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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.
Prognostic value of endometrial biopsy in the mare: a retrospective analysis. A retrospective analysis was made of 79 endometrial biopsy specimens obtained from mares with histories of infertility. The specimens were classified into 3 standard prognostic categories, according to the severity of the histologic changes. The 36 mares that had few endometrial lesions (category I) had a foaling rate of 78%. The 29 mares that had more severe endometrial changes (category II) had a foaling rate of 55%. The 14 mares with the most severe endometrial lesions (category III) had a foaling rate of 35%. The pregnancy losses for each category were 9.7%, 23.8%, and 44.4%, respectively....
Influence of photoperiod on the pregnant and postpartum mare. Over a 2-year period, mares (n = 32) of predominantly Quarter Horse breeding and their foals were used to study the effects of photoperiod on reproduction during the periparturient period. Specific objectives of the study were (i) to evaluate the effects of an extended photoperiod regimen (16 hours' light) on gestation length, foal development, and postpartum reproductive performance, and (ii) to measure changes in plasma progesterone concentrations during the last trimester of gestation and plasma luteinizing hormone (LH) concentrations after foaling until ovulation. Mares in the extended day...
Lymphocyte alloantigens of the horse. I. Serologic and genetic studies. A genetic system controlling lymphocyte alloantigens of the horse is described. Alloantisera to paternal histocompatibility antigens induced as a result of pregnancy in mares were used in an antibody-mediated complement-dependent microcytotoxicity assay to define 15 Equine Leukocyte Antigen (ELA) specificities using cluster analysis. In this study 369 sera were screened for alloantibody using lymphocytes from 10 randomly selected, unrelated horses. A high proportion (83%) of these sera were found to be positive for antibody to lymphocyte alloantigens. After initial cluster analysis, 120 of the...
Twinning in mares: A survey of veterinarians and analyses of theriogenology records. Responses of 22 veterinarians to a questionnaire and the records of three brood-mare farms were examined to obtain information on twinning. The incidence rates of multiple ovulations on the three farms were 9%, 11%, and 22%. The multiple ovulation rate was reduced 42-67% in foaling mares compared to barren and maiden mares. Multiple ovulations were significantly more frequent in Thoroughbreds (19%) than in Quarter Horses (9%) and Appaloosas (8%). Both the questionnaire and the farm records indicated a high degree of repeatability of multiple ovulations and twin pregnancies within mares and wit...
The role of androgens in follicular development in the ovary. I. A quantitative analysis of oocyte ovulation. In an attempt to understand more fully processes that control the selection or recruitment of follicles for ovulation, the superovulation paradigm in combination with the androgen, 5 alpha-dihydrotestosterone, or the antiandrogens, cyproterone or cyproterone acetate, was used in the immature mouse to alter the developmental potential of follicles destined to ovulate or to become atretic. Quantitative analysis of the numbers of eggs ovulated after one or more rounds of stimulation by pregnant mare's serum gonadotrophin followed by human chorionic gonadotrophin (PMSG-hCG), revealed a dose-depend...
Limb deformities in foals associated with ingestion of locoweed by mares. Five of 26 pregnant mares observed ingesting locoweed (Astragalus mollisimus) subsequently aborted and another 10 produced foals with various limb deformities. Seven of the foals had deformities of a flexion-extension type and 3 had angular deformities. Four foals were normal. The limb deformities either resolved spontaneously (5 cases) or were treated successfully (in 4 of the other 5 cases). The problems of abortion and limb deformities were attributed to locoweed ingestion on the basis of the mares having eaten the plants, and the similarity of the syndrome to that previously reported in sh...
Development of horse embryos up to twenty two days after ovulation: observations on fresh specimens. Forty nine embryos, twenty unfertilized eggs and five other fresh eggs of 'doubtful' status have been recovered from 58 pony mares in 122 flushes up to 22 days after ovulation. The fresh egg or embryo recovery rate was 78% with surgical methods (or at slaughter) and 40-60% with non-surgical methods of recovery. The fertilization rate was about 70%. It has been confirmed that horse embryos normally enter the uterus as blastocysts 5-6 days after ovulation. Three features of early embryo morphology have become clearer upon comparison with unfertilized eggs of similar ages; early embryos are often...
