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.
Ross KA, Kolb DS, Macedo A, Anderson M, Klein C.This study tested the hypothesis that the presence of prostaglandin E2 in seminal plasma would aid in the transport of phenolsulfonphthalein (PSP) across the uterotubal junction. Five mares in estrus were inseminated during estrus with PSP dissolved in phosphate-buffered saline and during the subsequent estrus with PSP added to a standard insemination dose. Serum and urine samples were obtained at hours 0, 1, 2, and 3 following treatment and examined for the presence of PSP. Phenolsulfonphthalein could not be detected in any of the urine samples collected from mares following either treatment....
Vincze B, Solymosi N, Debnár V, Kútvölgyi G, Krikó E, Wölfling A, Szenci O.Alpha-fetoprotein (AFP) is best known in human obstetrics for its association with fetal anomalies recognized in the 1970s. Although this fetal protein had been shown to be present in the sera of many mammalian species, its possible diagnostic role in the detection of abnormalities was evaluated only later, when a research laboratory published variable levels of AFP in different groups of mares with pregnancy problems (twins, conception failure, placentitis, embryonic loss), and subsequently differences were demonstrated in its serum levels between aborted and healthy mares. In this study, per...
Wynn MAA, Ball BA, May J, Esteller-Vico A, Canisso I, Squires E, Troedsson M.The objectives of this study were to compare via liquid chromatography-tandem mass spectrometry (LC-MS/MS) progesterone (P4), 5α-dihydroprogesterone (DHP), allopregnanolone, 3β-hydroxy-5α-pregnan-20-one (3β5P), 20α-hydroxy-5α-pregnan-3-one (20α5P), 5α-pregnan-3β,20α-diol (βα-diol), and 5α-pregnan-3β,20β-diol (ββ-diol) concentrations in plasma of mares with experimentally-induced, ascending placentitis compared to gestationally age-matched control mares. Placentitis was induced via intracervical inoculation of Streptococcus equi spp. zooepidemicus between 260 and 280 days of ge...
Vera L, Boyen F, de Visscher A, Vandenbroucke V, Vanantwerpen G, Govaere J.The use of commercial chromogenic agar plates for the rapid, easy and correct identification of equine endometritis-causing bacteria has been proposed. Preliminary tests in our lab revealed undescribed limitations. Therefore, we tested the ability of the Brilliance UTI agar, a commercially available chromogenic agar, to accurately identify bacteria causing equine endometritis. Objective: To 1) investigate whether bacteria present in the equine uterus are able to grow on this chromogenic agar plate, 2) determine whether these bacteria belong to the genera for which these agar plates were origin...
Hernández-Avilés C, Serafini R, Love CC, Teague SR, LaCaze KA, Lawhon SD, Wu J, Blanchard TL, Varner DD.Two experiments were conducted to evaluate the effects of antibiotic-containing extender of on sperm quality and control of bacterial growth. In Experiment 1, ejaculates were diluted in extender containing no antibiotics, potassium penicillin G-amikacin disulfate (PEN-AMIK), ticarcillin disodium-potassium clavulanate (TICAR-CLAV), piperacillin sodium/tazobactam sodium (PIP-TAZ), or meropenem (MERO). In freshly extended semen, only slight differences were detected among some antibiotic treatments for total sperm motility, curvilinear velocity, and viable acrosome-intact sperm (P < 0.05)....
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....
Lean NE, Ahern BJ.Mycotic rhinitis is a rare disease in horses, with few cases reported worldwide and none reported in Australia. Fungal infection of the upper respiratory tract can occur in all species, but its prevalence in horses is considerably lower than in canines or humans. The disease is linked to a variety of pathogens and the clinical signs are associated with subsequent upper respiratory tract damage. Methods: A 6-year-old Quarter Horse gelding in Queensland, Australia, was presented with chronic nasal discharge and dyspnoea following previous unsuccessful medical treatment of 9 months' duration. C...
Daglish J, Frisbie DD, Selberg KT, Barrett MF.High field magnetic resonance imaging (MRI) is increasingly used for horses with suspected stifle disease, however there is limited available information on normal imaging anatomy and potential incidental findings. The aim of this prospective, anatomic study was to develop an optimized high field MRI protocol for evaluation of the equine stifle and provide detailed descriptions of the normal MRI appearance of the stifle soft tissues, using ultrasound and gross pathological examination as comparison tests. Nine cadaver limbs were acquired from clinically normal horses. Stifles were evaluated ul...
