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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]

Simple Summary: Dülmen wild horses have been managed by the Dukes of Croÿ for about 180 years in the Merfelder Bruch, a region near Dülmen in Westphalia, Germany. The Dülmen wild horses are freely roaming in this area of about 1400 acres all year round without human intervention and have to cope with the harsh natural conditions. Each breeding season 2–3 stallions are employed to sire foals. Herdbook records for this herd are not available due to the wildlife living conditions, free from any human disturbances. In this present study, we analyzed the distribution of the male progeny by their sires and whether sire effects on the genetic diversity and structure in the male progeny can be found. The genetic substructure in female progeny could not be evaluated as the fillies could not be captured for sampling. The paternal half-sib groups showed a very similar genetic diversity, but pairwise genetic distances and neighbor-joining dendrograms indicated a clustering by sires and a marker variance of 9% between paternal progeny groups. Bayesian cluster analysis supported subdivision into paternal progeny groups. Cluster memberships to paternal progeny groups, which were sired in the same year but by different sires, may also be related to mares, while clusters of paternal progeny from the same sire, but in intervals of more than one year, could not be distinguished. The employment of sires which are able to withstand the harsh natural conditions may also ensure a high genetic diversity in their progeny. The objectives of the present study were to analyze the influence of the stallions employed in the Dülmen wild horses on the genetic diversity and population substructure using Bayesian cluster analysis. The Dülmen wild horse is maintained as a unique horse population exposed to the natural conditions all year round in the Merfelder Bruch near Dülmen in Westphalia, Germany. Stallions selected for breeding have to prove their abilities to survive under this harsh environment. We used multilocus genotypic information from a set of 29 autosomal microsatellites to determine the paternity of 185 male foals sired by nine stallions. As females could not be sampled, we could not make inferences on all yearlings and test whether there are differences in the genetic population parameters between both sexes. The mean number of progeny was 19.92 with a range of 2–32, caused by the length of the service period per stallion. The average observed and unbiased expected heterozygosity was 0.688 and 0.631, the mean number of alleles was 4.448, and Wright's FIS was −0.173. Pairwise genetic distances (FST and Nei's unbiased genetic distances) were significant and varied between 0.038 to 0.091 and 0.085 to 0.290, respectively. Neighbor-joining dendrogram plots clustered a large proportion of the paternal progeny groups in different branches. Posterior Bayesian analyses using seven paternal half-sib groups with 10–74 members supported a maximum of six clusters, with two paternal progeny groups not differing, and a median of five clusters, with two groups of two sires each falling into the same clusters. When sires were employed in non-consecutive years, progeny from these different years of the same sires were grouped in the same cluster, whereas the progeny of one sire from two consecutive years were in different clusters. We were able to distinguish male progeny from Dülmen wild horse stallions and to show the effects of stallion use on the genetic substructure in the Dülmen wild horse herd. In conclusion, the analyses showed the genetic potential of the Dülmen wild horse stallions to maintain a high genetic diversity and also the effects in which breeding seasons and for how long stallions are used to sire foals. The selection of stallions may be sensitive for the further development of genetic diversity and preserve this closed population as a valuable resource for further studies on the evolution of the horse. [ABSTRACT FROM AUTHOR]

Although under appropriate laboratory conditions, sperm from different mammalian species can be capacitated in vitro , the optimal conditions for sperm capacitation in the stallion have been elusive. This study evaluated the effect of different capacitating inducers in Whitten and Tyrode media and assessed their impact on capacitation-related factors. Stallion sperm were incubated with different combinations of capacitating inducers at 38.5 °C in an air atmosphere. Sperm quality variables such as motility, mitochondrial membrane potential, and lipid peroxidation were assessed. Membrane fluidity and intracellular calcium levels were evaluated as early markers of capacitation, while tyrosine phosphorylation events and the sperm's ability to perform acrosomal exocytosis were used as late capacitation markers. Finally, these sperm were evaluated using a heterologous zona pellucida binding assay. The findings confirm that capacitating conditions evaluated increase intracellular calcium levels and membrane fluidity in both media. Similarly, including 2 or 3 inducers in both media increased tyrosine phosphorylation levels and acrosomal exocytosis after exposure to progesterone, confirming that stallion sperm incubated in these conditions shows cellular and molecular changes consistent with sperm capacitation. Furthermore, the zona pellucida binding assay confirmed the binding capacity of sperm incubated in capacitation conditions, a key step for stallion in vitro fertilization success. Further studies are needed to evaluate the effect of these conditions on in vitro fertilization in the horse. • Different treatments for equine sperm capacitation were evaluated in two media. • Combination of capacitating inducers boosts phosphorylation and acrosomal exocytosis. • Capacitating conditions improve sperm's zona pellucida binding capacity. [ABSTRACT FROM AUTHOR]

Background: The Franches-Montagnes (FM) is the last native horse breed of Switzerland, established at the end of the 19th century by cross-breeding local mares with Anglo-Norman stallions. We collected high-density SNP genotype data (Axiom™ 670 K Equine genotyping array) from 522 FM horses, including 44 old-type horses (OF), 514 European Warmblood horses (WB) from Sweden and Switzerland (including a stallion used for cross-breeding in 1990), 136 purebred Arabians (AR), 32 Shagya Arabians (SA), and 64 Thoroughbred (TB) horses, as introgressed WB stallions showed TB origin in their pedigrees. The aim of the study was to ascertain fine-scale population structures of the FM breed, including estimation of individual admixture levels and genomic inbreeding (FROH) by means of Runs of Homozygosity. Results: To assess fine-scale population structures within the FM breed, we applied a three-step approach, which combined admixture, genetic contribution, and FROH of individuals into a high-resolution network visualization. Based on this approach, we were able to demonstrate that population substructures, as detected by model-based clustering, can be either associated with a different genetic origin or with the progeny of most influential sires. Within the FM breed, admixed horses explained most of the genetic variance of the current breeding population, while OF horses only accounted for a small proportion of the variance. Furthermore, we illustrated that FM horses showed high TB admixture levels and we identified inconsistencies in the origin of FM horses descending from the Arabian stallion Doktryner. With the exception of WB, FM horses were less inbred compared to the other breeds. However, the relatively few but long ROH segments suggested diversity loss in both FM subpopulations. Genes located in FM- and OF-specific ROH islands had known functions involved in conformation and behaviour, two traits that are highly valued by breeders. Conclusions: The FM remains the last native Swiss breed, clearly distinguishable from other historically introgressed breeds, but it suffered bottlenecks due to intensive selection of stallions, restrictive mating choices based on arbitrary definitions of pure breeding, and selection of rare coat colours. To preserve the genetic diversity of FM horses, future conservation managements strategies should involve a well-balanced selection of stallions (e.g., by integrating OF stallions in the FM breeding population) and avoid selection for rare coat colours. [ABSTRACT FROM AUTHOR]

