Reproduction in horses encompasses the biological processes and mechanisms involved in the breeding and development of equine offspring. This includes the study of reproductive anatomy, physiology, and endocrinology in both mares and stallions. Key areas of interest include the estrous cycle, ovulation, conception, gestation, and parturition. Researchers also examine factors influencing fertility, reproductive technologies such as artificial insemination and embryo transfer, and management practices that impact reproductive success. This page compiles peer-reviewed research studies and scholarly articles that explore the physiological, genetic, and environmental aspects of equine reproduction.
Nocera I, Bonelli F, Turini L, Madrigali A, Aliboni B, Sgorbini M.The body condition score (BCS) represents a practical but subjective method for assessing body fat reserves. Real time ultrasonography (RTU) has been proposed as an accurate method to objectively measure subcutaneous fat (SF) thickness and predict body fat reserves in cows, horses and donkeys. The aim of the present study was to describe RTU measures of SF thickness during periparturient period in jennies. The present prospective cohort study evaluated six dairy jennies. SF RTU were performed at 15 and 7 days before the presumptive delivery, and 2, 15 and 30 days after delivery. A portable ult...
Yu K, Pfeiffer C, Burden C, Krekeler N, Marth C.Increased ambient temperatures has been identified to contribute to reproductive outcomes for several domesticated species, but its impact on equine reproduction has not been previously investigated. Therefore, this study aimed to examine the relationship between ambient climatic conditions, as measured by temperature-humidity index (THI) between day 7 and day 14 of gestation, and early embryonic loss (EEL) in recipient mares undergoing embryo transfer. The study examined records from 834 embryo transfers at an equine breeding facility in Victoria, Australia. Early embryonic loss was defined a...
Boye JK, Bulkeley EA, Dujovne GA.To describe uterine prolapse, predispositions, and outcomes in mares treated between 1988 and 2019. 24 mares with uterine prolapse. Clinical records were retrospectively reviewed, and follow-up information was gathered. The Mann-Whitney U test and Fisher exact test were used to analyze results for history and outcome variables for potential association with mare survival to hospital discharge. The χ2 test was used to compare breed distribution. Age was known in 23 mares (median, 11.1 years). For 15 mares with exact known parity, the median parity was 3 births (range, 1 to 13 births). For 22 m...
This study investigated the effects of embryo reduction and transfer of Day 11 embryos, with or without subsequent reduction, on luteostasis in the mare. In Experiment 1, reduction of embryos at Days 10 (n = 15), 11 (n = 47), 12 (n = 36), 13 (n = 27), 14 (n = 5) and 16 (n = 2) of pregnancy resulted in luteostasis in 13%, 47%, 78%, 89%, 80% and 100% mares. Mares undergoing > 1 embryo reduction showed consistency in when luteostasis occurred. In Experiment 2, transfer of Day 11 embryos to recipient mares 10 (n = 9), 11 (n = 8), 12 (n = 9) and 13 (n = 8) days post ovulatio...
Sievert M, Schuler G, Büttner K, Wehrend A.The timely diagnosis of abnormalities in the passive transfer of colostral immunoglobulins is important for the health and development of newborn foals. This study investigated three different methods for measuring immunoglobulin G concentration in neonatal foals. Comparison of a commercial SNAP assay, total protein concentration determination, and total globulin calculation by subtracting the albumin fraction from total protein as an indirect parameter was performed on a quantitative ELISA, which served as a reference method. The study included 119 samples from 148 foals between the age of 1 ...
Botha AE, Schulman ML, Birrell J, du Plessis L, Laver PN, Soley J, Colenbrander B, Bertschinger HJ.The effects of the GnRH vaccine Improvac on testicular and epididymal morphometrics, histology and spermatogenesis were measured in 19 young (15-20 months) colts randomly assigned to one control (saline, castration at 57 days, n = 6) or either of two GnRH vaccine-treatment groups, T-57 (castration at 57 days, n = 7) or T-100 (castration at 100 days, n = 6), respectively. All were immunized on Day 0 with a single booster on Day 28. Excised testes and epididymides were weighed and processed for histology to measure tubule, epithelial and muscle dimensions, the ratio of interstitial tis...
