Pregnancy in horses, or equine gestation, is a physiological process that involves the development of a foal within the mare over approximately 11 months. This period is characterized by distinct stages, including fertilization, embryonic development, and fetal growth. Throughout gestation, mares undergo various physiological and hormonal changes to support the developing fetus. Monitoring pregnancy in horses involves assessing fetal health and mare well-being through veterinary examinations and diagnostic tools such as ultrasound. This page compiles peer-reviewed research studies and scholarly articles that explore the physiological processes, management practices, and health considerations associated with equine pregnancy.
Burns SJ, Irvine CH, Amoss MS.This study was undertaken to determine if fertility could be improved by increasing the interval from foaling to breeding. Forty-two mares, not bred during normal post-partum oestrus, were injected with a prostaglandin analogue on Day 6 or 7 following ovulation. Mares were mated artifically with antibiotic-treated semen during the resulting oestrus and, if necessary, for the following 4 cycles. Their fertility was compared, by cycles/pregnancy and rate of fetal loss, to mares bred by the same methods on 86 normal post-partum oestrous periods. The interval from foaling to the onset of breeding ...
Gygax AP, Ganjam VK, Kenney RM.The surprisingly rapid rate of uterine involution detected is consistent with a high rate of conception as the first post-partum heat. Furthermore, many of the immediately post-partum features have attained the pregravid state by the end of the first post-partum oestrus and virtually all by the second post-partum oestrus. There was no specific cause detected for the higher rate of early embryonic death associated with conception at the foal heat.
Günzel AR, Merkt H.Of 383 mares showing clinical evidence of suspected early fetal resorption between 20 and 60 days after mating, 217 were treated with a single injection of 200 mg CAP (a synthetic progestagen); the remaining 166 mares served as untreated controls. Treatment had neither a beneficial nor a detrimental effect on the continuation of pregnancy. Conception rates following loss of the conceptus were higher in lactating than in non-lactating mares. No increase in number of twin or deformed foals was evident in the treated animals.
Flood PF, Betteridge KJ, Irvine DS.Six samples of blastocoele fluid recovered between 10 and 22 days gestation were tested in human clinical radioimmunoassay systems measuring total oestrogens and total androgens. The results were erratic but in 5 cases measurements for oestrogen equivalent to between 1000 and 70,000 pg/ml and for androgen between 1000 and 85,000 pg/ml were recorded. Cells from two blastocysts were cultured in medium 199 with and without horse serum. When the used media were assayed, values equivalent to at least 8000 pg oestrogen/ml were obtained on 7 of 11 occasions. In 9 of 11 samples the androgen concentrat...
Gudev Kh, Kovachev G.Alantoamnion vascularization was studied on clarified preparations from three mares in advanced pregnancy. Two large blood vessels (artery and vein) beginning from the umbilical vessels were found in the alantoamnion wall. Numerous anastomoses were observed at the passage between the arterial and the vein section. The large arteries had a thick, jely-like vascular wall and snake-like folded lumen. In separate sections of the alantoamnion wall a well developed capillary net was observed consisting of individual particles, polygonal in shape. Vast avascular zones surrounded by numerous vascular ...
Silver M, Barnes RJ, Comline RS, Fowden AL, Clover L, Mitchell MD.The concentrations of the primary prostaglandins (PG) F-2alpha and E-2 and the metabolite 13,14-dihydro-15-oxo-prostaglandin (PGFM) in maternal and fetal plasma and in allantoic fluid were measured in chronically catheterized mares and fetuses. A gradual rise in all 3 PGs occurred with increasing gestational age. PGE-2 and PGF-2 alpha levels were highest in the allantoic fluid and lowest in the maternal plasma, whereas PGFM concentrations were greatest in maternal plasma. Significant venous-arterial plasma differences in PGFM concentration were detected across the uterine circulation between 1...
