Omneity® Pellets
All-In-One Vitamin & Mineral Pellet
Topic:Mares
Mares and horses are integral components of equine studies, focusing on the reproductive and behavioral aspects of equine biology. Mares, or adult female horses, play a significant role in breeding programs and are often studied for their reproductive physiology, gestation, and maternal behaviors. Horses, as a broader category, encompass both sexes and all age groups, providing a comprehensive view of equine anatomy, physiology, and behavior. Research in this area often investigates the differences and similarities between mares and other horses in terms of hormonal cycles, reproductive health, and social interactions. This page compiles peer-reviewed studies and scholarly articles that explore the biological and behavioral characteristics of mares and horses, offering insights into their roles in equine science and management.
p- and m-Cresols emitted from estrous urine are reliable volatile chemical markers of ovulation in mares. Urine samples from 14 mares, belonging to five breeds, were collected at estrus and diestrus to search for estrous specific volatile compounds which could be used to determine ovulation time. Around 150 volatiles were collected from urine head-space samples by solid phase micro extraction technique, and analyses were conducted by gas chromatography-mass spectrometry methods. Comparison of chromatographic profiles of volatile substances revealed that concentrations of m- and p-cresols were significantly greater during estrus while diethylphthalate was more abundant at diestrus. Monitoring of m-...
A clinical case of dourine in an outbreak in Italy. In May 2011, dourine was reported in Italy following the declaration of a positive result observed in a stallion undergoing routine testing for stud purposes. Clinical signs, anatomo-histopathological findings and laboratory results that resulted in the confirmation of diagnosis of dourine in a clinically affected mare, which was the likely source of infection in the stallion, are described.
Effect of embryo age and recipient asynchrony on pregnancy rates in a commercial equine embryo transfer program. In the present study, 809 uterine flushes and 454 embryo transfers performed in mares over a 4-yr interval were examined to evaluate the effects of: (1) the day of embryo collection on recovery rates; (2) the degree of synchrony between donor and recipient mares on pregnancy rates; (3) the recipient day post ovulation on pregnancy rates; and (4) the age of the embryo at recovery on pregnancy rates at 60 days. Uterine flushes were performed on Days 6, 7, 8, 9, and 10 (Day 0 = ovulation) and embryos were transferred to recipients with degrees of synchrony varying between +1 to -6 (recipient ovul...
The end of the tour de force of the corpus luteum in mares. Recent findings on the luteolytic process in mares are reviewed and differences from other farm species are noted. It is well known that the luteolysin, PGF2α (PGF), is secreted from the endometrium in the absence of pregnancy in farm animal species. But PGF is a potent chemical and safeguards have evolved so that only the corpus luteum (CL) is affected. The safeguards include a short PGF half-life and secretion in two or three pulses per day. In mares, endogenous PGF travels from the uterus to the CL through the systemic circulation, but the luteal-cell membranes are highly efficient in capt...
Gestation length and occurrence of daytime foaling of Standardbred mares on two stud farms in New Zealand. To examine the gestation lengths and occurrence of daytime foaling of Standardbred mares foaling outdoors at stud farms in Southland, New Zealand (latitude 45ËšS). Methods: Data were collected prospectively at two commercial Standardbred stud farms (Farms A and B), during the 2008/9 and 2009/10 breeding seasons (October to February). For each foaling, the identity of the mare, date and time of foaling, gender of foal, time the mare passed the fetal membranes, time the foal stood, and foaling problems including dystocias, were recorded. The effect of farm, season, gender of foal, month of artif...
Genetic analyses of new movement traits using detailed evaluations of warmblood foals and mares. Detailed movement evaluations of warmblood foals and mares were performed in connection with regular breeding events of the Oldenburg horse breeding societies in 2009 and 2010. Unfavourable movement characteristics considered indicative for impaired balance were noted by a special judge (SJ) and the regular judges of the breeding events (RJ) and served as the basis for definition of new movement traits. Detailed movement information on 3374 foals and 2844 mares showed that more severe findings like irregular motion pattern in hind legs or irregularity in general motion pattern occurred only sp...
Three-dimensional ultrasound imaging of the equine fetus. The objective was to assess the optimal procedure for real-time, three-dimensional (3D) ultrasound (US) imaging for assessing the equine fetus during the first half of gestation and the possibility of using 3D US imaging of the equine fetus in clinical applications. Seventeen pregnant mares were examined by 3D US between Days 35 and 180 of gestation. Abdominal and endo-vaginal real-time 3D transducers used in human medicine were used for transrectal and transvaginal examinations, respectively. Images were recorded by both 3D stationary and real-time movies. In a comparison of four methods, tra...