Pastorello M, Gastal MO, Godoi DB, Gastal EL.Among female livestock, the mare has the shortest interval from parturition to first ovulation. Due to the scarcity of research on postpartum mares, little progress has been made on the characterization of the resumption of ovarian cyclicity after parturition. This study compared follicular and gonadotropin dynamics during follicle emergence and deviation in postpartum lactating (PP Lactating) versus non-postpartum cycling (N-PP Cycling) mares. On the day of parturition, every PP Lactating mare was paired with a N-PP Cycling mare. Comparisons were made by considering the partum-ovulation inter...
Albrizio M, Lacalandra GM, Cinone M.In this study, we defined the composition of the culture medium that yield a significant percentage of alive and functional equine spermatozoa during enough time before artificial insemination. The effects of sodium bicarbonate were analyzed in fresh and frozen semen in respect to sperm viability, capacitation, spontaneous acrosome reaction and several kinetic parameters such as total motility, progressive motility, VCL, VSL, ALH, BCF, LIN. Moreover, employing Bayk-6844 and Nifedipine, the involvement of L-type voltage-gated calcium channels in the modulation of intracellular calcium concentra...
Da Silva-Álvarez E, Gómez-Arrones V, Martín-Cano FE, Gaitskell-Phillips G, Ortiz-Rodríguez JM, Carrasco JJ, Gil MC, Peña Vega FJ....In this study, uterine blood flow area (BFA) has been evaluated for the first time using power Doppler ultrasound (PD) as a marker of endometritis in mares and jennies. The uterine BFA in healthy mares was greater in oestrus than in diestrus (p < .001). However, differences in endometrial blood flow between oestrus and diestrus were not observed in mares with endometritis. The uterine blood flow in healthy jennies is not affected by the oestrus cycle. Both species showed an increase in endometrial BFA in pathological uterine conditions compared to controls. BFA was a good marker of endome...
Aurich C, Kaps M.The behaviour of mares is often detrimental to their performance resulting in frequent demand for methods to suppress gonadal function. In addition, prevention of unintended reproduction especially in feral horse populations may require methods for suppression of gonadal function. Surgical ovariectomy is a safe method but not an acceptable approach in feral mares and undesired in mares where future breeding is considered. There are different approaches for artificial prolongation of the luteal phase resulting in transient inhibition of oestrus and ovulation. Among those, treatment with natural...
Doyle JL, Carroll CJ, Corbally AF, Fahey AG.The breeding of sport horses to compete in the Olympic disciplines of show jumping, eventing, and dressage is fast becoming a global industry with the increased use of reproductive technologies, including artificial insemination and embryo transfer. Reproductive technologies have facilitated the dissemination of genetics from elite horses across multiple countries and breeds as breeders are no longer limited by location. Due to this increased level of crossbreeding, there is an increased need for estimated breeding values (EBVs) for sport horse performance that can be compared across breeds an...
Burns SJ, Westerman AG, Harrison LR.Mare Reproductive Loss Syndrome (MRLS) is the term given to abortions in mares associated with Eastern Tent caterpillars (ETC; Malacosoma americanum). This paper aims to examine if the hypothesis for a toxin as the cause of MRLS holds up to testing using Westerman's Correlates of Causal Strength of Evidence (WCCSE) and fits with known environmental factors that influence the occurrence of MRLS. Using WCCSE all correlates fit with a toxin as a potential causative agent. Environmental factors also fitted with this hypothesis. MRLS events were associated with higher than normal ambient temperatur...
Talluri TR, Kumaresan A, Paul N, Sinha MK, Ebenezer Samuel King JP, Elango K, Sharma A, Raval K, Legha RA, Pal Y.Seminal plasma proteins and pathways associated with sperm motility have not been elucidated in stallions. Therefore, in the current study, using the high throughput LC/MS-MS approach, we profiled stallion seminal plasma proteins and identified the proteins and pathways associated with sperm motility. Seminal plasma from six stallions producing semen with contrasting sperm motility ( = 3 each high-and low-motile group) was utilized for proteomic analysis. We identified a total of 1687 proteins in stallion seminal plasma, of which 1627 and 1496 proteins were expressed in high- (HM) and low-...
Smieszek A, Marcinkowska K, Pielok A, Sikora M, Valihrach L, Carnevale E, Marycz K.The study aimed to investigate the influence of obesity on cellular features of equine endometrial progenitor cells (Eca EPCs), including viability, proliferation capacity, mitochondrial metabolism, and oxidative homeostasis. Eca EPCs derived from non-obese (non-OB) and obese (OB) mares were characterized by cellular phenotype and multipotency. Obesity-induced changes in the activity of Eca EPCs include the decline of their proliferative activity, clonogenic potential, mitochondrial metabolism, and enhanced oxidative stress. Eca EPCs isolated from obese mares were characterized by an increased...