Induction of parturition in the mare with prostaglandin F2 alpha. Thirty-one mares of Quarter Horse and Thoroughbred breeding were utilized in two experiments to evaluate the efficacy of prostaglandin F2 alpha (PGF2 alpha) for induction of equine parturition and to monitor the effects of this treatment on viability of the resulting foals. Three of five mares given 5 mg PGF2 alpha (im) on day 338 of gestation foaled 19.6+/-8.2 hr postinjection. In the second experiment immediately following 3 daily injections of 10 mg estradiol cypionate (ECP) given on days 326, 327 and 328 of gestation, seven mares were infused (iv) with PGF2 alpha at the rate of 1.3 mg/hr f...
[The use of amikacin in the treatment of endometritis caused by Pseudomonas aeruginosa in mares]. After isolation of Pseudomonas aeruginosa from endometrial biopsies of 6 mares they were treated with amikacin sulphate. Three were treated by intra-uterine application of the drug, in one the drug was given by intramuscular injection, in another the intravenous route was used while in the last mare simultaneous local and intravenous treatment was applied. An intra-uterine Tris-EDTA instillation preceeded the uterine amikacin instillations to aid in the breakdown of the capsule around the bacterium. Serum concentrations of amikacin were determined after intravenous and intramuscular administra...
Observation on the morphology of contagious equine metritis bacterial colonies isolated from infected pony mares. In uterine or cervical specimens obtained from pony mares infected with streptomycin-resistant contagious equine metritis bacteria, several colonies of the bacteria which differed in morphologic characteristics were recognized during their primary isolation on Eugon chocolate agar and tryptose chocolate agar plates. The differences were usually not observed until plates were incubated 10 to 15 days. On Eugon chocolate agar plates, smooth colony, sandy colony with rings, and colony with blebs were recognized. On tryptose chocolate agar plates, only a round smooth convex colony was observed. By ...
Serological investigation of horse sera for antibodies against mycoplasmas and acholeplasmas. Sera from horses with respiratory disease (RD) have been investigated using the complement fixation test, indirect hemagglutination test, enzyme immune assay, and the metabolic inhibition test, and sera from mares after abortion, using the complement fixation test, indirect hemagglutination test and enzyme immune assay, for antibodies against Mycoplasma equirhinis, M subdolum, M. equigenitalium, M. pulmonis, M. felis, Acholeplasma laidlawii, A. hippikon and A. equifetale. Antibodies were found against all mycoplasma and acholeplasma species tested, more often against acholeplasmas. The antibod...
[Two cases of tetany in the horse (author’s transl)]. Two cases of tetany in the horse are reported. The two patients were thoroughbreds. One was eight and the other thirteen years old. The mares were in heat and were brought to the service (stud) station to be mated. Both patients were nursing a foal. One was a four-week-old foal and the other was seven weeks old. The calcium level of the serum had dropped in the two patients, to 4.0 mg and 5.4 per ml. respectively. The magnesium level was 1.0 mg and 1.9 mg per 100 ml. respectively. The animals responded satisfactorily to intravenous infusion of calcium borogluconate and magnesium chloride. One ...
Equine abortion associated with Enterobacter agglomerans. During a 20 month period Enterobacter agglomerans was
isolated from 17 cases of equine abortion. In 8 cases E
agglomerans was isolated in pure culture and in 9 cases it was
isolated in mixed culture from the foetus and/or foetal
membranes. Fifteen cases had histological evidence of foetal
infection and/or placentitis.
The occurrence of E agglomerans in pure culture, associated
with inflammatory lesions in the foetus and foetal membranes,
suggests it to be a cause of abortion in mares.
Milk production of quarter horse mares during 150 days of lactation. Milk production was measured in fourteen Quarter Horse mares at seven stages of a 150-d lactation period. Mares were divided into two groups of seven and fed diets containing either soybean meal or soybean meal and urea as nitrogen supplements. Rations were isocaloric, contained approximately 12.5% crude protein and were fortified with vitamins and minerals. Daily milk yield was estimated by the weigh-suckle-weigh method and milk composition was determined from samples taken by hand milking. Average daily milk yield ranged from 11.8 kg in early lactation to 9.8 kg in late lactation. Difference...
[ECG similarities in the parents and offspring of thoroughbred horses]. The ECG characters were studied in two sires (Manrico and Infernal) and their 26-membered set of progeny as well as in one mare (Victoire) and her five daughters. The confer of some ECG characters from the sire's side as well as from the mare's side to the offspring was demonstrated. The consistency of some ECG characters was particularly obvious in externally dominant Manrico sire and his offspring as well as in the breeding mare and her five daughters (inclination of the electric cardiac axis, intrinsicoid deflexion lag, P wave shape, deep S in the 3rd connection).
