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.
Sertich PL, Watson ED.Twelve mares were allowed to foal naturally, after which they were monitored to study uterine involution. Starting on day 3 after parturition, the internal genital tract was examined per rectum manually and ultrasonographically every other day for changes in uterine characteristics and ovarian activity. By day 5, gravid and nongravid uterine horns were similar in size, and by day 7, uterine fluid was absent. On day 7 after parturition, endometrial biopsy samples were obtained for histologic evaluation, and uterine swab specimens were obtained for microbiologic culture. Uterine swab specimens f...
Ball BA, Wilker C, Daels PF, Burns PJ.Administration of progesterone in poly(d-,l-lactide) microspheres was used to maintain pregnancy in mares after luteolysis was induced by treatment with prostaglandin F2 alpha at day 14 of pregnancy. Mares were given vehicle only (control, n = 6) or 0.75 g (n = 7), 1.5 g (n = 8), or 2.25 g (n = 5) of microencapsulated progesterone at days 12 and 22 of pregnancy. Serum progesterone concentrations were determined daily, and pregnancy was evaluated by transrectal ultrasonography on alternate days. Significantly (P less than 0.05) more mares given 1.5 or 2.25 g of progesterone (6 of 8 and 4 of 5 m...
Hohenhaus MU, Bostedt H.108 mares with a total of 135 oestrous cycles were examined. 30% of the mares showed development of double follicles, found by palpation and ultrasonography. Eight cases of double ovulation, four of them synchronous and four asynchronous, were examined closely. These cases of double ovulation showed different growth and different development of the follicular wall. This occurred at the same time in cases of synchronous double ovulation whereas it differed in case of asynchronous double ovulation. The later ovulating follicle was still growing while the first one had already burst. With both fo...
Perkins NR, Robertson JT, Colon LA.A 15-year-old Standard-bred mare was examined because of signs of abdominal discomfort in late gestation. Palpation per rectum revealed tight broad ligaments above and below the uterus, with the right broad ligament running across the top of the uterine body down toward the left, ventral side of the abdomen. A diagnosis of counterclockwise uterine torsion was made and surgical correction was approached via a left, flank laparotomy with the horse standing. The uterus was repositioned and a uterine tear encompassing 180 degrees of the uterine surface was found in the lateral, uterine body just c...
Freeman DA, Woods GL, Vanderwall DK, Weber JA.The hypothesis that equine embryos initiate oviductal transport in mares was tested by placing day 6 uterine embryos in the oviducts of day 2 (n = 10) or day 5 (n = 10) recipient mares and attempting to collect the embryos from the uterus 48 h later. To determine whether the surgical transfer procedure initiated oviductal transport, medium alone was placed in the oviducts of day 2 (n = 10) inseminated mares (sham transfer), and uterine embryo collections were attempted 48 h later. Embryos were transported through the oviduct of day 2 recipients by day 4 (instead of day 5 to 6) in six of ten ma...
Bergfelt DR, Woods JA, Ginther OJ.Characteristics of spontaneous embryonic loss in 21 mares were compared with those of 52 contemporary mares that maintained pregnancy. Embryonic losses were, in retrospect, grouped according to day of loss and length of the interovulatory interval, respectively, as follows: group 1, less than or equal to day 20 and less than or equal to 30 days (n = 10); group 2, less than or equal to day 20 and greater than 30 days (n = 3); and group 3, greater than day 20 and greater than 30 days (n = 8); ovulation was day 0. Mean diameter of the embryonic vesicle in group 1 was smaller (P less than 0.05) on...
Everett KA, Chaffin MK, Brinsko SP.A diaphragmatic hernia in which 90% of the large colon had herniated through a 16-cm linear tear in the diaphragm was found in a 12-year-old Quarter Horse mare. Clinical signs included lethargy and exercise intolerance. Diagnosis of diaphragmatic hernia was made based on careful thoracic auscultation, combined with ultrasonographic and radiographic examination of the thorax.
