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Topic:Reproduction

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.
Immunoexpression of androgen receptors in the reproductive tract of the stallion.
Annals of the New York Academy of Sciences    May 14, 2005   Volume 1040 227-229 doi: 10.1196/annals.1327.030
Bilinska B, Hejmej A, Gancarczyk M, Sadowska J.The objective of this study was to visualize androgen receptors (ARs) in the testis, epididymis, and prostate of the stallion by means of immunohistochemistry. Nuclear immunostaining was found in all somatic cells in the testis--Leydig, Sertoli, and peritubular myoid cells; in both types of epithelial cells of the epididymis; and in the secretory cells of the prostate. These results indicate that ARs are distributed throughout the reproductive tract cells of the stallion.
Changes in the heart rate and plasma epinephrine and norepinephrine concentrations of the stallion during copulation.
Reproductive medicine and biology    May 3, 2005   Volume 4, Issue 2 143-147 doi: 10.1111/j.1447-0578.2005.00093.x
Terada M, Momozawa Y, Komano M, Kusunose R, Sato F, Saito TR. The physiological indexes of the copulatory behavior of the stallion have not been investigated in detail and may differ from those of other species, such as humans and rats. In order to understand the breeding capability of various stallions, their behavior during copulation was observed, and heart rate (HR) and the plasma concentrations of norepinephrine (NA) and epinephrine (Ad) were measured sequentially for a total of 13 copulations carried out during 2 days. The mean HR at rest was 35.3 ± 0.9 beats per minute (b.p.m.) and it peaked during mounting (162.1 ± 5.4 b.p.m.). The HR a...
Expression of mRNA encoding insulin-like growth factor binding protein-2 (IGFBP-2) during induced and natural regression of equine corpora lutea.
Theriogenology    April 25, 2005   Volume 64, Issue 6 1371-1380 doi: 10.1016/j.theriogenology.2005.02.015
Watson ED, Bae SE, Al-Zi'abi MO, Hogg CO, Armstrong DG.The insulin-like growth factors, IGF-I and -II, have been shown to play a key role in luteal function in some species. The IGF binding proteins, IGFBP-2 and -3, have been shown to inhibit binding of IGF-I and -II to bovine luteal cells and decrease progesterone production. We have recently shown that equine follicles have the genetic capacity to produce IGFBP-2, and that levels decrease in healthy preovulatory follicles. In the present study expression of mRNAs encoding IGFBP-2, as well as the rate-limiting steroidogenic enzyme, P450scc, were studied in equine corpora lutea to investigate whet...
Expression of aromatase and oestrogen receptors in reproductive tissues of the stallion and a single cryptorchid visualised by means of immunohistochemistry.
Domestic animal endocrinology    April 19, 2005   Volume 29, Issue 3 534-547 doi: 10.1016/j.domaniend.2005.03.002
Hejmej A, Gorazd M, Kosiniak-Kamysz K, Wiszniewska B, Sadowska J, Bilińska B.Androgen metabolism may proceed to amplify the action of testosterone by its aromatisation to oestradiol. Recently, a growing body of evidence suggests a role of oestrogens in the male reproductive tract via their specific oestrogen receptors (ERs). In order to check whether androgens are converted to oestrogens in the testis, epididymis and prostate of the stallion, the expression of aromatase was visualised by means of immunohistochemistry. Moreover, to show the cellular targets for oestrogens the presence of oestrogen receptor alpha (ERalpha) and oestrogen receptor beta (ERbeta) was demonst...
Nitric oxide levels and nitric oxide synthase expression in uterine samples from mares susceptible and resistant to persistent breeding-induced endometritis.
American journal of reproductive immunology (New York, N.Y. : 1989)    April 19, 2005   Volume 53, Issue 5 230-237 doi: 10.1111/j.1600-0897.2005.00270.x
Alghamdi AS, Foster DN, Carlson CS, Troedsson MH.Breeding-induced endometritis (BIE) in the mare is resolved by 36 hr after insemination in resistant mares. However, 10-15% susceptible broodmares fail to do so because of impaired uterine contractility between 7 and 19 hr after exposure to seminal or bacterial challenge, which reduces their fertility. Methods: Nitric oxide (NO) in uterine secretions, and expression of nitric oxide synthase (NOS) in uterine biopsies were compared between susceptible and resistant groups 13 hr after insemination. Results: Susceptible mares had a higher NO in their uterine secretions and greater inducible NOS (i...
Dopamine receptors in equine ovarian tissues.
