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This paper includes the study of early embryonic death (EED), predisposing factors of EED and treatment. EED refers to the fetal mortality which varies in mare and camelids but most probably not later than 50 days of gestation. This duration may be divided into very early mortality, early mortality and late embryonic mortality. This also varies in mare and camelids. There are different embryonic, maternal, environmental/external, and infectious and noninfectious factors which lead to early embryonic loss. Diagnosis is very difficult as in most of the cases resorption of fetus occurs but it is done by the use of ultrasound. Unfortunately, there is no treatment to avoid early embryonic mortality. However, new reproductive technologies have increased the service rate in a herd, and efforts are still being made to determine the rate and frequency of camel embryonic loss.

Two cloned mares, produced from the same sample of skin fibroblasts, were bred during four breeding seasons from their second year of age, as embryo donors, in exactly the same conditions, using the same stallions for both cloned mares. The aim of this study was to test the embryo donor potential of cloned mares and to compare the results obtained from two cloned mares of the same mare with other embryo donor mares (n = 31-39 per breeding season) at the same stud. For both cloned mares, 19 embryos were recovered by 43 collection attempts (44%) (7/22 for one; 12/21 for the other), 16 (84%) pregnancies (5/7 for one, 11/12 for the other) were obtained at day 14 post-ovulation (D 14 ), and 12 (3/7 for one; 9/12 for the other) foals were born. One cloned mare was a less efficient donor mare than the other (p < .05), In control donor mares, 623 embryo collections were performed, with a recovery rate (80%-496/623) significantly higher than for cloned mares. The recovery rate in the subpopulation of 2-5-year-old control donor mares (same age of cloned mares) (89%-127/143) and The recovery rate in the subpopulation of 12 control mares bred with the seven same stallions as clones (55%-17/31), were both higher than for cloned mare (p < .05). The success rate of transfer was not different between embryos produced by cloned mares (84%-16/19) and those produced by control donor mares (79%-392/496). However, the foaling rate per embryo collection was significantly lower for cloned mares (28%-12/43) than for control donor mares (52% - 325/623) (p < .05)., (© 2019 Blackwell Verlag GmbH.)

Protein profile of the placenta expresses its function and maintenance. Any alterations can be reflected in qualitative and quantitative changes in this profile. The aim of the present study was the evaluation of protein profile in the placenta of mares suffering from the retention of foetal membranes (FMR) by two separation methods and the comparison with physiologically released tissues. Placentas from 14 healthy, heavy draft mares were collected immediately after the expulsion of newborn. Tissues after homogenization and staining with fluorescent dyes were subjected to electrophoretic as well as chromatographic separation. Electrophoretic gels were statistically analysed for the presence and abundance of examined proteins, while some proteins were identified in chromatographic fractions. Out of 248 spots detected in endometrium, 38 differed significantly between FMR and control animals, while in allantochorion, respective values reached 241 and 27 spots (p < .05). Among identified proteins that expressed higher abundance in endometrium of FMR mares than control animals were prostaglandin reductase, dehydrogenase/reductase SDR family, and placental growth factor. These proteins are involved in regulation of parturition. Additionally, the following proteins responsible for physiological activity of a cell-guanine methyl transferase, aspartyl/asparaginyl beta-hydroxylase and GTP-binding protein, were identified. These proteins expressed higher abundance in allantochorion of FMR mares than in controls. This preliminary study confirmed the disturbances in protein pattern between foetal membranes in FMR and healthy mares. Further qualitative and quantitative experiments are necessary to deepen our knowledge on the mechanisms of the retention of foetal membranes in mares., (© 2019 Blackwell Verlag GmbH.)

The prolactin hormone is involved in several biological functions, although its main role resides on reproduction. As it interferes on fertility changes, studies focused on human health have established a linkage of this hormone to fertility losses. Regarding animal research, there is still a lack of information about the structure of prolactin. In case of horse breeding, prolactin has a particular influence; once there is an individualization of these animals and equines are known for presenting several reproductive disorders. As there is no molecular structure available for the prolactin hormone and receptor, we performed several bioinformatics analyses through prediction and refinement softwares, as well as manual modifications. Aiming to elucidate the first computational structure of both molecules and analyse structural and functional aspects related to these proteins, here we provide the first known equine model for prolactin and prolactin receptor, which obtained high global quality scores in diverse software's for quality assessment. QMEAN overall score obtained for ePrl was (- 4.09) and QMEANbrane for ePrlr was (- 8.45), which proves the structures' reliability. This study will implement another tool in equine genomics in order to give light to interactions of these molecules, structural and functional alterations and therefore help diagnosing fertility problems, contributing in the selection of a high genetic herd.

Objectives: To determine the sedative effects and pharmacokinetic profile of detomidine when administered intravaginally as a gel formulation to horses., Study Design: Randomized, crossover, masked experimental design., Animals: A group of six healthy adult mares (494 ± 56 kg)., Methods: Mares were studied on two occasions and were administered either detomidine hydrochloride (10 μg kg -1 ) intravenously (treatment IV) or detomidine gel (40 μg kg -1 ) intravaginally (treatment IVG), separated by 1 week. Sedation, ataxia, muzzle-floor distance and heart rate (HR) were evaluated every 15 minutes for 240 minutes. Venous blood samples were collected at 15, 30, 45, 60, 90, 120, 150, 180, 240, 300 and 360 minutes postadministration and were analyzed for detomidine and metabolites using liquid chromatography-tandem mass spectrometry. Measured variables were compared over time and between treatments using mixed model analysis. Correlation between drug plasma concentrations and muzzle-floor distance, and sedation and ataxia scores was determined using the Spearman correlation coefficient. Data are presented as mean ± standard error of the mean and p value was set at <0.05., Results: Sedation was shorter with IV (119 ± 16 minutes) than with IVG (188 ± 22 minutes). Ataxia scores remained greater than baseline for 90 and 135 minutes for treatments IV and IVG, respectively. HR was lower than baseline for 45 and 30 minutes for IV and IVG, respectively, but did not differ between treatments. The mean maximum plasma concentration of detomidine, time to maximum concentration and bioavailability for treatment IVG was 8.57 ng mL -1 , 0.37 hour and 25%, respectively. There was a significant correlation (r = 0.68) between plasma detomidine concentrations and sedation score., Conclusions and Clinical Relevance: Detomidine gel administered intravaginally resulted in clinically important sedation and is a viable method for detomidine gel delivery in mares., (Published by Elsevier Ltd.)

An inhibitor of PGF2α biosynthesis (flunixin meglumine, FM) was used to study the role of endogenous PGF2α on the luteolytic effect of exogenous PGF2α in mares. A 2-h infusion of PGF2α at a constant rate (total dose, 0.1 mg) on Day 10 (ovulation = Day 0) was used to mimic the maximal concentrations of a spontaneous pulse of a PGF2α metabolite (PGFM). Treatment with FM (1.7 mg/kg) was done 1 h before and 5 h after the start of PGF2α infusion. In hourly blood samples beginning 1 h before the start of PGF2α infusion, progesterone decreased (P < 0.05) similarly by 5 h in each of the PGF2α and PGF2α+FM groups but not in the controls (n = 5). In a study of spontaneous luteolysis, the same FM dose was given every 6 h from Day 13 until Day 17 or earlier if CL regression was indicated by an 80% decrease in luteal blood-flow signals. Blood was sampled for progesterone assay each day and 8 h of hourly blood sampling was done each day to characterize PGFM concentrations and pulses. Progesterone (P4) was lower (P < 0.05) in controls than in an FM group (n = 7) by Day 15. Luteolysis (P4 < 1 ng/mL) ended on Days 14-19 in individual controls. In contrast, luteolysis did not end until after Day 20 in 4 of 7 FM-treated mares. In the three mares with completion of luteolysis before Day 20 in the FM group, the interval from beginning to end of luteolysis was longer (P < 0.02) (4.5 ± 0.6 days) than in the controls (3.0 ± 0.4 days). During 8-h sessions of hourly blood sampling on Day 14, concentration of PGFM was significantly lower in the FM group for the minimal, mean, and maximal per session. Pulses of PGFM were identified by a CV methodology on each day in 7 of 7 and 3 of 7 mares in the controls and FM group, respectively. The four FM-treated mares without a CV-identified pulse were the four mares in which luteolysis did not occur before Day 20. In mares with detected pulses, PGFM was lower at each nadir and at the peak (86% lower) in the FM group than in controls, but the interval between nadirs or base of a pulse was not different between groups. Hypothesis 1 that endogenous PGF plays a role in the luteolytic effect of exogenous PGF2α was not supported. Hypothesis 2 that an inhibitor of PGF2α biosynthesis prevented or minimized the prominence of PGFM pulses and increased the frequency of persistent CL was supported., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Equine reproduction is unique by having long behavioral estrus and differences in time of breeding between breeds and individuals of mares. An experimental study was conducted at the Balderas Sport Horses and Recreational Center, Addis Ababa, Ethiopia, from January to June, 2018, to evaluate conception rate to frozen semen in local and exotic crossbreed mares. Mares were teased to characterize estrus behavior and examined by ultrasound in determining imminent ovulation. Inseminations were done post ovulation within an average of 6-9 h using frozen-thawed semen. The overall conception rate to frozen semen was 15/21 (71.43%) with 8/11 (72.73%) in crossbreed and 7/10 (70%) in local breed mares. Age and body condition score (BCS) of animals had no significant effect on conception rate to AI with frozen semen. A slightly higher conception rate was obtained when ovulation was from the right ovary than when ovulated from the left ovary. A higher conception rate was obtained when the diameter of the preovulatory follicle was ≤ 45 mm than above diameter. The conception rate increased significantly with increased number of services/conception with an overall mean ± (SEM) of 2.2 ± 0.2 services/conception. A more number of services/conception were required for local breed (2.7 ± 0.2) than crossbreed mares (1.8 ± 0.3) and again for lower body condition scores than higher condition scores of mares. In conclusion, the increased number of services improved the conception rate with significant difference between breed of mares, whereas good management of mares for improved body conditions could be required to decrease the number of services per conception.