Claes A, Stout TAE.In vitro embryo production (IVEP) via Ovum Pick-Up (OPU) and Intracytoplasmic Sperm Injection (ICSI) has become a popular breeding technique in Warmblood mares because of the high success rate and several practical advantages. IVEP offers a solution for a variety of reproductive issues including, but not limited to, sub-fertility in stallions or mares, poor quality or scarce frozen semen, difficulty in synchronizing donor and recipient mares, and inefficient use of recipient mares. In 515 OPU-ICSI sessions performed in our facility in 2021, a mean of 25.9 antral follicles were aspirated yield...
Medica AJ, Gibb Z, Sheridan A, Harrison N, Aitken RJ.MTT is a commonly used cell vitality probe, due to its ability to form insoluble formazan deposits at cellular locations of intense oxidoreductase activity. Although this response is considered a reflection of mitochondrial redox activity, extra-mitochondrial sites of MTT reduction have been recognized within the spermatozoa of several mammalian species. Therefore, the aim of this study was to determine the major sites and causative mechanisms of MTT reduction in stallion spermatozoa. Our results show that stallion spermatozoa displayed substantial mitochondrial formazan deposition, as well as...
Bianchi CP, Bruno S, Videla Dorna I, Rodríguez E, Aba MA.In study I, plasma progesterone concentrations were evaluated in anoestrous mares that received an intravaginal progesterone release device (IPRD) for 10 days. Mares were divided into 3 groups based on the dosage of progesterone (0 g, n=3; 1.38 g, n=5; and 1.9 g, n=5). No statistical differences were found in plasma progesterone concentrations between the two doses tested. In study II, the effects of a protocol based on a short program of artificial light combined with an IPRD containing 1.38 g of progesterone on oestrous behaviour and onset of ovulation were evaluated. IPRDs were inserted int...
Macleay CM, Carrick J, Shearer P, Begg A, Stewart M, Heller J, Chicken C, Brookes VJ.Equine pregnancy loss is frustrating and costly for horse breeders. The reproductive efficiency of mares has significant implications for a breeding operation's economic success, and widespread losses can have a trickle-down effect on those communities that rely on equine breeding operations. Understanding the causes and risks of equine pregnancy loss is essential for developing prevention and management strategies to reduce the occurrence and impact on the horse breeding industry. This PRISMA-guided scoping review identified 514 records on equine pregnancy loss and described the global spatio...
Thieulent CJ, Carossino M, Balasuriya UBR, Graves K, Bailey E, Eberth J, Canisso IF, Andrews FM, Keowen ML, Go YY.Equine arteritis virus (EAV) is the causative agent of equine viral arteritis (EVA), a respiratory, systemic, and reproductive disease of equids. Following natural infection, up to 70% of the infected stallions can remain persistently infected over 1 year (long-term persistent infection [LTPI]) and shed EAV in their semen. Thus, the LTP-infected stallions play a pivotal role in maintaining and perpetuating EAV in the equine population. Previous studies identified equine C-X-C motif chemokine ligand 16 (CXCL16) as a critical host cell factor determining LTPI in the stallion's reproductive trac...
Pratt S, Bowen I, Hallowell G, Shipman E, Redpath A.Equine glandular gastric disease (EGGD) is a common condition causing signs of gastric pain although lesions are highly variable in their appearance. The only definitive method to diagnose EGGD ante-mortem is gastroscopy. The current recommended method for describing these lesions is the European College of Equine Internal Medicine (ECEIM) guidelines; however, repeatability between users is variable. This study aimed to validate the reliability of lesion descriptions using ECEIM consensus guidelines, using four blinded equine internal medicine diplomates. Ninety-two horses with EGGD with pre- ...
Peña FJ, O'Flaherty C, Ortiz Rodríguez JM, Martín Cano FE, Gaitskell-Phillips G, Gil MC, Ortega Ferrusola C.Significance: Proper functionality of the spermatozoa depends on the tight regulation of their redox status; at the same time these cells are highly energy demanding and in the energetic metabolism, principally in the electron transport chain in the mitochondria, reactive oxygen species are continuously produced, in addition to that observed in the Krebs cycle and during the β-oxidation of fatty acids. Recent Advances: In addition, in glycolysis, elimination of phosphate groups from glyceraldehyde 3-phosphate and dihydroxyacetone phosphate results in the byproducts glyoxal (G) and methylglyox...
