Search Results (139)

Reproductive efficiency is a critical determinant of productivity and profitability in both dairy and beef cattle systems. Progesterone-based estrus synchronization protocols have emerged as essential tools to control the timing of ovulation, enhance artificial insemination efficiency, and optimize herd reproductive performance. These protocols exploit the physiological regulation of the hypothalamic–pituitary–ovarian axis, maintaining elevated progesterone levels to suppress ovulation and coordinating luteolysis and follicular wave emergence through prostaglandins, GnRH analogues, and, in some cases, equine chorionic gonadotropin. In beef cattle, progesterone supplementation facilitates fixed-time artificial insemination, shortens calving intervals, and improves calf crop uniformity, whereas in dairy cows it mitigates poor estrus detection, enhances service rates, and reduces days open. Fertility outcomes are influenced by cow physiological status, metabolic condition, and protocol adherence, with pregnancy per AI typically ranging from moderate to high in beef cattle and lower in lactating dairy cows. Economic evaluation indicates that these protocols are cost-effective in herds with moderate to large size, low estrus detection efficiency, and intensive management, although labor, drug costs, and handling requirements must be considered. Critical analysis suggests that synchronization cannot compensate for underlying nutritional, health, or metabolic deficiencies, and future research should focus on precision application, individualized protocols, and integration with automated reproductive monitoring to improve both biological and economic efficiency. This review summarizes physiological principles, protocol designs, practical applications, fertility outcomes, and economic considerations of progesterone-based estrus synchronization in cows, highlighting current challenges and perspectives for enhanced reproductive management. Full article

Cryopreservation of stallion semen is associated with oxidative stress (OS), which can impair sperm function and fertility. This study evaluated antioxidant activities in seminal plasma and sperm cytosols and investigated their relationships with selected sperm functional parameters following cryopreservation, with or without antioxidant supplementation. Semen was collected from ten fertile stallions and processed using a split-ejaculate design, including fresh semen and six freezing treatments: HF-20 extender alone; HF-20 supplemented with matcha, spirulina, horseradish, or quercetin; and a commercial extender (INRA Freeze). Total antioxidant capacity (FRAP) and enzymatic activities (superoxide dismutase, SOD; catalase, CAT; and glutathione reductase, GR) were measured in seminal plasma and sperm lysates. Linear regression analyses revealed significant associations between seminal plasma and fresh spermatozoa with respect to SOD and GR activities. In frozen-thawed semen, FRAP and CAT activities differed between samples cryopreserved with and without antioxidant supplementation. Significant correlations were observed among antioxidant activities, sperm kinetics, OS markers, and DNA fragmentation indices. Principal component analysis provided an exploratory overview of multidimensional patterns of covariation among sperm kinetics, redox balance, and nuclear fragmentation, explaining for 73% of the total variance. Overall, the results suggest complex associations between the antioxidant system and sperm quality and indicate that antioxidant supplementation of freezing extenders may modulate the redox status of stallion sperm after thawing. Full article

This narrative review presents examples of omega-3 fatty acids supplementation in horse nutrition. Fats are essential in equine nutrition, serving not only as an energy source but also as functional components influencing health. Among them, omega-3 polyunsaturated fatty acids (PUFAs), particularly EPA and DHA, play a key role in modulating inflammatory and metabolic processes. This review summarizes their effects on respiratory health, equine metabolic syndrome (EMS), musculoskeletal function, reproduction, and early development. Omega-3 supplementation has been shown to support airway inflammation in horses, especially when combined with low-dust management practices. In EMS, these fatty acids support insulin regulation and reduce systemic inflammation, although they are not curative. In the musculoskeletal system, omega-3s help limit inflammation and cartilage degradation. Their reproductive benefits include improved semen quality in stallions and enhanced fatty acid profiles in mare’s milk, supporting foal development. The proposed mechanisms of omega-3 fatty acids’ effect are also provided. Overall, omega-3 fatty acids are a valuable supplement in equine functional nutrition and disease management. Full article