Bechert U, Rohde J, Freer H, Wagner B.SpayVac is an immunocontraceptive vaccine based on porcine zona pellucida (pZP) antigens and uses a patented liposome formulation (VacciMax or DepoVax). It has delivered single-dose, long-lasting (4-10 years) immunocontraception in several species. Previous studies have demonstrated a positive correlation between levels of pZP antibodies produced and contraceptive effect; however, individual mares that were consistently infertile did not necessarily have the highest antibody titers. The objective of this study was to identify potential differences in specific immunoglobulin G (IgG) isotype res...
Vieira GS, Paludo GR, Ramos AF, Pivato I, de Oliveira RA.For a long time, Pantaneiro and Campeiro breeds were raised only within their places of origin. Consequently, there are few of these horses; therefore, establishing reproductive and clinical standards for these animals is necessary to implant new biotechnologies for reproduction to preserve their genetics. This study aimed to perform a descriptive evaluation of fetal age determination by fetus ocular orbit measurement in mares of the Campeiro and Pantaneiro breeds. We also evaluated sequential changes in hematology and biochemistry for foals from birth to six months of life by counting red blo...
Koziorowska-Gilun M, Gilun P, Mietelska K, Kordan W.The key prerequisite for successful insemination is sperm characterized to have positive values for morphological and biological variables which are determined by, among others, effective antioxidant protection during the lifespan of sperm cells. This study evaluated the activity and relative abundance of mRNA for antioxidant enzymes in stallion testicular and epididymal tissues during breeding (n = 5) and non-breeding (n = 5) seasons. The activity of superoxide dismutase (SOD) was greater (P < 0.05) during the breeding season, in particular in the testes and the caput epididymis, ...
Rizzo M, Ducheyne KD, Deelen C, Beitsma M, Cristarella S, Quartuccio M, Stout TAE, de Ruijter-Villani M.Advanced mare age is associated with declining fertility and an increased risk of early pregnancy loss. Compromised oocyte quality is probably the primary reason for reduced fertility, but the defects predisposing to embryonic death are unknown. In women, advanced age predisposes to chromosome segregation errors during meiosis, which lead to embryonic aneuploidy and a heightened risk of miscarriage. Objective: To evaluate the effect of advanced mare age on chromosome alignment and meiotic spindle morphology in in vitro-matured (IVM) oocytes. Methods: Morphometric and morphological analysis. M...
Badial PR, Teixeira RBC, Delfiol DJZ, da Mota LSLS, Borges AS.Overo lethal white foal syndrome (OLWFS) is a genetic disorder caused by a dinucleotide mutation in the endothelin receptor type B (EDNRB) gene leading to the death of affected foals shortly after birth. The use of rapid and reliable genetic testing is imperative for the early diagnosis of the mutation avoiding, therefore, either additional suffering or the production of affected animals. In the present study, we developed and validated a high-resolution melting (HRM) genotyping assay to detect the OLWFS causative mutation, and we also determined the frequency of heterozygotes among American P...
Młodawska W, Grzesiak M, Kochan J, Nowak A.Steroidogenic activity in the equine ovary from birth to puberty has been poorly investigated. This study aimed to examine the capability of the ovarian follicles of prepubertal and pubertal fillies to produce steroid hormones and to evaluate the expression and cellular localization of androgen receptor (AR) in their ovaries. The ovaries of 6-18 month-old fillies were divided into two groups: prepubertal (PrP) - without preovulatory follicle (pF) and corpus luteum (CL), and ovulating/postpubertal (Ov/pB) - with pF and/or CL in at least one of the gonads. Adult mares (Me) were used as a control...
Nolan MB, Bertschinger HJ, Roth R, Crampton M, Martins IS, Fosgate GT, Stout TA, Schulman ML.An important determinant in the selection of any contraceptive agent is the impact on ovarian function, both in the short and longer term. In this study, ovarian activity was monitored in mares immunised with one of the following vaccine formulations; native porcine zona pellucida (pZP), recombinant zona pellucida proteins ZP3 and ZP4 (reZP), pZP and reZP combined or a commercially available anti-GnRH vaccine. The ZP antigens were prepared in an adjuvant formulation consisting of 6% polymeric adjuvant (Montanide™ PetGel A, Seppic, France) and 500 μg polyinosinic-polycytidylic acid - TLR3-...
Baker DL, Powers JG, Ransom JI, McCann BE, Oehler MW, Bruemmer JE, Galloway NL, Eckery DC, Nett TM.Wildlife and humans are increasingly competing for resources worldwide, and a diverse, innovative, and effective set of management tools is needed. Controlling abundance of wildlife species that are simultaneously protected, abundant, competitive for resources, and in conflict with some stakeholders but beloved by others, is a daunting challenge. Free-ranging horses (Equus caballus) present such a conundrum and managers struggle for effective tools for regulating their abundance. Controlling reproduction of female horses presents a potential alternative. During 2009-2017, we determined the lon...