Jeffcott LB, Rossdale PD.The position, posture and presentation of the fetus were studied by serial radiography of the abdomen in 18 crossbred Pony mares near term and during first- and second-stage labour. In 3 mares the fetal position was assessed before and after induction of parturition with the synthetic prostaglandin, fluprostenol. In late gestation and up to the time of first-stage labour the fetus lay in ventral position with the forelimbs and poll flexed or partly flexed. At this time fetal movements were confined to flexion and extension of neck and forelimbs, but at parturition the head and limbs gradually ...
Pascoe RR.An instrument has been designed to measure the effective length (l) and angle of declination (a) of the vulva in the mare. The product, la, provides an index (Caslick Index) suitable for determining the necessity for Caslick's operation in mares not exhibiting the classical symptoms associated with pneumovagina. The value l showed a significant increase (P less than 0.05) with increased age in breeding mares. Studies on 9020 mares revealed that all caslicked mares, and mares with a Caslick Index of less than 150, had a significantly higher pregnancy rate than non-caslicked mares of similar age...
Pashen RL, Allen WR.The effects of fetal gonadectomy on steroid production and the maintenance of pregnancy in the mare were studied. Removal of the fetal gonads resulted in an immediate fall in maternal plasma concentrations of conjugated and unconjugated oestrogens whereas progestagen levels remained unchanged. Hormone profiles in mares carrying sham-operated fetuses remained similar to those in unoperated control mares. Plasma levels of 13,14-dihydro-15-oxo-PGF-2 alpha (PGFM) were much lower, and uterine contractions weaker, during labour in mares carrying gonadectomized foals than in control mares. Pregnancy ...
Nett TM, Pickett BW.Two studies were conducted to determine the relationship between LH and progesterone and between PMSG and progesterone during pregnancy in mares. In the first, samples of jugular blood were collected daily from 7 mares from the first day of oestrus until Day 28 of pregnancy, and in the second, samples were collected weekly from 14 mares from Day 35 of gestation until parturition. In an attempt to prolong secretion of progesterone from accessory corpora lutea, 7 of these 14 mares were injected with increasing doses (2--10 mg) of diethylstilboestrol (DES) between Days 84 and 142 of gestation. Th...
Bhavnani BR, Woolever CA.A mixture of [4,8,12-14C]farnesyl pyrophosphate and [3H]dehydroepiandrosterone was injected into a horse fetus im during laparotomy, after which maternal urine was collected for 6 days. Steroid conjugates in the urine were extracted with Amberlite XAD-2 resin, hydrolyzed, and separated into phenolic and neutral fractions. Estrone, 17 alpha-estradiol, equilin [3-hydroxy-1,3,5(10),7-estratetraen-17-one], and 17 alpha-dihydroequilin [1,3,4(10),7-estratetraene-3,17 alpha-diol] were isolated from the phenolic fraction and their radiochemical purities were established. Only estrone and 17 alpha-estr...
Rance TA, Park BK.Oestrone, equilin and dehydroepiandrosterone were measured by radioimmunoassay in peripheral plasma from five pony mares; samples were taken from day 60 of pregnancy at approximately weekly intervals through to parturition. Of the three steroids measured, dehydroepiandrosterone showed the most consistent pattern of secretion. DHA concentrations remained low until day 105, increased rapidly from day 120 and attained maximum values between days 168–210; levels declined to day 300, but there was considerable variation between mares in DHA patterns prior to parturition. There was great variation...
Barnes RJ, Comline RS, Jeffcott LB, Mitchell MD, Rossdale PD, Silver M.The concentrations of 13, 14-dihydro-15-oxo-prostaglandin F(PGFM), the stable metabolite of prostaglandin F, were measured in the plasma of catheterized mares and foetuses and non-catheterized thoroughbred mares and ponies during the last months of gestation. The plasma concentration of PGFM increased gradually towards term in all groups of animals. During the operation for insertion of catheters, maternal and foetal concentrations of PGFM were high, but the values fell to basal levels 24--48 h after the operation. It was found the preoperative starvation (24 h) led to a rise in the concentrat...