Endometritis consists of an acute or chronic inflammatory process involving the endometrium and together with endometrosis constitute the main causes of infertility in mares. The aim of this study was to associate the histopathological findings with the immunohistochemical markers interleukins 6 (IL-6) and 10 (IL-10) to evaluate the inflammatory changes and progression of uterine tissue lesions of mares in the diestrus phase and their diagnostic implications. Twelve crossbred cyclic mares were used for endometrial biopsy collection. Samples were collected in the diestrus period (6 ± 1 day after ovulation) without previous artificial insemination. In the histopathological analysis the samples were classified according to the type and intensity of inflammation, alterations regarding endometrial fibrosis and biopsy categories (I, IIA, IIB and III). In the immunohistochemical analysis, the markers of IL-6 and IL-10 were evaluated by scores (0, 2, 4, 6) according to the intensity of the immunostaining and inflammatory cells (CD-3, CD-20, CD-68 and MPO antibodies) and were counted according to the number of cells immunostained in brown, in ten random fields. An association (p ≤ 0.05) occurred between low score (2) for IL-6 in the endometrial glandular area and moderate fibrotic nets; and between high scores (4 and 6) for IL-10 in sub-epithelial connective tissue and moderate periglandular fibrosis. In conclusion, immunohistochemical analysis demonstrated an association between interleukins and inflammatory cells with endometrial lesions. In addition, this research may be useful in the future to evaluate the progress of the inflammatory process, contributing to the adequate optimization of the reproductive management of the mares.

Effect of side (left ovary, LO; right ovary, RO) and intraovarian presence of the regressing corpus luteum (CL) on the preovulatory follicle (PF) and ovulation were studied using ultrasonic- records of complete interovulatory intervals (IOI) for 500 IOI in heifers and 485 IOI in mares. Only IOI with a recording of side of a single PF and a single CL at each end of the IOI were used. In heifers, ovulation at the end of the IOI occurred more frequently (P < 0.0001) from RO (n = 285, 57%) than LO (n = 215, 43%). In mares, frequency of ovulation did not differ between RO (n = 250. 52%) and LO (n = 235, 48%). In heifers but not in mares, the number of predeviation follicles has been reported to be greater in RO than LO. In heifers, RO ovulation was more frequent when CL was in PF ovary (66%) than when CL was in opposite ovary (50%). There was no difference in side of ovulation (RO, 50%, LO, 50%). In mares, there were no significant main effects or interactions for frequency of ovulation involving side and intraovarian presence of the CL. On a species comparative basis, the present and reported results supported hypothesis 1 that a greater number of predeviation follicles in RO than in LO is associated with the predilection for RO ovulation. Results also supported hypothesis 2 that ovulation from RO in heifers is more frequent when RO contains the regressed CL than when the CL is in LO., (Copyright © 2018 Elsevier B.V. All rights reserved.)

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. The concentration of progesterone (P4), testosterone (T) and estradiol (E2) in follicular fluid (FF) was measured by radioimmunoassay. AR distribution was assessed by immunohistochemistry, while AR protein expression was examined by Western blot analysis. In the female groups, E2 concentration in FF of small follicles (<10 mm) was low and increased with the diameter of the follicle reaching the greatest value in pF (Ov/pB and Me group). In follicles (11-30 mm) of PrP fillies, the concentration of E2 was similar to that from Ov/pB fillies, but less than half (P < 0.05) than in Me follicles. In FF from all classes of follicles of Ov/pB fillies, the concentration of all steroids was similar to that in Me. AR immunolocalization, predominantly nuclear, was observed in all types of follicular cells (granulosa and theca cells) as well as in stroma and luteal cells. The pattern of staining was dependent on the follicle size and the group of females. In smaller antral follicles and in pF, the nuclear AR staining in granulosa cells was stronger than that found in follicles of 21-25 mm. In theca interna cells of pF, both nuclear and faint cytoplasmic reactions were seen. In luteal cells, AR labeling was noted in the nuclei and the cytoplasm: the strongest one in the early CL and almost negative in the late CL. AR protein expression in filly and mare ovarian tissues was confirmed by Western blot analysis and detected as a single band at approximately 110 kDa. In summary, the ovaries of fillies aged at least 6 months are capable of active steroidogenesis. ARs are present either in the cell nuclei or cytoplasm of all compartments of the equine ovary. AR expression in follicular and stroma cells may indicate the sensitivity of the filly ovarian tissue to androgens, the impact of androgens on folliculogenesis and the development of the equine ovary via a receptor-mediated pathway., (Copyright © 2018 Elsevier Inc. All rights reserved.)