Hartmann C, Lidauer L, Aurich J, Aurich C, Nagel C.Observation of preparturient mares is labour-intensive and time requirements would be reduced with automated monitoring systems. Recently, small-size accelerometers have become available. We followed the hypothesis that increased restlessness in mares shortly before the expulsive stage of labour can be detected with such accelerometers. Accelerometers were attached medioventrally to the halter of eight late pregnant mares. To evaluate an influence of accelerometer position, in one mare two additional accelerometers were attached close to the mandibular and atlanto-occipital joints. Acceleromet...
Ferreira-Silva JC, Basto SRL, Moura MT, Rocha JM, Freitas Neto LM, Santos Filho JP, Silva Filho ML, Oliveira MAL.The work described here aimed to verify the efficiency of different extenders for cryopreservation of equine semen using sperm motility and acrosin activity as spermatic parameters. The semen was fractioned into two equal parts and resuspended in an 11% lactose solution in a 1:1 proportion, where it remained for 20 minutes at room temperature. The semen was centrifuged at 600 g for 10 minutes, and after the second centrifugation, each pellet received the freezing extender (Merck or Zorlesco) and was loaded into 4 mL straws. Each straw was placed in liquid nitrogen vapor steam for 15 minutes ...
Ishak GM, Bashir ST, Dutra GA, Gastal GDA, Gastal MO, Cavinder CA, Feugang JM, Gastal EL.In vivo studies involving molecular markers of the follicle wall associated with follicular fluid (FF) milieu are crucial for a better understanding of follicle dynamics. The inability to obtain in vivo samples of antral follicle wall (granulosa and theca cells) without jeopardizing ovarian function has restricted advancement in knowledge of folliculogenesis in several species. The purpose of this study in mares was to develop and validate a novel, minimally invasive in vivo technique for simultaneous collection of follicle wall biopsy (FWB) and FF samples, and repeated collection from the sam...
Janečka JE, Davis BW, Ghosh S, Paria N, Das PJ, Orlando L, Schubert M, Nielsen MK, Stout TAE, Brashear W, Li G, Johnson CD, Metz RP, Zadjali AMA....Dynamic evolutionary processes and complex structure make the Y chromosome among the most diverse and least understood regions in mammalian genomes. Here, we present an annotated assembly of the male specific region of the horse Y chromosome (eMSY), representing the first comprehensive Y assembly in odd-toed ungulates. The eMSY comprises single-copy, equine specific multi-copy, PAR transposed, and novel ampliconic sequence classes. The eMSY gene density approaches that of autosomes with the highest number of retained X-Y gametologs recorded in eutherians, in addition to novel Y-born and transp...
Quercia S, Freccero F, Castagnetti C, Soverini M, Turroni S, Biagi E, Rampelli S, Lanci A, Mariella J, Chinellato E, Brigidi P, Candela M.Even if horses strictly depend on the gut microbiota for energy homeostasis, only a few molecular studies have focused on its characterisation and none on the perinatal gut microbial colonisation process. Objective: To explore the perinatal colonisation process of the foal gut microbial ecosystem and the temporal dynamics of the ecosystem assembly during the first days of life. Methods: Longitudinal study. Methods: Thirteen Standardbred mare-foal pairs were included in the study. For each pair, at delivery we collected the mare amniotic fluid, faeces and colostrum, and the foal meconium. Milk ...
Sampaio BFB, Nogueira BG, Souza MIL, Silva EVDCE, Zúccari CESN.The aim of this experiment was to evaluate the effects of adding ascorbic acid 2-glucoside (AA2G), a water-soluble antioxidant and stable derivative of ascorbate, to the semen extender and compare it to the addition of vitamin C (Vit. C) and the fat-soluble antioxidant α-tocopherol (α-Toh), both individually and in combination, on the seminal variables of equine sperm submitted to cooling for 72 h. We used two ejaculates from 10 stallions and evaluated them for motility, membrane integrity, chromatin fragmentation, mitochondrial activity and lipid peroxidation. In the analysis of lipid pero...
Annandale A, Stroehle RM, Schulman ML, Sibeko-Matjila KP, Fosgate GT, Handler J, Vemming DC, Clift SJ.Persistent breeding-induced endometritis (PBIE) or delayed uterine clearance (DUC) are major causes of mare subfertility. Oxytocin and its receptor are thought to play significant roles in the pathogenesis of DUC but the specific roles of oxytocin receptor (OR) distribution and gene expression remain undefined. In this study both OR distribution and gene expression in the endometrium, myometrium and cervix during both luteal and non-luteal phases in non-pregnant mares (n = 27) of differing age (young: 2-9 years, n = 17; old: > 10 years, n = 10) and endometrial biopsy score were ...