Papkoff H, Farmer SW, Cole HH.The gonadotropin (PMEG) in pregnant mare endometrial cups was purified and compared to pregnant mare serum gonadotropin (PMSG). Purification methodology applicable to PMSG was employed. In vivo and in vitro assays for FSH and LH were used to evaluate PMEG preparations. In all cases, lower activities (11-54%) were observed with PMEG compared to PMSG. Antiserum raised in rabbits against PMSG cross-reacts fully with PMEG in agar double diffusion tests. The amino acid composition of PMEG is similar to PMSG, but amino terminal group analyses show PMEG preparations to be more heterogeneous than PMSG...
Basu R, Chatterjee A.The administration of pregnant mare's serum gonadotropin (PMSG), 30 IU on day 18 of pregnancy, resulted in premature labor in rats. However, this abortifacient efficacy of PMSG was not demonstrable when a simultaneous injection of progesterone, clomiphene, or indomethacin was scheduled, thus suggesting that the action of PMSG is medicated by the estrogen-stimulated release of prostaglandin. The termination of pseudopregnancy in bilaterally hysterectomized rats by PMSG and its reversal by indomethacin revealed that the inhibition of luteal function by PMSG does not require the presence of a ute...
Gupta T, Chatterjee A.Pregnant mare's serum gonadotropin (PMSG) of 10 IU on day 5 of pregnancy induced luteal demise and consequently an absolute resorption of fetuses and placentae resulted on day 16 of pregnancy. Simultaneous regimen of PMSG and indomethacin or cortisone was found to be consistently effective in preventing the luteolytic effect of PMSG. The growth of the fetuses, placentae as well as corpora lutea was found to be parallel to controls. Similarly, shortening of the duration of pseudopregnancy to 10--12 days in the bilaterally hysterectomized rat by PMSG and its retaining the normal duration of 18--...
Hunt B, Lein DH, Foote RH.Plasma and milk progesterone concentrations in 13 mares were determined 3 times a week for 5 months, beginning at parturition. The estrous cycle was divided into 2 phases. Estrus was considered to occur when the plasma progesterone concentration was less than 1 ng/ml, with diestrus occurring when plasma progesterone content was greater than or equal to 1 ng/ml. Based on this classification, the period of estrus averaged 8.9 days, diestrus averaged 13.9 days, and the estrous cycle averaged 22.8 days. During estrus, the progesterone concentration in plasma averaged 0.4 ng/ml and in milk averaged...
Graham EF, Crabo BG, Pace MM.From the studies cited it was concluded that short and long term preservation of stallion semen has encountered major obstacles. Fertilizing capacity of extended or extended and cooled spermatozoa has been impaired. With the hydrogen ion extenders, the fertility was depressed either with or without glycerol when the semen was inseminated immediately after extension. With the cream-gel extender, fertility was not impaired when inseminated immediately after extension, but was impaired after storage at 5 C for 24 hr or in the presence of glycerol. The fertilizing capacity of extended frozen sperm...
Weber JA, Woods GL, Freeman DA, Vanderwall DK.The objective of this experiment was to contrast the influence of the oviductal and uterine environments on development of Day-2 embryos. Embryos were transferred to oviducts or uteri of synchronous recipient mares, or were incubated in oviductal co-culture, in uterine co-culture or in defined culture medium. Significantly more (P < 0.02) embryos transferred to the oviduct versus the uterus survived until Day 11 after ovulation (5 7 vs 0 7 , respectively). Significantly more (P 0.1) in oviductal co-culture versus uterine co-culture (3 7 vs 6 7 , respectively), or in oviductal co-culture ve...
Magalhaes HB, Canisso IF.Practitioners are frequently requested to diagnose and stage pregnancy in donkeys with unknown breeding dates; however, scant work has been done to stage pregnancy in the species. Therefore, this study aimed to determine the association between measurements of fetal aortic, thoracic, and heartbeat with gestational age in donkeys carrying and delivering healthy foals. Multiparous Dezhou donkeys (n = 50) ranging from 4 to 16 years were enrolled in the study by 150 days of gestation. Transabdominal ultrasonography coupled with a 3.5 MHz sectorial convex transducer was performed at 30 day-interv...