Allen WR, Bracher V.During a 5-year period 65 Pony and 20 Thoroughbred pregnant mares were subjected to videoendoscopic hysteroscopy from 10 to 266 days of gestation. The aims of these examinations were to 1) observe foetal and placental development in vivo (60 Pony and 10 Thoroughbred mares); 2) eliminate one of unicornuate twin conceptuses (9 Thoroughbred mares); 3) recover embryonic foetal and placental tissues non-surgically for experimental purposes (47 Pony mares); 4) induce focal separation of the placenta in late gestation as an experimental model of placentitis (5 pony mares and 1 Thoroughbred mare). It ...
Smith KC, Whitwell KE, Binns MM, Dolby CA, Hannant D, Mumford JA.From 1988 to 1991, 51 pregnant pony mares were challenged intranasally or by aerosol with an isolate of EHV-1 (AB4) originally recovered from a quadriplegic mare. This resulted in 32 abortions, occurring from 9 to 29 days after infection. In 14 of the early abortions (Days 9-14), EHV-1 was not demonstrated in the foetal tissues by virus isolation or immunostaining despite no other non-viral cause for the abortion being evident. Application of the polymerase chain reaction to foetal tissues from 9 of these cases also proved negative. One of the 14 mares was destroyed immediately after abortion,...
Bracher V, Allen WR.The new generation of videoendoscopes uses an electronic, instead of an optical, system for image transmission. Advantages over conventional fibre-optic endoscopes include increased image quality, handling robustness and direct display of the image on a TV monitor for multiple simultaneous viewing. In the present study, hysteroscopy was performed on 14 normal fertile Welsh Pony and Thoroughbred mares at various times during the annual and ovarian breeding cycles. Oestrus was characterised by an oedematous, relaxed cervix lying on the floor of the vagina, diffuse oedema of the endometrium and t...
Martin RG, McMeniman NP, Dowsett KF.Intakes of milk and milk nutrients were determined for 8 foals at 11-18 days of age and for 10 foals at 30-44 days and 60-74 days of age while sucking grazing mares. Water intakes (sources other than milk) of the foals were determined at 30-44 days and 60-74 days of age. Five of the 10 mares were fed a protein supplement (24% crude protein) in addition to grazing during the stud season. The protein supplement did not influence foal intakes of milk and milk nutrients, milk composition, weight gains of the mares or the growth rate of the foals. Foal milk intakes increased (P less than 0.05) from...
Bracher V, Mathias S, Allen WR.Videoendoscopy of the reproductive tract was performed in 87 Thoroughbred mares with histories of reduced fertility. During hysteroscopy samples for cytological, microbiological and histological examinations were obtained under visual control. Common findings in these broodmares included: (a) endometrial degeneration, as assessed by an uneven distribution or atrophy of endometrial folds and/or a scarred appearance of the endometrium (49 mares, 56%); (b) endometrial cysts of various sizes and locations within the uterus with the most common location being at the base of the uterine horns (48 ma...
Crabbe BG, Freeman DA, Grant BD, Kennedy P, Whitlatch L, MacRae K.Testicular feminization syndrome was diagnosed in a mare with aggressive, stallion like behavior and a history of infertility. She was found to have a high baseline testosterone concentration suggesting that testicular tissue was present, and ovarian-like structures examined by use of transrectal ultrasonography had the appearance typical of testicular tissue. Although her external female genitalia appeared normal, her vagina ended in a blind sac, and no cervix or uterus were identified. Surgery was performed, and structures removed from the abdominal cavity were determined to be hypoplastic t...
Taira T, Fujinaga T, Okumura M, Yamashita K, Tsunoda N, Mizuno S.Haptoglobin (Hp) was isolated from equine serum by ammonium sulphate precipitation, anion-exchange chromatography and gel filtration. Equine Hp which migrated to the alpha 2-globulin region in electrophoresis, contained 2 fractions with molecular weights (NW) of 108,000 and 105,000, and each fraction consisting of 2 subunits. Quantitative measurement of Hp in equine serum was performed by the single radial immunodiffusion method using anti-equine Hp serum. In clinically normal horses, the highest concentration of serum Hp was found in newborn foals and a high value was maintained until 12 mont...