Bogle OA, Carrasco RA, Ratto MH, Singh J, Adams GP.The objectives of the study were to compare the presence and localization of ovulation-inducing factor (OIF)/nerve growth factor (NGF) in male reproductive organs and determine the abundance in ejaculates of species representative of both spontaneous and induced ovulators. We hypothesized that the protein is a widely conserved component of semen among mammals, but is most abundant in camelids. Immunohistochemical analysis was performed on tissues from the male reproductive system of llamas, rats, cattle, bison, elk, and white-tailed deer (n = 2 males/species), and the abundance of OIF/NGF in...
Wu S, Canisso IF, Yang W, Ul Haq I, Liu Q, Han Y, Zeng S.This study aimed to investigate the effects of different concentrations of 1,2-bis-(o-aminophenoxy)-ethane-N,N,N0 N0-tetraacetic acid, tetra-acetoxymethyl ester (BAPTA-AM), an intracellular calcium chelating agent, on stallion semen cooling and freezing-thawing. After collection, semen was extended (1:1 v/v) on a skim milk-based extender, centrifuged and resuspended at 400 million/ml into cooling or freezing extenders containing 0, 5, 25, 50, 100 and 200 μΜ BAPTA-AM. Motility parameters were assessed after cooling in Equitainer at 5°C for 12, 24, 48, 72 and 120 hr and after freezing-tha...
Kimura Y, Sasaki M, Watanabe K, Dhakal P, Sato F, Taya K, Nambo Y.Activin is secreted from equine uterine glands and plays important roles in establishment and maintenance of pregnancy in mares. This study aimed to localize activin receptors (ActRs) IA/B and IIA/B using immunohistochemistry in the uteroplacental tissues of seven pregnant Thoroughbred mares. At the time of tissue collection, the mares were at the following days of pregnancy: 88, 120, 161, 269, 290, 313, and 335 days. We fixed the uteroplacental tissues in 4% paraformaldehyde and obtained serial sections that were subsequently stained for analysis. All four isoforms of ActR were expressed in t...
Gonzalez-Castro RA, Carnevale EM.Limited clinical information is available regarding sperm population parameters that are important for use with equine intracytoplasmic sperm injection (ICSI). Therefore, the appropriateness of a sample of sperm is typically not known before ICSI. The aim of our study was to determine which sperm population characteristics were predictive of ICSI outcome. Frozen-thawed sperm samples (n = 114) from 37 stallions in a clinical program were analyzed after ICSI for percentages of normal morphology (MORPH+), live as assessed by eosin/nigrosin stain (LIVE+), membrane intact as assessed by hypoosmot...
Liu LL, Fang C, Liu WJ.The utility of high-density single nucleotide polymorphism (SNP) data help to accurately identify genomic regions that have undergone positive selection. In this study, the Affymetrix Equine 670 K high-density SNP array was used to genotype Kazakh and Yili horse population. After quality control, 370,227 autosomal SNPs were used to detect selection signatures by using global fixation index (F) and cross-population extended haplotype homozygosity (XP-EHH). The database of Ensemble, Genecards, and NCBI were used to make gene annotation and functional analysis. The results showed that there wer...
Müller V, Curcio BR, Toribio RE, Feijó LS, Borba LA, Canisso IF, Nogueira CEW.This study aimed to evaluate steroid hormones in foals born from mares treated for ascending placentitis with different combinations of trimethoprim-sulfamethoxazole (TMS), flunixin meglumine (FM), long-acting altrenogest (ALT) and estradiol cypionate (ECP) for ten consecutive days, starting two days after experimental induction of placentitis with Streptococcus zooepidemicus. Fourty-six pregnant mares and respective foals were assigned as healthy group (Control, n = 8) or treated groups as follows: TMS+FM (n = 8), TMS+FM+ALT (n = 8), TMS+FM+ALT+ECP (n = 6), TMS+FM+ECP (n = 6) and no...
Hidalgo M, Consuegra C, Dorado J, Diaz-Jimenez M, Ortiz I, Pereira B, Sanchez R, Crespo F.Vitrification is based on rapid freezing by direct exposure of sperm to liquid nitrogen (LN). This study evaluated the effect of non-permeable CPAs and equilibration temperature on stallion sperm quality after vitrification. In Experiment 1, different concentrations of sucrose (20, 50, 100 mM; mmol/L) and bovine serum albumin (BSA 1%, 5%, 10%) were compared including different temperatures for the equilibration (≈22 °C or 5 °C). Vitrification was performed dropping 30 μl sperm suspension directly into LN In Experiment 2, conventional sperm freezing using 2.2% of glycerol in 0.5 ...