Simple Summary: Equine gastric ulcer syndrome is a common disease in horses worldwide, with different prevalences in various categories and breeds. It is divided into two different illnesses, based on the mucosa affected: Equine Squamous Gastric Disease, if it involves the squamous mucosa, and Equine Glandular Gastric Disease, if the lesions are located in the glandular portion of the stomach. The effect of sex on gastric ulcers, especially on the squamous mucosa, is not completely elucidated: some studies found a higher prevalence of lesions of the squamous mucosa in geldings and stallions, while others failed to identify a sex as a risk factor. The few studies on glandular lesions did not show any correlation between sex and ulcers. A paper investigating only Thoroughbred mares at pasture found that about 70% of them had gastric ulcers, especially on the squamous mucosa. The aim of this study was to determine the prevalence of the disease in a population of male horses, and determine if their breeding or sports career can influence the development of gastric lesions. Gastroscopies were performed in 101 males, after recording data about their breeding and exercise history, management, and presence of clinical signs. Breeding activity does not determine the presence or severity of gastric lesions in either mucosa, while exercise and a combination of both exercise and breeding is associated with ulcers in the glandular mucosa. Clinical signs are correlated only with the severity of lesions in the squamous one. Equine gastric ulcer syndrome (EGUS) is a worldwide disease, and includes two different syndromes, Equine Squamous Gastric Disease (ESGD), affecting the squamous mucosa, and Equine Glandular Gastric Disease (EGGD), affecting the glandular mucosa. These two diseases are present in different categories (different activities, ages, etc.) and breeds of horses. The effect of sex on gastric health is not clear: some studies found a higher prevalence of ESGD in geldings and stallions, while others found no influence of sex on the squamous mucosa. The few studies conducted on glandular diseases failed to identify sex as a risk factor. The only study on breeding horses, focused on Thoroughbred mares at pasture, found that 70% of them were affected by gastric ulcerations especially in the squamous mucosa. The aim of this study was to determine the prevalence of EGUS, ESGD, and EGGD in intact males while also investigating the potential influences of breeding and exercise activity on the occurrence and severity of the diseases. A total of 101 intact males were admitted for gastroscopic examination. Comprehensive data regarding their breeding and sports history, management, and presence of clinical signs were recorded. A statistical analysis was performed. Within this equine population, no discernible relationship was found between breeding activity and occurrence and severity of ESGD or EGGD. Exercise and a combination of exercise and breeding activities were found to be associated with the occurrence of EGGD. The presence of clinical signs was correlated only with the grade of ESGD in this cohort of horses. [ABSTRACT FROM AUTHOR]

The breeding history of the Einsiedler horse is closely connected with the Benedictine cloister Einsiedeln. In the mid‐nineteenth century, it was decided to use European Warmblood stallions for cross‐breeding and to abandon the selection of stallions. Since that time, it has only been possible to trace back the origin of Einsiedler horses using maternal ancestry information. Here, we collected high‐density genotype data for European Warmblood horses (Selle Français, Swiss Warmblood and Einsiedler) and Franches‐Montagnes horses, the last native Swiss horse breed, to unravel the current population structure of the Einsiedler horse. Using commonly applied methods to ascertain fine‐scale population structures, it was not possible to clearly differentiate the Einsiedler from other European Warmblood horses. However, by means of runs of homozygosity (ROH) we were able to detect breed‐specific ROH islands for the Einsiedler horse, including genes involved in domestication and adaptation to high altitude. Therefore, future breeding activities should involve the screening of these breed‐specific ROH segments, the revival of cryopreserved sperm and the selection of Einsiedler stallions. [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]

The aim of this work was to evaluate selected influencing factors during the breeding of young Czech warmblood stallions in test farms on the results of the performance test. In six breeding farms for young horses (Měník, Písek, Skály, Suchá, Tlumačov and Železnice), 119 stallions were tested and 413 offspring were evaluated. During the performance test, the factors test farm, year of birth, father and parental descent were examined with regard to their influence on the characteristics of cannon bone circumference, conformation values, movement mechanics, jumping ability and overall evaluation. The data were collected from the Morgan ČT program and then analyzed using the GLM (Generalized Linear Model) analysis of variance method. The rearing operation, the year of the performance test, the test person's father and the ancestry of the parents had a significant influence. The influence of breeding on the overall evaluation, the exterior and the movement mechanics could be proven. The year of the test was proven to have an influence on chest circumference. The Tlumačov breeding farm was the best-rated testing station for young horses. The results confirmed the hypothesis that the farm influences the test results of young Czech Warmblood horses. Therefore, it is crucial to focus further on the evaluation system for the performance of young stallions. [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]

A body condition index for equines was proposed by Potter et al in 2015. This index showed, as the Henneke body condition score, a high correlation with the estimation of body fat content by the deuterium oxide dilution method. The purpose of this research was to validate the index by Potter as an objective method to estimate body fat content in Thoroughbred racing horses in competition, through its correlation with the Henneke score modified by Koehne (1992). Fifty Thoroughbred racing horses in training were used (2 stallions, 26 geldings and 22 mares) between 3 to 9 year old. Modified Henneke body condition score was estimated for each horse, along their height at withers, neck circumference, heart girth and belly girth were measured to calculate the body condition index. Measurements were compared between sexes by analysis of variance and Tukey test. Pearson correlation was calculated between the modified Henneke body condition score and the body condition index. The body condition index showed a high correlation with the modified Henneke body condition score in Thoroughbred racing horses (r=0.922, p<0.00001). This study suggests that the body condition index is a good method to estimate the modified Henneke body condition score in Thoroughbred racing horses in training. [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]

The present work was designed for a thorough investigation into the sperm morphology and morphometry of Kurdish stallions. The semen samples were collected from 10 Kurdish stallions. Three preparations from each ejaculate were stained with eosin–nigrosin (EN), Diff‐Quik (DQ) and Rose Bengal (RB). The area, perimeter, length and width of the sperm head as well as tail length and total sperm length were measured. The parameters ellipticity, elongation, roughness and regularity were calculated. The morphology of sperm was also investigated under scanning and transmission electron microscopes. DQ and RB provided more clarified images for examining sperm structures compared to the EN method. The head length, head width, area and perimeter in EN were significantly higher than those in DQ and RB (p ≤.05). Furthermore, the difference in head width, head area and head perimeter between DQ and RB was not significant (p ≥.05). The tail length and total sperm length in all methods were close together (p ≥.05). The highest percentage of normal sperm was seen in DQ and RB methods (82.55 ± 2.88 and 88.31 ± 5.19) respectively. The highest values for ellipticity, elongation and regularity were found in RB, whereas the highest value for roughness was measured in EN. Tail defects including coiled tails, and folded midpieces were the most frequent. Scanning electron microscope revealed two types of head shapes: heads with round anterior border, and heads with flat anterior border. The results indicated that despite the routine use of EN for morphological assessment of stallion sperm, RB and DQ can be considered for more clarified details of sperm structure including acrosome and midpiece. Furthermore, the Kurdish stallion sperm has morphometric traits in the normal range established for stallions; yet, some traits were larger than those reported for other breeds. It seems that the sperm of the Kurdish stallion has a longer head and tail in comparison with other horse breeds. [ABSTRACT FROM AUTHOR]