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 responses among mares treated with SpayVac (VacciMax formulation) to improve our understanding of vaccine efficacy and potential management applications. We analyzed serum samples collected 1, 2 and 4 years post-vaccination from mares in another study that were continuously infertile or had foaled at least once during the 4-year period (n = 14 each). Additional samples from the continuously infertile mares were collected 5 years post-vaccination. A fluorescent bead-based assay was used to distinguish IgG isotype responses against pZP. IgG1 antibodies were generally higher in the infertile compared to the fertile mares, but only IgG4/7 antibodies were significantly higher in infertile mares during years 1 and 2 post-vaccination (p < 0.05). Interestingly, IgG4/7 isotype levels were significantly higher during year 5 compared to year 4 in the continuously infertile mares (p < 0.02). SpayVac's ability to preferentially stimulate IgG4/7 antibodies may contribute to its long-term immunocontraceptive efficacy, and measuring IgG4/7 isotypes may help differentiate effectively contracepted mares from those that may need additional vaccination., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Early and definitive separation between offspring and their mothers has negative consequences on behavioral and physiological responses. This study compared sudden and definitive weaning (Sudd group, N = 16) and weaning involving progressive habituation to separation using a fence line during the month preceding definitive separation (Prog group, N = 18). The impact of these two methods was assessed in both foals and their mothers through behavioral and biological parameters, including salivary cortisol, telomere length and blood transcriptomes. On the day of definitive separation, Prog foals neighed and trotted less and presented lower cortisol levels than Sudd foals. The weaning type also acted on the foals' personality development; Prog foals became more curious, less fearful and less gregarious than Sudd foals, and the effects remained visible for at least 3 months. In principal component analysis, the Sudd and Prog groups were well separated along a factor where fear, reactivity and gregariousness correlated with high cortisol levels, but curiosity was associated with an increased telomere length and higher expression of genes involved in mitochondrial functions. Progressive weaning was also beneficial in mares. Principal component analysis showed that most Sudd group mares had higher cortisol levels and displayed more alert postures, neighs and activity on the day of weaning, indicating higher stress levels, while Prog mares had profiles that were characterized by more time spent resting on the day of weaning and longer telomere lengths. In conclusion, this study shows that progressive habituation to separation alleviates the negative effect of definitive weaning on both the mother and her young compared to sudden separation., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Growth hormone (GH) and insulin-like growth factor (IGF-I) exert essential functions to maintain an adequate metabolic activity for correct placental and fetal development. Although fructosamine (FRUCT) is used in clinical evaluation to assess the glycaemic state, the relationships between GH, IGF-I and FRUCT remain unknown in the mare. Therefore, the objectives of this study were to evaluate the relationships among these parameters in pregnant mares. A total of 30 healthy Spanish Purebred mares, with an age range of 9.33 ± 3.31 years, were studied during the 11 months of gestation. Serum concentrations of GH, IGF-I and FRUCT were analyzed by EIA, competition ELISA and spectrophotometry, respectively. GH showed a biphasic pattern, the first occurred during 4th and 5th month and the second which was higher than the 1st one during the 7th, 8th and 9th month (P < 0.05). Compared to the 1st month, the IGF-I concentrations increased in the 2nd month (P < 0.05), decreased in the 3rd and 4th month and increased to reach the maximum average value in the 5th month (P < 0.05); after slight oscillations between the 6th and 8th month, IGF-I concentrations increased in the 9th month (P < 0.05), decreasing until the end of gestation. FRUCT increased progressively and significantly from the 6th month of gestation, reaching the maximum values in the last month of gestation (P < 0.05). These results suggest that alternative mechanisms other than GH and IGF-I could be involved in the regulation of glycaemic metabolism in pregnant mare., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Diameter deviation or follicle selection during a follicular wave begins with continuous growth rate of F1 (dominant or selected follicle; DF) and decreasing growth rate of F2 (largest subordinate). Intraovarian patterns based on presence or absence of the DF and CL are DF-CL, DF, CL, and devoid (neither DF nor CL). The DF and CL relationships in a pair of ovaries are ipsilateral (DF-CL pattern and devoid pattern) and contralateral (DF pattern and CL pattern). The effects of patterns and relationships on F1, F2, and FSH during deviation were determined in 21 mares. Diameters of F1 and F2 at expected beginning of deviation (F1, 22.5 mm; day 0) defined deviation classifications of conventional (F2 ≥ 18.5 mm on day 0), F2-undersized (F2 < 18.5 mm), and F1,F2-switched (F2 larger than F1 on day -1 or 0). During the decline in the FSH surge, an interaction (P < 0.001) of deviation classification and day indicated that FSH concentration was greater (P < 0.05) in undersized than in conventional deviations on days -3 and -1 and intermediate in switched deviation. Low FSH during days -3 to -1 in switched deviation began to increase on day -1 during switching in diameter rank between F1 and F2. The number of subordinate follicles per wave that attained a maximum of 11 to <16 mm was greatest in the DF-CL and devoid patterns and in ipsilateral (4.2 ± 0.5 follicles) than in contralateral (2.5 ± 0.7) relationships (P < 0.03). Concentration of FSH was greater (P < 0.04) on days -4 to 5 in ipsilateral (5.3 ± 0.2 ng/mL) than in contralateral (4.2 ± 0.4 ng/mL) relationships consistent with more follicles 11 to < 16 mm. In a survey (N = 63), an ipsilateral vs contralateral relationship was associated with 17 vs 17 conventional deviations and 7 vs 22 nonconventional deviations (P < 0.04), and conventional deviation (54%) was more frequent (P < 0.0001) than undersized (21%) or switched (25%) deviations. Results supported the hypotheses that (1) diameter deviation can be classified in mares into distinct categories based on diameter and rank of the future largest subordinate at expected deviation, (2) the number of subordinate follicles is influenced by ipsilateral vs contralateral relationships of DF and CL, and (3) conventional deviation is more common when the relationship between DF and CL is ipsilateral. Knowledge on follicle diameters for the different deviation classifications should be considered in studying follicle selection especially when terminal follicle sampling is done before expected deviation., (Copyright © 2018 Elsevier Inc. All rights reserved.)

This study aimed to correlate the inflammatory reaction (IR) caused by a progesterone-releasing intravaginal device (P4) with ovarian activity and pregnancy rate (PR) in embryo-recipient anestrus mares (to decrease the spring transitional period). 50 animals were assigned to three groups: GP4 (P4 group; n = 16), GP4OH (P4 + oxytetracycline hydrochloride and hydrocortisone sprayed onto the device; n = 14), and GNP4 (no intravaginal P4; n = 20). The administration protocol for GP4 was: Day 0, 750 mg P4 + ovarian examination by ultrasonography (US) + vaginal sample collection; Day 8, US; Day 11, P4 removal + 7.5 mg PGF2α + US + second vaginal sample collection; Days 13 to 16, US; Days 17 to 21, US + 750 IU hCG to mares with follicles 35 mm or more in diameter; Days 19 to 23 US (ovulation check); Days 24 to 28, embryo transfer + intravenous flunixin meglumine; and Days 30, US pregnancy diagnosis. The GP4OH and GNP4 mares received the same administration protocol as GP4, except that no P4 device was administered to the GNP4 group on Day 0. Although neutrophil-mediated IR occurred in the GP4 and GP4OH groups, the IR was significantly reduced in GP4OH as compared with that in GP4 (P < 0.0001). From Day 0 to Day 17, the GP4 and GP4OH mares developed a greater number of follicles per animal than did the GNP4 mares (P < 0.05), and the average diameter of the follicles was larger in the GP4 and GP4OH mares. The ovulation rates in GP4, GP4OH, and GNP4 mares were, respectively, 43.7%, 64.3%, and 30.0%, and ovulation occurred at 6.8, 6.5, and 23 days after P4 removal (P < 0.05). On Day 17, endometrial edema was verified in 50%, 64.2%, and 35.0% of the GP4, GP4OH, and GNP4 mares, and the PRs after embryo transfer were 80%, 100%, and 66.6%, respectively. Although intravaginal devices caused IR in both the device-recipient groups (P = 0.0001), IR and vaginitis had no negative impact on follicle diameter, ovulation rate, period to ovulation after the removal of P4, endometrial edema, or PR. In addition, P4 reactivated the ovarian function and the IR eliminated a large percentage of bacteria (Bacillus spp., Enterobacter spp., Proteus spp., Pseudomonas spp., and Staphylococcus spp.), especially in GP4; the application of oxytetracycline hydrochloride and hydrocortisone on the devices reduced the severity of vaginitis., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Managing the return to regular cyclicity after the winter anestrous period in the mare has been a challenge for the equine breeding industry. Specifically, efforts have been made to shift or shorten the vernal transition period and to have it followed by a predictable first ovulation at the commencement of the breeding season. Intravenous administration of kisspeptin is known to stimulate an LH response in both reproductively active and inactive mares. This study examined the effects of a constant rate infusion (CRI) of kisspeptin on mares during vernal transition. Mares were given a 30 hours infusion of kisspeptin at a low and high rate (66 nmol [88 μg] and 100 nmol [130 μg] per hour, respectively) or saline, and the LH and follicular response tracked. Plasma samples were collected every 15 minutes for the first 6 hours to determine if there is an acute effect of kisspeptin infusion on LH secretion. Plasma samples were then collected every 3 hours for a total of 72 hours to examine the ability of kisspeptin to stimulate an LH surge. A CRI of kisspeptin increased LH secretion in these mares but was not able to stimulate an LH surge. To examine the effect of kisspeptin on ovarian activity, follicular measurements were collected ultrasonographically until ovulation occurred or the follicles regressed. CRI of kisspeptin at these rates was unable to induce ovulation earlier than controls., (Copyright © 2016 Elsevier Inc. All rights reserved.)

The objective of this study was to compare in detail the total and free iodothyronines' pattern of mares from the first ovulation of the year over an extended period of 12 weeks. A total of 20 mares were used in the study. The mares were classified into two groups: mares mated at the ovulation (n = 10) used as observational group and mares unmated at the ovulation (n = 10) used as control group. Serum total and free triiodothyronine (T3, fT3) and thyroxine (T4, fT4) levels were measured in baseline conditions at the first ovulation of year and once a week until 12 weeks later. For the experimental group, the first week of postovulation mating was considered as the first week of gestation. One-way analysis of variance showed a significant effect of time over 12 weeks for T3 (F = 2.44; P = 0.007) in pregnant mares, with the higher levels at the seventh and 12th weeks (P < 0.05) than baseline values, and for fT3 (F = 2.36; P = 0.009), with the higher levels at the 11th week (P < 0.05) than baseline values. Two-way analysis of variance showed a significant pregnancy effect compared with nonpregnancy stage for T3 (F = 15.82; P = 0.009), with the higher levels at the seventh and 12th weeks (P < 0.05) of pregnancy than that in nonpregnant values. Thus, it appears that, under similar environment, management and nutritional regime, the first trimester of pregnancy plays a dynamic role on the thyroid patterns by their anabolic activity; therefore, significant effects of time points on the T3 and fT3 concentrations probably may contribute to the control of early embryonic growth and development, before the onset of fetal thyroid activity. Considerable additional research, outwith the aim of this study, will be required to elucidate the mechanisms by which gestational age affects the physiological thyroid function in mares and/or fetus ratio in the first pregnancy stage., (Copyright © 2016 Elsevier Inc. All rights reserved.)