Taira T, Fujinaga T, Tamura K, Izumi M, Itoh H, Tsunoda N, Yamashita K, Okumura M, Mizuno S.Equine alpha 1-acid glycoprotein (alpha 1AG) was isolated from equine serum by successive ammonium precipitation, anion- and cation-exchange chromatographies, and gel filtration. Purified equine alpha 1AG had a molecular weight of 46,000 +/- 1,000, and contained 31.4% carbohydrate. Gel isoelectric focusing revealed an isoelectric point range of 2.8 to 3.7. With immunoelectrophoresis, it was found that alpha 1AG migrated to the alpha 1-globulin region. Single radial immunodiffusion was used for quantitative measurement of alpha 1AG in equine serum. In clinically normal foals, serum alpha 1AG wa...
Gift LJ, Gaughan EM, Schoning P.A 5-year-old Quarter Horse mare was referred for evaluation of an acute non-weightbearing lameness of the left hind limb in which musculoskeletal abnormalities had not been detected. After admission, the mare had signs of colic. Exploratory laparotomy revealed the left ovary to be large, masses in the left sublumbar space, and diffuse infiltration of the mesentery, omentum, liver, and spleen with variably-sized masses. The mare was euthanatized, and granulosa cell tumor was identified on histologic examination of the left ovary, left sublumbar and cranial thoracic lymph nodes, omentum, mesente...
Chirnside ED.The causative agent of the respiratory disease equine viral arteritis is a small, single-stranded RNA virus with a genome organization and replication strategy related to that of coronaviruses and toroviruses. Clinical signs of infection in horses vary widely and severe infection can lead to pregnant mares aborting. Infected horses generally make good recoveries but stallions may become semen shedders of equine arteritis virus (EAV). These carrier stallions play an important role in the dissemination and perpetuation of EAV. Laboratory tests exist to detect virus and the equine immune response...
Ball BA, Miller PG.In this study we examined the ability of equine oviductal epithelial cells (OEC) to support the development of four- to eight-cell equine embryos in vitro and investigated the ability of co-cultured embryos to continue normal development after transfer to synchronous recipient mares. Equine embryos obtained at Day 2 after ovulation were cultured with or without OEC for 5 days. Those OEC co-cultured embryos that reached the blastocyst stage and embryos recovered from the uterus at Day 7 were surgically transferred to synchronous recipient mares. Co-culture with OEC improved (P < 0.01) develo...
Carnevale EM, Ginther OJ.The uterine function and reproductive efficiency of 31 nonlactating pony mares were compared for two age groups: young (5 to 7 years, n=9) and old (>/=15 years, n=22). For pregnant mares, differences between age groups were not significant for the diameter of the largest follicle, cross-sectional area of the corpus luteum, growth profile of the embryonic vesicle or embryo mobility characteristics. Uterine contractility scores were lower (P<0.05), day of fixation of the embryonic vesicle was later (P<0.05), and uterine tone tended (P<0.10) to be lower in the old than the young mares...
Schumacher J, Schumacher J, Blanchard T.The endometrial response of mares to repair of third-degree rectovestibular lacerations was evaluated. Endometrial biopsy specimens from 8 mares with third-degree rectovestibular laceration were obtained immediately before surgery and from 9 to 15 days after repair. Presurgical endometrial biopsy specimens were classified as category I for 2 mares; category II, attributable to slight endometritis, for 5 mares; and category III, attributable to moderate-to-severe endometritis, for 1 mare. Within 15 days after rectovestibular repair, all endometrial biopsy specimens were classified as category I...
Mohammed HO, Rebhun WC, Antczak DF.A retrospective case-control study was conducted to identify risk factors in horses associated with the development of the common skin tumours known as sarcoids. The study involved 503 sarcoid cases diagnosed (January 1980-December 1989) at New York State College of Veterinary Medicine and a similar number of controls (non-sarcoid cases). Data on age, breed and sex of cases and controls were obtained from computerised records. Multiple logistic regression analysis was used to identify risk factors. Separate data were obtained for the same 10-year period from the Veterinary Medical Data Program...
