral organs.
Neely DP, Stabenfeldt GH, Kindahl H, Hughes JP, Kendrick JW.The intrauterine infusion of 500 ml of warm sterile saline solution into mares on days 12, 13, or 14 after ovulation failed to alter the ovulatory interval, although intervals were shorter for days 12 and 13 (20.6 days) when compared with those in control mares (21.6 days). The IU fusion shortened luteal-life-span on days 12 (12.0 vs 13.8 days) and 13 (13.0 vs 14.4 days) (P is less than 0.05), but not day 14 (14.0 vs 13.5 days), when comparing the effects of IU infusion with an average of before and after base-line data. There was no effect on the interval from corpus luteum regression to ovul...
Sharp DC, Garcia MC, Ginther OJ.Luteinizing hormone (LH) was quantified in pony mares during artificially induced sexual maturation. Ovarian follicular development was also assessed by rectal palpation of the ovaries. With the exception of large periovulatory LH concentrations in two mares that ovulated, LH concentrations were not significantly different in mares undergoing sexual maturation and thus having marked follicular development when compared with mares that were not undergoing sexual maturation and thus did not have marked follicular development. These results indicate a dissociation in time between the onset of fol...
Allen WE, Newcombe JR.The three groups of bacteria that cause endometritis in the mare are reviewed. The different methods of swabbing are assessed and the criteria which should be observed when developing a swabbing technique listed. The choice of speculum and swabs available are described.
Neely DP, Stabenfeldt GH, Sauter CL.Daily injections of 150 units oxytocin administered to 6 mares on Days 4, 5, 6, 7 and 8 after ovulation (Day 0 = ovulation) failed to induced luteolysis as indicated by the maintenance of normal plasma progestagen concentrations and the occurrence of normal ovulatory intervals. Three additional mares were given oestrogen injections 24 h before an injection of oxytocin on Day 7 after ovulation, but this treatment also failed to induce luteolysis since plasma progestagen concentrations were maintained in all three mares. Two mares exhibited normal ovulatory intervals, while the third developed a...
Hughes JP.Contagious Equine Metritis (CEM) is a highly contagious venereal disease of horses caused by a fastidious, Gram-negative coccobacillus which grows best on chocolate agar under microaerophilic conditions (5-10% CO2). Clinically, the disease is characterized by a copious watery-to-mucopurulent, vaginal discharge two to ten days after breeding by an infected stallion (11, 13). Shortened estrous cycle lengths are common and may be the only indication of endometritis in some instances (7). Inapparent carriers of the disease in both the mare and stallion make control of the disease more difficult. O...
Menzer C, Schams D.A double-antibody radioimmunoassay for PMSG, especially for meauring PMSG in cattle blood after exogenous application, has been developed. A rabbit antiserum against PMSG and pure PMSG for radioiodination were used. There was a strong cross-reaction against equine LH and FSH, but the slight cross-reaction against bovine LH and FSH could be eliminated by adding bovine LH to each tube during the assay. Unspecific, interfering influences of equine or cow serum could be eliminated by adding a constant amount of PMSG-free serum to each tube. PMSG added to 200 microliter of serum could be recovered ...
Allen WE.The situations and conditions that can disrupt the mares normal oestrous cycle are described. Season of the year is a major influence; maximum reproductive efficiency does not totally coincide with the artificially defined "breeding season". Other abnormalities are associated with spontaneously persistent luteal function, psychological influences over behavioural activity, the presence of endometritis, multiple ovulation, reproductive behavior after pregnancy failure and granulosa cell tumours.
König HE, Ries R.The ovary of the mare is vascularized by two branches of the A. ovarica, which differ in diameter. They take a characteristic course in this organ. Near the ovulation fossa several branches of 1st and 2nd class leave the A. ovarica to provide the functional structures. These vessels are formed like a corkscrew. At the veins and its ramifications there are sphincter-like structures which support the venous valves. They are of haemodynamic importance for the different phases of the functional structures.
Garner C, Stephen C, Pant SD, Ghorashi SA.Streptococcus equi subsp. zooepidemicus (S. zooepidemicus) is one of the causative agents of equine endometritis. In this study, a panel of different bacterial species, and colonies derived from bacteriological cultures of 38 clinical samples, were subjected to Loop-Mediated Isothermal Amplification (LAMP) assay and PCR, followed by high-resolution melt (HRM) curve analysis. All clinical samples were genotyped into three distinct groups based on HRM curve analysis. Differences in melting curve profiles were a reflection of DNA variation in sorD gene which was confirmed by DNA sequencing. A mat...
McCue PM, Bisiau C, Divine C, May E.Congential amastia, a medical condition in which mammary tissue fails to develop, was detected in a 3-year-old Quarter Horse mare. The dam of the mare was also afflicted with amastia, suggesting that the condition was due to an inherited genetic mutation as noted in other species. In addition, on presentation the mare had a purulent vaginal discharge secondary to a pyometra.