Cytokines tumor necrosis factor-α and interferon-γ participate in modulation of the equine corpus luteum as autocrine and paracrine factors. Knowledge on the regulation of corpus luteum (CL) function in the mare is scarce. In this study, the presence of cytokines tumor necrosis factor alpha (TNF) and interferon gamma (IFNG), and their receptors (TNFRI, TNFRII and IFNRI), was investigated in equine CL throughout the luteal phase. The effects of TNF and IFNG on secretory function and viability of luteal cells were defined in vitro. Cytokine ligands and receptors were present in steroidogenic and endothelial cells. Protein expression for TNF was greater in mid-phase and regressing CL, while TNFRI was increased in regressing CL and TNF...
Nonruminant Nutrition Symposium: Involvement of gut neural and endocrine systems in pathological disorders of the digestive tract. The functioning of the gastrointestinal tract is under the control of the most extensive system of peripheral neurons in the body, the enteric nervous system, and the largest endocrine system of the body, the GEP endocrine system. The enteric nervous system in large mammals contains 500 million neurons, and the GEP endocrine system produces more than 30 hormones. Numerous enteric neuropathies affecting both humans and animals have been described and digestive disorders affect commercially important species, such as horses and cattle. The most severe enteric neuropathies (e.g., lethal white syn...
Comparison of eosin-thiazin and Papanicolaou-Shorr staining for endometrial cytologies of broodmares. Technical Note. Exfoliative endometrial cytology is an easy and valuable diagnostic tool for the detection of inflammatory processes of the uterus that correlates well to culture results. The practical use of this procedure is limited due to the time-consuming Papanicolaou-Shorr staining technique. In this study the suitability of the rapid eosin-thiazin staining for endometrial smears was investigated. Methods: Sample collection was carried out with a guarded culture swab (Knudsen-catheter) in 27 broodmares during routine gynaecological examination. Two smears were prepared from each collection. One was stai...
The influence of mare numbers, ejaculation frequency and month on the fertility of Thoroughbred stallions. Although considerable variation in per cycle pregnancy rates exists between Thoroughbred (TB) stallions, there is little information on factors that may influence this figure. Objective: To assess the influence of month, mare numbers and mating frequency on the fertility of TB stallions standing on studfarms in East Anglia, England. Methods: The daily breeding records of 31 TB stallions mating 3034 mares on 4851 occasions during the 2010 season were surveyed and related to first scan pregnancy rates. The influences of mare book size, month, number of matings per day and mating frequency or abs...
Investigation of strongyle EPG values in horse mares relative to known age, number positive, and level of egg shedding in field studies on 26 farms in Central Kentucky (2010-2011). A parasite study was done in 1,300 horse mares on 26 farms in Central Kentucky over a 5-month period in 2010 and 2011. The mares included 1,114 Thoroughbreds (TB) on 24 farms, 64 Standardbreds (SB) on 1 farm, and 122 mixed light horse types (MLH) on 1 farm. The objective of this research was to determine strongyle eggs per gram of feces (EPG) counts for evaluation by known age, number positive, and level of egg shedding by the mares. This was done to establish strongyle EPG profiles for the mares to aid in determining whether antiparasitic treatment was necessary. Eggs found were considered th...
Effect of progesterone on the in vitro response of peripheral blood mononuclear cells stimulated by Escherichia coli in mares. Escherichia coli(E. coli) isolated from the uterus of a Thoroughbred mare with bacterial endometritis was used to evaluate the effect of progesterone (P(4)) on the immune response of mares. Peripheral blood mononuclear cells (PBMCs) were collected from 10 nonpregnant clinically healthy adult mares (range, 4-12 years) during diestrus, four Thoroughbreds and six Hokkaido native horses. Cell proliferation and expression of cytokine mRNA, including interferon (IFN)-γ, tumor necrosis factor (TNF)-α and interleukin (IL)-10, of PBMCs stimulated with E. coli and P(4) were examined in vitro. P(4) was...
Efficacy of human chorionic gonadotropin to induce ovulation in the mare, when associated with a single dose of dexamethasone administered at breeding time. Human chorionic gonadotropin (hCG) and dexamethasone have a role in the reproductive management protocols of mares susceptible to persistent mating-induced endometritis (PMIE). However, it is possible that there is interference between these 2 drugs. Objective: The objective of this retrospective study was to determine the efficacy of hCG to induce ovulation in mares treated with dexamethasone at breeding time. Methods: Medical records from 152 mares and 223 cycles were analysed. In 113 cycles, mares susceptible to PMIE were treated with 1500 iu hCG and a single dose of 50 mg dexamethasone, 11...