Watson ED, Aubrey ES, Zanecosky HG, Sertich PL.Glandular epithelial and stromal cells were isolated from the endometrium of mares by collagenase digestion and were incubated on plastic for 7-9 days until the cells formed confluent monolayers. The cells differed in morphology: epithelial cells appeared polyhedral and stromal cells were spindle like. The monolayers were incubated in the presence and absence of oxytocin. Medium was removed from wells after 2, 8 and 24 h of incubation. Concentrations of prostaglandin F (PGF) in the medium increased significantly during this time. Glandular epithelial cells produced significantly more PGF than ...
Gilbert RO, Marlow CH.Records of 1,009 pregnancies in 574 foaling, barren and maiden Thoroughbred mares on a single stud farm, over a period of 12 years were examined. The farm is situated in the eastern Cape Province of South Africa, at an elevation of 1,800 m, and in an area of climatic extremes. Records of 604 pregnancies in 249 foaling Thoroughbred mares were examined. For these purposes, those pregnancies in which a mare conceived in the same breeding season during which she had foaled were considered as pregnancies in foaling mares. Pregnancy was confirmed by rectal palpation by a single experienced practitio...
Squire KR, Adams SB, Conley R.The bladder of a 750-kg Clydesdale mare had everted through the urethra into the vagina immediately after parturition. The bladder was reinverted into the peritoneal cavity by an attending veterinarian, but 4 days later, the bladder was everted again in the vagina. The mare was able to void urine through both ureters, which could be seen in the mucosal surface of the bladder. The everted bladder had become edematous and could not be reinverted through the urethra. A considerable portion of the fundus was necrotic. The mare was administered xylazine epidurally to induce perineal analgesia, and ...
Thompson DL, Rahmanian MS, DePew CL, Burleigh DW, DeSouza CJ, Colborn DR.Short-term patterns of growth hormone (GH) secretion and factors affecting it were studied in mares and stallions. In Exp. 1, hourly blood samples were collected from three mares and three stallions in summer and winter. Although GH concentrations varied in a pulsatile manner in all horses, there was no effect of sex or season (P greater than .1) on plasma GH concentrations and no indication of a diurnal pattern of GH secretion. In Exp. 2, 10-min blood samples were drawn for 8 h from 12 mares; after 6 h, porcine GH-releasing hormone (GHRH) was administered i.v. at 0, 45, 90, or 180 micrograms/...
McDonnell SM.This article includes a brief description of the reproductive patterns and specific behaviors comprising courtship and copulation in equids. The author then focuses on breeding behavior of the domestic stallion. Descriptions of normal breeding behavior under a variety of domestic management systems, comments on sexual behavior of donkeys and exotic equids, and the most common types and treatments of sexual behavior dysfunction are included.
Hochi S, Fujimoto T, Oguri N.Viability following vitrification of equine blastocysts with different sizes was investigated in vitro. Twenty-four blastocysts were classified into three groups according to their diameters ( 300 microns; n = 8 each). The solution used for vitrification was defined as EFS and contained 40% ethylene glycol, 18% Ficoll and 0.3 M sucrose in modified-phosphate-buffered saline (m-PBS). During pretreatment with 20% ethylene glycol in m-PBS for 20 min, the larger blastocysts responded to the osmotic pressure caused by 20% ethylene glycol more slowly than the smaller blastocysts. Single blastocysts w...
Drummer HE, Reynolds A, Studdert MJ, MacPherson CM, Crabb BS.Sera from 33 Australian thoroughbred mares were tested during an outbreak of equine herpesvirus 1 (EHV1) abortion with an enzyme-linked immunosorbant assay (ELISA) for the presence of EHV1-specific antibodies. The ELISA used a recombinant EHV1 antigen derived from glycoprotein G (gG) and distinguished antibodies to EHV1 from those of the antigenically related and widespread herpesvirus EHV4. Sera were obtained from most of the mares on three occasions, three, 13 and 67 days after the first abortion. Mares which were negative in the ELISA were kept separate from mares which were positive. A sec...
Roberts CJ.Manual crushing of one blastocyst performed on 181 bicornuate twin pregnancies between Days 24 and 45 has shown that the uncrushed blastocyst can either survive and develop normally to full term or may be rejected and resorbed like its crushed twin, depending mainly on the stage of pregnancy. Crushing, which causes rupture of fetal membranes, results in a rapid fall in the survival rate of the uncrushed blastocyst when performed after Day 31. In some mares rupture is not possible after Day 35 even if extreme pressure is used. Crushed, but unruptured, blastocysts mainly between Days 35 and 45 m...