Domestic animal endocrinology    April 14, 2005   Volume 28, Issue 4 405-415 doi: 10.1016/j.domaniend.2005.02.001
King SS, Campbell AG, Dille EA, Roser JF, Murphy LL, Jones KL.Dopamine (DA) agonist and antagonist treatments can affect ovarian reproductive events in the mare. To support our theory that DA produces these effects by acting directly on the ovary, we analyzed equine ovarian tissues for the presence of dopamine receptor-1 (D1r) and dopamine receptor-2 (D2r) mRNA by reverse transcription polymerase chain reaction (RT-PCR) and D1r and D2r proteins by Western blot and immunohistochemistry (IHC). RT-PCR was performed on RNA isolated from ovarian cortex, medulla, granulosa/theca or corpus luteum (CL) tissues and from pituitary (D2r control) and renal artery (D...
LH and IGF-1 release during oestrus and early luteal phase in lactating and non-lactating horse mares.
Animal reproduction science    April 14, 2005   Volume 91, Issue 1-2 97-106 doi: 10.1016/j.anireprosci.2005.03.002
Deichsel K, Aurich J, Parvizi N, Bruckmaier RM, Aurich C.The aim of the present study was to determine effects of lactation on basal LH and IGF-1 concentrations and on the LH response to a GnRH-analogue at different stages of the oestrous cycle in mares. A total of 17 cyclic Haflinger mares were included in the study. Experiments were performed on lactating mares in first postpartum oestrus, the subsequent early luteal phase, and second postpartum oestrus. Non-lactating mares were used in oestrus and early luteal phase. Blood samples were taken for 1 h at 15 min intervals. Mares were then injected with the GnRH-analogue buserelin (GnRHa; 5 microg i....
Regulation of circulating gonadotropins by the negative effects of ovarian hormones in mares.
Biology of reproduction    April 13, 2005   Volume 73, Issue 2 315-323 doi: 10.1095/biolreprod.105.040253
Ginther OJ, Gastal EL, Gastal MO, Beg MA.The functional and temporal relationships between circulating gonadotropins and ovarian hormones in mares during Days 7-27 (ovulation = Day 0) was studied using control, follicle ablation, and ovariectomy groups (n = 6 mares/group). In the follicle-ablation group, all follicles > or = 6 mm were ablated on Day 7, and every 2 days thereafter, newly emerging follicles were also ablated. Estradiol concentrations decreased (P < 0.01) similarly in the controls and the follicle-ablation group between Days 7 and 11 and by Day 15 began to increase in the controls and continued to decrease in the ...
Inheritance of hereditary equine regional dermal asthenia in Quarter Horses.
American journal of veterinary research    April 13, 2005   Volume 66, Issue 3 437-442 doi: 10.2460/ajvr.2005.66.437
Tryon RC, White SD, Famula TR, Schultheiss PC, Hamar DW, Bannasch DL.To assess heritability and mode of inheritance for hereditary equine regional dermal asthenia (HERDA) in Quarter Horses. Methods: 1,295 horses with Quarter Horse bloodlines, including 58 horses affected with HERDA. Methods: Horses were classified as affected or unaffected or as undetermined when data were insufficient to assess phenotype. Pedigree data were analyzed to determine the probable mode of inheritance. Heritability was estimated by use of Bayesian statistical methods. Results: Heritability (mean+/-SD) of HERDA was estimated to be 0.38+/-0.13, with both sexes having an equal probabili...
Acute insulin-induced hypoglycaemia does not alter IGF-1 and LH release in cyclic mares.
Reproduction in domestic animals = Zuchthygiene    April 12, 2005   Volume 40, Issue 2 117-122 doi: 10.1111/j.1439-0531.2005.00564.x
Deichsel K, Hoppen HO, Bruckmaier R, Kolm G, Aurich C.Lactation in the mare is associated with changes in the release of metabolic as well as reproductive hormones. Plasma glucose concentration is constantly reduced in lactating compared with non-lactating mares. Several metabolic signals have been proposed to link nutrition and somatic metabolism with reproductive function. The following experiment was performed to study the effect of acute hypoglycaemia on the release of insulin-like growth factor-1 (IGF-1) and luteinizing hormone (LH) in cyclic mares. Different doses of insulin (0.1 and 0.2 IU/kg body weight) were given to induce a decrease in...
The early conception factor (ECF) lateral flow assay for non-pregnancy determination in the mare.
