Adult Female Horses Research Articles

Early Evidence of Post-Mortem Fetal Extrusion in Equids: A Case from the Western Zhou Period (1045-771 BC) Site of Yaoheyuan in Northwestern China.

Post-mortem fetal extrusion, also known as "coffin birth", refers to the phenomenon where a fetus is pushed out of a deceased female due to pressure from decomposing gas in the abdominal cavity. While post-mortem fetal extrusion has been documented in humans at several archaeological sites, there are few reports of it occurring in non-human animals. In this study, we present a case of post-mortem fetal extrusion in equids observed in a chariot-horse pit (CMK2) at the Western Zhou period site of Yaoheyuan in northwestern China, dating to the early first millennium BC. This specific pit, one of four excavated at the site, contained at least 29 horses and 3 wooden chariots. Most of these horses were young adults aged between 4 and 12 years. Out of the 22 horses with sex estimates, 21 were males. Among these individuals, one adult female horse (Horse 6) and one infantile horse (Horse 10) were of particular importance. Based on the age-at-death, sex, and head orientation of the two individuals, alongside their spatial relationships, it is highly likely that Horse 6 was the fetus of Horse 10 and was extruded in the pit. According to the parturition stage of Horse 10, Horse 6 was likely interred in CMK2 in late spring or early summer of the year, during which the relatively high temperature may have generated gas that led to the extrusion of the fetus. Although the specific reason for the inclusion of a pregnant mare in a chariot-horse pit at Yaoheyuan remains a topic for future research, this case marks the first report of post-mortem fetal extrusion in archaeological horses. The findings offer insights into the timing of horse interment as part of ritual practices among the settled elites during the Bronze Age in China and provide valuable reference data for contemporary equine veterinary science.

Performance of three techniques for diagnosing equine tapeworm infection

Tapeworm infection in horses can cause serious health concerns, and recent data have documented treatment failures in the most common species, Anoplocephala perfoliata. The threat of anthelmintic resistance in A. perfoliata is of particular concern because of poor diagnostic performance of standard egg counting techniques for detecting this parasite. This study compared the performance of three diagnostic techniques 1) Mini-FLOTAC, 2) Cornell-Wisconsin, and 3) Proudman and Edwards used to detect and quantify A. perfoliata eggs in naturally infected horses. Eighteen adult female horses from the University of Kentucky’s historic parasitology herd were included in this study. Fecal samples were collected from all horses at five collection time points two weeks apart and analyzed with the three techniques. A total of 90 samples were collected and 270 counts determined in the study. The proportions of positive samples determined by the three techniques were significantly different from each other (p<0.05): Mini-FLOTAC (16%), Cornell-Wisconsin (47%), and Proudman and Edwards (70%). The Proudman and Edwards technique counted consistently higher numbers of tapeworm eggs compared to the other two techniques throughout the study [p < 0.05]. Total raw counts of tapeworm eggs across the study for each technique were 16, 88, and 410 for the Mini-FLOTAC, Cornell-Wisconsin, and Proudman and Edwards, respectively. This study demonstrated that the Proudman and Edwards technique was superior in diagnosing A. perfoliata infection. Future work needs to assess this technique’s potential for Fecal Egg Count Reduction Testing (FECRT).

Evaluation of blastocyst re-expansion, quality in relation to storage temperature, and sexing using blastocoel fluid after manual perforation with a hand-held needle involving in vivo produced equine embryos