A procedure for oxytocin (OT) administration on Day 13 postovulation was developed in mares for stimulation of a pulse of PGFM (a PGF2α metabolite) that mimics a natural PGFM pulse during luteolysis. Bolus treatment with each of five OT doses (1-10 IU/mare, n = 3) stimulated a burst of PGFM that was maximum in 4 minutes and was unlike a natural pulse. A 2-hour OT infusion of 1.25, 2.5, or 5 IU/100 kg (n = 4) induced a PGFM pulse similar to reported pulses; lower doses did not. The peak of an induced pulse (approximately 260-380 pg/mL) seemed similar to reported natural peaks (approximately 200-300 pg/mL), using the same assay system. The interval from nadir to nadir was 6.6 ± 0.2 hours. Percentage decrease in progesterone (P4) within 8 hours was greater (P < 0.05) for doses of 1.25, 2.5, or 5 IU/100 kg (43%-50%) than that for a vehicle group (11%). Treatment with flunixin meglumine (1.0 mg/kg), a cyclooxygenase inhibitor, decreased (P < 0.008) P4 concentration, but treatment 2 hours before the beginning of OT infusion (2.5 IU/100 kg) did not prevent the OT-induced PGFM pulses and the decrease in P4. In conclusion, a PGFM pulse was simulated by infusion of OT during 2 hours but not by a single OT bolus, and an OT-simulated PGFM pulse stimulated a decrease in P4 that was not prevented by a cyclooxygenase inhibitor. These are the first firm demonstrations that OT in mares as in other species has a role in luteolysis., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Doppler ultrasonography is a noninvasive technique which enables us to follow the physiologic and physiopathologic changes in blood flow in tissues. It is becoming an essential tool in veterinary medicine, especially in theriogenology. Twenty-seven Arabian mares were grouped by age ('young', 3-10 y, n=15; 'old', 19-23 y, n=12). The uterine arteries of the mares were examined using Doppler ultrasonography when an ovarian follicle ≥35mm was visible (Day -1). After these measurements, human chorionic gonadotropin (hCG; 2500IU) was administered to 14 mares selected randomly. One day later (Day 0) Doppler ultrasonography was repeated and then the dominant follicles were aspirated to collect follicular fluid in all groups. On the next day (Day +1), Doppler indices of the uterine artery blood flow were measured again. Blood samples were also collected just prior to ultrasonography, for measuring serum estradiol and progesterone levels. We found that preovulatory hCG administration had no significant effects on uterine artery blood flow indices, or serum or follicular fluid estradiol concentrations. The uterine artery resistance index might decrease in young mares after ovulation, possibly because of increased uterine perfusion., (Copyright © 2014 Elsevier B.V. All rights reserved.)

The concentrations of carboxyterminal cross-linked telopeptide of type I collagen (CTx), osteocalcin (OCN), parathyroid hormone (PTH) and insulin-like growth factor (IGF-I) were measured in the blood serum of two age groups of mares during late pregnancy (70-50 days before foaling), during early lactation and at the peak of lactation (10-30 and 55-80 days after foaling, respectively). During late pregnancy, the PTH was higher in older (8-19 years old), compared to younger animals (3.5-4 years old) (P < 0.05). The OCN was higher in younger group during late pregnancy (P < 0.05). IGF-I was higher in the younger group during early lactation, in comparison to late pregnancy and the peak of lactation (P < 0.05). IGF-I did not differ between two age groups of mares. The results indicate on the differences in adaptation of bone metabolism to late pregnancy and lactation in older animals, in comparison to younger animals, reflected by elevated PTH secretion., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

The effects of inhibition of PGF2α synthesis on luteolysis in mares and on the incidence of prolonged luteal activity were studied in controls and in a group treated with flunixin meglumine (FM), a PGF2α inhibitor (n = 6/group). The FM was given every 8 hours (1.0 mg/kg) on each of Days 14.0 to 16.7. Concentration (pg/mL) of PGF2α metabolite averaged over 8 hours of hourly blood sampling at the beginning of each day, was lower in the FM group than in the controls on Day 14 after ovulation (6.7 ± 1.3 vs. 13.8 ± 2.9, P < 0.05), Day 15 (15.0 ± 3.9 vs. 35.2 ± 10.4, P < 0.10), and Day 16 (21.9 ± 5.7 vs. 54.7 ± 11.4, P < 0.03). Concentration (ng/mL) of progesterone (P4) was greater in the FM group than in the controls on Day 14 (10.1 ± 0.9 vs. 7.7 ± 0.9, P < 0.08), Day 15 (9.2 ± 1.0 vs. 4.3 ± 1.0, P < 0.008), and Day 16 (5.6 ± 1.6 vs. 1.2 ± 0.4, P < 0.02). The interval from ovulation to the beginning of a decrease in P4 and to the end of luteolysis (P4 < 1 ng/mL) was each delayed (P < 0.03) by ~1 day in the FM group. Intervals involving the luteal phase were long (statistical outliers, P < 0.05) in two mares in the FM group, indicating prolonged luteal activity. Results supported the hypotheses that (1) inhibition of PGF2α synthesis interferes with luteolysis in mares and (2) inhibition of PGF2α at the expected time of luteolysis may lead to prolonged luteal activity., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Relatively little is known about the physiological roles of microRNAs (miRNAs) during follicular development. Previous evidence from in vitro studies suggests specific roles for a subset of miRNAs, including miR-21, miR-23a, miR-145, miR-503, miR-224, miR-383, miR-378, miR-132, and miR-212, in regulating ovarian follicle development. The objective of this study was to gain insight on the involvement of these miRNAs during follicle maturation. Follicular fluid was aspirated from dominant follicles (>32 mm) during the ovulatory season (July to October) and the anovulatory season (January to March) in each of 5 mares, and the levels of steroids, IGF1, and miRNAs were analyzed by immunoassays and quantitative PCR. Levels of progesterone, testosterone, and IGF1 were lower (P ≤ 0.05) in anovulatory than in ovulatory follicles. Relative to ovulatory follicles, anovulatory follicles had higher (P < 0.05) mean levels of miR-21, miR-23b, miR-378, and miR-202 and tended to have higher (P = 0.06) levels of miR-145. Levels of miR-224 and miR-383 could not be detected in follicular fluid. These novel results indicate a physiological association between increases in follicular miRNA levels and seasonal anovulation in mares; further studies should elucidate the precise involvement of miR-21, miR-23b, miR-145, miR-378, and miR-202 in follicle maturation in the mare., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Background Case reports Conclusion Equine Coronavirus (ECoV) can cause gastrointestinal disease and was first described in 2000 in the USA followed by several international outbreak case reports. Disease manifestation is characterised by vague clinical signs, including mild pyrexia, lethargy and anorexia. Morbidity ranges greatly from 10% to 83%. Although uncommon, ECoV may result in death secondary to disruption to the gastrointestinal barrier causing endotoxaemia and hyperammonaemic encephalopathy. Unfortunately to date, there is no vaccine available to prevent ECoV.Three faecal quantitative polymerase chain reaction (qPCR)‐positive ECoV cases are described that presented with mild to severe colic signs: a 2‐year‐old Miniature Pony gelding from South Australia, an 8‐year‐old Arabian Riding Pony gelding, and a 6‐year‐old Warmblood mare, both from Western Australia. The diagnosis was based on a positive faecal qPCR, which is currently the gold standard diagnostic tool. All horses in this case series survived after medical management. The Miniature Pony presented with anorexia and mild colic signs. On day 5, the pony revealed severe colic signs unresponsive to analgesia along with severe abdominal distension secondary to caecal distension requiring surgical intervention.To the authors' knowledge, this case series is the first published report of ECoV cases in Australia, and it adds both to the clinical description of the disease in horses and to the differential diagnosis list of colic signs. [ABSTRACT FROM AUTHOR]