Hyde KA, Aguiar FLN, Alves BG, Alves KA, Gastal GDA, Gastal MO, Gastal EL.Characterization of the ovarian preantral follicle population is a necessary step to improve understanding of folliculogenesis and ovarian physiology. Therefore, in the present study, the preantral follicle population in the equine ovary in young and old mares was investigated according to follicular morphology, follicular class, distance from the geometric center using ovarian maps, and follicular density within ovarian portions (lateral vs intermediary) and regions (dorsal vs ventral). Ovaries were collected from an abattoir and histologically processed for evaluation, and the follicle popul...
Silberzahn P, Rashed F, Zwain I, Leymarie P.An homogenate from cortical tissue of mare adrenals was incubated in the presence of tritiated pregnenolone. The (3H) androstenedione and the (3H) testosterone synthesized during the incubation were extracted, purified, and co-crystallized to constant specific activity in the presence of unlabeled carriers. The rate of conversion of pregnenolone to androstenedione and testosterone was of the order of 5 and 0.15 per cent respectively. The high ratio of (3H) androstenedione to (3H) testosterone observed in this study suggests that androstenedione is the main androgen produced by mare adrenals. I...
Merlo B, Mari G, Iacono E.The increase in demand for in vitro produced horse embryos is fostering the development of commercial laboratories for this purpose. Nevertheless, blastocyst production after intracytoplasmic sperm injection (ICSI) is still not as great as desired in most of these laboratories. In relation to horse oocyte classification, both expanded and compact cumulus-oocyte-complexes (COCs) are used for in vitro embryo production. The aim of this study was to compare in vitro embryo developmental capacity of COCs from horses including those with only the corona radiata, frequently collected after aspiratio...
Gomez-Cuetara C, Flores JM, Sanchez J, Rodriguez A, Sanchez MA.An histological study of the postpartum period in 29 mares was carried out. Uterine biopsies were taken daily during the first 10 days postpartum in a total of 87 samples. At day 0, equine endometrium was characterized in the surface by the presence of regularly ordered microcaruncles; the stratum spongiosum was oedematous and contained distended and scarce glands. Degenerative changes in microcaruncles and endometrial glands were present on day 1 postpartum. The epithelium of the microcaruncles from 2 to 5 days postpartum showed cytoplasmic vacuolization, karyorrhexis and an inflammatory reac...
Oberhaus EL, Thompson DL, Foster BA, Pinto CR.This experiment assessed the hormonal production, secretory aspects, and changes in luteinizing hormone (LH) receptor gene expression of early induced ovulatory-sized follicles relative to the first ovulatory-sized follicles occurring naturally in the spring. Anovulatory mares were treated on January 21 with (1) 50 mg of estradiol cypionate (ECP, n = 8) alone or (2) with ECP followed by two 3-g sulpiride injections (n = 8), 5 and 12 days later. Half of each group also received complete follicle ablation via transvaginal aspiration before ECP treatment. Ovaries were scanned regularly until ...
Gahne S, Gånheim A, Malmgren L.Different insemination doses have been used for artificial insemination(AI) in horses. Since the insemination dose can affect the pregnancy rate, it is important to ensure that an adequate dose be used regardless of the type of inseminationprotocol used. The aim of this study was to find out if it is possible to decrease the insemination dose from 500 x 10(6) progressively motile spermatozoa to 300 x 10(6) progressively motile spermatozoa and still maintain an acceptable pregnancy rate when using extended fresh semen. Thirteen stallions of known fertility and a well-defined group of 64 mares w...
Hodge SL, Kreider JL, Potter GD, Harms PG, Fleeger JL.Over a 2-year period, mares (n = 32) of predominantly Quarter Horse breeding and their foals were used to study the effects of photoperiod on reproduction during the periparturient period. Specific objectives of the study were (i) to evaluate the effects of an extended photoperiod regimen (16 hours' light) on gestation length, foal development, and postpartum reproductive performance, and (ii) to measure changes in plasma progesterone concentrations during the last trimester of gestation and plasma luteinizing hormone (LH) concentrations after foaling until ovulation. Mares in the extended day...