This article presents a case study of a 20-year-old Corolla wild horse stallion that was admitted to a veterinary teaching hospital with colic signs. The horse had previously been domesticated from a wild population and showed abnormal biochemistry findings, including mild hyperbilirubinemia and elevated liver enzymes. Blood smear evaluation revealed the presence of microfilariae, which were identified as Setaria equina through molecular analysis. The article discusses the potential causes of microfilaremia in horses and highlights the need for further research on the prevalence of S. equina in domestic and wild horse populations. [Extracted from the article]

Horse domestication and breed selection processes have profoundly influenced the development and transformation of human society and civilization over time. Therefore, their origin and history have always attracted much attention. In Italy, several local breeds have won prestigious awards thanks to their unique traits and socio-cultural peculiarities. Here, for the first time, we report the genetic variation of three loci of the male-specific region of the Y chromosome (MSY) of four local breeds and another one (Lipizzan, UNESCO) well-represented in the Italian Peninsula. The analysis also includes data from three Sardinian breeds and another forty-eight Eurasian and Mediterranean horse breeds retrieved from GenBank for comparison. Three haplotypes (HT1, HT2, and HT3) were found in Italian stallions, with different spatial distributions between breeds. HT1 (the ancestral haplotype) was frequent, especially in Bardigiano and Monterufolino, HT2 (Neapolitan/Oriental wave) was found in almost all local breeds, and HT3 (Thoroughbred wave) was detected in Maremmano and two Sardinian breeds (Sardinian Anglo-Arab and Sarcidano). This differential distribution is due to three paternal introgressions of imported stallions from foreign countries to improve local herds; however, further genetic analyses are essential to reconstruct the genetic history of native horse breeds, evaluate the impact of selection events, and enable conservation strategies. [ABSTRACT FROM AUTHOR]

The specifics of breeding and selection significantly affect genetic diversity and variability within a breed. We present the data obtained from the genetic analysis of 21 thoroughbred and warmblood horse breeds. The most detailed information is described from the following breeds: Arabian, Trakehner, French Trotter, Standardbred, and Soviet Heavy Horse. The analysis of 509,617 SNP variants in 87 stallions from 21 populations made it possible to estimate the genetic diversity at the genome-wide level and distinguish the studied horse breeds from each other. In this study, we searched for heterozygous and homozygous ROH regions, evaluated inbreeding using FROH analysis, and generated a population structure using Admixture 1.3 software. Our findings indicate that the Arabian breed is an ancestor of many horse breeds. The study of the full-genome architectonics of breeds is of great practical importance for preserving the genetic characteristics of breeds and managing breeding. Studies were carried out to determine homozygous regions in individual breeds and search for candidate genes in these regions. Fifty-six candidate genes for the influence of selection pressure were identified. Our research reveals genetic diversity consistent with breeding directions and the breeds' history of origin. [ABSTRACT FROM AUTHOR]

Background: Laminitis is a systemic condition resulting in debilitating pain and structural changes within the feet, and hence has major welfare implications. Causes include endocrine and systemic inflammatory conditions. Ponies are frequently affected, and observations in the field suggest that occurrence of laminitis is also common in Norwegian breeds. The aim of this study was to estimate the prevalence and risk factors for laminitis within the Norwegian pony breed Nordlandshest/Lyngshest. Results: The study was a cross-sectional study based on questionnaires sent to members of the Norwegian Nordlandshest/Lyngshest breed association. Questionnaires were received for 504 animals, of which 464 records were eligible and included in analyses. The population comprised 71 stallions, 156 geldings, and 237 mares, with an age between 1 and 40 years (median and interquartile ranges: 12 (6–18) years). The estimated 3-year period prevalence of laminitis was 8.4% (95% confidence interval (CI95): 6.0–11.3%), whereas lifetime prevalence was 12.5% (CI95: 9.6–15.9%). Mares had a significantly higher period- and lifetime prevalence of laminitis than male horses, and horses 10 years and older had a significantly higher prevalence than younger horses. The lifetime prevalence of laminitis was 3.2% in horses 9 years and younger, whereas from 17.3–20.5% in older horses. Multivariable logistic regression analysis identified age, sex, and regional adiposity as significantly (P < 0.05) associated with the 3-year period outcome of laminitis: Horses older than 9 years had a three-fold increase in the likelihood of having laminitis compared to the younger horses (Odds Ratio (OR)10–14 years = 3.37 (CI95 = 1.19–9.50), OR15-19 years = 3.06 (CI95 = 1.04–9.05), and OR>20 years = 2.70 (CI95 = 0.90–8.02). Mares were more than twice as likely (OR = 2.44 (CI95 = 1.17–5.12) to have laminitis compared to male horses, and horses with regional adiposity had increased odds (OR = 2.35 (CI95 = 1.15–4.82) of laminitis compared to horses without regional adiposity. Conclusions: Laminitis appears to be a considerable welfare issue in the Norwegian pony breed Nordlandshest/Lyngshest. The identified risk factors age, sex, and regional adiposity highlight the need for improved owner education and awareness of strategies to reduce laminitis risk. [ABSTRACT FROM AUTHOR]

The history of the 'Horse Centre' Stadl-Paura has its origin in the early 19th century. In 1826, the stallions from the public stallion depot in Lichtenegg were transferred to Stadl-Paura. One year later, the establishment of the historic military stallion depot started with 186 stallions. Until 1998, the main function of the stallion depot was to provide stallions for regional breeders. The privatisation of the institution came along with the end of public stallion stations. Since then, the Horse Centre has been focusing on organizing and carrying out sport and breeding events as well as on the education of horses and humans. The goal of this study was to evaluate the agreement of customer opinions with the Centre's mission statement. For this purpose, four online surveys were created, addressing the main target groups, the competition riders and drivers, breeders, horse owners who had their horse trained in Stadl-Paura and students of the Agricultural Education Centre Lambach. Only completely answered questionnaires were considered in the analysis; these were 198 for the sport survey, 88 for the breeding survey, 25 for the riding survey and 62 for the student survey. The results show a high customer satisfaction across the stakeholder groups; the horse center was rated best by the competition riders and drivers. Across all groups, the infrastructure was perceived better than the offered services. As the company is a key driver for the economic factor horse, a high customer satisfaction is of great importance. [ABSTRACT FROM AUTHOR]