Hernández-Avilés C, Castaneda C, Raudsepp T, Varner DD, Love CC.Acrosomal dysfunction has been considered as a cause of subfertility in males of different species, including stallions. A subset of subfertile stallions with acrosomal dysfunction is unique because they have normal sperm quality (motility, morphology, viability, and DNA quality). The current work aims to describe the clinical characteristics of subfertile stallions that were diagnosed with Impaired Acrosomal Exocytosis (IAE) by using two high throughput methods: flow cytometry and molecular genetic analysis, and to identify the prevalence of subfertility due to IAE in stallions evaluated at T...
Carvelli A, Nielsen SS, Paillot R, Broglia A, Kohnle L.Equine herpesvirus-1 (EHV-1) can affect the entire equine sector in EU, and the large outbreak reported in 2021 in Spain drew attention to the needs of the European Commission for scientific advice for the assessment of EHV-1 infection within the framework of Animal Health Law. EHV-1 is considered endemic in the EU; its main risk is linked to the characteristic of producing latent life-long infections. These can reactivate producing clinical disease, which can include respiratory, abortive and possibly fatal neurological forms. From the epidemiological and genomic viewpoint, there are no speci...
Knott LE, Fonseca-Martinez BA, O'Connor AM, Goodrich LR, McIlwraith CW, Colbath AC.To evaluate the use of mesenchymal stem cells (MSCs), autologous conditioned serum (ACS), platelet-rich plasma (PRP), and autologous protein solution (APS) for the treatment of equine musculoskeletal disease by diplomates of the American College of Veterinary Surgery (ACVS), and American College of Veterinary Sports Medicine and Rehabilitation (ACVSMR). Methods: Cross-sectional study. Methods: Diplomates (n = 423). Methods: An email link was sent to ACVS and ACVMR diplomates. A survey contained 59 questions regarding demographics, as well as indications, frequency, adverse effects, and limit...
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...
Lemonnier LC, Wolfsdorf KE, Kreutzfeldt N, Fedorka C, Chigerwe M, Bozorgmanesh R.Prognosis for life and future fertility in broodmares following hydrops is reportedly good, but evidence to support these reports is limited. The objective of this case series was to describe the prognosis for survival and fertility in mares presented to a referral hospital following diagnosis of hydrops. Medical records were reviewed to identify mares diagnosed with hydrops. Data collected included history (gestation, sire of the foal), clinical findings at presentation and throughout hospitalization (complications, treatments, survival to discharge) and future foaling rates. Thirty mares wer...
Renaudin CD, Kass PH, Bruyas JF.A table was generated, based on foetal ultrasonographic measurements in light breed mares, for each day of gestation beginning with day 100, to provide the predicted value of four biometric parameters: biparietal diameter (BPD), eye approximated volume (EyV), foetal aortic diameter (AortD) and femur length (FL). Using this table, day of gestation was successfully predicted in 23 Quarter Horses (QH) with known mating or ovulation dates. BPD, EyV and FL were the best foetal age predictors between 100- and 200-days gestation predicting within 2 weeks of the actual day of gestation, while BPD and...
Giaretta E, Mislei B, Martínez-Pastor F, Nesci S, Spinaci M, Galeati G, Nerozzi C, Mari G, Tamanini C, Bucci D.Equine spermatozoa highly rely on oxidative phosphorylation for their energy management. The present work aimed to characterize the role of mitochondria on horse sperm motility and ROS production by incubating spermatozoa with specific inhibitors of the different mitochondrial complexes. Equine spermatozoa were incubated 1 h and 3 h at 37 °C with: complex I inhibitor rotenone (5 μM, ROT), complex II inhibitor dimethyl-malonate (10 mM, DMM), complex III inhibitor antimycin A (1.8 μM, ANTI), the uncoupling agent carbonyl cyanide m-chlorophenyl hydrazine (5 μM, CCCP), ATP synthase inhi...
Diel de Amorim M, Klein C, Foster R, Dong L, Lopez-Rodriguez MF, Card C.Leucyl and cystinyl aminopeptidase (LNPEP/oxytocinase) is an enzyme that metabolizes oxytocin in serum and tissues. The presence of oxytocin/neurophysin I (OXT), oxytocin and LNPEP and their relationship to other genes is unknown in the equine conceptus. Our objective was to characterize gene expression of LNPEP and OXT on D8, 10, 12, 14, 15, 16 and 21 conceptuses in relationship to other genes. Immunohistochemistry, western blot and liquid chromatography with tandem mass spectrometry (LC-MS/MS) were used for identification of oxytocin and LNPEP in D15, 16 and 18 conceptuses. LNPEP was increas...