Progesterone (P4) exerts important vascular and immunomodulatory effects that influence platelet (PLT) activation and serotonin (5-HT) handling across mammalian species; nevertheless, its role in modulating PLT physiology during diestrus in mares remains poorly defined. This study hypothesized that physiological variations in luteal activity during diestrus are associated with changes in PLT activation and 5-HT-related parameters. The first objective was to determine whether changes in circulating P4 during diestrus are associated with alterations in PLT aggregation, circulating 5-HT, and PLT morphological indices in healthy mares; the second objective was to identify a diestrus day providing consistent physiological conditions for assessing PLT-related biomarkers. Twenty clinically healthy Spanish Purebred mares aged 4–9 years old were monitored. Blood samples were collected on days 5, 14, and 16 post-ovulation, with luteal status confirmed by ultrasonography. P4 concentrations were determined using a solid-phase I-125 radioimmunoassay (RIA), 5-HT concentrations were quantified using a competitive enzyme immunoassay, and PLT indices were measured using an ADVIA 2120i hematology analyzer. Data were compared using appropriate parametric or non-parametric tests after assessing distribution, and correlations were analyzed using rank-based correlation analysis, using Pearson or Spearman coefficients according to variable distribution. P4 concentrations were higher on days 14 and 16 compared with day 5 (p < 0.05), with no significant differences between days 14 and 16. Platelet aggregates (AGREG) showed the greatest variation, with significantly higher values on day 14 compared with day 5 (p < 0.05). In contrast, circulating 5-HT and all PLT morphological indices (PLT count, PCT, MPV, PLCR, PDW, PCDW, MPM, and PMDW) remained unchanged across diestrus. PLT aggregation showed a strong positive association with circulating P4 concentrations (r = 0.88, p < 0.05), whereas no meaningful correlations were observed between 5-HT and AGREG or between 5-HT and PLT morphological parameters. Internal correlations among PLT indices followed expected biological patterns, confirming the stability of structural PLT traits over short physiological intervals. These findings demonstrate that during diestrus, PLT activation—but not PLT morphology or circulating 5-HT—varies in parallel with P4 in mares. Day 14, corresponding to mid-diestrus, characterized by high luteal activity, represents an informative time point for assessing PLT activation and related biomarkers, providing a framework for standardizing sampling protocols for PLT-derived products in equine reproductive medicine. Full article

The equine reproductive microbiota has emerged as an important factor influencing reproductive health and fertility in both mares and stallions. Traditionally, the equine uterus was considered sterile, and microbial presence was interpreted primarily in the context of infection. However, sequencing-based studies have demonstrated that the reproductive tract, including the uterus and semen, contains detectable microbial communities or microbial DNA signatures, challenging this traditional paradigm. In mares, the vaginal microbiota is consistently dominated by Firmicutes, Bacteroidetes, Proteobacteria, and Actinobacteria, whereas the uterine environment represents a low-biomass niche in which interpretation is complicated by contamination risk and the inability of sequencing-based methods to distinguish viable from nonviable microorganisms. Culture-based studies consistently identify opportunistic pathogens such as Streptococcus equi subsp. zooepidemicus, Escherichia coli, and Pseudomonas aeruginosa in association with endometritis and persistent breeding-induced endometritis, while sequencing-based studies suggest broader community-level dysbiosis rather than simple pathogen presence. In stallions, semen is not sterile and commonly contains taxa such as Porphyromonas, Corynebacterium, Peptoniphilus, and other opportunistic bacteria that may influence sperm quality and microbial transmission to mares during breeding. However, most reported associations remain correlative, and direct longitudinal evidence for persistent stallion-to-mare microbial transmission is limited. This review synthesizes current evidence on microbial composition, hormonal influences, dysbiosis, and reproductive implications of the equine reproductive microbiota, integrating culture-based and sequencing-based findings while emphasizing methodological limitations associated with low-biomass samples. Improved understanding of these microbial ecosystems may support more evidence-based reproductive diagnostics and microbiome-informed fertility management in horses. Full article

The Kazakh horse represents a significant genetic resource within China’s equine population, characterized by notable resilience and an ability to thrive on coarse forage. Nevertheless, a decline in its numbers has been observed recently, making the improvement of its reproductive performance crucial for the preservation of this breed and the advancement of the related industry. In this study, testicular tissues from 1-year-old (pre-pubertal) and 2-year-old (post-pubertal) Kazakh horses were analyzed. miRNA sequencing was conducted on tissues from these age groups, followed by bioinformatics analyses to elucidate the functions of differentially expressed miRNAs (DEmiRNAs). The reliability of the sequencing data was subsequently verified using RT-qPCR. Analysis revealed 165 differentially expressed miRNAs (DEmiRNAs) in the testicular tissues between the two age groups. Of these, 118 DEmiRNAs (e.g., eca-miR-206 and eca-miR-2483) were significantly up-regulated (p < 0.05), and 47 DEmiRNAs (e.g., eca-miR-196a and eca-miR-211) were significantly down-regulated (p < 0.05). These DEmiRNAs were mainly implicated in biological processes including lipid metabolism and signal transduction. Their predicted target genes are potentially involved in key reproductive processes, notably testicular development and spermatogenesis. This study identifies candidate miRNAs and potential regulatory pathways associated with sexual maturation in Kazakh horses, providing a preliminary molecular basis for future functional validation and improvement of equine reproductive performance. Full article