Theriogenology    April 7, 2005   Volume 64, Issue 5 1061-1071 doi: 10.1016/j.theriogenology.2005.02.012
Horteloup MP, Threlfall WR, Funk JA.The horse early conception factor (ECF) test is designed for qualitative determination of the ECF glycoprotein in the mare that has conceived. The objectives of this study were to determine the performance of the horse ECF test for the detection of the non-pregnant mare, and to determine the agreement among subjects or "readers" regarding the interpretation of the test. Blood samples from 60 mares were collected on Days 0, 5, 8, 11 and 18 following ovulation. Pregnancy status diagnosed with the ECF test was compared (2 x 2 table) to pregnancy status diagnosed by palpation per rectum and ultras...
Follicular fluid concentrations of free insulin-like growth factor (IGF)-I during follicular development in mares.
Domestic animal endocrinology    April 7, 2005   Volume 29, Issue 4 573-581 doi: 10.1016/j.domaniend.2005.03.003
Spicer LJ, Santiago CA, Davidson TR, Bridges TS, Chamberlain CS.The objective of the present study was to evaluate changes in concentrations of free insulin-like growth factor (IGF)-I in follicular fluid (FFL) during follicle development in the mare. Mares (n = 14) were classified as either in the follicular phase (n = 8) or luteal phase (n = 6). Follicles (n = 92) were categorized as small (6-15 mm; n = 54), medium (16-25 mm; n = 23) or large (>25 mm; n = 15) and FFL was collected. Free IGF-I levels in FFL in large follicles of follicular phase mares were greater (P < 0.05) than in large follicles of luteal phase mares and small or medium follicles ...
Application of MTT reduction assay to evaluate equine sperm viability.
Theriogenology    April 2, 2005   Volume 64, Issue 6 1350-1356 doi: 10.1016/j.theriogenology.2005.02.009
Aziz DM, Ahlswede L, Enbergs H.The assay of MTT reduction depends on the ability of metabolically active cells to reduce the tetrazolium salt (3[4,5-dimethylthiazol-2-y1]-2,5-diphenyltetrazolium bromide) to formazan. This study was conducted to examine and validate of a simple and less costly MTT test in determining equine sperm viability and compare the efficiency of this test with a flow cytometer. Fresh ejaculates from 11 stallions (warm blood) were included in this study. Semen was diluted to 100 million cells/ml in a Hepes 0.1% BSA. The rates of MTT reduction were measured in microtiter plates after incubation for 1 an...
[Horse Advisory Committee: ‘newborn foal’].
Tijdschrift voor diergeneeskunde    March 31, 2005   Volume 130, Issue 6 177-179 
Wesselink HG, Sloet van Oldruitenborgh-Oosterbaan MM.No abstract available
[Horse Advisory Committee: ‘Sperm handling’].
Tijdschrift voor diergeneeskunde    March 31, 2005   Volume 130, Issue 6 179-181 
Stout TA, Seuren-Coppens ML, Parlevliet JM, Colenbrander B.No abstract available
In vivo effects of pregnancy-associated plasma protein-A, activin-A and vascular endothelial growth factor on other follicular-fluid factors during follicle deviation in mares.
Reproduction (Cambridge, England)    March 31, 2005   Volume 129, Issue 4 489-496 doi: 10.1530/rep.1.00555
Ginther OJ, Gastal EL, Gastal MO, Beg MA.During a follicular wave in mares, the two largest follicles (F1 and F2) begin to deviate in diameter when F1 is a mean of 22.5 mm. The intrafollicular effects of pregnancy-associated plasma protein-A (PAPP-A), IGF-I, activin-A and vascular endothelial growth factor (VEGF) on other follicular-fluid factors during deviation were studied. In four treated groups (n = 7/group), a single dose of one of the four factors was injected into F2 when F1 was > or = 20.0 mm (expected beginning of deviation). In a control group (n = 7), F2 was injected with vehicle. One day after treatment, a sample of f...
Theriogenology question of the month. Endometrial cups.
Journal of the American Veterinary Medical Association    March 25, 2005   Volume 226, Issue 6 877-879 doi: 10.2460/javma.2005.226.877
Willis LA, Riddle WT.No abstract available
Genetic diagnosis of sex chromosome aberrations in horses based on parentage test by microsatellite DNA and analysis of X- and Y-linked markers.
Equine veterinary journal    March 23, 2005   Volume 37, Issue 2 143-147 doi: 10.2746/0425164054223787
Kakoi H, Hirota K, Gawahara H, Kurosawa M, Kuwajima M.Sex chromosome aberrations are often associated with clinical signs that affect equine health and reproduction. However, abnormal manifestation with sex chromosome aberration usually appears at maturity and potential disorders may be suspected infrequently. A reliable survey at an early stage is therefore required. Objective: To detect and characterise sex chromosome aberrations in newborn foals by the parentage test and analysis using X- and Y-linked markers. Methods: We conducted a genetic diagnosis combined with a parentage test by microsatellite DNA and analysis of X- and Y-linked genetic ...