Arfuso F, Quartuccio M, Bazzano M, Fazio F, Piccione G.Knowledge of hematologic function in postparturient mares and foals is crucial for the monitoring of their health status and for the prompt diagnosis of pathologic conditions. Objective: The aim of this study was to evaluate erythrocyte osmotic fragility (EOF) and select hematologic variables in mares and their foals during the first month after foaling. Methods: Blood samples were collected from each animal every 3 days from day 1 until day 30 after foaling, and tested for RBC count, HGB, HCT, MCV, and EOF. Two-way repeated measures analysis of variance (ANOVA) and Bonferroni post hoc compari...
Ginther OJ, Douglas RH, Lawrence JR.Responses of 22 veterinarians to a questionnaire and the records of three brood-mare farms were examined to obtain information on twinning. The incidence rates of multiple ovulations on the three farms were 9%, 11%, and 22%. The multiple ovulation rate was reduced 42-67% in foaling mares compared to barren and maiden mares. Multiple ovulations were significantly more frequent in Thoroughbreds (19%) than in Quarter Horses (9%) and Appaloosas (8%). Both the questionnaire and the farm records indicated a high degree of repeatability of multiple ovulations and twin pregnancies within mares and wit...
Hannan MA, Haneda S, Murata K, Takeuchi S, Cheong SH, Nambo Y.Until now, there have been no reports of foals born through embryo transfer after artificial insemination using frozen semen in Japan. The aims of this study were to develop a riding crossbred horse and evaluate the prospects of embryo transfer technology in multiplying horse population. In both donor and recipient mares, luteolysis was induced by the administration of 0.1 mg Cloprostenol to synchronize the onset of estrus, and ovulation was induced by administering 2000 IU human chorionic gonadotropin (hCG) or 0.75 mg Deslorelin. Frozen semen from an Irish Connemara pony stallion was used to ...
Cekiera A, Popiel J, Siemieniuch M, Jaworski Z, Slowikowska M, Siwinska N, Zak A, Niedzwiedz A.This study aimed to assess the biophysical parameters of the skin in Polish Konik horses (Polish primitive horses). According to the authors, this is the first assessment performed on such a wide scale in this group of animals. The evaluation carried out is innovative both with regards to the breed of the animals and the wide scope of the physicochemical skin assessment. The study group comprised mares, stallions and geldings, and the evaluations concerned transepidermal water loss, corneometry, pH, skin temperature assessment and mexametry. These parameters were assessed in five skin regions:...
Rua MAS, Quirino CR, Rodrigues ACC, Christo MM, Barreto MAP.The objective of this study was to evaluate the environmental effects on embryo recovery rate and pregnancy rate of Mangalarga Marchador mares. The reproductive characteristics of donor and recipient mares were evaluated during five years in Brazilian tropical environment. The mares were used throughout the year and seasons were classified as: October to April (breeding season - BS); May (autumn transition out of the breeding season - ATBS); June to August (non-breeding season - nBS); and September (vernal transition into the breeding season - VTBS). Daily temperature rainfall and hours of day...
Alexander SL, Irvine CH, Evans MJ.We used our nonsurgical technique for collecting pituitary venous blood to relate the dynamics of thyrotrophin-releasing hormone (TRH) secretion to the secretion patterns of both prolactin and thyrotrophin in periovulatory mares, either euthyroid (n = 5) or made hypothyroid by treatment with propyl-thiouracil (n = 5). Pituitary venous blood was collected continuously and divided into 1-min aliquots for 4 h. To test the effect of dopamine on the relationship between secretion patterns, sulpiride, a selective D2 receptor antagonist, was given i.m. after 2 h of sampling. Thorough testing of the m...
Henderson K, Stewart J.A dipstick, competitive immunoassay for rapidly measuring serum oestrone sulfate (OS) concentrations in horses was developed to distinguish mares 100 or more days pregnant from non-pregnant animals. 6-Ketoestrone 6-carboxymethyloxime conjugated to bovine serum albumin (oestrone CMO-BSA) was 'dotted' 25 mm from the bottom edge of 45 x 5 mm strips of polyester-film-supported cellulose nitrate membrane, pore size 3 microm. The strips were blocked, dried and a 15 x 5-mm cellulose absorbent sink attached 10 mm from the top of each strip. The manufactured dipsticks were stored with desiccant at room...