Hinrichs K, Provost PJ, Torello EM.A nonovulating, hormone-treated mare was used successfully as an oocyte recipient. The mare's ovarian activity was suppressed using progesterone and estrogen treatment. This treatment was stopped, then estrogen was administered for 3 d prior to the transfer. An oocyte was recovered from the follicle of a donor mare and was transferred via flank laparotomy into the recipient's oviduct. The recipient mare was inseminated 7 h before transfer. The recipient was treated with intramuscular progesterone from the day after transfer until 47 d after transfer, and then with oral altrenogest until 150 d ...
Albrecht BA, MacLeod JN, Daels PF.At the onset of equine chorionic gonadotrophin (eCG) secretion, eCG stimulates luteal androgen and oestrogen production. Although eCG concentrations increase exponentially from day 37 to day 60 of gestation and eCG is detectable in maternal serum until about day 120-150 of gestation, luteal androgen and oestrogen production peaks between 5 and 10 days after initial exposure to eCG and then decreases gradually. It is not clear how eCG regulates luteal androgen and oestrogen production. In the present study, the steady-state mRNA expression of 3beta-hydroxysteroid dehydrogenase (3beta-HSD), cyto...
Jacobs PH, Elsinghorst TA.Endometrial cups in horses are outgrowths appearing in the uterine wall of the pregnant horn between approximately 38 days and 150 of gestation. The cups are structures which vary in shape from oval to irregular and have distinct raised edges, showing an ulcer-like form. The maximum measurements are approximately 5 X 2.5 X 2.5 cm. Microscopic examination shows that they consist of large epithelioid decidual-like cells having large nucleoli. Pregnant Mare Endometrium Gonadotrophin (PMEG) is produced in the endometrial cups. PMEG may be regarded as a precursor of Pregnant Mare Serum Gonadotrophi...
Lanci A, Ingallinesi M, Morini M, Freccero F, Castagnetti C, Mariella J.Hydramnios is an excessive accumulation of fluid within the amniotic compartment. It is a rare condition in mares, often associated with fetal anomalies. Hydrops of fetal membranes predisposes to the rupture of the prepubic tendon, and many authors suggest the induction of parturition to preserve mare's reproductive career. This report presents the case of a 15-year-old multiparous Quarter Horse mare, referred at 268 days of gestation for suspected hydrops. Repeated ultrasonographic exams confirmed an increase in the depth of the amniotic fluid and reduced fetal viability. During the hospitali...
Klem ME, Kreider JL, Harms PG, Potter GD, Kraemer DC, Godke RA.Thirty-one mares of Quarter Horse and Thoroughbred breeding were utilized in two experiments to evaluate the efficacy of prostaglandin F2 alpha (PGF2 alpha) for induction of equine parturition and to monitor the effects of this treatment on viability of the resulting foals. Three of five mares given 5 mg PGF2 alpha (im) on day 338 of gestation foaled 19.6+/-8.2 hr postinjection. In the second experiment immediately following 3 daily injections of 10 mg estradiol cypionate (ECP) given on days 326, 327 and 328 of gestation, seven mares were infused (iv) with PGF2 alpha at the rate of 1.3 mg/hr f...
Thompson DL, Reville SI, Derrick DJ, Walker MP.Eight seasonally anestrous mares were administered intravaginal polyurethane sponges on December 15 and then weekly thereafter until February 1. Control mares received no sponges or genital contact. Sponge insertion caused an immediate surge in follicle-stimulating hormone (FSH) concentrations in jugular plasma in 50% of treated mares whereas no control mares had surges in FSH (P less than .05). The effect of treatment on luteinizing hormone (LH) concentrations was much less dramatic and only three treated mares appeared to have positive responses. Sponge-treated mares exhibited positive respo...