We evaluated the hematological and biochemical parameters of apparently healthy horses in Ibadan polo Ibadan, Nigeria. A total of 20 apparently healthy Polo horses were used for this study. Breeds were established by their morphological features; Age was grouped based on the birth record and sexes morphologically established. Hematological and Biochemical analysis were established by adopting standard procedures and the use of specific kits respectively. Breed demography showed 14 (70%) Sudanese breed and 6 (30%) Cross breeds. Sex demography represents 18 (90%) female and 2 (10%) males. Age group demography reveals as follows; young horses (4-6yrs) were 4 (20%), middle-aged horses (7-9yrs) were 8 (40%) and older horses (10-13yrs) category were 8 (40%). All hematological and biochemical indices were within the normal ref range. Except for total bilirubin and Cholesterol with relatively higher Mean ± SD values of 0.58 ± 0.23 and 146.20 ± 12.98 respectively. Statistical significance (P<0.05) was observed in the values of High-density lipoprotein (HDL) among breeds. HDL was significantly higher in Sudanese breed with higher Mean ± SD values of (45.43±4.65) compared to Cross bred with Mean ± SD values of (39.67±6.62). Hematological and biochemical parameters of male (Stallion) appeared better to female (Mare) when compared to normal reference range. Statistical difference of (P<0.05) existed in the value of Mean ± SD values of glucose (mg/dL) within age groups with significant lower value of 79.38±2.92b in 7-9yrs age group compared to the value of 84.5±2.56ain 10-13yrs age group. We observed no significant variation in hematology and most biochemical parameters among breeds, sexes and age groups. There may be need for further investigation to unravel the cause of higher HDL in Sudanese breed and hypoglyceamia observed in 7-9yrs age group of horses as seen in this present study. [ABSTRACT FROM AUTHOR]

Simple Summary: The stallion is a horse like any other horse, and social interactions are an important part of daily life. Although many free-roaming stallions fulfil their life's purpose, reproduction, only those with special characteristics enabling the formation and long tenure of a harem can sire a large number of offspring. The harem leader role is, however, a difficult one; the welfare of free-living stallions can be challenged by a range of factors. In this review, we discuss these challenges and explain how understanding the pressures that have shaped the evolution of stallion behaviour can be used to argue for the importance of the social environment to the stallion in captivity. In captivity, intact male horses, due to their sexual drive, are usually socially isolated from other horses. This lifestyle strongly contrasts with that experienced by horses living in free-roaming, feral, or semi-feral conditions, where adult stallions have several roles in their social group, with successful reproduction being their primary drive. Reproductive skew in wild populations is high; many stallions will fail to reproduce at all, while others achieve high levels of reproductive success, siring a large number of foals. Successful stallions are those with particular characteristics and abilities that facilitate harem formation and tenure, allowing them to successfully take over a harem or establish a new one, protect mares from rival stallions, employ appropriate social behaviour to maintain group cohesion, and avoid kin-mating, for example through kin recognition mechanisms. Whilst the life of free-living stallions is far from stress-free, they retain ancestral adaptations to selection pressures (such as predation and competition) exhibited by their natural environment over thousands of years. Here, we discuss the challenges faced by free-living horse stallions, the roles they play in social groups, and their resulting social needs. By understanding these pressures and how stallions react to them, we highlighted the importance of the social environment for the stallion. It is hoped that a better understanding of wild stallions' lives will lead to their needs being more clearly met in captivity, reducing stereotypical behaviour and improving welfare. [ABSTRACT FROM AUTHOR]

Summary: A 19‐year‐old Thoroughbred stallion developed severe curvature of its penis, preventing intromission, after breeding a mare. The cause of the curvature was found, during ultrasonographic examination of the penis, to be rupture of the trabeculae on the left side of the corpus cavernosum penis (CCP) between the cul de sac of the external preputial cavity and the scrotum, resulting in the formation of a seroma. Aspiration of the seroma performed 13 days after injury, with the horse anaesthetised, largely resolved the deviation. A complication of treatment was excessive belling of the glans penis during erection, which may have been the result of a temporary shunt created between the CCP and the corpora spongiosum penis (CSP) by inadvertently passing the spinal needle used to aspirate the seroma through the CSP. Excessive belling resolved after 3 weeks. [ABSTRACT FROM AUTHOR]

This article, published in Equine Veterinary Education, presents the findings of a retrospective study on 850 horses with Equine Gastric Ulcer Syndrome (EGUS). The study aimed to identify the clinical signs of EGUS and distinguish between Equine Gastric Squamous Disease (EGSD) and Equine Gastric Glandular Disease (EGGD). Gastroscopic examinations were conducted, and detailed questionnaires were given to horse owners. The results showed that riding problems and anxiety during saddling were the most common signs reported by owners. Weight loss and colic episodes were also observed, with differences between the EGSD and EGGD groups. The study highlights the complexity of EGUS and the importance of proper diagnosis for effective treatment. [Extracted from the article]

Simple Summary: Stallion fertility is a vast subject, with a wide array of factors that can impact reproductive performance in either positive or negative ways. To better valorize horses' genetic resources and understand the factors affecting variations in stallion fertility per cycle and end-of-season fertility, we have performed a statistical analysis study on some breeding factors: year of breeding, stud farm, age of the stallion, number of covered mares per stallion, reproduction methods, and age of the mare using 94 purebred Arabian stallions in four different regions of Tunisia. The pertinent results are: Sidi Thabet's stud farm contained the highest number of purebred Arabian stallions. The majority of stallions were between 15 and 21 years old and had covered 1 to 20 mares; 95.19% of the stallions were used in natural mating. Depending on the year and stud, there was a variation in the fertility per cycle and end-of-season fertility of the stallions. The use of artificial insemination with fresh semen showed a high average value for fertility per cycle and end-of-season fertility. The used statistical model showed that the breeding year, the stud, the age of the stallion, the number of covered mares by stallions, and the method of reproduction significantly affected both fertility per cycle and end-of-season fertility (with p = 0.001). Moderate to high heritability estimations for fertility per cycle (hs2 = 0.08) and end-of-season fertility (hes2 = 0.36) were obtained. Identification of the stallion fertility variations based on different breeding factors is useful to improve the stallion's reproductive efficiency, to help the breeders to make the most relevant choices before the beginning of the breeding season, and to have better profitability and the sustainable use of their animals. A consistently high level of stallion fertility plays an economically important role in modern horse breeding. To better understand the factors affecting variation in stallion fertility, we have performed a statistical analysis study on some breeding factors: year of breeding, stud farm, age of the stallion, number of covered mares per stallion, reproduction methods, and age of the mare. This work was conducted on 94 purebred Arabian stallions in four different regions of Tunisia. The results showed an increase in the number of stallions during the study period, ranging from 11.33% in 2011 to 13.29% in 2018. Sidi Thabet's stud farm contained the highest number of purebred Arabian stallions. The majority of stallions were between 15 and 21 years old and had covered 1 to 20 mares; 95.19% of stallions were used in natural mating (Nat); 50.36% had low fertility, 17.69% had medium fertility, and 32.3% had excellent fertility according to fertility standards. Depending on the year and stud, there was a variation in fertility per cycle (FERPCE) and end-of-season fertility (FERPSE) of the stallions. The highest average FERPCE and FERPSE values were obtained using artificial insemination with fresh semen (AIF). Analysis of FERPCE and FERPSE showed that the model used in our study explained 40.21% of total variability observations for FERPCE and 42.1% for FERPSE. The used statistical model showed that the breeding year, the stud, the age of the stallion, the number of covered mares by stallions and the method of reproduction significantly affected both FERPCE and FERPSE (with p = 0.001). Low to moderate heritability estimations for FERPCE (hs2 = 0.08) and FERPSE (hes2 = 0.36) were obtained. [ABSTRACT FROM AUTHOR]