Simple Summary: Herds of free-roaming, unowned horses can grow rapidly on rangelands with limited resources. Contraception can offer a humane, publicly acceptable method for slowing or stopping horse population growth and protecting the range. The best-tested and most widely used contraceptive for wild horses, porcine zona pellucida (PZP), a protein-based vaccine, has successfully stabilized or reduced free-roaming horse herds in different environments. While extensive research has shown that the PZP vaccine is safe, concerns still exist about its possible effects on the behavior and well-being of treated mares, and especially the survival of their offspring. Reporting the results of an eight-year study of PZP contraception in wild horses at two sites in the western USA, we show here that mares without foals improved the body condition faster than mares with foals. We also found that the foaling seasons of the PZP-treated herds were later in the year and more spread out. However, deaths of the foals born to PZP-treated mares through their second year of life were very rare and no more frequent than those of foals born to untreated mares. Thus, at our study sites, the timing of breeding was changed by PZP treatments, but we found no evidence that these changes were harmful either to the treated mares or their foals. Wildlife managers and the public have expressed considerable interest in the use of contraception to help manage the populations of wild horses and burros (Equus caballus and E. asinus). Field testing has shown that two preparations of the porcine zona pellucida (PZP) vaccine, a simple emulsion (ZonaStat-H) and PZP-22 (which supplements ZonaStat-H with a controlled-release component) effectively prevent pregnancy in individual mares and can substantially reduce population foaling rates. To determine whether some PZP preparations might have secondary effects that harm treated mares or their foals, we examined the effects of PZP-22 vaccinations and the follow-up boosters of either PZP-22 or ZonaStat-H on adult female body condition, foaling season, and foal mortality in two wild horse herds in the western USA, Cedar Mountains Herd Management Area, Utah (CM; 2008–2015), and Sand Wash Basin Herd Management Area, Colorado (SWB; 2008–2014). At both sites in every study year, summer body condition scores improved faster in mares without foals than mares with foals (p < 0.001; CM, n = 234; SWB, n = 172), but PZP treatments did not affect mare body condition apart from their contraceptive effects. Births to mares treated with PZP within the previous three years were delayed and spread out over the foaling season, but foal mortality rates through the first and second year were low, unrelated to date of birth, and virtually identical for the foals of PZP-treated and untreated mothers (all comparisons n.s.; CM, n = 775, SWB, n = 640). Thus, in these two populations, we found no evidence that changes in reproductive timing associated with PZP treatments were harmful to either mares or foals. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Slow hoof growth poses a clinical challenge when hoof wear exceeds natural growth. Many treatment options have been reported without controlled prospective trials. The objective of this study was to evaluate the effect of transdermal CO2 on the rate of growth in treated hooves. METHODS: A prospective, randomized, blinded, crossover study of 14 Warmblood mares. Horses were randomly assigned a number and allocated for treatment of the front feet with room air or CO2 for 30 minutes 3 times per week, and groups were switched after 5 weeks. Hoof growth was measured on the dorsal midline and the quarters of each front foot. The distance from coronary band to lines made on the hoof wall was measured at the beginning, middle, and end of the study. The percentage of change in length at each location relative to baseline was evaluated at 5 weeks and 10 weeks using nonparametric analyses. RESULTS: All treatments were successfully administered. The left front medial (P = .028) and right front lateral (P = .03) sites of the CO2-treated hooves increased growth compared to the room air group at the 5-week point. CONCLUSIONS: The Results of this study suggest that repeated, noninvasive transdermal application of CO2 may accelerate hoof growth in normal horses over a 5-week treatment period. CLINICAL RELEVANCE: This study suggests that transdermal CO2 may increase the rate of hoof growth in normal horses. The mechanism of action of this treatment is unclear, and further studies are required to fully elucidate the potential effects. [ABSTRACT FROM AUTHOR]

Background: Understanding and finding the correlation between morphometric measurements and horse blood parameters is crucial for predicting equine metabolic issues. Objective: This study aims to analyse morphometric measurements and blood samples in horses with varying adiposity levels. Study design: Cross‐sectional observational. Methods: A total of 50 horses were included in the study and categorized into groups based on their body condition score (BCS) and cresty neck score (CNS). Results: The insulin concentration was significantly higher in overweight horses (p = 0.022). Female horses exhibited higher cortisol concentrations (p = 0.025) and girth circumference at the withers (p = 0.004) compared to males. Lactating mares exhibited higher concentrations of serum total protein (p = 0.012) and globulin (p = 0.003). A positive correlation was observed between BCS and insulin concentrations (r = 0.290, p = 0.041). Negative correlations were found between neck circumference to height at withers and glucose (r = −0.309, p = 0.029), CNS and glucose (r = −0.315, p = 0.026) as well as between crest diameter and cortisol (r = −0.360, p = 0.01). Main limitations: Increasing the sample size and conducting longitudinal studies would enhance the study's validity and reliability. Conclusion: Although insulin, glucose and cortisol concentrations have predictive capabilities based on signs and certain morphometric measurements, their correlations are not always strong. Therefore, this study challenges the notion that all overweight horses are unhealthy, as overweight horses can still have good metabolic health. Conversely, lean horses may also experience metabolic issues. Hence, relying solely on visual cues is insufficient to diagnose the metabolic status of horses. Other factors must also be considered to assess their health status accurately. [ABSTRACT FROM AUTHOR]

In the past, small population sizes and unequal ancestor contributions have resulted in high inbreeding rates (ΔF) in the Friesian horse. Two decades ago, the studbook implemented a mating quota and started publishing individual kinships and reduced ΔF below 1% per generation. However, since then, the breeding population size has decreased and this raises the question whether current breeding strategies are sufficient to keep ΔF below desired rates. The aim of this study was to (1) reflect on past inbreeding trends and their main determinants, using pedigree analysis and (2) evaluate the effectiveness of the current and additional breeding strategies using stochastic simulations. We estimated the current ΔF (2013–2022) at 0.72% per generation. While the total contribution of the top 10 sires to the number of offspring per year has decreased from 75% in 1980 to 35% in 2022, this was mainly due to an increased number of approved studbook sires, and not due to more equalized contributions among sires. Of the simulated breeding strategies, selecting only breeding stallions with a below average mean kinship (i.e., "mean kinship selection") was most effective to decrease ΔF (from 0.66% to 0.33%). Increasing the number of breeding sires only had an effect when also a mating quota was applied. However, its effect remained limited. For example, a ~1.5 fold increase, combined with a mating quota of 80 offspring per sire per year, reduced ΔF from 0.55% to 0.51%. When increasing the number of breeding mares, a practically unfeasible large increase was needed for a meaningful reduction in ΔF (e.g. twice as many mares were needed to reduce ΔF from 0.66% to 0.56%). Stratified mating quotas, a novel approach in which we assigned each sire a mating quota (of 60, 80, 100 or 120 offspring per year) based on its mean kinship to recently born foals, resulted in a lower ΔF (0.43%) than a general mating quota of 90 offspring per sire per year (0.55%). Overall, while the current ΔF is below 1%, we recommend to implement additional strategies to further reduce ΔF below 0.5% in the Friesian horse population. For this breed and similar populations, we recommend to focus on breeding strategies based on kinship levels to effectively reduce ΔF. [ABSTRACT FROM AUTHOR]

This report describes a multicentric intermediate‐size B‐cell lymphoma with epitheliotropism in a Freiberger mare affecting multiple mucous membranes, skin and internal organs. The clonal neoplastic B‐cell population was accompanied by numerous reactive polyclonal small T cells. Differential diagnoses for these unusual findings are discussed. [ABSTRACT FROM AUTHOR]

Finnhorse is Finland's native and national horse breed and it has genetic affinities to northern European and Asian horses. It has historical importance for agriculture, forest work and transport and as a war horse. Finnhorse has four breeding sections in the studbook and is under conservation and characterisation efforts. We sequenced and annotated the genome of a Finnhorse mare from the working horse section using PacBio and Omni‐C data. This genome can complement the existing Thoroughbred reference genome (EquCab 3.0) and facilitate genetic studies of horses from northern Eurasia. We assembled 2.4 Gb of the genome with an N50 scaffold length of 83.8 Mb and the genome annotation resulted in a total of 19 748 protein coding genes of which 1200 were Finnhorse specific. The assembly has high quality and synteny with the current horse reference genome. We manually curated five genes of interest and deposited the final assembly in the European Nucleotide Archive under the accession no. PRJEB71364. [ABSTRACT FROM AUTHOR]