Blanco M, Foss R, Tönißen A, Rohn K, Burger D, Sieme H.This retrospective evaluation of data from a large commercial embryo transfer facility aimed to determine the extent to which age and treatment on the day of embryo transfer in recipient mares influence the likelihood of pregnancy. Methods: Embryo recovery was carried out on days 8-10 post-ovulation using transcervical uterine flushing. Recipient mares grouped according to their age were treated once on the day of embryo transfer (Day 3-8 post ovulation) and were assigned randomly to 1 of 3 groups: Mares in Group A (n=101) received antispasmodic, antimicrobial, and anti-inflammatory drugs. Mar...
Mouncey R, de Mestre AM, Arango-Sabogal JC, Verheyen KL.Gestational and early-life exposures may modulate development during growth and influence future athletic performance. Objective: To investigate associations between gestational and early-life exposures in Thoroughbreds and (i) likelihood of racing, (ii) total number of runs and (iii) total prizemoney by the end of the 3-year-old year. Methods: Prospective cohort. Methods: Daily records were kept on the location and duration of turnout, management and veterinary-attended episodes of disease or injury from birth until leaving the farm or study exit for 129 Thoroughbred foals on six stud farms. ...
Fehin B, Scott CJ, Arango-Sabogal JC, de Mestre AM, Mouncey R.To date, relationships between pre-covering endometrial swab cytology and bacteriology and fertility outcomes in Thoroughbred broodmares in the United Kingdom are unknown and could aid clinical decision making. Objective: To investigate associations between cytology and bacteriology findings from the last endometrial swab taken in the breeding season (15 February to 15 July) and live-foal rates (predicted mean probability of producing a live foal) in UK Thoroughbred broodmares. Methods: Retrospective cohort study. Methods: Endometrial cytology and bacteriology findings were extracted from labo...
Blue MG.Minor accidents during natural mating are common occurrences during the breeding of horses. Mares may suffer from a variety of genital injuries including vulval separations, vaginal lacerations and, less commonly, vaginal rupture. Possible sequelae to, and management of, these injuries are described, with additional mention of false entry by the stallion and persistent hymen in maiden mares. Vaginal rupture during natural mating can lead to death of the mare. The implications for litigation involving veterinary surgeons and horse breeders are discussed.
Da Silva-Álvarez E, Martín-Cano FE, Alonso JM, Becerro-Rey L, Zabalo-Palomo C, Gil MC, Peña FJ, Ortega-Ferrusola C.This study aims to characterize and compare the uterine fluid proteome and cytokine profile of reproductively healthy mares (HM; n = 15) and mares with Streptococcus equi subsp. zooepidemicus (S. zooepidemicus)-associated endometritis (SAE; n = 9). Uterine flush samples collected during the follicular phase were analyzed by shotgun proteomics and multiplex cytokine assays. Equine proteins were mapped to human orthologs, and enrichment and network analyses were performed using g:Profiler, Metascape, ToppGene, and STRING/MCODE. SAE mares showed higher levels of IL-1α, IL-1β, GRO, IL12p...
Haluska GJ, Lowe JE, Currie WB.Recordings of uterine electrical activity were made from 5 pregnant pony mares from Day 141 to 320 of pregnancy. Three types of activity were identified. Short, medium and long bursts were quantified as the percentage of time each occurred during the hour analysed and further categorized according to frequency, amplitude and duration. The uterus was most active during the early stages recorded and became increasingly quiescent after Day 240. Short-burst activity was greatest when the uterus was most quiescent. Long bursts showed the greatest percentage of activity until Day 220 and then decrea...
Antal V, Antal T, Szabó I, Vajda G, Polner A, Szollár I, Totth B, Laber G, Stipkovits L.The authors examined 585 samples from 92 mares of 2 studs and 346 nasal swabs taken from their foals for the presence of mycoplasmas. The positive rates of mares and foals were 81.5% and 71.7%, respectively, with positivity of samples being variable. Clinical symptoms developed in 2-4 waves and lasted 3-7 days, with intervals of 7-12 days. The disease started in April among foals born in February, at an average age of 88 days. Later on, the average age of the affected foals decreased. There was a correlation between presence of mycoplasmas in nasal cavity and disease of foals.
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.
Stabenfeldt GH, Hughes JP, Wheat JD, Evans JW, Kennedy PC, Cupps PT.The effect of hysterectomy on ovarian activity was studied
in four mares. The cyclic secretion pattern of plasma progestins normally
observed in the intact mare was interrupted by hysterectomy. Follicular
activity was observed in all four hysterectomized mares, in spite of pro-
longed luteal activity, with a large number of follicles attaining ovulatory
size without the occurrence of ovulation. Some ovulations were observed
at irregular intervals in two out of four hysterectomized mares in spite
of plasma progestin levels which ranged from 2 to 6 ng/ml. While all
ovulations which occur...