Jasko DJ, Little TV, Lein DH, Foote RH.Information pertaining to evaluation of single ejaculates of semen and records for 2 consecutive breeding seasons were obtained. In all, data for 99 individual breeding seasons (n = 43 Standardbreds and 56 Thoroughbreds) were evaluated. Included in each semen evaluation was examination of semen characteristics and computer-aided analysis of spermatozoal movement characteristics. On the basis of the analysis of breeding records for 4,175 mares (7,017 estrous cycles), a per-estrous cycle fertility rate was calculated from data for 96 of the breeding seasons. Stallions with lower fertility than t...
Abdelnaby EA, Emam IA, Salem NY, Ramadan ES, Khattab MS, Farghali HA, Abd El Kader NA.This study aimed to evaluate the use of Doppler ultrasound for determining alterations in uterine thickness and uterine arteries, use of chromohysteroscopy in evaluating endometritis with biopsies, and the impact of endometritis on oxidative and hormonal status. Twenty Arabian mares were divided into control and endometritis groups. Each underwent a physical examination, Doppler ultrasound, chromoendoscopy, and uterine biopsy. Blood samples from each animal were collected for hematologic, hormonal, and oxidative analysis. Results revealed a significant increase in estradiol, malondialdehyde (M...
Thompson RE, Meyers MA, Veeramachaneni DNR, Pukazhenthi BS, Hollinshead FK.Organoids are a type of three-dimensional (3D) cell culture that more closely mimic the in vivo environment and can be maintained in the long term. To date, oviductal organoids have only been reported in laboratory mice, women, and cattle. Equine oviductal organoids were generated and cultured for 42 days (including 3 passages and freeze-thawing at passage 1). Consistent with the reports in mouse and human oviductal organoids, the equine oviductal organoids revealed round cell clusters with a central lumen. Developing a 3D model of the mare oviduct may allow for an increased understanding of t...
Timoney PJ.Contagious equine metritis (CEM) is a highly contagious venereal infection of equids caused by Taylorella equigenitalis, a bacterium with fastidious growth requirements. A disease of major international concern, CEM can be the cause of short-term infertility and, very rarely, abortion in mares. Unlike the mare, stallions exposed to T. equigenitalis do not develop clinical signs of disease. CEM is transmitted by direct or indirect venereal contact. The carrier state occurs in the mare and the stallion and carrier animals are frequently the source of infection for new outbreaks of the disease. T...
Hanada M, Maeda Y, Oikawa MA.Uteri from 50 necropsied nonpregnant Japanese Thoroughbred brood mares (1-30 years of age) were investigated to clarify the histopathological characteristics of endometrosis in Japanese Thoroughbred mares and the distribution pattern of endometrosis lesions in the uterus as a whole. Endometrosis was observed in all animals over 6 years of age and in all of the 21 mares aged over 12 years of age. The affected mares showed elastofibrosis of arteries, veins and lymphatic vessels in the uterine wall, atrophy of the uterine smooth muscle layers and hyperplasia of collagen fibers among the smooth mu...
Gmel AI, Druml T, Portele K, von Niederhäusern R, Neuditschko M.Linear description (LD) of conformation traits was introduced in horse breeding to minimise subjectivity in scoring. However, recent studies have shown that LD traits show essentially the same problems as traditionally scored traits, such as data converging around the mean value with very small standard deviations. To improve the assessment of conformation traits of horses, we investigated the application of the recently described horse shape space model based upon 403 digitised photographs of 243 Franches-Montagnes (FM) stallions and extracted joint angles based on specific landmark triplets....
Crowe MW, Swerczek TW.In a 13-year survey of equine congenital defects that resulted in death or required euthanasia in central Kentucky, necropsies were performed on 608 deformed fetuses or newborn foals. The following congenital anomalies were observed: contracted foal syndrome (33.2%), miscellaneous limb contraction (20%), multiple defects (5.3%), microphthalmia (4.6%), craniofacial malformations (4.3%), cleft palate (4.0%), heart defects (3.5%), umbilical defects (3.5%), and hydrocephalus (3.0%). Eleven less frequently occurring anomalies constituted the balance of the congenital defects in fetuses and newborn ...