Simple Summary: Young Friesian stallions have to complete a 10-week training program (70-day test) to become studbook approved breeding stallions. The effect of this training program, consisting of dressage and driving training, on fitness progress was evaluated in this study. Data were collected in the 9 weeks preceding the training program, and during the 70-day test. Duration and time spent at walk, trot and canter for all training sessions were measured in the participating 16 stallions. Each stallion had to perform three ridden standardized exercise tests in week 1, 6 and 10 of the 70-day test, during which heart rate and plasma lactate concentration were measured. Horses were trained for a longer duration in the 70-day test compared to the preceding weeks. Heart rate and plasma lactate concentration of the horses increased in the second and third exercise test compared to the first exercise test, indicating that the stallions were more fatigued during the second and third exercise tests. These results indicate that the fitness of Friesian stallions decreased during 70-day test, suggesting overtraining. The 10-week training program needs to be adjusted to optimize training effects and welfare of the horses. Friesian stallions have to complete a 10-week studbook approval test (70-day test) consisting of dressage and driving training for acceptance as a breeding stallion. Training response of the horses to this approval program was evaluated. External workload (EW) of 16 stallions (3.2 ± 0.4 years old) was registered during the 9 weeks preceding the 70-day test (preparation period) and during 70-day test. Ridden indoor standardized exercise tests (SET), measuring heart rate (HR) and plasma lactate concentration (LA) at walk, trot and canter, were performed in week 1 (SET-I), 6 (SET-II) and 10 (SET-III) of the 70-day test. Linear mixed effect models were used to analyze HR and LA related to SETs and EW related to the phase of the study, using Akaike's information criterion for model reduction. EW was higher in the 70-day test compared to the preparation period, with longer duration of training sessions. Compared to SET-I, horses showed increased HR and LA after canter in SET-II and SET-III, indicating that they were more fatigued. The fact that the fitness of these Friesian stallions decreased during the 70-day test suggests overtraining. To optimize training effects and welfare of these horses, the workload of the training program needs to be adjusted. [ABSTRACT FROM AUTHOR]

Simple Summary: Among equids, the mule (jackass stallion × mare) is the most common hybrid, followed by the hinny (horse stallion × jenny). This study describes the outcome of inseminating mares and jennies with either fresh horse or donkey semen of proven fertility. Pregnancy rates in horse females were significantly higher than in donkey females, while horse and donkey males did not affect pregnancy rates. Overall, intraspecific pregnancy rates were significantly higher than interspecific ones. Horses and donkeys differ phenotypically and karyotypically, although they can interbreed freely. Eight Standardbred mares and nine Amiata donkey jennies were included in the study. Semen was collected from two horses and two donkey stallions of proven fertility. A first pregnancy diagnosis was performed on day 10 after ovulation and repeated every day until embryo detection or until day 16. Irrespectively of the sire species, pregnancy rates in horse females (20/30, 66.7%) were significantly higher than in donkey females (19/70, 27.1%) (p < 0.05), while horse and donkey males did not affect pregnancy rates. Comparing overall intraspecific and interspecific AI, pregnancy rates were 25/37 (67.6%) and 14/63 (22.2%), respectively (p = 0.0001). The lowest pregnancy rate was obtained when inseminating jennies with horse stallion semen (8/49, 16.3%). No statistical differences were found when comparing embryo diameters, day at first pregnancy diagnosis, or in vitro embryo morphological quality among groups. In this study, much poorer results were obtained with jennies than with mares. Interspecific AI resulted in lower pregnancy rates than intraspecific Al, and AI to produce hinny hybrids resulted in the lowest pregnancy rate. Further studies are required to better understand the mechanism involved in such different outcomes in relation to intra- and interspecific breeding in domestic equids. [ABSTRACT FROM AUTHOR]

Summary: Background: The Caspian miniature horse (CMH) is a small horse breed, which has not previously been evaluated for ophthalmic diseases. Objectives: The purpose of this study was to describe the ocular findings and to declare the normal ocular parameters seen in a small herd of CMH. Study design: Cross‐sectional study. Methods: Forty‐five Caspian miniature horses (25 mares and 20 stallions) were examined. Complete ophthalmic examination, commensal ocular surface microbiota culture and measurement of the horizontal and vertical fissure length were performed. Results: Mean ± SD age of horses was 52.0 ± 33.9 months (range: 12–122 months). Nine different ocular disorders were observed: dacryocystitis, conjunctivitis, linear keratopathy, Haab's striae, corpora nigra atrophy, iris hyperpigmentation, cataract, peripapillary butterfly inactive lesions and inactive choroiditis were detected. In total, 17 eyes (18.8%) of 12 horses (26.2%) had ocular related lesions. Two horses (4%) had more than one ocular lesion; the lesions were consistent with a diagnosis of either traumatic or recurrent uveitis. No vision loss was detected in these horses despite the identified ocular disorders. Main limitations: Limited number of studied animals. Conclusions: This study reported ocular findings in a small herd of CMH. A minority of horses in the herd had ocular lesions suggesting a history of glaucoma and/or equine recurrent uveitis. [ABSTRACT FROM AUTHOR]

The application of the 'omics' studies in the field of animal reproduction has been aimed at identifying novel biomarkers of fertility since the last few years. When assessing reproductive efficiency in horses, breed should also be taken into account as it can influence semen quality and fertility. Considering the growing interest in metabolomic analysis to evaluate male fertility, we aimed to investigate the metabolomic profile of seminal plasma in two different horse breeds. Twelve healthy stallions, n.6 American Quarter Horse (AQH) and n.6 Italian Draft Horse (IDH) stallions, regularly used for artificial insemination, were included in the study. Two semen collections, performed 30‐day apart, were considered for the assessment of semen parameters including gel‐free volume, spermatozoa (spz) concentration, spz progressive motility and seminal plasma analysis by 1H‐NMR.Semen characteristics differed between IDH and AQH (p <.05) as well as the first cycle conception rate that was higher in AQH than IDH (p =.001). Metabolomic analysis quantified 56 molecules in equine seminal plasma, with 11 metabolites showing different concentrations in IDH compared to AQH (p <.05).This study provided evidence of differences in seminal plasma metabolites' concentrations between studied horse types, highlighting specific metabolomic fingerprints characterizing AQH and IDH sperm. [ABSTRACT FROM AUTHOR]