The present study was designed to evaluate equine blastocyst re-expansion rate, quality, and sex following perforation of the blastocoel, collection of blastocoel fluid (BF), and PCR amplification of free DNA. Experiment 1 tested the feasibility of the BF sample collection with a hand-held, small-gauged needle (26g) and subsequent PCR amplification of the TSP-Y gene for males and AMEL-Y gene for males and AMEL-X gene for females. Experiment 2 tested the application of the technique. Equine embryos were collected via uterine flushes 8d after ovulation. Thereafter, embryos (n = 19) were initially assessed and transferred to a 50 μL droplet of holding medium in which the blastocoel was manually perforated as in Experiment 1. Within 1 min of detecting a diameter decrease or collapse, the entire volume of each droplet of medium was collected and stored at −20 °C until PCR. In Experiment 1, amplification of the TSP-Y gene was positive for males at 60% (9/15) and negative for females at 40% (6/15). In Experiment 2, a total of 42 embryos were randomly assigned to a collapsed embryo (CE) or intact embryo (IE) groups and stored at room temperature (RT, 25 °C) or cold temperature (CT, 5 °C) for 24h as follows: 1) CERT, n = 11; 2) CECT n = 11; 3) IERT, n = 10; and 4) IECT, n = 10. After 24h, embryo diameter and quality were reassessed. For all collapsed embryos (n = 19), blastocoel fluid was subjected to double PCR amplification of the TSPY gene with blood from adult male and female horses as controls. Positive gene amplification indicated 57.9% (11/19) of embryos were male and negative amplification indicated 31.6% (6/19) of embryos were female. Relative to the least diameter (0%) after perforation of collapsed embryos or fullest diameter (100%) of intact embryos at T0, percentage change in diameter and quality Grade 1 or 2 embryos after 24h of storage for all groups were, respectively: 31.2% and 54% for CERT group, 28.2% and 0% for CECT group, 25.9% and 100% for IERT group, 4.3% and 80% for IECT group, respectively. Thus, needle-induced leakage and collapse of the blastocoel at T0 resulted in a high rate of blastocyst re-expansion (69%) with many embryos (54%) achieving good quality at T24 with potential for transfer as either male or female embryos. For both collapsed and intact embryos, it was observed that storage for 24h at room temperature (25 °C) was associated with improved embryo growth and morphological quality compared to storage at cold temperature (5 °C).

Bioaccumulation, Bioindication and Health Risk Assessment of Heavy Metals in Cape Horse Mackerel (Trachurus trachurus) and Slinger Seabream (Chrysoblephus puniceus) in the Durban Basin and Cape Vidal, South Africa.

The bioaccumulation of heavy metals (HMs) in marine fish is a growing global concern due to potential human health risks. The study analyzed HM in the muscle tissue, gills, and gut of adult male and female cape horse mackerel and slinger seabream caught in the polluted Durban Basin and pristine Cape Vidal from April 2018 to February 2019. Results revealed interspecific, spatial, and organ-specific variability in HM levels. In the Durban Basin, slinger seabream had bioaccumulation (in mg/kg) of As (2.3 ± 0.2), Cr (2.6 ± 0.2), Ni (2.0 ± 0.1), and Pb (4.1 ± 0.3) while cape horse mackerel had Ni (1.6 ± 0.2), Pb (4.7 ± 0.6), and Zn (52 ± 3.01) exceeding World Health Organization (WHO) regulatory limits. Metal pollution index (MPI) values were also higher in Durban Basin (> 5.13) than Cape Vidal (< 3.32) for both species' muscles. Liver and gills of slinger seabream and gut of cape horse mackerel exhibited higher HM accumulation patterns proportionate to the environmental concentrations, indicating the bioindicative potential of HM pollution by the two species. Risk assessment indicated that both fish species had target hazard quotient > 1 for Cr, and target cancer risk < 10-4 for Pb, implying significant potential non-carcinogenic and carcinogenic health risks associated with fish consumption from the Durban Basin. The study recommends daily consumption limits of 16g/day for slinger seabream and 14g/day for cape horse mackerel to ensure health safety. The findings contribute to the understanding of HM pollution in the Durban Basin and provide important information for decision-makers and policymakers in developing effective strategies to mitigate and manage HM contamination in fish populations.