A correct diagnosis of lameness necessitates the accurate interpretation of both the clinical examination and the radiological findings. The objective of this study was to identify the typical radiographic characteristics of the distal phalanx in a mature, healthy Caspian horse. The study population consisted of 10 mature Caspian horses. The samples consisted of five mares and five stallions of a similar size and weight, and they underwent the same training and management procedures. Radiographic imaging of the distal phalanx and associated soft-tissue structures of the front feet of horses was conducted. Subsequently, lateromedial (LM) radiographic views of each front distal phalanx were employed to ascertain pertinent distances, angles, and ratios pertaining to the hoof wall. To obtain the actual distances, the measurements from the latero-medial radiographs were multiplied by the magnification correction factor. The mean ± SD thickness of the soft tissues dorsal to the proximal and distal aspects of the distal phalanx was 12.55 ± 0.39 and 11.73 ± 0.71 mm, respectively. The average D-founder measurement was 8.17 mm. No statistically significant difference was observed between the right and left digits. In conclusion, the results of this study indicate that the normal parameters of the Caspian horse were obtained and compared with those of ponies and warm-blooded horses. The parameters obtained from the Caspian horse were found to be lower than those observed in warm-blooded horses and ponies, which may be attributed to the smaller size of their feet. These differences underscore the significance of investigating morphometric variables across diverse breeds. [ABSTRACT FROM AUTHOR]

A 17-y-old Arabian mare was presented to the Auburn Large Animal Veterinary Teaching Hospital with a long-term history of intermittent mild recurrent colic that responded to medical treatment. CBC revealed mild lymphopenia; serum biochemistry findings were of increased gamma-glutamyl transferase and creatine kinase activities, hyperferremia, hyperglycemia, hypomagnesemia, and hypokalemia. Abdominocentesis was compatible with low-protein transudate. Due to the progression and duration of clinical signs, the owner elected euthanasia. Postmortem examination and histopathology confirmed a cholangiocarcinoma. The neoplastic cells were arranged in large cysts containing lakes of mucin that comprised 90% of the tumor volume; thus, a mucinous variant was determined. The neoplastic cells had strong cytoplasmic immunolabeling for cytokeratin 19 and lacked immunolabeling for hepatocyte paraffin 1, supporting bile duct origin. Cholangiocarcinomas are infrequent tumors in horses with nonspecific and slow progressive clinical signs, including recurrent colic. Mucinous cholangiocarcinomas are seldom reported in veterinary medicine and, to our knowledge, have not been reported previously in horses. [ABSTRACT FROM AUTHOR]

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Simple Summary: Understanding the genetic makeup of microorganisms provides information on their evolutionary relationship with other similar organisms. It also sheds light on their ability to cause disease in susceptible individuals and to resist the hosts' defense mechanisms, including the effects of antimicrobial therapy. In this study, we performed complete genome sequencing and characterization of bacteria called Arcanobacterium hippocoleae, which were isolated from the reproductive tract of infected mares. These bacteria displayed small and large phenotypes when grown on artificial media. The whole genome sequences between the large phenotypes were closely related, while the small and large types were distant from each other in terms of sequence size and identity. Putative genetic elements that might be associated with disease conditions were identified in both bacterial phenotypes. Several genes that express hypothetical proteins with unknown functions were also detected. This study provides the complete genetic structure and analysis of different phenotypes of Arcanobacterium hippocoleae and will serve as a benchmark for future studies to identify the potential function and role of the bacterial proteins in the ability of the bacterium to produce reproductive tract diseases in mares. Arcanobacterium hippocoleae is a Gram-positive fastidious bacterium and is occasionally isolated from the reproductive tract of apparently healthy mares (Equus caballus) or from mares with reproductive tract abnormalities. Apart from a few 16S rRNA gene-based GenBank sequences and one recent report on complete genome assembly, detailed genomic sequence and clinical experimental data are not available on the bacterium. Recently, we observed an unusual increase in the detection of the organism from samples associated with mare reproductive failures in Atlantic Canada. Two colony morphotypes (i.e., small, and large) were detected in culture media, which were identified as A. hippocoleae by MALDI-TOF mass spectrometry and 16S rRNA gene sequencing. Here, we report the whole genome sequencing and characterization of the morphotype variants. The genome length of the large phenotypes was between 2.42 and 2.43, and the small phenotype was 1.99 Mbs. The orthologous nucleotide identity between the large colony phenotypes was ~99%, and the large and small colony phenotypes was between 77.86 and 78.52%, which may warrant the classification of the two morphotypes into different species. Phylogenetic analysis based on 16S rRNA genes or concatenated housekeeping genes grouped the small and large colony variants into two different genotypic clusters. The UvrA protein, which is part of the nucleotide excision repair (NER) system, and 3-isopropoylmalate dehydratase small subunit protein expressed by the leuD gene were identified as potential virulence factors in the large and small colony morphotypes, respectively. However, detailed functional studies will be required to determine the exact roles of these and other identified hypothetical proteins in the cellular metabolism and potential pathogenicity of A. hippocoleae in mares. [ABSTRACT FROM AUTHOR]

The International Society for Animal Genetics (ISAG) currently advocates for a transition towards single nucleotide polymorphism (SNP) markers as a potential alternative for equine parentage verification. To ascertain the efficacy of this transition, it is imperative to evaluate the performance of parentage testing using SNPs in juxtaposition with short tandem repeats (STRs). As per ISAG's recommendation, we used an equine genotyping‐by‐sequencing panel with 144 SNPs for this purpose. Equine parentage is currently realized using 16 microsatellites (STRs) excluding the LEX3 marker. In this study, 1074 horses were genotyped using the 144 SNPs panel, including 432 foals, 414 mares, and 228 stallions, from five different breeds: 293 Arabians, 167 Barbs, 189 Thoroughbreds, 73 Anglo‐Arabians, and 352 Arabian‐Barbs. As a result, two SNPs markers were eliminated from the panel system due to inconsistent amplification across all examined individuals leaving 142 SNPs markers for analysis. A comparative analysis between SNPs and STRs markers revealed that the mean expected heterozygosity was 0.457 for SNPs and 0.76 for STRs, while the mean observed heterozygosity stood at 0.472 for SNPs and 0.72 for STRs. Furthermore, the probability of identity was calculated to be 5.722 × 10−57 for SNPs and 1.25 × 10−15 for STRs markers. In alignment with the Hardy–Weinberg equilibrium in polyploids test, 110 out of the total SNPs were consistent with the Hardy–Weinberg equilibrium in polyploids test (p > 0.05). Employing both SNPs and STRs markers, the mean polymorphic information content was discerned to be 0.351 for SNPs and 0.72 for STRs. The cumulative exclusion probabilities for SNP markers exceeded 99.99%, indicating that the 142 SNPs panel might be adequate for parentage testing. In contrast, when utilizing STRs markers, the combined average exclusion probabilities for one and both parents were determined to be 99.8% and 99.9%, respectively. Our comprehensive study underscores the potential of SNPs in equine parentage verification, especially when compared to STRs in terms of exclusion probabilities. As a corollary, the application of SNPs for parentage verification and identification can significantly contribute to the conservation initiative for the five Moroccan horse breeds. Nonetheless, further research is required to address and replace the deficient SNPs within the panel. [ABSTRACT FROM AUTHOR]

Vulvo-vaginal epithelial tumors are uncommon in mares, and data on the epithelial-to-mesenchymal transition (EMT) and the tumor-immune microenvironment (TIME) are still lacking. This is a study investigating the equus caballus papillomavirus type 2 (EcPV2) infection state as well as the EMT process and the tumor microenvironment in vulvo-vaginal preneoplastic/ benign (8/22) or malignant (14/22) epithelial lesions in mares. To do this, histopathological, immunohistochemical, transcriptomic, in situ hybridization, and correlation analyses were carried out. Immunohistochemistry quantification showed that cytoplasmic E-cadherin and β-catenin expression as well as nuclear β-catenin expression were features of malignant lesions, while benign/preneoplastic lesions were mainly characterized by membranous E-cadherin and β-catenin expression. Despite this, there were no differences between benign and malignant equine vulvo-vaginal lesions in the expression of downstream genes involved in the canonical and noncanonical wnt/β-catenin pathways. In addition, malignant lesions were characterized by a lower number of cells with cytoplasmic cytokeratin expression as well as a slightly higher cytoplasmic vimentin immunolabeling. The TIME of malignant lesions was characterized by more numerous CD204+ M2-polarized macrophages. Altogether, our results support the hypothesis that some actors in TIME such as CD204+ M2-polarized macrophages may favor the EMT process in equine vulvo-vaginal malignant lesions providing new insights for future investigations in the field of equine EcPV2-induced genital neoplastic lesions. [ABSTRACT FROM AUTHOR]