Turner RM, McDonnell SM.Significant amounts of alkaline phosphatase (AP) activity have been found in semen plasma from numerous species. In species in which the majority of semen plasma AP (SPAP) activity originates from the epididymis and testicle, SPAP activity can be used clinically as a marker to differentiate testicular origin azoospermia or oligospermia from ejaculatory failure. Information on SPAP activity in stallions to date has been limited. In this study, a standard clinical chemistry analyzer was used to determine AP activity in pre-ejaculatory fluid and ejaculates from groups of normal stallions. Additio...
Liu IK, Troedsson MH.Diagnosis and treatment of endometritis in the mare has been controversial and mostly empirical. The lack or inability of researchers to establish or develop a model that can serve as a standard or control makes this area of equine reproduction difficult to address scientifically. However, major advances have been made, particularly with the demonstration of the importance of uterine contractility in the elimination of bacteria, fluid, and inflammatory products from the uterus after breeding. This review provides a historical perspective of what has been done, and where we are now, in the appr...
Díaz-Bertrana ML, Deleuze S, Pitti Rios L, Yeste M, Morales Fariña I, Rivera Del Alamo MM.Endometritis is one of the main causes of infertility in mares. In the present study, 363 mares with a history of repetitive infertility, and positive endometrial cytology and/or vaginal discharge were included. An endometrial swab for microbiological purposes plus sensitivity test was obtained from each mare. A positive culture was obtained in 89% of mares. The main isolated genera were (25.1%), (18.2%), (17.3%) and (12.1%). With regard to species, the most isolated microorganism was (17.3%), spp. (15.6%) and spp. (13.5%). Sensitivity tests showed that the most efficient antimicrobial ...
Imboden I, Janett F, Burger D, Crowe MA, Hässig M, Thun R.The aim of this study was to evaluate the effect of active immunization against GnRH on ovarian activity, plasma progesterone and estradiol concentrations and on estrous behavior in adult mares. Eighteen cyclic mares were randomly divided into a treatment and control group. Nine mares were immunized twice with 2 mL (400 microg GnRH-protein conjugate) of a GnRH-vaccine (Improvac, CSL Limited, Australia) administered intramuscularly, 4 weeks apart. Control mares received the same amount of saline solution. Ovaries and uterus of all mares were examined weekly by ultrasonography from 3 weeks befor...
LeBlanc MM, Neuwirth L, Asbury AC, Tran T, Mauragis D, Klapstein E.The percentage of Technetium 99m-albumin colloid (99mTc-microAA), a radiocolloid, cleared from the uterine lumen within 4 h of intrauterine infusion, was measured in 15 mares during 2 consecutive cycles, on Day 3 of oestrus and 48 h after ovulation. Four nulliparous (Group 1) and 4 multiparous (Group 2) mares were classified as resistant and the remaining 7 multiparous mares were classified as susceptible (Group 3) to endometritis. Mares in Groups 1 and 2 cleared more 99mTc-microAA from their uteri than did mares in Group 3 during oestrus (P < 0.01) and 48 h after ovulation (P 50% of the c...
Livolant F.The fine structure of chromatin in sperm heads was investigated by different microscopic techniques: in vivo examinations in the polarizing microscope, thin sections and freeze-fracture replicas observed by transmission electron microscopy. The freeze-fractured chromatin appears to be formed of superimposed lamellae, each one 330 A thick. These lamellae are parallel to the flattening plane of the sperm head. This situation was already described in other mammal spermatozoa and in particular in the bull and the rabbit. This work presents a new interpretation of this lamellated aspect. The chroma...
Stout TA.The first month of equine pregnancy covers a period of rapid growth and development, during which the single-cell zygote metamorphoses into an embryo with a functional circulation and precursors of many important organs, enclosed within extraembryonic membranes responsible for nutrient uptake and gaseous exchange. After exiting the oviduct, the conceptus must influence uterine physiology to ensure adequate nutrition and preparation for implantation, while continued development results in the chorioallantois superseding the yolk sac as the primary interface for maternal interaction and exchange...
Kaneene JB, Ross WA, Miller R.A prospective study was designed to document the frequencies of equine health problems in the state of Michigan, USA. A total of 2469 horses from a random sample of 138 equine operations were monitored in the study in two 12-month periods: 1992-1993 and 1993-1994. All the major breeds of horses in the state were proportionately represented in the sample. Using weighted annual incidence densities as measures of disease frequencies, the 10 most frequently observed groups of health problems were (from most to least frequent) leg lameness, dermatological problems, respiratory problems, hoof and fo...