Pascoe RR.Within a group of 130 mares which, in the event, carried twin pregnancies, 29 (22.3 per cent) produced their twins following diagnosis of a single palpable follicle at service and a single pregnancy 42 days later. The whole group of 130 twin-pregnant mares gave birth to only 17 live foals (13 per cent). Breeding results for the following season were available for 102 of these mares, when 38 (37 per cent) produced live foals. Thus over the two seasons an average 23 per cent of this group produced live foals. In a second group, comprising 70 mares, twin pregnancy had been diagnosed in all of the...
Dippert KD, Jasko DJ, Seidel GE, Squires EL.Embryo recovery per ovulation has been shown to be lower in superovulated mares than in untreated controls. The objectives of this study were to 1) determine whether follicles stimulated with superovulatory treatment ovulate or luteinize without ovulation, 2) determine fertilization rates of oocytes in oviducts of superovulated and control mares, and 3) evaluate viability of early stage embryos from superovulated and control mares when cultured in equine oviductal cell-conditioned medium. Cyclic mares were randomly assigned to 1 of 2 groups (n=14 per group) on the day of ovulation (Day 0): Gro...
Scudamore CL, Pemberton AD, Miller HR, McDonnell AM, Thomson SR, Dawson A, Watson ED.An enzyme linked immunosorbent assay (ELISA) was developed and used to estimate the concentrations of the serine proteinase inhibitor, alpha-1 proteinase inhibitor (API), in uterine flushings recovered from mares at different stages of the oestrous cycle and before and after the induction of experimental endometritis. There was a significant increase in the concentrations of API and albumin relative to total protein in flushings recovered during oestrus compared with dioestrus but no difference was observed in the concentrations of these proteins relative to total protein before and after the ...
Beltman ME, Walsh SW, Canty MJ, Duffy P, Crowe MA.The objective was to characterise the hormonal composition of follicular fluid from mares with distinct anovulatory-cystic follicles. Follicular fluid was aspirated from six mares that presented with cystic follicles and from pre-ovulatory follicles of five normal mares (controls). Differences in progesterone, oestradiol, testosterone, IGF-I and IGF binding were analysed using Fisher's exact test. There were greater (P < 0.03) follicular fluid oestradiol concentrations in normal follicles and the testosterone concentration of the cystic fluid was greater (P < 0.05) than that of t...
Kaps M, Okada CTC, Gautier CM, Aurich J, Aurich C.There is an increasing interest in the manipulation of ovarian follicular populations in large domestic animals because this could prove beneficial for assisted reproductive techniques such as ovum pick-up (OPU). The aim of the present study was to evaluate the effects of deslorelin slow-release implants (SRI) on the interovulatory interval, antral follicle count (AFC), number of follicles of different size ranges and plasma anti-Muellerian hormone (AMH) concentration in mares. To synchronize their estrous cycles, Haflinger mares (n = 12) were treated twice with a PGF2α analogue. One day afte...
Frank N, Sojka JE, Latour MA.Blood lipid and lipoprotein concentrations were measured and compared between euthyroid and thyroidectomized mares on low-fat or high-fat diets to test the hypothesis that hypothyroidism alters the blood lipid response to higher dietary fat intake. Four healthy adult mares and four adult mares that had been thyroidectomized 3 to 6 mo earlier were placed on low-fat or high-fat diets according to a replicated 2 x 2 Latin square design consisting of two 5-wk feeding periods separated by a 2-wk washout interval. Plasma lipid concentrations were measured at 0, 3, 4, and 5 wk, and plasma lipase acti...