Henderson KM, Eayrs K.To develop a means of determining pregnancy status in horses based on measuring serum oestrone sulphate (OS) concentrations using a rapid lateral flow immunoassay, and to determine the assay's effectiveness using a visual end-point. Methods: Serum samples from mares >100 days post-mating (n=701) were assayed using a nitrocellulose membrane-based lateral flow immunoassay device. The device was developed using membrane-bound 1,3,5 (10)-estratrien-3-ol-17-one conjugated to bovine serum albumin as the capture antigen, and an OS-detection monoclonal antibody coupled to colloidal gold as the visi...
Munk Z, Dusek J.The fertility problems were studied in the herd of the English Thoroughbred horse on the Napajedla stud farm. Breeding records for the period from 1880 to 1972 were used as the starting data. The survey comprised 32 stallions. The relationship between fertility and the number of matings was calculated by the chi 2 quantity. The calculated values are highly variable. However, it is generally seen in most of the stallions that the number of matings per heat (i. e. one or several matings) had no significant influence on the pregnancy of mares and on the fertility values of the stallions. A higher...
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 ...
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...
Peltier MM, Peltier MR, Sharp DC, Ott EA.The objective of this study was to determine whether supplemental beta-carotene would influence reproductive function in mares maintained on spring and summer pastures and to characterize plasma carotene concentrations during the estrous cycle. Carotene concentrations in plasma did not vary with day of estrous cycle (P = 0.7455). Mares receiving every other day injections of beta-carotene (400 mg; n = 4) or saline (10 ml; n = 4) during proestrus/estrus did not differ in plasma estradiol (E(2)) concentrations (P = 0.6313), follicle development (P = 0.8068), or plasma progesterone (P(4)) concent...
Macpherson ML, Giguère S, Pozor MA, Runcan E, Vickroy TW, Benson SA, Troedsson MHT, Hatzel JN, Larson J, Vanden Berg E, Kelleman AA, Sanchez LC....Eleven pregnant pony mares (D270-326) were administered ceftiofur sodium intramuscularly at 2.2 mg/kg (n = 6) or 4.4 mg/kg (n = 5), once daily. Plasma was obtained prior to ceftiofur administration and at 0.5, 1, 2, 4, 8, 12, and 24 hr after administration. Eight pony mares were re-enrolled in the study at least 3 days from expected foaling to ensure steady-state concentrations of drug at the time of foaling. Mares were administered ceftiofur sodium (4.4 mg/kg, IM) daily until foaling. Parturition was induced using oxytocin 1 hr after ceftiofur sodium administration. Allantoic and am...
Allen WE.The ovaries of twenty pregnant mares were examined daily, per rectum, for the first 4 months of gestation and note was made of their estimated size and follicular content. Serial blood samples from sixteen of the mares were assayed for PMSG. A marked seasonal effect was noted on ovarian size, follicular content and ovulation rate during pregnancy but there was no such effect on PMSG production. It is concluded that PMSG is synergistic with gonadotrophins of pituitary origin and that the latter hormone are the primary stimulus on the ovary of the pregnant horse.
Flisińska-Bojanowska A, Gill J, Komosa M.1. The diurnal changes in the levels of lactic (LA) and pyruvic (PA) acids and in values of pH, pO2 and pCO2 were studied in the blood of barren and later on in pregnant and lactating mares, throughout three subsequent years. 2. Blood samples were taken every 4 hr, for one day, each month, throughout 3 years. 3. The mares were kept and fed in the same conditions, lighting was natural. 4. In barren mares, diurnal rhythm in LA, PA, pO2 and pCO2 was found. 5. The pregnancy as well as lactation masked diurnal rhythms in parameters studied, except the LA level during lactation but then the acrophas...