Nambo Y, Kaneko H, Nagata S, Oikawa M, Yoshihara T, Nagamine N, Watanabe G, Taya K.Physiological roles of inhibin in mares were investigated by means of passive immunization using an antiserum to inhibin that had been raised in a castrated goat. Eight mares were given an intravenous injection of either 100 mL (n = 4) or 200 mL (n = 4) of inhibin antiserum 4 d after a single intramuscular injection of PGF2 alpha on Day 8 after ovulation, 4 control mares were treated with 100 mL castrated goat serum in the same manner. Jugular vein blood samples were collected after treatment with the serum until 192 h post treatment. Follicular growth and ovulations were monitored by ultrasou...
Bolaños JM, Morán AM, da Silva CM, Dávila MP, Muñoz PM, Aparicio IM, Tapia JA, Ferrusola CO, Peña FJ.To investigate the role of the processed autophagy marker light chain 3 (LC3B) protein in sperm survival in stallion semen processing during cooled storage, split ejaculates were diluted in two different extenders, KMT and INRA 96, and LC3B processing and sperm quality evaluated during incubation at 5°C for five days. After 3 days of incubation there was a drop in total motility in both extenders, although the percentage of progressive motile sperm was greater (P<0.05) in samples extended in INRA96. On Day 5 of cooled storage all sperm parameters decreased significantly independent of the ...
Fowden AL, Forhead AJ, Ousey JC.In adapting to life ex utero, the foal encounters a number of physiological challenges. It has to assume the nutritional, respiratory and excretory functions of the placenta and activate full regulatory control over its own internal environment for the first time. To achieve this, there must be structural and functional changes to a wide range of tissues including several endocrine glands. In most species, including the horse, these maturational changes begin in late gestation and continue into the first few days of neonatal life. Consequently, during this perinatal period, there are major cha...
Balasuriya UBR, Hedges JF, Nadler SA, McCollum WH, Timoney PJ, MacLachlan NJ.An imported carrier stallion (A) from Europe was implicated in causing an extensive outbreak of equine viral arteritis (EVA) on a Warmblood breeding farm in Pennsylvania, USA. Strains of equine arteritis virus (EAV) present in the semen of two carrier stallions (A and G) on the farm were compared to those in tissues of foals born during the outbreak, as well as viruses present in the semen of two other stallions that became persistently infected carriers of EAV following infection during the outbreak. The 2822 bp segment encompassing ORFs 2-7 (nt 9807-12628; which encode the G(S), GP3, GP4, G(...
de Mestre AM, Miller D, Roberson MS, Liford J, Chizmar LC, McLaughlin KE, Antczak DF.The objective of this study was to identify transcription factors associated with differentiation of the chorionic girdle, the invasive form of equine trophoblast. The expression patterns of five transcription factors were determined on a panel of conceptus tissues from early horse pregnancy. Tissues from Days 15 through 46 were tested. Eomesodermin (EOMES), glial cells missing homologue 1 (GCM1), heart and neural crest derivatives expressed transcript 1 (HAND1), caudal type homeobox 2 (CDX2), and distal-less homeobox 3 (DLX3) were detected in horse trophoblast, but the expression patterns for...
Donahue JM, Williams NM.The clinical signs, laboratory findings, diagnosis, epidemiology, treatment, and prevention and control of two emerging causes of placentitis and abortion in horses are described in this article. Leptospirosis has been reported as a significant cause of fetal loss in horses in Kentucky, Northern Ireland, and England. Most abortions result from infection by serovars kennewicki or bratislava. Nocardioform placentitis has become the most common cause of placentitis in central Kentucky horses. Nocardioform placentitis is associated with infection by unnamed, gram-positive, filamentous, branching b...
Wilsher S, Clutton-Brock A, Allen WR.A total of 78 day 10 horse embryos were transferred non-surgically to recipient mares that had ovulated 9, 7, 6, 5, 4, 3, 2 or 1 day after (negative asynchrony), on the same day (synchronous), or 2 or 4 days before (positive asynchrony) the donor (n=6 or 8 mares per group). Pregnancy rates between 100% (6/6) and 63% (5/8) were seen in recipient mares that were between +2 and -6 days asynchronous. Embryo survival to the heartbeat stage declined in recipients that were -7 days asynchronous and no embryos survived in recipients that were -9 days asynchronous. Irrespective of uterine asynchrony, c...