The aim of this study was to compare the changes in the content of cTnI, cTnT and some biochemical parameters (CK–MB, LDH, AST, ALT) in Arabian racehorses before and after training. Diagnosis of myocardial disease in horses is very difficult due to the lack of specific cardiac signs. Cardiac diseases are seen as a cause of sudden death or decreased performance in horses. It has also been reported that excessive exercise may cause transient myocardial damage. In our study, 20 healthy stallion Arabian racehorses aged 4–10 y (6.00 ± 0.52 y) were used. Five millilitres of blood was collected from the V. jugularis of clinically healthy horses into serum tubes before and after training. Training time was determined as 30 min for each horse. Pre-training cTnI, cTnT, CK–MB, LDH, AST, and ALT contents were determined to be 0.130 ± 0.01 ng/mL, 0.007 ± 0.00 ng/mL, 231.15 ± 8.96 U/L, 692.45 ± 34.12 U/L, 309.92 ± 18.48 U/L, and 11.83 ± 0.92 U/L, respectively. After training, cTnI, cTnT, CK–MB, LDH, AST, and ALT contents were determined to be 0.169 ± 0.01 ng/mL, 0.008 ± 0.00 ng/mL, 289.80 ± 10.96 U/L, 704.25 ± 22.03 U/L, 328.47 ± 19.58 U/L, and 15.24 ± 1.03 U/L, respectively. As a result, it was determined that exercise triggered myocardial damage to some extent in Arabian horses. Exercise stimulates troponin release and the differences that may occur in troponin tests in horses after exercise should be taken into consideration. [ABSTRACT FROM AUTHOR]

The study involved the analysis of the mares included in the brood stock between 1989-2018 and the public breeding stallions registered in the ranking sheets ranged from 2000-2010 of the Shagya Arabian horse breed, from the Radauti Stud farm, Suceava county, Romania. The dynamics of the average values of height, heart girth, and cannon girth were studied for both breeders category, to follow the evolution of the breed within the stud. The average values of the female's height ranged from 156.7±0.069 cm to 159.9±0.102 cm; the average values for heart girth felt within the 180.1±0.151 cm - 180.8±0.153 cm interval; the average values of cannon girth varied between the 18.0±0.11 cm to 18.8±0.09 cm. The minimal value for height at withers in stallions was 157.66±1.21 cm while the maximal was 161.22±0.84 cm; average values of the hearth girth varied between 177.25±4.09 cm and 183.33±1.83 cm; cannon girth had average values of 18.5±0.77 - 19.16±0.31 cm. On the morphometric indices, it was found that stallions had higher values of massiveness index (113.21%) vs. mares (113.06%) and for the dactylo-thoracic index, as well (stallions had 11.11% and the mares 10.55%), while the bone index was higher in females (11.93%) vs. males (11.81%). [ABSTRACT FROM AUTHOR]

The article presents a case of a 5-year-old Arabian stallion presenting with severe colic and unilateral testicular enlargement. The initial physical examination revealed a mildly enlarged left testicle that felt firm and cool to the touch. After further evaluation, a 360 degree spermatic cord torsion was confirmed, and the horse underwent hemi castration with a primary closure.

Objective: The semen quality of stallions including sperm motility is an important target of selection as it has a high level of individual variability. However, effects of the molecular architecture of the genome on the mechanisms of sperm formation and their preservation after thawing have been poorly investigated. Here, we conducted a genome-wide association study (GWAS) for the sperm motility of cryopreserved semen in stallions of various breeds. Methods: Semen samples were collected from the stallions of 23 horse breeds. The following semen characteristics were examined: progressive motility (PM), progressive motility after freezing (FPM), and the difference between PM and FPM. The respective DNA samples from these stallions were genotyped using Axiom Equine Genotyping Array. Results: We performed a GWAS search for single nucleotide polymorphism (SNP) markers and potential genes related to motility properties of frozen-thawed semen in the stallions of various breeds. As a result of the GWAS analysis, two SNP markers, rs1141327473 and rs1149048772, were identified that were associated with preservation of the frozen-thawed stallion sperm motility, the relevant putative candidate genes being NME/NM23 family member 8 (NME8), olfactory receptor family 2 subfamily AP member 1 (OR2AP1), and olfactory receptor family 6 subfamily C member 4 (OR6C4). Potential implications of effects of these genes on sperm motility are herein discussed. Conclusion: The GWAS results enabled us to localize novel SNPs and candidate genes for sperm motility in stallions. Implications of the study for horse breeding and genetics are a better understanding of genomic regions and candidate genes underlying stallion sperm quality, and improvement in horse reproduction and breeding techniques. The identified markers and genes for sperm cryotolerance and the respective genomic regions are promising candidates for further studying the biological processes in the formation and function of the stallion reproductive system. [ABSTRACT FROM AUTHOR]

In stallions temporarily not intended for breeding, reversible suppression of testicular function by vaccination against GnRH can be of interest. In the present study, effects of GnRH agonist treatment on the resumption of testicular function after GnRH vaccination were investigated. Testis size, testosterone release, semen characteristics and behavior were evaluated. We hypothesized that GnRH agonist treatment would restore testicular function. Shetland stallions were assigned to an experimental and a control group (n = 6 each). Experimental stallions were GnRH-immunized twice, four weeks apart. Ejaculates for semen analysis and blood for analysis of testosterone concentration and GnRH antibody titers were collected. Each experimental stallion was hemicastrated together with an age-matched control animal when testosterone concentration decreased below 0.3 ng/mL. Three weeks thereafter, daily treatment with the GnRH agonist buserelin was initiated (4 μg/day for 4 weeks followed by 8 μg/day). The remaining testicle was removed when testosterone concentration exceeded 0.5 ng/mL in vaccinated stallions. Time from exposure to a mare until mounting increased in GnRH-vaccinated stallions and decreased with buserelin treatment. Total sperm count decreased after vaccination but increased only slightly in response to buserelin. Sperm motility and percentage of membrane-intact spermatozoa decreased after vaccination and returned to pre-vaccination values with buserelin treatment. Testosterone concentration and testis volume decreased after GnRH vaccination and started to increase with buserelin treatment. In conclusion, the downregulation of testicular function by GnRH vaccination can be counteracted with buserelin. This approach may be useful in GnRH-vaccinated stallions with prolonged suppression of testicular function. • Resumption of testicular function after GnRH immunization varies among stallions. • Daily low dose buserelin for 10 weeks supports resumption of testicular function. • Sexual behavior resumed in the majority of GnRH immunized stallions with daily buserelin treatment. • Buserelin treatment improved semen characteristics after GnRH vaccination. [ABSTRACT FROM AUTHOR]