The reproductive performance of Thoroughbred mares treated with intravaginal progesterone at the start of the breeding season. The objective of this study was to investigate the effects of intravaginal progesterone on the reproductive performance of transitional Thoroughbred mares on commercial stud farms. Two hundred twenty-seven (227) non-lactating transitional Thoroughbred mares aged between 4 and 18 y (mean 9.4 ± 3.2 y) located on three stud farms in the Waikato region of New Zealand were used in the study performed during four consecutive breeding seasons (2007-10). Mares were age-matched in pairs and either treated with an intravaginal progesterone releasing device (Cue-Mare, 1.72 g progesterone, 10% w/w) for u...
Comparison of three methods of sampling for endometrial cytology in the mare. Preliminary study. This prospective study aims to compare three different sampling techniques for the collection of endometrial cytological specimens in the mare: the guarded culture swab, the uterine cytobrush and the low volume uterine flush. Methods: The study population consisted of six healthy Standardbred mares in dioestrus. In each mare an acute endometritis was induced by performing a low- volume uterine flush 6days after ovulation using a sterile isotonic solution (lactated Ringer's solution or ViGroâ„¢ Complete Flush Solution). Two days after initiating inflammation, samples were collected from each ma...
Persistent breeding-induced endometritis after hysteroscopic insemination in the mare. Low-dose insemination has been proposed to reduce persistent breeding-induced endometritis (PBIE) in mares with delayed uterine clearance (DUC). Others proposed that hysteroscopic insemination induces an exaggerated inflammatory response and should be avoided in DUC mares. The objectives here were to evaluate presence and severity of PBIE in normal and DUC mares after hysteroscopic insemination with fresh semen, and to determine if hysteroscopy could be used in DUC mares without inducing excessive inflammation. Reproductively normal (n = 4) and DUC (n = 5) mares received four treatments in ran...
The mare: a 1000-pound guinea pig for study of the ovulatory follicular wave in women. The mare is a good comparative model for study of ovarian follicles in women, owing to striking similarities in follicular waves and the mechanism for selection of a dominant follicle. Commonality in follicle dynamics between mares and women include: (1) a ratio of 2.2:1 (mare:woman) in diameter of the largest follicle at wave emergence when the wave-stimulating FSH surge reaches maximum, in diameter increase of the two largest follicles between emergence and the beginning of deviation between the future dominant and subordinate follicles, in diameter of each of the two largest follicles at th...
Immunohistochemical localisation of progesterone and oestrogen receptors at the placental interface in mares during early pregnancy. Previous reports documenting progesterone receptors (PR) and oestrogen receptors (ER) in the endometrium of early pregnant mares included specimens only up to Day 20 post ovulation. This study aimed to localise PR and ERα on equine feto-maternal tissues between Days 20 and 68 to encompass the period around fixation of the conceptus, development of the endometrial cups and attachment and initial interdigitation of the allantochorion. During early pregnancy mares had the same pattern of PR in the endometrium as that reported for other mammals; namely, a loss of PR from the endometrial epithelia...
Influence of the uterine environment on the development of in vitro-produced equine embryos. The necessity for early interaction between the embryo and the oviductal and/or uterine environment in the horse is reflected by several striking differences between equine embryos that develop in vivo and those produced in vitro. Better understanding of the salient interactions may help to improve the efficiency of in vitro equine embryo production. In an initial experiment, cleavage-stage in vitro-produced (IVP) equine embryos were transferred into the uterus of recipient mares that had ovulated recently to determine whether premature placement in this in vivo environment would improve subse...
Relationship between dose of cloprostenol and age of corpus luteum on the luteolytic response of early dioestrous mares: a field study. The objective of this study was to establish and characterize the relationship between the dose of cloprostenol (37.5, 250, 500 and 750 μg) and the age of the early corpus luteum (CL) (80, 88, 96, 104 and 112 h) on the luteolytic response of mares. Behavioural oestrus and ultrasonographic signs of return to oestrus were considered as the occurrence of full luteolysis. A total of 298 mares were divided into groups according to dose of cloprostenol and CL age. There was an effect of dose of cloprostenol (p < 0.001) and age of the CL at the time of treatment (p 0.05); and that of 500 similar...