Radiation hybrid and linkage mapping of six new type I markers in the horse.
Animal genetics    March 18, 2005   Volume 36, Issue 2 182-184 doi: 10.1111/j.1365-2052.2005.01257.x
Bricker SJ, Brault LS, DelValle A, Millon LV, Murray JD, Penedo MC.No abstract available
Effect of clenbuterol on the clearance of particles of charcoal (4 to 90 microm) from the uteri of mares.
The Veterinary record    March 16, 2005   Volume 156, Issue 9 279-281 doi: 10.1136/vr.156.9.279
Kolm G, Gemeiner M, Deichsel K, Budik S, Aurich J, Aurich C.The failure of clearance mechanisms in the mare's uterus results in persistent inflammation and is considered a major cause of subfertility. Eighteen mares, of which three were susceptible to endometritis and four had been ovariectomised, underwent charcoal clearance testing to evaluate their clearance mechanisms. This consisted of installing 500 mg of charcoal (particle size 4 to 90 microm) added to 50 ml of phosphate-buffered saline (PBS) into the uterus. Forty-eight hours later the uterus was flushed out with 0.0012 per cent methylene blue in 50 ml of PBS for determination of the diluting f...
Effects of GnRH immunization in sexually mature pony stallions.
Animal reproduction science    March 16, 2005   Volume 86, Issue 3-4 247-259 doi: 10.1016/j.anireprosci.2004.07.010
Turkstra JA, van der Meer FJ, Knaap J, Rottier PJ, Teerds KJ, Colenbrander B, Meloen RH.Immunization against gonadotrophin releasing hormone (GnRH) was studied as an alternative for the commonly used surgical castration in stallions. Two GnRH vaccines comprising non-mineral oil adjuvants were evaluated for their potential to induce high antibody titers directed against GnRH and subsequent effects on reproductive characteristics. Twelve sexually mature male hemicastrated Shetland ponies were assigned to three groups. Group 1 and 2 were injected with 1mg peptide equivalent of G6k-GnRH-tandem-dimer conjugated to ovalbumin (OVA) in CoVaccine HT adjuvant (GnRH/CoVaccine) and in Carbop...
Sperm motility patterns and metabolism in Catalonian donkey semen.
Theriogenology    March 15, 2005   Volume 63, Issue 6 1706-1716 doi: 10.1016/j.theriogenology.2004.07.022
Miró J, Lobo V, Quintero-Moreno A, Medrano A, Peña A, Rigau T.The Sperm-Class Analyzer detected four subpopulations of spermatozoa with different motility characteristics in the ejaculate of the Catalonian donkey. Significant differences (P < 0.001) in the distribution of these subpopulations, as well as in total sperm number and percentage total motility, were seen in the diluted semen of four sampled donkeys. All the ejaculates evaluated showed excellent semen quality characteristics; the sperm they contained was more rapid than horse sperm. Principal components analysis showed sperm l-lactate production to be a good predictor of semen condition. This,...
Relationship of seminal plasma level and extender type to sperm motility and DNA integrity.
Theriogenology    March 15, 2005   Volume 63, Issue 6 1584-1591 doi: 10.1016/j.theriogenology.2004.05.030
Love CC, Brinsko SP, Rigby SL, Thompson JA, Blanchard TL, Varner DD.The relationship between seminal plasma level (0, 10, or 20%) and extender type [Kenney type (EZ-Mixin-CST) or Kenney-modified Tyrodes-KMT] to the susceptibility of sperm DNA to denaturation and sperm motility measures were investigated in cooled (5 degrees C) stallion sperm. Three ejaculates from each of three fertile stallions were collected in an artificial vagina and processed as follows: diluted one part uncentrifuged semen with four parts of extender to a final concentration of 20% seminal plasma in either CST or KMT (20% CST; 20% KMT); diluted to a final concentration of 25 million sper...
Cloned horse pregnancies produced using adult cumulus cells.
Reproduction, fertility, and development    March 3, 2005   Volume 16, Issue 7 675-679 doi: 10.1071/rd04025
Vanderwall DK, Woods GL, Aston KI, Bunch TD, Li G, Meerdo LN, White KL.The objectives of the present study were to: (1) clone horses using adult cumulus cells; and (2) determine whether the cumulus cell donor affected the outcome. In vivo-matured cumulus-oocyte complexes were obtained using transvaginal ultrasound-guided follicle aspiration; oocytes were used as cytoplasts, whereas cumulus cells (from one of three different mares) were used as donor cells. Immediately following nuclear transfer and activation procedures, cloned embryos were transferred surgically to the oviduct of recipient mares (n = 2-5 embryos per recipient) that had ovulated within 24 h prior...