The Journal of physiologyNovember 15, 2002
Volume 547, Issue Pt 1 67-76 doi: 10.1113/jphysiol.2002.027409
Giussani DA, Forhead AJ, Gardner DS, Fletcher AJ, Allen WR, Fowden AL.This study used between-breed embryo transfer in the horse to investigate the effects of maternal size and uterine capacity on fetal growth and postnatal cardiovascular and neuroendocrine functions. Equine embryos were transferred to establish eight Thoroughbred-in-Thoroughbred (TinT), seven Pony-in-Pony (PinP), five Thoroughbred-in-Pony (TinP) and eight Pony-in-Thoroughbred (PinT), pregnancies. Maternal and foal weights and placental microscopic area were measured at birth. At 6 days of postnatal life, arterial blood pressure and heart rate were monitored and blood samples were taken for horm...
Al-Kass Z, Guo Y, Vinnere Pettersson O, Niazi A, Morrell JM.Bacteria colonize stallion semen during collection and processing which may cause disease in inseminated females or negatively affect sperm quality during storage prior to insemination. Antibiotics are added to semen extenders to control the growth of these bacteria but may induce antimicrobial resistance. Research into alternatives to antibiotics for this purpose requires knowledge of which bacteria are present in semen. Not all bacteria in semen, however, can be identified by conventional microbiological techniques. The objectives of the study were to: i) determine which bacteria are present...
Martin Muñoz P, Ortega Ferrusola C, Vizuete G, Plaza Dávila M, Rodriguez Martinez H, Peña FJ.Oxidative stress has been linked to sperm death and the accelerated senescence of cryopreserved spermatozoa. However, the molecular mechanisms behind this phenomenon remain poorly understood. Reactive oxygen species (ROS) are considered relevant signaling molecules for sperm function, only becoming detrimental when ROS homeostasis is lost. We hereby hypothesize that a major component of the alteration of ROS homeostasis in cryopreserved spermatozoa is the exhaustion of intrinsic antioxidant defense mechanisms. To test this hypothesis, semen from seven stallions was frozen using a standard tech...
Science (New York, N.Y.)April 16, 1965
Volume 148, Issue 3668 382-383 doi: 10.1126/science.148.3668.382
BENIRSCHKE K, MALOUF N, LOW RJ, HECK H.The chromosome number of the domestic horse is 2n = 64; different races have the same complement. The chromosomes of two Przewalski's horses (at Catskill Game Farm, New York), presumably ancestral wild horses from Mongolia, are identical: 2n = 66, with more acrocentric and fewer metacentric elements than the chromosomes of the domestic horse. This apparent difference in karyotype may help resolve the questions of "purity" in the relatively few remaining Przewalski's horses. Moreover, these findings are of interest in relation to the apparent fertility of hybrids between these species.
Schuh EM, Friedman MS, Carrade DD, Li J, Heeke D, Oyserman SM, Galuppo LD, Lara DJ, Walker NJ, Ferraro GL, Owens SD, Borjesson DL.OBJECTIVE-To optimize the isolation and culture of mesenchymal stem cells (MSCs) from umbilical-cord blood (UCB), identify variables that predicted successful MSC isolation, and determine whether shipping, processing, and cryopreservation altered MSC viability, recovery rates, and expansion kinetics. SAMPLE POPULATION-UCB samples from 79 Thoroughbred and Quarter Horse mares. PROCEDURES-UCB samples were processed to reduce volume and remove RBCs. Nucleated cells (NCs) were cryopreserved or grown in various culture conditions to optimize MSC monolayer expansion and proliferation. Donor and UCB-s...
Vandenberghe E, Boshuizen B, Delesalle CJG, Goehring LS, Groome KA, van Maanen K, de Bruijn CM.In May 2018, Wolvega Equine Hospital (WEH) experienced an EHV-1 outbreak. This outbreak caused significant economic losses and negative publicity for the hospital. How should hospitals prepare themselves for these outbreaks and prevent shedding of the virus on multiple neighboring premises? The hospital transformed most of its activities into mobile practice and the entire infected hospital population was moved to a separate remote location. The hospital was cleaned and disinfected according to the latest recommendations before reopening. Four neighboring professional equine businesses and thr...