Klebsiella pneumoniae has been associated with reproductive infections in equines. The detection of β-lactam resistance determinants, especially extended-spectrum β-lactamase (ESBL) genes, within genomic regions linked to horizontal gene transfer (HGT), is of a particular concern. In this study, we characterize the whole-genome sequences (WGS) of three K. pneumoniae equine isolates harboring multiple antimicrobial resistance genes. Two isolates were recovered from uterine washes of mares: one with endometritis (YAH-KPEM1) and one clinically normal (YAH-KPSE1), and a third from the feces of a diarrheic foal (YAH-KPF132). WGS was performed using the Illumina MiSeq platform, and the reads were subsequently processed through hybrid assembly in Unicycler v0.5.1. Genome annotation was completed using PROKKA v1.14.5. Strain YAH-KPEM1 was classified as ST127, whereas YAH-KPSE1 and YAH-KPF132 belonged to ST1630 and ST224, respectively. Notably, K. pneumoniae ST1630 and ST224 have not been reported before in equines. All three genomes encoded multiple antimicrobial resistance (AMR) determinants, including two encoding ESBL genes (CTX-M-15), as well as virulence factors and regions associated with HGT. Additionally, two (YAH-KPEM1 and YAH-KPSE1) isolates were found to be multidrug resistant (MDR), harboring an IncFIB(K) plasmid replicon, and another isolate, YAH-KPF132, carried an IncFII replicon. The detection of AMR and virulence genes in equine Klebsiella isolates has important clinical implications for guiding antimicrobial selection and improving treatment success. Full article

Research on the reproductive tract microbiology of broodmares has primarily focused on the uterus, with a limited set of tools for the rapid detection of pathogenic bacteria in the perineal region. Accurate, real-time identification of bacterial contamination could improve the diagnosis and management of post-breeding infectious endometritis. In this proof-of-concept study, we evaluated the ability of a portable MolecuLight i:X fluorescence imaging device for the rapid, non-invasive detection of potentially pathogenic perineal bacteria in healthy broodmares, comparing results with microbiological culture as the gold standard. Using ultraviolet-induced fluorescence imaging guided for swabbing and microbiological culture, the device demonstrated 80% sensitivity, 96% specificity, and 91% accuracy in differentiating potential pathogenic from commensal bacteria in clinically healthy broodmares. These preliminary findings may represent the basis for further assessment of the real-time, fluorescence-based technology in diseased or symptomatic broodmares, potentially aiding timely clinical decision-making. Further multicentred studies with larger inclusion of mares with confirmed endometritis are needed to strengthen the relevance of this technology and to expand the device’s application in equine reproductive health. Full article

Assisted reproductive techniques are often extrapolated from horses to donkeys, despite poorer fertility outcomes in jennies. This issue has been attributed to unknown uterine species-specific differences. This study compared, through histomorphometry, the endometrium of jennies and mares. Endometrial biopsies (N = 12) were taken from reproductively sound jennies (n = 6) and mares (n = 6) in estrus. Histomorphometric analysis evaluated luminal (LE, µm) and glandular epithelium height (GE, µm), glandular lumen diameter (LD, µm), glandular area (GA, µm²), the number of glands (#G), and glandular tissue percentage (GT, %), measured in the stratum compactum (SC) and spongiosum (SS). A total of 30 measurements of glandular size parameters and 10 fields of glandular density parameters per sample were recorded. Results were statistically compared between species (jennies vs. mares), parity status (maiden vs. foaling), and stratum (SC vs. SS). Jennies exhibited higher (p < 0.05) values than mares for LE, LD-SC, GA-SC, and GT-SC. These findings suggest that the histomorphometric features observed in reproductively sound jennies reflect anatomical differences that might partly explain previously observed species differences in post-breeding uterine response. In conclusion, histomorphometry revealed significant endometrial differences between species, with jennies displaying taller luminal epithelium, greater glandular size, and higher glandular tissue percentage in the SC than mares. Full article