Equine blastocyst re-expansion rate, quality, and sex following embryonic collapse using needle perforation of blastocoel and subsequent PCR amplification of blastocoel DNA

Collapse of equine blastocysts following needle perforation of the blastocoel prior to vitrification (Ferris et al., Journal of Equine Veterinary Science. 2016; 100:64-65) and collection and amplification of the free DNA blastocoel fluid may be used for sexing embryos (Herrera et al., Theriogenology. 2015; 83:415-420). The present study aimed to evaluate equine blastocyst re-expansion rate, quality, and sex following manual perforation of the blastocoel and PCR amplification of blastocoel fluid DNA. Embryos (n=19) were collected on day 8 after ovulation, assessed initially and transferred to a 50µL droplet of holding medium in which the blastocoel was manually perforated with a 26g hypodermic needle. Within one minute of detecting a diameter decrease or collapse, the entire volume of each droplet of medium was collected and stored at -20°C until PCR. Some of the collapsed embryos (n=11) were moved and immersed in 2mL of holding medium and cultured in isothermal boxes at 25°C. After 24h, embryo size and quality were reassessed. Post-culture, collapsed blastocysts had partially re-expanded to their initial diameter with a mean expansion rate of 68.8%. Quality of re-expanded embryos was Grade 2 (good, 6/11), Grade 3 (poor, 4/11), and Grade 4 (degenerated, 1/11) (McKinnon,Squires, J. Am. Vet Med. Assoc. 1988; 192:401-406). Non-perforated embryos (n=10) used as controls were initially Grade 1 (excellent, 8/10) and Grade 2 (2/10) and, after 24h of culture, Grade 1 (9/10) and Grade 2 (1/10) with a 25.9% growth rate. Blastocoel fluid from all collapsed embryos (n=19) was subjected to double PCR amplification of the male TSPY gene with blood of an adult male and female horse used as controls. Gene amplification indicated 57.9% (11/19) of embryos were male and non-amplification indicated 31.6% (6/19) of embryos were female. Gene amplification was inconclusive for 10.5% (2/19) of the embryos even though they were completely collapsed. Thus, needle-induced leakage and collapse of the blastocoel resulted in a high rate of blastocysts re-expansion (69%) with many embryos (54%) achieving good quality and potential for transfer as either male or female embryos. In summary, while the number of potentially transferable embryos that recovered from collapse was less than in the control group, the success of these preliminary results warrants further development to decrease damage and increase the culture re-expansion rate and quality of transferable male or female embryos for field application in an equine embryo transfer program.

Diagnostics of the heart condition in ukrainian riding horses with a portable ecg monitor

Abstract. Electrocardiographic reference values of clinically healthy horses are needed for assessment of the reduced performance or cardiac pathology animals. The purpose of this study was to establish the rate of occurrence of arrhythmias in clinically healthy horses of the Ukrainian riding breed at rest, during exercises and recovery period. Experimental group of animals included 36 horses of 3 – 17-years old, 16 mares (adult female horses), 11 geldings (castrated males) and 9 stallions (adult males). The electrodes were placed with modified base-apex system on the surface of animals’s body. ECG recording was performed at rest (15 minutes), during exercises and recovery period, for 30–40 and 15 minutes, respectively. Prevalence and rate of occurrence of arrhythmias was analyzed with obtained recordings. A significant number of the second degree atrioventricular blocks were detected in 13.9 % cases (n=5) during the recovery period. 33.3 % (n=12), 8.3 % (n=3) and 19.4 % (n=7) of cases of supraventricular premature contractions were detected during exercises, at rest and during recovery period, respectively. The incidence of supraventricular premature contractions was < 3/animal and < 5/animal during exercises and recovery period, respectively; with exception for one animal which 9 and 7 premature contractions were detected, respectively. Ventricular premature contractions were identified in 2.7 % (n=1) and 5.6 % (n=2) cases, at rest and exercises, respectively. Supraventricular tachycardia with 6–9 consecutive premature contractions during trot was detected in 1 horse (2.7 %). The results of this study have confirmed the presence of arrhythmias in clinically healthy horses. The type of arrhythmias significantly depends on the period (rest, exercises and recovery) of the animal’s activity, particularly. Key words: arrhythmias, heart condition diagnostics, portable ECG-monitor, ECG records, horses

Pharmacokinetics of magnesium and its effects on clinical variables following experimentally induced hypermagnesemia.