Background: Artificial insemination with chilled sperm is a reproductive biotechnology often used in horse breeding. However, maintaining the acceptable sperm quality after cooling, which affects the frequency of pregnancy, remains an urgent problem at the present time. Therefore, clarifying the role of important physiological metabolites, such as L-carnitine and nitric oxide, is a significant aspect in terms of possible improvement of the quality of cryopreserved sperm. Methods: The study included 35 breeding stallions, 27 of which were stallions of the Arabian breed and 8 were of the Soviet heavy draft breed. The content of total, free and bound carnitine and NO metabolites was determined by photometric method in the samples of seminal plasma and blood plasma. The correlation coefficient between the content of L-carnitine and the level of NO metabolites was also determined. Result: We have found a direct moderate correlation between the level of total and free L-carnitine in the seminal plasma and blood plasma. The study has also revealed a positive correlation between the level of all L-carnitine fractions and NO metabolites in seminal plasma. In addition, there was a positive correlation between the total L-carnitine of blood plasma and NO metabolites in seminal plasma. [ABSTRACT FROM AUTHOR]

Possessing high meat and dairy productivity and good reproductive and adaptive qualities to year‐round grazing, the Kushum breed plays an exceptional role in the improvement of productive qualities in horse herding in Kazakhstan and the former Soviet republics. The aim of the study was to develop breeding methods for creating new highly productive breeding lines for the Kushum breed horses. The leading method was linebreeding, which is based on the systematic use of remarkable animals, the offspring of which will accumulate and develop all the desired qualities and traits. The practical significance of the study lies in the fact that new highly productive breeding lines of the Kushum horse have been created. On this basis, a new intra‐breed type of horses with increased live weight, high productivity and adaptive qualities for winter grazing in the Republic of Kazakhstan was created. The results of the study were introduced in farms engaged in breeding Kushum horses. Highly productive stallions of the Kushum breed of new genotypes are sold in horse breeding farms of the republic. These studies are used in the development of a comprehensive plan for selection and breeding work and a scientifically grounded system for conducting productive horse breeding in the Republic of Kazakhstan. The scientific novelty of the study lies in the creation of new highly productive breeding lines of stallions of the Kushum breed Krepysh and Grom, as well as in substantiating the creation of the Samotsvet line with high adaptive qualities. [ABSTRACT FROM AUTHOR]

Simple Summary: In a broad sense, "paedomorphosis" refers to the similarity within a species between the adult form and its juvenile counterpart, as seen in certain species such as dogs and cats. Yet in horse breeds, the study of phenotypic characteristics in juveniles primarily focuses on body and limb proportions, e.g., distal limb length. Conversely, in the Purebred Arabian Horse (PAH), the juvenile form is clearly representational in the adult, and in particular, the phenotypic characteristics of the head. In this study, we investigate paedomorphosis by examining the left lateral profile of the head from photographs of PAH and first-generation crossbred PAHs (F1 crossbreds). This enabled a somewhat consistent image to be examined. By utilizing methods of geometric morphometry, a set of 23 semi-landmarks were studied that defined the profile of the head. The results implied the concave profile of the juvenile remained consistent with age and, therefore, there is a retention of juvenile traits into adulthood. This suggests that PAHs and F1 crossbreds could be considered paedomorphic-like animals. This study examined paedomorphosis in PAH and F1 crossbreds. A sample of 99 horses was selected from 40 different breeders and consisted of three groups: stallions (n = 16), mares (n = 53), and geldings (n = 30), ranging from 10 months to 27 years in age. All horses presented a concave celloid lateral left head profile in the acquired photographic images. The hypothesis proposed in this study suggested the lateral profile of the head in juveniles was representational in the adult form due to the neonate's facial bones (part of the splanchnocranium) developing at a different rate to those of the skull. The methodology utilized geometric morphometrics to identify 23 landmarks so as to identify profile curvature indicative between the three groups (stallions, mares, and geldings). Principal component analysis reduced the number of variables to 14 examinable landmarks. Using a two-NPMANOVA and multivariate regression test, it was demonstrated that an isometric relationship between the concave celloid profile in the juvenile and its adult counterpart existed. This result supported the hypothesis that PAH and F1 crossbreds expressed a paedomorphic trait due to the adult form retaining the concave celloid profile identified in the juvenile. [ABSTRACT FROM AUTHOR]

Horses are seasonal polyoestrous animals, and the photoperiod is the main factor modulating their reproductive activity. There is no consensus on the andrological and biochemical factors that influence breeding seasonality. To assess the involvement of climate in reproduction, Mangalarga Marchador stallions were monitored over 1 year regarding semen quality and seminal plasma proteome. Here, we show that kallikrein (KLKs) proteoforms in seminal plasma are involved in climate conditioning of reproduction. During the breeding season, greater abundance and different types of KLKs occurred simultaneously to lower sperm motility, greater semen volumes and higher concentrations of glucose and cholesterol. Considering that vasodilation due to activation of the kallikrein-kinin system and the consequent inhibition of the renin-angiotensin system may be associated with lower sperm motility, unravelling the involvement of KLK proteoforms in reproductive seasonality is a priority in horse breeding. [ABSTRACT FROM AUTHOR]

The objective of the current study was to determine the photoperiod-induced variations and the impact of exercise on oxidative stress biomarkers [2-thiobarbituric acid reactive substances (TBARS), aldehydic (AD) and ketonic (KD) derivatives of oxidatively modified proteins (OMP), total antioxidant capacity (TAC), and activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx)] and biomarkers of metabolic alterations [glucose, urea, and uric acid and the activity of lactate dehydrogenase (LDH)] in the blood of Shetland pony mares and stallions involved in recreational horseback riding. Twenty-one healthy adult Shetland ponies (11 mares and 10 stallions) aged 6.5 ± 1.4 years old from the central Pomeranian region in Poland were used in this study. Blood samples were taken once per season for one year: spring (3 April), summer (5 July), autumn (1 October) and winter (25 January). A MANOVA analysis revealed that the photoperiod factor had a leading role in alterations of these biomarkers, while the exercise and sex of the ponies exerted a lower impact. The lipid peroxidation biomarkers, for example, the plasma TBARS level, indicated the maximum adjusted coefficient of determination R2ad = 0.77. Before exercise (at rest), the plasma of the stallions and mares exhibited minimum values of TBARS levels in the spring and summer photoperiods and maximum levels in autumn and winter. A statistically significant reduction in the levels of both aldehydic and ketonic derivatives of OMP in the blood of ponies was observed during the autumn and winter periods; additionally, the level of ketonic derivatives of OMP declined after exercise in spring. TAC was statistically significant in the spring and winter photoperiods both before and after exercise. SOD activity did not have a pronounced photoperiod-induced pattern but was dependent on the sex and exercise. CAT activity varied and was statistically significant only in the plasma of the mares after exercise in the spring, summer, and winter photoperiods. The minimum GPx activity in the blood of the mares before exercise (at rest) was observed in autumn, while the maximum was noted in winter and summer. Photoperiod- and exercise-induced alterations in markers of oxidative stress and antioxidant defences may contribute to the adaptation of animals to exercise, depending on sex. The seasonal variations in the antioxidant defences demonstrated in our study, as well as substrates of energy metabolism in the blood of mares and stallions, depending on exercise capacity, could be an important aspect in the ability of endogenous adaptive mechanisms of animals to react in advance to environmental changes associated with seasons. [ABSTRACT FROM AUTHOR]