Cryopreservation is a key tool in assisted reproduction, but it often compromises post-thaw sperm quality due to cryodamage. Optimizing the initial cooling phase, specifically from room temperature to 5 °C, is a critical determinant of successful outcomes. This study aimed to evaluate the impact of different pre-freeze cooling rates on stallion sperm quality using a novel, precision cooling device. Semen samples from five healthy stallions were divided into three groups and cooled at distinct rates: Slow (0.3 °C/min), Moderate (1 °C/min), and Fast (approximately 30 °C/min). Sperm motility parameters were assessed using a Computer-Assisted Sperm Analyzer (CASA) before freezing and after thawing. Additionally, sperm integrity and physiological parameters, including viability, acrosomal integrity, Reactive Oxygen Species (ROS) expression, and mitochondrial membrane potential, were assessed by flow cytometry post-thaw. The analysis of post-thaw kinematics revealed a significant interaction between the cooling rate and processing stage (post-cooling vs. post-thaw). The Fast-cooling protocol resulted in higher post-thaw total motility (51.8%) compared to the Slow protocol (45.01%). Crucially, no significant differences were detected among cooling rates for the critical parameter of progressive motility or curvilinear velocity (VCL). Circle motility had higher values in the Fast-cooling group compared to the Slow group. Cell viability demonstrated a tendency (p = 0.08), where the Slow cooling group exhibited higher mean values (65.59%) compared to the Fast group (61.67%). Comprehensive flow cytometry assessments of other cellular integrity markers, including acrosomal integrity, mitochondrial function (MMP), and ROS expression, were statistically equivalent across all cooling rates (p > 0.05). The results confirm that this fast pre-freeze cooling rate, integrated within the highly controlled environment of Directional Freezing technology, successfully preserved essential sperm function and structure. Critically, the demonstrated functional equivalence in progressive motility validates the Fast protocol as an efficacious strategy to increase the efficiency and adaptability of equine semen cryopreservation protocols for commercial utilization. Full article

Background: Pain after giving birth is commonly observed in horses, yet there has not been a specific tool developed for assessing this pain in postpartum mares. The goal was to adapt existing equine pain scales and to preliminarily validate a practical pain scale for use by veterinarians and caregivers after foaling. Methods: The pain scale was developed by adapting items from other pain scales, including established orthopedic and colic equine pain scales, and incorporating caregiver feedback. The final scale includes eight areas for assessing pain: behavior, facial expressions, vital signs, udder examination, gastrointestinal function, hoof temperature, response to food, and movement. Observations were conducted on ten heavy draft mares that experienced dystocia, with pain scores recorded twice daily for 1 to 4 days postpartum. Simultaneous saliva samples were collected to measure cortisol levels. Results: The pain scale proved feasible for use at the stall and allowed for partial scoring when certain assessments were deemed risky. Pain scores were highest on the first day after foaling and decreased as the mares recovered. In a case of clinical deterioration, a substantial increase in pain score was noted. Increased pain scores were associated with elevated cortisol levels, supporting the biological relevance of the scale. In clinical practice, if a pain score exceeded 40% of the maximum score, the mare was identified as a patient requiring analgesic treatment. Conclusions: This postpartum-specific pain scale provides a standardized method for assessing pain in mares after foaling and may assist in guiding appropriate pain management. Although the proposed pain scale shows promise as a clinical tool, the present results are preliminary and require confirmation in larger studies. Full article

Equine endometrosis is a chronic degenerative condition of the endometrium. A hallmark feature of endometrosis is endometrial fibrosis accompanied by degenerative changes in the adjacent tissue structure. Tumor necrosis factor α (TNFα), a pleiotropic cytokine produced by various immune cells, plays a dual role in coordinating immune responses and regulating cell/tissue homeostasis, making it an important regulator of fibrotic-related disorders. However, the exact role of TNFα in the development of equine endometrial fibrosis remains to be discovered and explained. Therefore, the main aim of the current study was to establish the effects of TNFα on the equine endometrial fibroblast transcriptome as well as on proliferation and expression of ECM-associated factors in in vitro cultured fibroblasts derived from non-fibrotic equine endometrium. RNA-sequencing revealed changes in the expression of 737 genes (p_adjusted < 0.05; log2FC ≥ 1.0/log2FC ≤ −1.0) between untreated and TNFα-treated equine endometrial fibroblasts. These genes are involved in, i.a., B cell activation, proliferation and differentiation, cell cycle, canonical NF-κB signal transduction, ERK1 and ERK2 cascade, and p53 signaling pathway. Moreover, it was found that TNFα increased fibroblast proliferation and affected the expression of metalloproteinases and their tissue inhibitors in mare endometrial fibroblasts. Results of the current study highlight that TNFα modulates the expression of genes related to immune cell activation, cell fate, and ECM remodeling in in vitro cultured equine endometrial fibroblasts, suggesting TNFα contribution in development of fibrosis in the mare endometrium. Since the current study provides mechanistic insight into TNFα action, these findings provide a foundation for future research aimed at targeting TNFα-mediated pathways as potential therapeutic strategies to mitigate equine endometrial fibrosis progression. Full article