Cope SE, Catts EP.Parahost behavior of adult Gasterophilus intestinalis (DeGeer) was observed during the summers of 1978 and 1979 near pastured horses on two farms near Newark, Del. Adult fly occurrence, although sparse in early summer, indicated a gradual increase, with three surges in emergence. In the laboratory, males lived 1-3 d and females 1-2 d. In the field, marked flies were not seen on days following their release. Adult behavior indicated an urgency in mating and oviposition dictated by a short life span. Male flight patterns were characterized by in-flight searches for females and intraspecific conf...
Adams AP, Oriol JG, Campbell RE, Oppenheim YC, Allen WR, Antczak DF.This research tested the hypothesis that immunological sensitization of mares by skin allografting, followed by the establishment of pregnancy using semen from the skin-graft donor, would give rise to secondary immune responses to the developing horse conceptus, resulting in an earlier demise of the fetally derived endometrial cups. Maiden mares received skin allografts from a stallion homozygous for Major Histocompatibility Complex (MHC) antigens and/or equivalent autografts and were subsequently mated to the skin-graft donor stallion during the next two breeding seasons. Mares that had been ...
de Andrade AF, Zaffalon FG, Celeghini EC, Nascimento J, Tarragó OF, Martins SM, Alonso MA, Arruda RP.Effect of seminal plasma addition after thawing on viability or cryocapacitation is not definitively established. This experiment was performed to verify the effect of adding seminal plasma, autologous or homologous (from an animal with good semen freezability). Five ejaculates from each of four stallions with proven fertility were collected and cryopreserved. The semen was subsequently thawed and divided into the following three treatment groups: no seminal plasma addition after semen thawing (NOSP); the addition of homologous seminal plasma after semen thawing (HSP) and the addition of autol...
Ginther OJ.Prolonged luteal activity is one of the most formidable terminology challenges in mare reproductive biology. Prolonged luteal activity can be a result of persistence of an individual corpus luteum or the sequential development of luteal glands, each of which may have a normal life span. Luteal tissue can originate from an unovulated follicle or from an ovulation occurring during either follicular or luteal dominance. These complexities, together with ambiguous and inconsistent terminology, have resulted in confusion regarding those conditions which can be grouped broadly under the term prolong...
Donadeu FX, Watson ED.The annual reproductive cycle in the horse involves a reduction in ovarian activity during short days. The absence of ovulatory activity during winter has important consequences for an equine industry eager to breed mares early during the year. The anovulatory season results from a reduction in the secretion of pituitary gonadotropin that is in turn triggered by the inhibitory effects of short photoperiod on the hypothalamus-pituitary axis. Recent studies have provided evidence that the response of the ovaries to endocrine stimuli during the anovulatory season is affected not only by circulati...
Proft A, Spiesschaert B, Izume S, Taferner S, Lehmann MJ, Azab W.The serine-threonine protein kinase encoded by gene (pUS3) of alphaherpesviruses was shown to modulate actin reorganization, cell-to-cell spread, and virus egress in a number of virus species. However, the role of the US3 orthologues of equine herpesvirus type 1 and 4 (EHV-1 and EHV-4) has not yet been studied. Here, we show that is not essential for virus replication in vitro. However, growth rates and plaque diameters of a -deleted EHV-1 and a mutant in which the catalytic active site was destroyed were significantly reduced when compared with parental and revertant viruses or a virus in w...
Brogan PT, Beitsma M, Henning H, Gadella BM, Stout TA.Short-term storage of equine sperm at 5°C in an extender containing milk and/or egg yolk components is common practice in the equine breeding industry. Sperm motility, viability, DNA integrity and, consequently, fertilizing ability decline over time, partly due to reactive oxygen species (ROS) generation. We investigated whether adding the anti-oxidant d-penicillamine to a commercial milk/egg yolk extender delayed the decrease in semen quality. Semen was recovered on four consecutive days from eight 3-year old Warmblood stallions. On day 5, seven of the stallions were castrated and sperm reco...
Albrizio M, Moramarco AM, Nicassio M, Micera E, Zarrilli A, Lacalandra GM.It is well known that insemination of cryopreserved semen always results in lower fertility when compared with fresh semen, but there is an increased interest and demand for frozen equine semen by the major breeder associations because of the utility arising from semen already "on hand" at breeding time. In this article, we report that equine sperm cells express L-type voltage-gated calcium channels; their localization is restricted to sperm neck and to the principal piece of the tail in both fresh and frozen-thawed spermatozoa. We also studied the causes of cryoinjury at the membrane level fo...