Insulin-dependent diabetes mellitus associated with presumed autoimmune polyendocrine syndrome in a mare. A 5-year-old Thoroughbred-cross mare was diagnosed with insulin-dependent diabetes mellitus. Partial glycemic control and clinical improvement were achieved with daily insulin administration for 18 mo. The mare subsequently developed evidence of hypoadrenocorticism and died. Necropsy findings included lymphocytic infiltration of the pancreas, adrenal cortex, adrenal medulla, and thyroid glands, suggestive of an immune-mediated polyendocrinopathy. Une jument Thoroughbred croisée âgée de 5 ans a été diagnostiquée avec le diabète insulino-dépendant. Le contrôle glycémique partiel et lâ...
A questionnaire study on parasite control practices on UK breeding Thoroughbred studs. Improved education of veterinarians and equine owners/managers is essential in implementing parasite control strategies that are less reliant on chemicals. Methods: This questionnaire study, conducted on 61 UK Thoroughbred (TB) establishments during 2009 and 2010, was designed to obtain an understanding of current helminth control practices on studs. To our knowledge, this is the first occasion that statements obtained from TB studs via questionnaire have been supported by statistical analysis. Results: Despite many respondents indicating high levels of concern regarding anthelmintic resistanc...
Unilateral and bilateral laparoscopic ovariectomy in 157 mares: a retrospective multicenter study. To evaluate surgical techniques, perioperative complications and outcome of laparoscopic surgery for unilateral and bilateral ovariectomy in mares. Methods: Retrospective multicenter case series. Methods: Mares (n = 157). Methods: Indications for surgery were neutering, fertility problems, elimination of hormone-related abnormal behavior, ovarian tumors as well as nonregressive ovarian hematomas or cysts. Ovariectomy (n = 206) were performed by a standard laparoscopic procedure in 157 standing sedated mares. Dissection and hemostasis were achieved by using either (1) a linear stapling device, ...
Transfer of tumour necrosis factor-α via colostrum to foals. This study aimed to determine whether TNF-α is transferred to equine neonates via colostrum and the relationship between TNF-α and IgG concentrations in the equine neonate. Colostrum, presuckle and postsuckle foal serum samples were collected from healthy mares and their foals. Equine TNF-α ELISA and IgG SRID kits were used to determine the concentrations of TNF-α and IgG, respectively. Statistical analysis was performed using the Spearman rank correlation. TNF-α concentrations in all presuckle foal serum were below the limit of detection in 15/16 foals and increased in postsuckle foal se...
Replacing egg yolk with soybean lecithin in the cryopreservation of stallion semen. The objective of this study was to determine whether replacing the egg yolk with soybean lecithin in the Botu-Crio® cryodiluent would maintain the fertility of cryopreserved stallion sperm. Two experiments were performed to evaluate cell freezability. In experiment 1, sperm from 15 stallions were frozen in Botu-Crio® (BC) or Botu-Crio® which contained 45g/L soybean lecithin (BCLS45) in place of the egg yolk. In experiment 2, we compared different concentrations of soybean lecithin: 0, 10.0, 12.5, 15.0, 17.5 and 20.0g/L (BC, BCLS10, BCLS12.5, BCLS17.5 and BCLS20, respectively). In experiment...
Manual reduction of multiple embryos in the mare: the effect on subsequent pregnancy outcome. To determine whether manually reduced multiple pregnancies (MPs) are at a greater risk of pregnancy loss than single pregnancy (SP) in mares, and to examine if a difference exists in the timing of pregnancy loss between manually reduced MPs and SPs, 1916 Thoroughbred mares were ultrasonically monitored every 2 days during oestrus to confirm ovulation, and up to Day 40 post-ovulation to confirm pregnancy. Ultimate pregnancy outcome was ascertained from the General Thoroughbred Stud book and classified as live foal (LF), early abortion (EA; Days 40-150), slipped foal (SF; Days 150-term), and bar...
Equine fetal sex determination using circulating cell-free fetal DNA (ccffDNA). In this study, polymerase chain reaction (PCR) reamplification of the first PCR product (2nd-PCR) and a qPCR assay were used to detect the sex determining region Y (SRY) gene from circulating cell-free fetal DNA (ccffDNA) in blood plasma of pregnant mares to determine fetal sex. The ccffDNA was isolated from plasma of 20 Thoroughbred mares (5-13 y old) in the final 3 mo of pregnancy (fetal sex was verified after foaling). For controls, plasma from two non-pregnant mares and two virgin mares were used, in addition to the non-template control. The 182 bp nucleotide sequence corresponding to the ...