Cryopreservation of stallion spermatozoa remains a challenge in equine reproduction, as it induces mitochondrial dysfunction that cannot be fully captured by conventional sperm quality assessment and requires further investigation. This study provides a detailed bioenergetic evaluation of cryopreserved stallion sperm using Seahorse XFp technology to measure basal oxygen consumption rate (OCR) and to perform a MitoStress Test. Three ejaculates from 20 Warmblood stallions (licensed by the Holsteiner Verband, Elmshorn, Germany) were analyzed at 15 min intervals from 15 to 120 min after thawing. CASA and multiparametric flow cytometry were used to assess motility, sperm viability, reactive oxygen species (ROS) synthesis, lipid peroxidation (LPO), and DNA fragmentation index (%DFI). Seahorse analysis revealed marked intra- and inter-individual variability in basal OCR among frozen–thawed samples. Functional mitochondrial parameters showed only partial correlations with motility and viability results, underlining the added diagnostic value of combined metabolic profiling. Over the 2 h measurement, viability and motility displayed an increasingly negative correlation with ROS synthesis, while no significant relation was found between OCR and ROS synthesis or LPO. These findings demonstrate that stallion sperm mitochondria are highly sensitive organelles whose functional state cannot be fully assessed by routine motility or viability testing alone. Integrating Seahorse-based profiling with CASA and flow cytometry can improve sperm quality assessment. Moreover, this novel approach has been proven to be a valuable tool, offering broad opportunities for further research in stallion reproduction. Full article

Equines play a crucial role in global food security, economic development, and recreation, particularly in regions such as Central Asia, parts of Africa, and South America. However, parasitic infections significantly impact their health, productivity, and reproductive performance, leading to economic losses and reduced animal welfare. This review synthesizes the effects of parasitic infections, including protozoan, helminthic, and ectoparasitic species, on equines. These infections cause hematological alterations like anemia, leukocytosis, leukopenia, and thrombocytopenia, compromising overall health and resilience. Protozoan parasites, such as Trypanosoma spp., Theileria equi, and Babesia caballi, directly affect semen quality and fertility by causing testicular lesions, orchitis, and hormonal disruptions. Helminths like Cyathostomins and Strongyles reduce nutrient absorption, impairing productivity, while some protozoan species can cause abortion through transplacental transmission. Zoonotic parasites, including Sarcocystis spp. and Toxoplasma gondii, pose a human health risk through contaminated meat and milk consumption. Despite the effectiveness of conventional anthelmintics, emerging biological control methods like Duddingtonia flagrans (BioWorma^® and Bioverm^®) show promise. However, the development of standardized herbal anthelmintics and vaccines is hindered by limited efficacy validation, complex parasite biology, and inadequate funding. The need for better diagnostic tools and sustainable treatments remains critical for the long-term sustainability of the equine industry. Full article

Equine herpesvirus (EHV) infections represent a significant global veterinary and economic challenge affecting both horses and donkeys across all inhabited continents. This narrative review comprehensively examines the nine distinct EHV species (EHV-1 through EHV-9), their taxonomic classification within Alphaherpesvirinae and Gammaherpesvirinae subfamilies, and their diverse host tropism patterns. The complex molecular pathogenesis involves sophisticated viral glycoproteins (gK, gB, gC, gH, gM, gL, gG, gD, gI, gE) that orchestrate cellular invasion, immune evasion, and intercellular transmission. Clinical manifestations vary considerably, ranging from respiratory diseases and reproductive failures to severe neurological disorders, with EHV-1 demonstrating the most severe presentations including myeloencephalopathy. Global distribution analysis reveals widespread circulation across Europe, Asia, Africa, the Americas, and Oceania, with species-specific clinical patterns. Current therapeutic options remain largely supportive, with experimental compounds like berbamine and cepharanthine, celastrol, blebbistatin, and hyperoside showing promise in preclinical studies. Vaccination programs demonstrate limited effectiveness, failing to prevent transmission at population levels despite inducing individual immune responses. The sophisticated immune evasion strategies employed by EHVs, including the “Trojan horse” mechanism utilizing infected leukocytes, highlight the complexity of host–pathogen interactions and underscore the urgent need for innovative prevention and treatment strategies. Full article