Silvia PJ, Meyer SL, Fitzgerald BP.Twelve horse mares were used in a repeated-measures design consisting of 3 replicates of 4 mares each. On Day 6 following ovulation, luteolysis was initiated with an i.m. injection of prostaglandin F2 alpha (PGF2 alpha; Lutalyse, 10 mg). Either 12 (-12) or 36 (-36) h before PGF2 alpha (PRE), blood samples were collected simultaneously from the intercavernous sinus (ICS) and jugular (JUG) vein at 10-min intervals for an 8-h period. Pituitary capacity to exogenous GnRH (2 micrograms/kg BW, i.v.) was evaluated at the alternate time point within this period. Frequent sampling and GnRH challenge we...
Pazinato FM, Curcio BDR, Varela Junior AS, Corcini CD, Wendt CG, Moreira F, Schmit RA, Nogueira CEW.Placental tissues from humans, rodents, and farm animal contain leptin and its receptor. Expression of leptin has already been described in horses, although there is no description about immunolocalization of leptin and its receptor. The aim of the present study was to investigate the presence and distribution of leptin and ObR-b in the equine placenta at term by immunofluorescence staining, and the changes on plasma leptin concentrations during late gestation. The present study involved eight Criollo-type mares carrying healthy pregnancies. Blood samples were collected during the third trimes...
Ferreira JC, Ignácio FS, Rocha NS, Thompson DL, Pinto CR, Meira C.The present experiment was divided into two studies to investigate the effect of age and endometrial degeneration on uterine blood flow of mares throughout the immediate post-breeding period. In study 1, uterine blood flow was characterized in mares (n = 7 mares/group) with minimal, moderate or severe endometrial degenerative changes (GI, GII and GIII, respectively). In study 2, the effect of age was investigated using young (≤ 6 years) and old (≥ 15 years) mares (n = 7 mares/group). Uterine vascular perfusion and mesometrial pulsatility index (PI) were evaluated every hour from H0 (moment...
Ewert M, Böröcz J, Uphaus H, Oldenhof H, Distl O, Sieme H.The aim of this study was to evaluate factors affecting pregnancy rates in the German Thoroughbred Breed with particular emphasis on optimisation of fertility rates for breeding stallions of older ages. Methods: Data from the studbooks of the German Thoroughbred Breeding Association from 1996 to 2009 analysed. This analysis included the records of 319 stallions and 6622 brood mares, resulting in 21,372 pregnancies at the end of the season. Results: Pregnancy rates were significantly affected by the age of the stallion and mare as well as the season (month in the breeding season in which coveri...
Murase H, Matsui A, Endo Y, Sato F, Hada T.The lying behavior of Thoroughbred foals on breeding farms was continuously measured using triaxial accelerometers. Accelerometers were attached on the side of the hind limb cannon and under the halter of six foals to record triaxial angle data every 10 sec for a period of 24 hr. Lying behavior was divided into sternal lying and lateral lying based on head angle. Sampling was performed for two consecutive days each week until weaning. Sampling periods were divided into two periods on the basis of pasturing time: daytime pasturing (period A: 7-hr pasturing period, 2-60 days of age) and overnigh...
Gokbulut C, Ozuicli M, Aksit D, Aksoz E, Korkut O, Yalcinkaya M, Cirak VY.The horse milk gains increasing interest as a food product for sensitive consumers, such as children with food allergies or elderly people. We investigated the plasma and milk disposition, faecal excretion and efficacy of per os ivermectin (IVM) and pour-on eprinomectin (EPM) in horses. Ten mares were divided into two groups. The equine paste formulation of IVM and bovine pour-on formulation of EPM were administered orally and topically at dosage of 0.2 and 0.5 mg/kg bodyweight. Blood, milk and faecal samples were analysed using high-performance liquid chromatography. The plasma concentration...
Viñoles C, Quintans G, Paiva N, Cavestany D.The ovarian responses of anoestrus beef cows to a combined treatment with medroxy-progesterone acetate (MAP) sponges and oestradiol benzoate or equine chorionic gonadotrophin (eCG) were evaluated. Forty-five suckling Hereford cows were allocated to three equal groups. Group 1 received a MAP sponge for seven days plus an injection of 2 mg oestradiol benzoate when the sponge was inserted (day 0) and 1 mg when the sponge was withdrawn; group 2 received identical treatment until day 7, when a dose of 400 iu of eCG was administered, and group 3 were left untreated as control animals. From day 0 to ...