Ledeck J, Dubrowski T, Schoumacher M, Peeters S, Le Goff C, Egyptien S, Deleuze S, Cavalier E, Ponthier J.Refined profiling of conjugated estrogens and androgens during equine pregnancy using liquid chromatography-tandem mass spectrometry (LC-MS/MS) could provide accurate fetal-sex determination. Current methods for fetal-sex prediction remain limited by timing, accuracy, and operator expertise. This study investigated sex-specific differences in maternal conjugated steroid profiles to develop a reliable, non-invasive predictive method. Samples were collected from 141 mares of various breeds starting at sixteen weeks of pregnancy. The samples were pooled according to gestational stage, divided int...
Jafari H, Wang Z, Li C, Yang G, Yang Q, Han J, Hu Q, Muhatai G, Lei C, Dang R.Mongolian horses are famous for their lactation traits. Their milk contains a high protein content and low levels of fatty acids. Given their superior milk composition and historical use in dairy production across Inner Mongolia and Central Asia, Mongolian horses serve as a valuable model for understanding lactational biology. Multiple factors regulate the lactation process; however, a detailed study of this biological process has not been performed with single-nucleus RNA sequencing (snRNA-seq) technology. Insights gained from snRNA-seq of their mammary glands can inform molecular strategies ...
Ginther OJ, Pinaffi FL, Rodriguez MB, Duarte LF, Beg MA.During the luteolytic period in mares, the peak of 65% of pulses of a PGF2α metabolite (PGFM) and the peak of a pulse of PRL have been reported to occur at the same hour. It is unknown whether the synchrony reflects an effect of PGF2α on PRL or vice versa. Controls, a flunixin meglumine (FM)-treated group (to inhibit PGF2α), and a bromocriptine-treated group (to inhibit PRL), were used at 14 days postovulation in June and in September (n = 6 mares/group/mo). Blood samples were collected hourly from just before treatment (Hour 0) to Hour 10. Concentrations of PGFM in the FM group were lower ...
Brooks DE, McCoy DJ, Martin GS.Uterine rupture was diagnosed in 2 postpartum mares with hemorrhagic vaginal discharge. Both mares had abdominal pain, as evidenced by pawing, kicking at the abdomen, or attempting to roll. Peritoneal fluid analysis was useful in establishing a diagnosis. One mare had many RBC in the peritoneal fluid and was anemic; this mare was managed medically with oxytocin, antibiotics, and blood transfusion. The mare was able to raise her foal to weaning age. The second mare had many RBC, degenerate neutrophils, and intracellular and extracellular bacteria in peritoneal fluid. Surgical repair of the uter...
Shand N, Alexander SL, Irvine CH.For aqueous extracts of pituitary glands of oestrous mares, luteinizing hormone (LH) profiles were found to be similar to each other and to earlier work after chromatofocussing (CF) and isoelectricfocussing (IEF). After CF, both LH and follicle-stimulating hormone (FSH) in pituitary extracts focussed in multiple peaks in the acidic range, with 86% of LH and 80% of FSH found between pH 4 and 6. By contrast, in pituitary venous plasma, only 18% of the LH focussed in this range, whereas a significantly greater proportion (P less than 0.01) eluted above pH 7 than occurred in pituitary extracts (37...
Quirk KS.There are myriad problems that can arise when training the novice stallion for natural service. Many problems can be avoided by proper early training of the novice stallion. In the final analysis, common sense should prevail. The major ally of common sense is patience. One should keep in mind that the goal is to have a stallion behave in a disciplined manner, allowing for his expression of libido and effective mounting, intromission, and ejaculation. This is accomplished through judicious training and, as with any training process, takes some time and work. Proper training will help circumvent...
Purcell SH, Seidel GE, McCue PM, Squires EL.The aim of this study was to compare the efficacy of three approaches for recovering equine oocytes via transvaginal ultrasound-guided follicular aspiration. Fourteen mares were used as oocyte donors during the spring transition period and physiologic breeding season, and 11 mares were bred for use as oocyte donors during early gestation. In all mares, large (>20 mm) and small (10-20 mm) follicles were aspirated in eight rounds every 10-11 days. In each of the four rounds during the transition period, half the mares received 12.5 mg eFSH once daily for 4 days prior to aspiration. For each of t...
Allison N, Moeller RB, Duncan R.A teratocarcinoma was diagnosed in the amnion of a 5-year-old Arabian mare that delivered a healthy, full-term foal. The foal died at 2.5 months of age as a result of metastasis of an undifferentiated component of the mass. This case is unique because it is the first reported case of placental teratocarcinoma in animals and the malignant component apparently metastasized to the foal resulting in its death.