Ginther OJ, Williams D, Curran S.Transrectal ultrasonic examinations were made in 31 pregnant pony mares once a week during Months 6 to 11. Each uterine horn was divided into 3 approximately equal segments (caudal, middle, cranial). The percentage of examinations with cranial fetal presentation increased (P<0.05) progressively from 58% at Month 6 to 99% at Month 9 and was followed in all mares by entry of the fetal hind limbs into one uterine horn. The mean number of uterinehorn segments with limb parts increased (P<0.05) between each set of consecutive months from Month 6 to Month 10. Initially (Months 7 and 8), retrac...
Cohen ND, Carey VJ, Donahue JG, Seahorn JL, Harrison LR.Epidemiological and pathological findings of 433 late-term abortions associated with the mare reproductive loss syndrome (MRLS) in central Kentucky were identified by reviewing the records of the University of Kentucky Livestock Diseases Diagnostic Center. The distribution of dates of abortion was clustered during a brief period of time, presumably from a simultaneous environmental exposure. The most common pathological findings were microscopic pulmonary lesions consisting of squamous epithelial cells present in alveoli with or without concurrent infiltration of inflammatory cells (neutrophil...
Inoue S.Maternal aging has negative influences on the development and racing performance of their offspring in racehorses. However, the mechanism by which pregnancy at old age reduces the race performance of the offspring is unknown. Here, two hypotheses were posited: 1) Foals born to older mares are more likely to have muscular, skeletal, and cognitive disadvantages (direct effects). 2) Foals born to older mares are more likely to be affected by non-physiological factors correlating with the mare's age, such as the quality of sires (e.g. low-quality sires are likely to be chosen as partners of older ...
Raeside JI, Christie HL.C(18) neutral steroid formation by cytochrome P450 aromatase has been recorded for several equine and porcine tissues. High activity of P450 aromatase is reflected in the quantities of estrogens in yolk-sac (y-s) fluid of early equine conceptuses. In a previous study of y-s fluid we detected large amounts of androgens by radioimmunoassay (RIA), using an antiserum for androstenedione (A(4)). Here, we report that RIA, following chromatography, gave tentative identification of the major peak as norandrostenedione (19-norA) not as A(4). Furthermore, even greater quantities of 19-norA seemed to be ...
Coffman EA, Pinto CR, Snyder HK, Leisinger CA, Cole K, Whisnant CS.A single dose of PGF2α does not consistently induce luteolysis in the equine CL until at least 5 days after ovulation, leading to the erroneous assumption that the early CL is refractory to the luteolytic effects of PGF2α. We hypothesized that serial administration of PGF2α in early diestrus would induce a return to estrus similar to mares treated with a single injection in mid-diestrus, and fertility of the induced estrus would not differ. The objectives of the study were to evaluate the effects of the 2 approaches as reflected by: (1) concentrations of plasma progesterone; (2) interovulat...
Roberts SJ, Myhre G.Equine twinning, related abortion and progestogen plasma concentrations during the gestation period were reviewed. The supplemental administration of exogenous progesterone apparently prevented impending twin abortions in three mares after midgestation. A single viable twin and a mummified fetus were delivered at term by the mares.
Whyte A, Allen WR.Pre- and post-implantation endometrial tissue was removed from equids at known stages of pregnancy. Thin sections of this material were reacted with fluorescein conjugates of several lectins. Two lectins in particular, with specificities for L-fucose and N-acetylglucosamine, reacted strongly with the endometrial epithelium. The reaction for N-acetylglucosamine occurred in small patches on the endometrial epithelium and extended to cover the entire epithelial surface and endometrial glands after implantation. L-Fucose was observed in larger surface deposits particularly at the openings of endom...
Oikawa M, Yoshihara T, Kaneko M, Yoshikawa T.The morphology of the equine allantochorion at the tip of the pregnant horn was studied in the membranes of 14 mares. The findings in the allantochorion at the tip of the pregnant horn were of two types; one was growth retardation (hypoplastic villi, tunica adventitia of the vessels resembling embryonal connective tissue and the extended spaces of remnants of the extraembryonic coelom), the other was placental hypoxia or ischaemia (parakeratosis, stratified squamous metaplasia, necrosis of the trophoblasts, thickening of the basement membrane and fibrous hyperplasia of villous stroma). It seem...