The members of the Chlamydiaceae family are important pathogens that infect a wide range of vertebrate hosts, including humans. Among them, Chlamydia psittaci, historically considered as an avian agent, has recently been identified in livestock, primarily sheep and cattle, but also in horses, with the infection being linked to reproductive disorders, such as abortion, absorption of embryos, stillbirth, and the birth of weak foals. Much less is known about chlamydial infections in the Sardinian equine population. This study aimed to identify the chlamydial diversity in genital samples from asymptomatic Sardinian horses. However, some horses had a previous history of reproductive disorders, i.e., abortion and infertility. A total of 60 horses (39 mares and 21 stallions) were opportunistically recruited from 17 equine farms in central-northern Sardinia. Vaginal and uterine swabs from mares and urethral swabs and seminal fluid from stallions were sampled for the presence of chlamydial DNA. Samples from environments where the horses lived were also tested for the detection of Chlamydia spp. Eight vaginal swabs (8/39; 20%), two uterine swabs (2/27; 7%), two seminal fluid samples (2/20; 10%), and one urethral swab (1/21; 4.7%) were found to be positive for Chlamydia spp. by PCR analysis. In addition, results from environmental samples showed the presence of Chlamydia spp. in three environmental swabs (3/8; 37.5%) and five water samples (5/16; 31.2%). Sequencing results revealed that strains here identified were 99–100% similar to members belonging to the Chlamydiaceae family, including C. abortus, C. psittaci, and uncultured Chlamydia genotypes. ompA species-specific PCR performed on samples was found to be positive after 16S rRNA amplification gave positive results for C. psittaci. These results reveal the first presence of C. psittaci in the genital tract of horses and in the environment in Sardinia and indicate that this pathogen could be the prevailing cause of infertility and abortion in the tested equines. However, these findings need further proof and highlight the importance of adopting a 'One Health' approach to control the presence of this zoonotic bacteria in domestic animals in order to understand its impact on people exposed to the infection risk. [ABSTRACT FROM AUTHOR]

Maternal condition is influenced by multiple variables that individuals experience at seasonal and local levels, and thus condition‐dependent sex allocation is likely also multifactorial. Here, we test the Trivers‐Willard Hypothesis (TWH) using a multivariable approach on a dataset of thoroughbred mare breeding records. There is no sex ratio variation when examined at univariable level, mirroring the usual approach to test condition‐dependent sex allocation. Conversely, the multivariate model shows multiple variables interact to influence the likelihood of producing a male. Mare and management variables that represent better body condition is associated with an increase in likelihood of a male offspring. The magnitude and direction of sex ratio skew correspond closely with predicted mare energy balance, consistent with TWH predictions. Our findings therefore support the TWH and show that, while sex allocation is multifactorial, maternal energy status emerges as the dominant driver. The additive and agonistic interactions of different variables demonstrate that a multifactorial approach should be a key consideration in sex allocation studies. [ABSTRACT FROM AUTHOR]

Background: Proper handling and a well-established human-animal relationship influence both the behavior and the welfare of an animal. Methods: In this study, we compared the behavioral responses to touch and leading in mares using two handling methods. A traditional method (T) was based on forced cooperation and a natural (TTEAM) on tactile stimulation and mares' natural behavior. Twenty-two group housed Lipizzan mares participated. Throughout four consecutive weeks, there were six observational days per method and based on a predefined ethogram, mares were scored daily on a 6-point scale. Higher scores indicated better reception of touch and leading, relaxation and cooperation, whereas lower scores indicated agonistic and/or fear-related behaviors. The time spent to implement touch and leading was also recorded. Result: Despite significant individual differences, touch and leading scores were found to be higher in the TTEAM compared to the T. Our results imply that mares were more relaxed, displayed better cooperation and had reduced agonistic and fear-related behavior during TTEAM. We suggest that implementation of TTEAM positively affected mares' reception of touch and leading, but due to variation in behavioral plasticity, the importance of mare's individuality is accentuated. [ABSTRACT FROM AUTHOR]

Summary: This case report describes the diagnosis and treatment of noncongenital atlanto‐axial luxation in a 10‐year‐old Irish Draught mare. The mare initially presented to our referral hospital for dullness and colic signs. After resolution of the colic signs, the horse displayed increasing levels of dullness. Physical examination revealed that the horse could not flex and extend its neck freely to reach food from the ground. Radiographic and standing computed tomographic investigations revealed atlanto‐axial luxation that was subsequently successfully reduced using a surgical approach under general anaesthesia. To the author's knowledge, this is the first case report describing the successful surgical treatment of presumed traumatic atlanto‐axial luxation in an adult horse. [ABSTRACT FROM AUTHOR]

Context. Tryptophan (Trp) is the precursor of melatonin (MT) and the latter plays vital physiological roles in mares. Aims. The purpose of this experiment was to investigate the effects of dietary Trp supplementation on the plasma Trp, kynurenine (Kyn), 5-hydroxytryptophan (5-HT), and melatonin (MT) concentrations in female Yili horses. Methods. Twenty Yili mares aged 2 years with mean bodyweight (BW) of 263.5 ± 14.77 kg and of similar stature were selected and randomly allocated to the control (CON; basal diet), basal diet plus Trp at 20 mg/kg BW(TRP1), basal diet plus Trp at 40 mg/kg BW(TRP2), or basal diet plus Trp at 60 mg/kg BW(TRP3) group. Key results. The plasma total Trp, Kyn, andMT concentrations in all Trp groups steadily increased, reached their peak values, and gradually decreased after Trp supplementation between 0 h and 12 h. However, the plasma 5-HT concentration displayed the opposite trend. Peak plasma total Trp and 5-HT concentrations were attained between 1 h and 3 h, while those of KYN and MT appeared between 4 h and 6 h after Trp supplementation. The plasma total Trp and Kyn concentrations were significantly higher in TRP2 and TRP3 than in CON between 1 h and 12 h (P < 0.05) after Trp supplementation. The plasma 5-HT concentration was significantly (P < 0.05) lower in TRP1 than in CON at 3 h, 4 h, 6 h, 9 h, and 12 h after Trp supplementation. The plasma MT concentrations in TRP1 and TRP2 were significantly (P < 0.05) higher than in CON at 3 h, 4 h, and 12 h, and at 0 h, 1 h, and 12 h after Trp supplementation (P < 0.05). Conclusions. Dietary Trp supplementation can increase the plasma total Trp, Kyn, and MT concentrations in Yili mares and the optimal Trp dosage was 20 mg/kg BW. Implication. The addition of Trp to a basal diet or feed may increase the plasma total Trp, Kyn, and MT concentrations in female horses. [ABSTRACT FROM AUTHOR]

Context. There has been a contraction within the New Zealand Thoroughbred racing industry and there are limited data demonstrating how this has affected, or been reflected, within the breeding industry that supplies horses for the racing industry. A reduction in the breeding industry, to a greater extent in the sector servicing domestic rather than export market has been speculated. Aim. To describe the demographics, breeding pattern, reproductive career and workload of New Zealand Thoroughbred stallions between 2005 and 2015. Methods. The breeding records of all Thoroughbred stallions covering >10 mares during 2005/2006-2015/2016 breeding seasons and the lifetime breeding records of all the mares covered by these stallions were extracted from the New Zealand Thoroughbred Racing website. The demographics, population numbers, career pattern, and 10-year trend in market share of stallions in different stud fee categories were examined using descriptive analysis. The stallion's reproductive workload was modelled deterministically. Results. The breeding population reduced over the 10 years examined (mares by 20%, sires by 32%). This industry consolidation was almost entirely due to the 50% reduction in the number of mares mated to the low-priced stallions, which generated horses for the domestic market. The relative proportion of mares sent to medium- and high-priced stallions (breed to sell and export sector) doubled. The commercial breeding career of low- and medium-priced stallions and shuttle stallions was short (4-5 years). The number of mares covered by a stallion increased with stud fee category. Stallions covered a greater number of mares in October and November than in September and December because of the restricted opportunity to cover foaled mares early in the season, caused by the long gestation length of mares and the need to cover mares before December. Conclusions. Findings in this study support that the contraction in the New Zealand Thoroughbred breeding industry was due to a reduction in the industry sector that focuses primarily on supplying horses for domestic racing. Commercial pressure and biological constraints heavily influenced the reproductive management of the breeding industry. The breeding management of stallions during the season is heavily influenced by stallion service fee category, which reflects his book size and the commercial appeal of the resultant progeny. Implications. The contraction within the domestic sector of the breeding industry was reflected in the concurrent contraction within New Zealands domestic racing population and fewer colts and geldings entering racing. Industry breeding trends demonstrate that economic viability and optimisation of revenue depend on the breeding industry focusing on the export rather than domestic market. [ABSTRACT FROM AUTHOR]