Sikora M, Król J, Nowak M, Stefaniak T, Aubertsson G, Kozdrowski R.Endometritis is a common problem in a broodmare practice, often leading to infertility. The diagnosis is based on several methods such as cytology, bacteriology and histopathology; however the outcome of these methods may be inconclusive even when used together. The objectives of this study were: (1) to investigate the usefulness of acute phase proteins as an additional diagnostic tool for diagnosis of subclinical endometritis in mares and (2) to evaluate the association between macroscopic changes in uterine flushes and inflammation of the uterus. Materials were collected from 53 Icelandic ma...
Pereira GR, Lorenzo PL, Carneiro GF, Bilodeau-Goeseels S, Kastelic JP, Esteller-Vico A, Lopez-Bejar M, Liu IK.Immature oocytes synthesize a variety of proteins that include the enzyme glucose-6-phosphate dehydrogenase (G6PDH). Brilliant cresyl blue (BCB) is a vital blue dye that assesses intracellular activity of G6PDH, an indirect measure of oocyte maturation. The objective was to evaluate the BCB test as a criterion to assess developmental competence of equine oocytes and to determine if equine growth hormone (eGH) enhanced in vitro maturation (IVM) of equine oocyte. Cumulus-oocytes complexes (COCs) were recovered by aspirating follicles 0.05). Maturation was not affected significantly by BCB class...
The Journal of physiologyNovember 1, 1974
Volume 242, Issue 3 805-826 doi: 10.1113/jphysiol.1974.sp010735
Comline RS, Silver M.1. Blood gas tensions, pH, PCV, O(2) affinity and red cell 2,3-diphosphoglycerate (DPG) levels have been measured in uterine and umbilical blood in conscious cows and mares with indwelling vascular catheters and in sows under sodium pentobarbitone anaesthesia.2. Large P(O2) gradients (20-24 mmHg) were observed between the uterine and umbilical venous blood in the cow and pig, while in the mare the corresponding P(O2) difference was only 2.7 +/- 1.7 mmHg. Alterations in maternal arterial P(O2) did not affect the large vein-to-vein P(O2) difference in either ruminant or pig.3. In the cow the pre...
Rasch K, Schoon HA, Sieme H, Klug E.The aim of this field study was to examine the influence of the uterotonic substance oxytocin in 2 different therapeutic dosages of 15 and 25 i.u., respectively on the uterine drainage of oestrous mares and on their fertility. In addition endometrial biopsies of mares with and without intrauterine fluid accumulations around the time of ovulation were evaluated histomorphologically regarding the aetiology of susceptibility to uterine infection. A population of 59 Hanoverian Warmblood mares was used in this study. The mares were divided into Group A (mares with intrauterine fluid accumulations [...
Gamboa S, Rodrigues AS, Henriques L, Batista C, Ramalho-Santos J.A group of stallions with different reproductive indexes were used to study seasonal variations in sperm quality (Equus caballus). Semen samples were collected from late September to July and analyzed according to four seasonal periods: late September-December, January-March, late March-May, and June-July. Parameters monitored included sperm concentration, sperm motility, sperm morphology, sperm viability, acrosomal status, plasma membrane stability, and sperm mitochondrial membrane potential. Overall, seminal parameters monitored are affected mostly by time period, followed by animal and last...
Kozdrowski R, Sikora M, Buczkowska J, Nowak M, Raś A, Dzięcioł M.The aim of this study was to ascertain if (1) the stage of reproductive cycle influences cytological results, (2) cytology obtained from an endometrial biopsy is more accurate than cytology derived using the cytobrush, and (3) different methods used for evaluation of cytological samples produce similar diagnostic results. Material was collected from 46 mares in estrus, 48 in diestrus and from 33 mares in anestrus. Smears were evaluated using two criteria. In criterion I, a total of 300cells were counted and the percentage of polymorphonuclear cells was recorded. In criterion II, the number of ...
Bailey CS, Heitzman JM, Buchanan CN, Bare CA, Sper RB, Borst LB, Macpherson M, Archibald K, Whitacre M.Early, accurate diagnosis of ascending placentitis in mares remains a key challenge for successful treatment of the disease. Doppler ultrasonography has shown promise as a tool to diagnose pregnancy abnormalities and is becoming more available to equine clinicians. However, to date, no studies have prospectively compared this technique to standard B-mode measurement of the combined thickness of the uterus and placenta (CTUP). Objective: The objective of the current study was to compare Doppler and B-mode ultrasonography for the detection of experimentally-induced ascending placentitis in mares...