The objectives of this study were to describe pharmacokinetic and pharmacodynamic changes as a result of a single intravenous administration of magnesium sulfate (MgSO4 ) to healthy horses. MgSO4 is a magnesium salt that has been used to calm horses in equestrian competition and is difficult to regulate because magnesium is an essential constituent of all mammals. Six healthy adult female horses were administered a single intravenous dose of MgSO4 at 60mg/kg of body weight over 5min. Blood, urine, and cerebrospinal fluid (CSF) samples were collected, and cardiovascular parameters were monitored and echocardiograms performed at predetermined times. Noncompartmental pharmacokinetic analysis was applied to plasma concentrations of ionized magnesium (Mg2+ ). Objective data were analyzed using the Wilcoxon rank-sum test with p<.05 used as a determination for significance. Plasma concentrations of Mg2+ increased nearly fivefold, ionized calcium (Ca2+ ) decreased by nearly 10%, and the Ca2+ to Mg2+ ratio declined more than 3.5-fold and remained different than baseline until 24hr (p<.05). Significant changes were seen with urinary fractional excretion of electrolytes, cardiovascular parameters, and echocardiographic measurements. No changes were detected in CSF electrolyte concentrations. The decrease in Ca2+ result of hypermagnesemia supports the interaction between these cations. Alterations detected in plasma electrolyte concentrations and urinary fractional excretion of electrolytes may serve as biomarkers for regulatory control for the nefarious administration of MgSO4 .

ELISA of amyloid A in paired bronchoalveolar lavage fluid and serum samples of healthy horses

ABSTRACT: Pulmonary disorders are common in horses, and treatment efficiency depends on an adequate diagnosis. Amyloid A is the most sensitive indicator of pathology in horses. The objective of this study was to establish the concentration of amyloid A of bronchoalveolar lavage fluid (BALF) in healthy horses. Health condition of horses was considered normal based on physical examination, complete blood count, biochemical parameters, and BALF cytology. Blood and BALF were collected from thirty adult female horses. Amyloid A concentrations in serum and BALF were measured using commercial ELISA tests. Amyloid A was detected in serum (mean ± SD = 3.71±2.51) and BALF (mean ± SD = 0.000745±0.000785) of all horses. In conclusion, SAA can also be measured in bronchoalveolar fluid, affording early detection of respiratory infections or inflammatory conditions.

Evaluation of the effect of laser salpingopharyngostomy on the guttural pouch environment in horses.

Laser salpingopharyngostomy has been used as an adjunct to primary medical therapy allowing for topical debridement, topical treatment or to potentially alter the guttural pouch environment in horses with guttural pouch disease. To evaluate the effect of a laser salpingopharyngostomy on the guttural pouch environment in healthy horses. Experimental study. In six adult Standardbred female horses, under standing sedation a stab incision was made ventral to the sternocephalicus tendon and a customised trocar inserted into the medial guttural pouch compartment. Baseline (day 0) temperature, humidity, oxygen (O2 ) and carbon dioxide (CO2 ) levels were recorded. A laser salpingopharyngostomy was subsequently made into the right guttural pouch. The guttural pouch environment was re-sampled as above on days 7 and 14 to detect differences in the local environment of the guttural pouch caused by the laser salpingopharyngostomy. The guttural pouch environment was altered by the laser salpingopharyngostomy. Baseline recorded values within the guttural pouch were highly constant within each horse. Post laser salpingopharyngostomy there was considerable variation within the guttural pouch between horse and during the period of sampling. Specifically, CO2 levels post laser salpingopharyngostomy appeared to be linked directly to the horse's respiratory pattern with peaks and troughs recorded post laser salpingopharyngostomy. The variation in CO2 was significantly different at days 7 and 14 post laser salpingopharyngostomy compared with baseline levels (day 7=6mmHg, day 14=8.83mmHg). Oxygen levels were also more varied during sampling compared with baseline (day 7=3.4%, day 14=1.83%). There was no change in humidity or temperature during the study. This study was conducted on horses with no evidence of guttural pouch abnormalities or disease. Laser salpingopharyngostomy alters the guttural pouch environment and this may be useful in the treatment of guttural pouch disease where this alteration is desirable.