Context. The New Zealand Thoroughbred breeding industry is heavily focused on producing horses for the export market and there has been a reduction in the number of horses racing in the past 20 years. The impact of these production constraints, and changes in production focus, have not been described at a national herd level. Aim. To describe the breeding management, reproductive performance, and careers of the New Zealand Thoroughbred broodmare herd during the 2005/06-2015/16 breeding seasons. Methods. The demographics, population structure, reproductive efficiency, breedingmanagement and career descriptors of Thoroughbred mares were examined using descriptive analysis. Gestation length was modelled using a linear mixed effects model. The impact of different variables on breeding career were quantified by calculating odds ratio. Results. There was a consistent reduction in the size of the national broodmare herd over the 10 years investigated. Half of the mares not retained for breeding were mares that were breed to low-cost stallions. Despite a short (~100 days) commercial breeding season few (20%) mares were mated early in the season (September), with most mating (70%) occurring between October and November. The 27 days mean foaling to conception interval (FCI) suggests that FCI was artificially shortened and most pregnancy was achieved within first oestrus cycle post-partum. Mare career length and lifetime productivity was positively associated with the stud fee of the first stallion that the mare was mated to and number of foals registered for racing. Conclusion. Mare replacement and loss within the national herd was disproportionately associated with mares that were producing foals for a contracting domestic racing market. There was a constricted breeding season with most mares being mated within the first oestrous cycle post-partum. Mare retention and breeding success were positively associated with the service fee of the sire and progeny that had raced, reflecting the commercial pressure of the industry on mare management. Implication. The changes in the broodmare herd and management reflects the increasing proportion of the industry focusing on breeding foals that will appeal to the export market. The economic drivers for early born foals provide management challenges as these are not aligned with the optimal reproductive season of the horse. [ABSTRACT FROM AUTHOR]

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Behaviour is one of the most important indicators for assessing horse health and well-being. However, direct observation traditionally relies on observation methods that are time consuming and can limit the accuracy and the amount of data collected. Therefore, several systems have been developed to automatically record behavioural traits, including the RumiWatchSystem (Itin and Hoch GmbH, Liestal, Switzerland). The aim of our experiment was to evaluate the usefulness of the presented technology in studies of equine feeding behaviour and to compare the differences in chewing activity when different forms of feed are added. The trial lasted nine days and was carried out on three mares. The mares were fed hay, and on the fifth day the concentrate was introduced. The results showed that the mares spent 9.08 hours feeding, with low intake activity in the early morning hours (00:00 - 8:00) and around midday and significant peaks in intake in the morning and late afternoon. The study confirmed that the developed monitoring sensor system was successful in monitoring the feeding behavior of horses. [ABSTRACT FROM AUTHOR]

In the years since their first appearance in Cheny's Racing Calendar of 1743, a group of celebrated yet vague beings, the Royal Mares, have from time to time attracted scholarly attention. Suggested to be the foundation mares of the Thoroughbred breed, they have subsequently been variously described as imported mares, as mares bred on the island of Britain, or a mixture of both. This paper explores the origins and progress of the story, around which mythology has accumulated, showing that there is a core of truth within the legend of imported mares, but that certain aspects of the historiography have been influenced by unreliable sources. The evidence for imported horses from the sixteenth to the mideighteenth century is also examined in depth. Part 3 takes up the narrative in the early eighteenth century, and reveals how the inaccurate story of imported Arabian mares developed further in the twentieth century. [ABSTRACT FROM AUTHOR]

Copper (Cu) and zinc (Zn) are trace minerals with multiple biological functions, playing roles in fetal development and immune regulation. Despite their known significance, research on Cu and Zn administration and supplementation for pregnant mares is insufficient. This study aims to evaluate Cu and Zn serum concentrations monthly throughout the year and through pregnancy in Polish Konik mares. The study was conducted in 2020 on 36 mares from the Polish state stud farm, with 24 mares in the pregnant group and 12 mares in the non-pregnant group. Monthly blood samples were collected, and serum Cu and Zn concentrations were measured. The total Cu concentration in the serum of all mares was higher (p < 0.0001) in August and September (13.98 ± 3.00 μmol/L) than in May, June, July, and November (11.04 ± 2.74 μmol/L). Similarly, the total Zn concentration was higher (p < 0.0001) in August, September, October, November, and December (19.80 ± 9.72 μmol/L) than in May, June, and July (14.50 ± 6.94 μmol/L). No evidence of a linear relation between Cu and Zn concentrations was demonstrated (slopes difference p < 0.001). No differences in Cu (p > 0.05) or Zn (p > 0.05) concentrations were found between pregnant (Cu: 12.08 ± 3.01 μmol/L; Zn: 18.02 ± 9.03 μmol/L) and non-pregnant (Cu: 11.23 ± 2.51 μmol/L; Zn: 18.59 ± 10.37 μmol/L) mares in any of the examined months of the year. In conclusion, the month of the year, rather than pregnancy, affects serum Cu and Zn concentrations. [ABSTRACT FROM AUTHOR]

Literature provides indications that the personality and temperament of a horse are sufficiently genetically determined. This background was the impetus to continue collecting phenotypic information on the temperament in the South Tyrolean Haflinger horses, not only to have marketing tools but also to be able to estimate genetic parameters for a future genetic evaluation. The latter should open the possibility to include temperament traits in the breeding goal. Therefore, the aim of the present study was to consider for the very first-time phenotypic information from character testing for estimating genetic parameters for temperament in Haflinger horses. For the present study, data from routine character testing of 210 South Tyrolean Haflinger mares between 2019 and 2021 were considered. A multivariate estimation of heritability (h2) and genetic correlations (r) was carried out for the criteria 'Interest', 'Activity' and 'Excitement'. In addition, univariate and bivariate estimation runs were also carried out. The pedigree-based heritability for the behavioural trait Interest was lowest with 0.07 and a standard error of ±0.04. For the other two criteria, Activity and Excitement, h2 was 0.19 ± 0.05 and 0.21 ± 0.04, respectively. The genetic correlation between Interest and Activity and between Interest and Excitement was in both cases negative with −0.52 and −0.61, respectively while the genetic correlation between Excitement and Activity was positive (0.99). Results of the present study highlight the potential of considering temperament traits in breeding of Haflinger horses. Character testing in Haflinger horses provided phenotypic data for estimating heritability for selected temperament traits. Heritability for the temperament traits describing interest, activity, and excitement in Haflinger horses were low to moderate. In future, a larger number of tested animals is required for obtaining more robust data for genetic parameters and implementation of a routine genetic evaluation. [ABSTRACT FROM AUTHOR]

The Lipizzan horse breed was established in the 16th century in Lipica and later spread throughout Central and Eastern Europe. In addition to six classical stallion lines, 17 classical mare family lines were established in the old Lipica stud. Additional 44 mare family lines, including local lines, were established in other Lipizzan studs. The founders of the classical Lipizzan mare family lines date back to the period between the 18th and 20th century and came from various breeds, including the Karst, Spanish, Italian, Kladruber and Arabian horses. The history of the Lipizzan mare family lines is well described and supported by the availability of 44 nucleotide sequences of the mtDNA control region. In this study, the mtDNA control region of 23 Serbian Lipizzans, representing the established Lippizan mare family lines, as well as the local mare family line Zora, have been sequenced. The objective of this study was to test whether the Zora mare family line could be distinguished from other Lipizzan mare family lines according to the mtDNA sequence. Sequences were aligned to the entire set of mtDNA control region sequences representing 44 Lipizzan mtDNA haplotypes. Based on the alignment, a median-joining network was constructed. The individuals in this study formed a cluster with the existing Lipizzan mare family lines. However, a total of ten individuals belonging to the local Zora mare family line formed a compact cluster close to the mtDNA haplotypes, representing the classical mare family lines Wera, Betalka, and Monteaura. Additional pedigree data are needed to clarify the origin of the mtDNA haplotype variant identified in this study. [ABSTRACT FROM AUTHOR]