Scholtz EL, Krishnan S, Ball BA, Corbin CJ, Moeller BC, Stanley SD, McDowell KJ, Hughes AL, McDonnell DP, Conley AJ.One of the most widely accepted axioms of mammalian reproductive biology is that pregnancy requires the (sole) support of progesterone, acting in large measure through nuclear progesterone receptors (PRs) in uterine and cervical tissues, without which pregnancy cannot be established or maintained. However, mares lack detectable progesterone in the latter half of pregnancy. Instead of progesterone, several (mainly 5α-reduced) pregnanes are elevated and have long been speculated to provide progestational support in lieu of progesterone itself. To the authors' knowledge, evidence for the bioacti...
Ebel F, Vallejos A, Gajardo G, Ulloa O, Clavel E, Rodríguez-Gil JE, Ramírez-Reveco A.The aim of this study was to evaluate seasonal changes in basic parameters of sperm quality and freezability behaviour of ejaculates from 10 fertile heavy draft stallions. A total of 140 ejaculates were collected, processed and evaluated during both the breeding (September-November) and non-breeding seasons (April-June). Fresh semen was evaluated for volume, concentration, total spermatozoa per ejaculate, plasma membrane integrity and total sperm motility. Cryopreserved samples were evaluated for plasma membrane integrity and sperm motility by the CASA system, and for the freezability index (F...
Grøndahl C, Hyttel P.The nucleolus is believed to be the active site of rRNA synthesis in all eukaryotic cells. In preimplantation embryos, the embryonic genome is apparently more or less silent up to a species-specific developmental stage at which a major burst of transcription occurs. Here we report on nucleologenesis and some ultrastructural aspects of the onset of RNA synthesis in equine embryos during in vivo development. The zygotes and embryos up to blastocyst stages were surgically recovered from normally cycling mares. Mares were induced to ovulate by treatment with 3000 IU hCG and inseminated 20 and 34 h...
Cudd TA, LeBlanc M, Silver M, Norman W, Madison J, Keller-Wood M, Wood CE.Fetal maturation and the timing of parturition in both sheep and primates are thought to be controlled by the hypothalamic-pituitary-adrenal axis but little is known about the endocrinology of the equine fetus. We investigated the ontogeny of plasma concentrations of adrenocorticotropic hormone (ACTH), cortisol and corticosteroid binding capacity in the late-gestation fetal horse. We also wished to determine whether there is ultradian rhythmic release of ACTH and cortisol in fetal horses and we compared fetuses to maternal and non-pregnant adult horses. Six fetuses, 278-304 days gestation (ter...
Samper JC.The two most common procedures for breeding management of mares involve induction of luteolysis and induction of ovulation. Although both of these events are usually achieved, physiologic conditions affect the timing of the response. In a diestrus mare treated with prostaglandin F(2alpha) (PGF), or a PGF analogue, it is well documented that, on average, the interval from treatment to the onset of estrus is 3-4 days, whereas ovulation occurs 8-10 days after treatment. However, the diameter of the ovulatory follicle, as well as its status at the time of PGF treatment, determines the intervals fr...
Lear TL, Lundquist J, Zent WW, Fishback WD, Clark A.Repeated early embryonic loss (REEL) represents a considerable economic loss to the horse industry. Mares that experience REEL may be overlooked as potential carriers of a chromosome abnormality. Here we report three different autosomal translocations in Thoroughbred mares presented for chromosome analysis because of REEL. The karyotypes were 64,XX,t(1;21), 64,XX,t(16;22), and 64,XX,t(4;13), respectively. In order to confirm the chromosomes involved in the translocations, to map the breakpoints, and to determine if the translocations were reciprocal, genes surrounding the breakpoints were iden...
Virgin J, Hendrickson D, Wallis T, Rao S.To compare the presence or absence of pain, pain-related behavioral responses, and hormonal responses to noxious stimuli during standing laparoscopic ovariectomy in mares sedated with continuous intravenous (IV) detomidine infusion and caudal epidural detomidine. Methods: A double blind prospective study. Methods: Mares (n=12) Methods: Mares were divided into 2 treatment groups; 6 were sedated using continuous IV detomidine infusion and 6 were sedated with caudal epidural detomidine. All mares received IV xylazine (0.33 mg/kg) and butorphanol tartrate (5 mg) premedication before detomidine adm...
Fitzgerald BP, Davison LA, McManus CJ.In seasonally breeding species photoperiodic information is thought to be conveyed to the reproductive and prolactin axis via changes in circulating concentrations of melatonin. For some species, a constant melatonin stimulus is perceived as a short day, whereas in others no photoperiodic information is provided. In the mare, a preliminary study demonstrated that constant administration of melatonin did not modify prolactin secretion, suggesting that this treatment regimen failed to provide photoperiodic information. To further investigate this proposal and to investigate an alternative explan...