Stronger social bonds do not always predict greater longevity in a gregarious primate.

In group‐living species, individuals often have preferred affiliative social partners, with whom ties or bonds can confer advantages that correspond with greater fitness. For example, in adult female baboons and juvenile horses, individuals with stronger or more social ties experience greater survival. We used detailed behavioral and life history records to explore the relationship between tie quality and survival in a gregarious monkey (Cercopithecus mitis stuhlmanni), while controlling for dominance rank, group size, and life history strategy. We used Cox proportional hazards regressions to model the cumulative (multi‐year) and current (single‐year) relationships of social ties and the hazard of mortality in 83 wild adult females of known age, observed 2–8 years each (437 subject‐years) in eight social groups. The strength of bonds with close partners was associated with increased mortality risk under certain conditions: Females that had strong bonds with close partners that were inconsistent over multiple years had a higher risk of mortality than females adopting any other social strategy. Within a given year, females had a higher risk of death if they were strongly bonded with partners that changed from the previous year versus with partners that remained consistent. Dominance rank, number of adult female groupmates, and age at first reproduction did not predict the risk of death. This study demonstrates that costs and benefits of strong social bonds can be context‐dependent, relating to the consistency of social partners over time.

Efficacy of SpayVac® as a contraceptive in feral horses

ABSTRACTWe tested the efficacy of 2 formulations of the immunocontraceptive SpayVac®, which packages the immunogen porcine zona pellucida (PZP) and an adjuvant in multilamellar liposomes, as a contraceptive in captive feral horses (Equus caballus) for 3 consecutive breeding seasons (Pauls Valley, OK, USA; 2012–2014) following a single inoculation. Annual fertility rates in control adult female horses (n = 30 each yr) were 100%, 96.7%, and 100%. In the nonaqueous treatment group, fertility was 16.7% in the first year (n = 30) and 75.9% in the second year (n = 29), at which point we dropped the group from the study. Fertility rates in the aqueous group were 13.3%, 46.7%, and 43.3% (n = 30 each yr). Fifteen of the females in the aqueous group were infertile in all 3 years. Across 11 sampling dates postvaccination, mean PZP antibody titers in serum were 33.7–91.9% greater in nonpregnant females than pregnant females for the aqueous treatment group and 7.8–82.8% greater for the nonaqueous group. However, the 15 consistently infertile females did not necessarily have the greatest antibody titers. Reactions at the injection site occurred in 29.8% of the 84 females that received an injection other than saline solution, but there was no evidence that the reactions were painful or affected mobility. The nonaqueous formulation produced more local reactions than did the aqueous, but presence of PZP did not increase the frequency of reactions above that seen with liposomes + adjuvant. Uterine edema was not found at frequencies greater than would be expected in untreated females. Additional research to explore relationships between vaccine dose, adjuvant, and efficacy is warranted. Published 2017. This article is a U.S. Government work and is in the public domainin the USA.