Jones DM, Fielden ED, Carr DH.Two intact and 2 ovariectomized mares aged 3-16 years had bipolar electrodes implanted in the myometrium to measure electromyographic (emg) activity during normal and exogenously simulated (with oestrogen and progesterone) cyclical activity (anoestrus, transition, oestrus and dioestrus). Oxytocin, cloprostenol, propantheline bromide and clenbuterol were administered during each cycle stage. In 1 mare, emg activity was recorded during natural breeding (4 times) and through the first 20 days of pregnancy. Simultaneous intrauterine pressure recordings (IUP) using an open tipped catheter system we...
Wilsher S, Rigali F, Kovacsy S, Allen WT.Vitrification of embryos >300 µm in diameter requires puncture of the glycoprotein capsule, although the size of the hole compatible with embryo survival is unknown. Forty-five day-7 or -8 embryos were punctured using a 30-µm glass biopsy pipette mounted on a micromanipulator (n = 20) or manually with either an acupuncture needle (∼100-µm diameter -hole; n = 10) or a microneedle with a <1 µm tip to produce a ∼30-µm diameter hole (n = 15) before transferring to recipient mares; further 12 embryos were punctured with either the acupuncture needle or microneedle before being cultured ...
Sirois J, Betteridge KJ.To recover intact Day-10.5 to Day-16.5 equine conceptuses (Day 0 = ovulation), a rigid catheter was used for 131 collections from donor mares diagnosed pregnant by ultrasonography. A total of 139 conceptuses were recovered, comprising 124 singletons, six pairs of twins and one set of triplets. Of these, 120 (86%) were intact after the collection, 14 (10%) had collapsed, and in five cases (4%), collapsed trophoblastic membranes were surrounded by an intact capsule. The recovery rate of intact conceptuses ranged from 99% on Days 10.5 to 12.5 to 40% on Day 16.5. More uterine flushes per recovery ...
Vandeplassche M, Simoens P, Bouters R, De Vos N, Verschooten F.In 214 cases of severe dystocia in mares, of which 141 (66 per cent) were Draught horses, deviation of the head and neck, with or without torticollis, malformed head and limbs were found to be the cause of dystocia. No evidence of a genetic lethal factor was found and torticollis was often combined with scoliosis of the head and, frequently, with malformation of one or more limbs. This is considered evidence of a common aetiology and pathogenesis of the syndrome of malformation. The malformations were found to be associated with an increased incidence of caudal and, particularly, transverse pr...
Klewitz J, Krekeler N, Ortgies F, Heberling A, Linke C, Sieme H.To assess pregnancy and live foaling rates after reduction of twin pregnancy via transvaginal ultrasound-guided aspiration (TUA) in mares and evaluate effects of gestational period, localization of conceptuses, fluid aspiration volume, and combination of TUA with embryonic or fetal puncture on these outcomes. Methods: Clinical trial. Methods: 44 mares pregnant with twins (25 to 62 days of gestation). Methods: TUA was performed in all mares and combined with embryonic or fetal puncture in 13. Follow-up ultrasonographic examinations were performed by referring veterinarians. Effects of gestation...
Howey WP, Jochle W, Barnes WJ.Alfaprostal (K 11941), a novel prostaglandin F2 alpha analogue was clinically tested in 24 dioestrous mares, 40 anoestrous mares and 31 postpartum mares, all being given 2 or 3 mg intramuscularly. Blood samples were taken for the determination of plasma progesterone levels and the objective confirmation of luteolytic drug effects. Two hundred and thirty-six mares at the same location were used for comparisons of the rates of pregnancy, early embryonic loss and foaling. Alfaprostol was found to act as a potent luteolytic agent with good oestrus induction, follicular development and normal conce...