Expression of endothelial and inducible nitric oxide synthases is modulated in the endometrium of cyclic and early pregnant mares.
Reproduction, fertility, and development    March 3, 2005   Volume 16, Issue 7 689-698 doi: 10.1071/rd03103
Welter H, Bollwein H, Weber F, Rohr S, Einspanier R.The expression of the endothelial and inducible nitric oxide synthases (eNOS and iNOS, respectively) was examined in the endometrium of cyclic and pregnant mares by real-time polymerase chain reaction and immunohistology. The concentration of eNOS mRNA varied throughout the oestrous cycle, with significantly higher transcripts on Day 5 of the oestrous cycle (P 0.05). In early pregnant mares both eNOS and iNOS mRNA increased between Days 12 and 15 (P < 0.05). In cyclic mares, eNOS protein was detected immunocytochemically in endometrial epithelia, the basement membrane, the endothelial laye...
High pressure flow cytometric sorting damages sperm.
Theriogenology    March 2, 2005   Volume 64, Issue 5 1035-1048 doi: 10.1016/j.theriogenology.2005.02.002
Suh TK, Schenk JL, Seidel GE.Sexing sperm by high-speed flow cytometry subjects them to high pressure. The routine operating pressure of the MoFlo SX flow cytometer for sperm sorting for commercial production has been 50 pounds/square inch (psi), with a standard 70 microm standard nozzle tip. It was hypothesized that lowering the sorting pressure could reduce sperm damage. Therefore, a series of experiments using semen from six bulls, sorted with three MoFlo SX sorters, was conducted to determine optimal pressure. An additional experiment was done with stallion spermatozoa. In Experiment 1, sorting at 30 psi compared to 5...
Establishment of pregnancies after serial dilution or direct transfer by vitrified equine embryos.
Theriogenology    February 24, 2005   Volume 63, Issue 5 1308-1319 doi: 10.1016/j.theriogenology.2004.06.015
Eldridge-Panuska WD, di Brienza VC, Seidel GE, Squires EL, Carnevale EM.Experiments were conducted to determine viability of equine embryos in vivo after vitrification. In a preliminary study (Experiment 1), embryos were exposed in three steps to vitrification solutions containing increasing concentrations of ethylene glycol and glycerol (EG/G); the final vitrification solution was 3.4 M glycerol + 4.6 M ethylene glycol in a base medium of phosphate-buffered saline. Embryos were warmed in a two-step dilution and transferred into uteri of recipients. No pregnancies were observed after transfer of blastocysts >300 microm (n = 3). Transfer of morulae or blastocyst...
Pregnancy status determination in mares using a rapid lateral flow test for measuring serum oestrone sulphate.
New Zealand veterinary journal    February 24, 2005   Volume 52, Issue 4 193-196 doi: 10.1080/00480169.2004.36428
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...
Seasonal reproduction in the mare: possible role of plasma leptin, body weight and immune status.
Domestic animal endocrinology    February 24, 2005   Volume 29, Issue 1 203-213 doi: 10.1016/j.domaniend.2005.02.006
Ferreira-Dias G, Claudino F, Carvalho H, Agrícola R, Alpoim-Moreira J, Robalo Silva J.The primary objective of this study was to evaluate the possible role of leptin, body weight and immune status on reproductive activity throughout the transition period from cyclicity to seasonal anestrus, during anestrus and resumption of ovarian activity in Lusitano mares. Mares in good body condition were monthly monitored throughout 2 years (10 mares in each year) for evaluation of their reproductive status by sequential ultrasonography and plasma progesterone determinations. On the second year, all mares were weighed. Progesterone and leptin were assayed by radioimmunoassay (RIA). Paramet...
Activity of glutathione peroxidase, superoxide dismutase and catalase and lipid peroxidation intensity in stallion semen during storage at 5 degrees C.
Theriogenology    February 24, 2005   Volume 63, Issue 5 1354-1365 doi: 10.1016/j.theriogenology.2004.07.005
Kankofer M, Kolm G, Aurich J, Aurich C.Sperm cell membranes are susceptible to peroxidative damage by an excess of reactive oxygen species (ROS). Antioxidative defence systems consisting of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and catalase (CAT) physiologically control the balance between ROS production and neutralization. In the present study the hypothesis was tested that lipid peroxidation occurs during storage of semen at 5 degrees C and that semen extender has positive effects on the antioxidative potential of equine semen. The aim of the study was to determine the activity of GSH-Px, SOD and CAT and the...