Influence of Aguamiel (Agave atrovirens) as a Natural Feed Additive on Cecal Fermentation Kinetics of Some Forage Species in Horse Feeding

This study aimed to evaluate the effect of different dose levels of aguamiel (Agave atrovirens) on in vitro cecal gas, methane (CH4), and carbon dioxide (CO2) productions of five forage species (Avena sativa [hay]), Moringa oleifera, Caesalpinia coriacea, Salix babylonica, and Eichhornia crassipes using inocula from the horse. The forage samples were incubated with three doses of aguamiel: 0, 34, and 68 μg of aguamiel/g dry matter (DM) of substrate. Cecal inocula were collected from four adult female Criolla horses (3–4 years of age and weighing 300 ± 15.0 kg) grazed on native grasses for about 8 hours without supplementation. Forage type affected (P < .001) cecal asymptotic, rate and lag time of gas, CH4 and CO2 productions (mL/g DM), pH and DM degradability. Aguamiel dose had linear and quadratic effects (P < .05) on the asymptotic and rate of CH4 productions and rate and lag time of CO2 productions (mL/g DM). Forage type × aguamiel dose interactions were significant (P < .05) for asymptotic, rate and lag time of gas, and CH4 and CO2 productions (mL/g DM). Forage species effects were pronounced (P < .05) on CH4 and CO2 productions (mL/g incubated and degraded DM) and proportional CH4 production at all hours of incubation, except for CO2 production (mL/g incubated DM). Aguamiel dose affected (P < .05) CO2 production (mL/g incubated DM) and proportional CO2 production at the incubated hours. Forage type × aguamiel dose interactions were observed (P < .05) for CO2 production (mL/g incubated DM) and proportional CO2 production at the incubated hours but had no impact on CH4 production. It is concluded that addition of aguamiel to five forage species affected fermentation kinetics of gas production resulting in different in vitro cecal gas, CH4 and CO2 productions from these substrates.

Expression and immunolocalisation of follicle-stimulating hormone receptors in gonads of newborn and adult female horses.

In mares, FSH and its receptor (FSHR) are essential for ovarian function. The objective of the present study was to analyse FSHR gene expression at the mRNA and protein levels in ovarian tissue from newborn and adult horses. Expression of mRNA was analysed by reverse transcription polymerase chain reaction, whereas FSHR protein was visualised by immunohistochemistry (IHC), immunofluorescence labelling (IF) and western blot. FSHR mRNA was detected in ovarian follicles and luteal tissue from adult mares, as well as in the ovaries of neonates. Follicular growth up to 4mm in diameter was already present in neonates. Using IHC and IF, FSHR protein was detected in granulosa cells, cumulus cells and inconsistently in oocytes, independent of the animal's age or the stage of folliculogenesis. A lower FSHR expression was observed in theca cells in comparison to granulosa cells. FSHR was abundant in the ovarian stroma cells of neonates but not of adults. Luteal cells stained positive for FSHR independent of the stage of corpus luteum development. The presence of FSHR protein in various cell populations of the ovary was confirmed by western blot. In conclusion, FSHR is present in horse ovaries consistently from birth onwards and expression remains constant during the oestrous cycle.

Pharmacokinetics and physiologic effects of alprazolam after a single oral dose in healthy mares.

The objective of this study was to evaluate the pharmacokinetic properties and physiologic effects of a single oral dose of alprazolam in horses. Seven adult female horses received an oral administration of alprazolam at a dosage of 0.04mg/kg body weight. Blood samples were collected at various time points and assayed for alprazolam and its metabolite, α-hydroxyalprazolam, using liquid chromatography/mass spectrometry. Pharmacokinetic disposition of alprazolam was analyzed by a one-compartmental approach. Mean plasma pharmacokinetic parameters (±SD) following single-dose administration of alprazolam were as follows: Cmax 14.76±3.72ng/mL and area under the curve (AUC0-∞ ) 358.77±76.26ng·h/mL. Median (range) Tmax was 3h (1-12h). Alpha-hydroxyalprazolam concentrations were detected in each horse, although concentrations were low (Cmax 1.36±0.28ng/mL). Repeat physical examinations and assessment of the degree of sedation and ataxia were performed every 12h to evaluate for adverse effects. Oral alprazolam tablets were absorbed in adult horses and no clinically relevant adverse events were observed. Further evaluation of repeated dosing and safety of administration of alprazolam to horses is warranted.