Han H, Chen Q, Gao Y, Li J, Li W, Dang R, Lei C.In the biological process of testicular spermatogenesis, the expression and interaction of many genes are regulated by microRNAs (miRNAs). However, comparisons of miRNA expression between descended testes (DTs) and undescended testes (UDTs) are rarely done in horses. In this study, we selected two UDTs (CKY2b and GU4b) from Chakouyi (CKY) and Guanzhong (GU) horses and eight DTs (GU1-3, CKY1, CKY3, CKY2a, GU4a, and GU5). Three groups were compared to evaluate expression patterns of testicular miRNA in stallion testes. Group 1 compared normal CKY horses and GU horses (CKY1 and CKY3 vs. GU1-3). G...
Bouré L, Marcoux M, Laverty S.The purposes of this study were to develop a technique of paralumbar fossa laparoscopic ovariectomy using Endoloop ligatures and to avoid a laparotomy incision for ovary removal by using a 33-mm diameter muscle spreader trocar-cannula unit. Methods: Seven mares. Methods: Bilateral laparoscopic ovariectomy was performed under general anesthesia in two horses and under neuroleptanalgesia and local anesthesia in five standing mares. Ovaries were approached from the ipsilateral paralumbar fossa through two portal sites located in the paralumbar fossa and a third between the 17th and 18th ribs. Ins...
D'Anza E, Albarella S, Galdiero G, Tafuri S, Del Prete C, Cocchia N, Ciani F, Mastellone V, Pasolini MP, Carotenuto D, Selvaggi M, Ciotola F....The reproductive performances of livestock play an essential role in the economic management of the farm. The improvement of semen quantity and quality through the use of food supplements that lack substances which are forbidden in animal feeding, or that may have detrimental effects, is an important goal. Maca (Lepidium meyenii) is a plant that has been used for centuries in the Andes for nutrition and fertility enhancement in humans and animals. The aim of this study was to evaluate the effects of food supplementation of stallions with maca during the breeding season on spermatozoa parameter...
Nevins M, Heinemann F, Janke UW, Lombardi T, Nisand D, Rocchietta I, Santoro G, Schupbach P, Kim DM.The objective of this proof-of-principle multicenter case series was to examine the bone regenerative potential of a newly introduced equine-derived bone mineral matrix (Equimatrix) to provide human sinus augmentation for the purpose of implant placement in the posterior maxilla. There were 10 patients requiring 12 maxillary sinus augmentations enrolled in this study. Histologic results at 6 months demonstrated abundant amounts of vital new bone in intimate contact with residual graft particles. Active bridging between residual graft particles with newly regenerated bone was routinely observed...
Feh C, Munkhtuya B.The sexual selection hypothesis explains infanticide by males in many mammals. In our 11-year study, we investigated this hypothesis in a herd of Przewalski's horses where we had witnessed infanticidal attacks. Infanticide was highly conditional and not simply linked to takeovers. Attacks occurred in only five of 39 cases following a takeover, and DNA paternity revealed that, although infanticidal stallions were not the genetic fathers in four cases out of five, stallions present at birth did not significantly attempt to kill unrelated foals. Infanticide did not reduce birth intervals; only in...
Ferreira-Dias G, Botelho M, Zagrajczuk A, Rebordão MR, Galvão AM, Bravo PP, Piotrowska-Tomala K, Szóstek AZ, Wiczkowski W, Piskula M, Fradinho MJ....Phytoestrogens exist in plants that are present in forages fed to horses. They may compete with 17-β estradiol and influence the estrous cycle. Therefore, the objective was to determine whether coumestrol from clover-mixed pastures is present in mare's plasma after their ingestion (experiment I), and when this phytoestrogen was present in mare's plasma after ingestion (experiment II). The effect of a long-term ingestion of phytoestrogens on estrous cycle disruption was assessed (experiment III; clinical case). Experiment I was carried out in nonpregnant anestrous and cyclic Lusitano mares (n ...
Battut I, Colchen S, Fieni F, Tainturier D, Bruyas JF.The purpose of this study was to evaluate the exact age when the equine embryo reaches the uterus. The time of ovulation was determined by hourly ultrasound examinations starting 32 h after an injection of crude equine pituitary gonadotrophin or human chorionic gonadotrophin, or after the first of 4 injections of buserelin. Nonsurgical uterine flushings were carried out 144 h (Day 6), 156 h (Day 6.5) or 168 h (Day 7) after ovulation. Induction of ovulation was attempted in 101 oestrous cycles and 61 of 101 mares (60.4%) ovulated 32-44 h post injection. Sixty embryo collections were performed w...