The influence of nutrition on the insulin-like growth factor system and the concentrations of growth hormone, glucose, insulin, gonadotropins and progesterone in ovarian follicular fluid and plasma from adult female horses (Equus caballus).

BackgroundFeed intake affects the GH-IGF system and may be a key factor in determining the ovarian follicular growth rate. In fat mares, the plasma IGF-1 concentration is high with low GH and a quick follicular growth rate, in contrast to values observed in thin mares. Nothing is known regarding the long-term effects of differential feed intake on the IGF system. The objective of this experiment was to quantify IGFs, IGFBPs, GH, glucose, insulin, gonadotropin and progesterone (P4) in blood and in preovulatory follicular fluid (FF) in relation to feeding levels in mares.MethodsThree years prior to the experiment, Welsh Pony mares were assigned to a restricted diet group (R, n = 10) or a well-fed group (WF, n = 9). All mares were in good health and exhibited differences in body weight and subcutaneous fat thickness. Follicular development was scanned daily and plasma was also collected daily. Preovulatory FF was collected by ultrasound-guided follicular aspiration. Hormone levels were assayed in FF and plasma with a validated RIA.ResultsAccording to scans, the total number of follicles in group R was 53% lower than group WF. Insulin and IGF-1 concentrations were higher in WF than in R mares. GH and IGF-2 concentrations were lower in plasma from WF mares than from R mares, but the difference was not significant in FF. The IGFBP-2/IGFBP-3 ratio in FF was not affected by feeding but was dramatically increased in R mare plasma. No difference in gonadotropin concentration was found with the exception of FSH, which was higher in the plasma of R mares. On the day of puncture, P4 concentrations were not affected by feeding but were higher in preovulatory FF than in plasma.ConclusionsThe bioavailability of IGF-1 or IGF-2, represented by the IGFBP2/IGFBP3 ratio, is modified by feed intake in plasma but not in FF. These differences partially explain the variability in follicular growth observed between well-fed mares and mares on restricted diets.

Blood gas analysis, anion gap, and strong ion difference in horses treated with polyethylene glycol balanced solution (PEG 3350) or enteral and parenteral electrolyte solutions

Large volumes of different electrolytes solutions are commonly used for ingesta hydration in horses with large colon impaction, but little is known about their consequences to blood acid-base balance. To evaluate the effects of PEG 3350 or enteral and parenteral electrolyte solutions on the blood gas analysis, anion gap and strong ion difference, five adult female horses were used in a 5x5 latin square design. The animals were divided in five groups and distributed to each of the following treatments: NaCl (0.9% sodium chloride solution); EES (enteral electrolyte solution), EES+LR (EES plus lactated Ringer's solution); PEG (balanced solution with PEG 3350) and PEG+LR (PEG plus lactated Ringer's solution). Treatments PEG or PEG + LR did not change or promoted minimal changes, while the EES caused a slight decrease in pH, but its association with lactated Ringer's solution induced increase in AG and SID values, as well as caused hypernatremia. In turn, the treatment NaCl generated metabolic acidosis. PEG 3350 did not alter the acid-base balance. Despite it's slight acidifying effect, the enteral electrolyte solution (EES) did not cause clinically relevant changes.

A study of some hormones concentrations in horses: Influences of reproductive status and breed differences

Objective To learn more about reproductive physiology of adult female Arabian horses over a period of 24 months and to examine the effect of breed’s difference between Arabian and European female horses over a period of 36 months on the circulatory levels of both metabolic hormones (IGF-1 and leptin).

Generation and Characterization of Leukemia Inhibitory Factor-Dependent Equine Induced Pluripotent Stem Cells from Adult Dermal Fibroblasts

In this study we have reprogrammed dermal fibroblasts from an adult female horse into equine induced pluripotent stem cells (equiPSCs). These equiPSCs are dependent only on leukemia inhibitory factor (LIF), placing them in striking contrast to previously derived equiPSCs that have been shown to be co-dependent on both LIF and basic fibroblast growth factor (bFGF). These equiPSCs have a normal karyotype and have been maintained beyond 60 passages. They possess alkaline phosphatase activity and express eqNANOG, eqOCT4, and eqTERT mRNA. Immunocytochemistry confirmed that they produce NANOG, REX1, SSEA4, TRA1-60, and TRA1-81. While our equiPSCs are LIF dependent, bFGF co-stimulates their proliferation via the PI3K/AKT pathway. EquiPSCs lack expression of eqXIST and immunostaining for H3K27me3, suggesting that during reprogramming the inactive X chromosome has likely been reactivated to generate cells that have two active X chromosomes. EquiPSCs form embryoid bodies and in vitro teratomas that contain derivatives of all three germ layers. These LIF-dependent equiPSCs likely reflect a more naive state of pluripotency than equiPSCs that are co-dependent on both LIF and bFGF and so provide a novel resource for understanding pluripotency in the horse.

Behavioral and physiological responses of young horses to different weaning protocols: A pilot study

In this study, effects of weaning on behavioral and physiological stress parameters in young horses (foals) were determined. Foals were weaned either simultaneously without the presence of adult horses (group A, n = 6), or in the presence of two adult females familiar but unrelated to the foals (group B, n = 5), or weaned consecutively by removing two mother horses per day (group C, n = 6). Behavior, locomotion, salivary cortisol concentration, beat-to-beat (RR) interval, heart rate variability (HRV) and weight were determined. Group A foals lost weight for 2 days (mean ± SEM) − 8.3 ± 1.6 kg, p < 0.05. Weaning was followed by increased vocalization which was least pronounced in foals of group B (p < 0.05). Locomotion was most pronounced on weaning day in foals of group A and lowest in group B (p < 0.05). Weaning increased salivary cortisol concentration on the day of weaning in groups A and B and for 2 days in group C (p < 0.05). The RR interval decreased most pronouncedly in group A foals (p < 0.05). There were no consistent changes in HRV. Based on cortisol release and behavior, weaning is associated with stress but this was least pronounced in foals weaned in the presence of two familiar but unrelated adult female horses.

Effects of Intravenously Administered Esomeprazole Sodium on Gastric Juice pH in Adult Female Horses

Gastric ulcers are common in horses and treatment of horses that cannot be administered oral medication can be problematic. To evaluate the efficacy of esomeprazole sodium administered intravenously on gastric juice pH and gastric ulcer scores in horses. Twelve adult female Quarter Horses. Esomeprazole sodium (0.5 mg/kg IV) was administered once daily to 8 horses (treatment group) and saline (5 mL IV) was administered to 4 horses (control group) for 13 consecutive days. Gastroscopy was performed and gastric juice pH and gastric ulcer score were recorded before and 1 hour after the administration of esomeprazole sodium or saline on days 1 and 5, then on day 14, 23 hours after the 13th daily dose of esomeprazole sodium or saline. When compared with values before treatment, gastric juice pH was higher in esomeprazole sodium-treated horses after treatment (4.25 ± 2.39 versus 6.43 ± 1.18; P = .002). Also, gastric juice pH was higher (P = .001) in esomeprazole sodium-treated horses compared with saline-treated control horses on day 5 and on day 14 values. Gastric ulcers were seen in 5/12 (43%) horses in the study. Esomeprazole sodium shows promise for treatment of gastric ulcers in horses with signs of dysphagia, gastric reflux, or other conditions that restrict oral intake of the current Federal Drug Administration-approved omeprazole paste.