Simple Summary: Regardless of age, breed, physiological condition, or gender, all horses are social animals, requiring the company of their own kind. Due to their natural instincts to fight each other, adult stallions are often kept in isolation. Several studies have shown the possibility of free group housing and recommended methods to reduce the detrimental effects of limited social contact on their physical and/or mental wellbeing. Nevertheless, the beneficial effect of transitioning from tie-stalls to free housing on adult stallions' overall welfare has not been researched before. According to our results, in only two weeks after the management change, the studied stallions had significantly better welfare, improving further over time. Additionally, their human-related responses improved, and their docility did not decrease, despite minimal human–animal contact during the study. Although positive emotional states were identified within the study, these did not correlate consistently with the other parameters assessed. Given the findings in this paper and accounting for all precautions required while making such a management change, we conclude that adult stallions can and should be kept in free group housing to provide them with the best possible conditions to support their optimal welfare. Despite an increase in awareness of their essential needs, many stallions continue to be kept in conditions limiting their social interactions and movement. To supplement the studies which highlight the effects of these practices on selected aspects of equine mental and physical wellbeing, we aimed to monitor a group of 32 adult intact stallions during their transition from tethered housing with limited outdoor access to free group housing through the lens of their overall welfare, perceived emotional status, and docility toward humans. Over three visits (before the management change, two weeks, and three months after, respectively), their welfare, qualitative behavior, and docility were assessed. Analysis of the data collected showed an improvement in the stallions' overall welfare and no decrease in their docility after their group-release, with a constant correlation between these two aspects. The evaluation of their emotional states was less relevant, lacking consistency between the assessments for most of the descriptors used, warranting further research in similar conditions. Although our study covered a relatively short period of time, our results provide encouraging support for stallion owners in deciding on a similar management change for the welfare of their animals. [ABSTRACT FROM AUTHOR]

Simple Summary: Since 2014, the genetic evaluation of the population of Czech sport horses has been based only on the evaluation of results from jumping competitions. The performance test is an integral part of the testing of young horses in the Czech Republic, as is the linear description of horses. The results from both the linear description and the performance test show low to medium heritability for the observed traits. The genetic parameters obtained in this study indicate that the data obtained from the performance test are suitable for inclusion in the genetic evaluation of sport horses in the Czech Republic, as the breeding values would be refined, especially in young mares and stallions. The aim of this study was to estimate the genetic parameters of a one-day performance test together with the linear type traits of 3-year-old warmblood horses. The study of genetic parameters was based on 5958 tested horses in the period 1998–2021. A total of 22 traits of linear description, three quantitatively measured traits, and one summary mark from the performance test were tested. The model equation included the fixed effect of gender and combination effects of classifier–year of evaluation–place. A single-trait animal model was used for the estimation of heritability and genetic variance, while the two-trait animal model was applied for the estimation of variance and covariance between all traits. The heritability of the overall score of the performance test was 0.25. The range for heritability was between 0.04 and 0.33 for the linear type traits and between 0.46 and 0.57 for the quantitatively measured traits. Genetic correlations were between −0.47 and 0.92. The estimated genetic parameters suggest that the results from the performance test can be incorporated into genetic evaluation in the Czech Republic. [ABSTRACT FROM AUTHOR]

Background: This study is a part of an ample research concerning the genetic history of Hucul horse breed. The genetic analysis studies are part of animal genetic resources management because just start of them we elaborate the strategies for inbreeding management. The itself genetic relationship of a population is the average genetic relationship of all individuals between them, existing at a time. Therefore, this parameter can be described three components: the genetic relationship between stallions, between mother mares themselves and the genetic relationship between stallions and mares. The last component is most important because of the average population inbreeding increases in successive generations. Methods: The research was carried out during 2012-2020. The material are represented by genealogical information from reproductive nucleus of Hucul breed from Lucina studfarm. The sample extracted from population was represented by seven sire stallions and seventy-three broodmares. The method are based on A matrix coefficients. All analysis were performed in the profile laboratories of Animal Sciences Faculties from Bucharest and Timisoara. Result: Between individual average genetic relationship values of stallions with mares, is found significant differences, highlighted by the global test of homogeneity test (F=4.891). These differences allow us to assert that, through stallions selection, is made a reproductive discrimination much more intense than in mares case. The average genetic relationship of the population was calculated at 0.1941±0.0053. [ABSTRACT FROM AUTHOR]

The Kushum breed is one of the top breeds in the structure of horse breeds in the Aktobe region. In terms of numbers, it ranks third after the Kazakh and Mugalzhar breeds. The Kushum breed in the Aktobe region compares favorably with a number of horse-draft factory breeds in terms of early maturity, fertility, high meat, milk productivity, and economy of keeping. This article describes a new intra-breed type, the “Mamyr-Aktobe” type of the Kushum horse breed of the Aktobe population. The structure of the intra-breed type of Mamyr Aktobe of the Kushum breed includes three factory lines of stallions: 118 Krepysh 33-64, 116 Grom 98-58, and 137 Samotsvet 77-73 tested in 2010 and 2015 (Samotsvet) and patents No. 187,186 and No. 586were obtained for them. Adult stallions of a new intra-breed type are characterized by high measurements and live weight: 159.7-165.3-202.5-21.0 cm and 626.5 kg and massiveness - 153.8 and exceed the breed standard in live weight by 126.5 kg or by 25.3%, according to the massiveness index by 31.8%, and mares, respectively: 155.2-159.1- 187.8-19.8 cm and 531.0 kg and massiveness - 165.2 and also exceed the breed standard in terms of live weight by 71.0 kg or 15.4% and terms of massiveness index by 7.9%. [ABSTRACT FROM AUTHOR]

The Thoroughbred breed, considered a king of galloping, developed in England during the 17th - 18th centuries, by mating mares on the island with stallions brought from the East of Berber region, Turkoman and Arab origin. Historical records mark the stallions Darley Arabian (1704), Byerley Turk (1680) and Godolphin Barb (1729) as the founders of the lines. Other stallions that contributed to the development of the breed but were less influential were: Alcock’s Arabian, D’Arcy’s White Turk, Leedes Arabian, and Curwen’s Bay Barb and Brownlow Turk, the latter being considered to be the one that caused the appearance of the gray color in the Thoroughbred breed. Keywords: Thoroughbred, origin, genetics [ABSTRACT FROM AUTHOR]

Simple Summary: Equine breeding is often based on conformation traits, describing the proportions, shape and joint angles of a horse. These conformations traits are, however, mostly subjectively judged and not measured objectively, affecting the response of selection through lower heritabilities and precision. In this study, we measured joint angles, quantified the variation in shape of 608 Swiss Franches-Montagnes (FM) horses and estimated the heritability of these traits. We found that the poll angle had the highest heritability of all joint angles (h2 = 0.37), and variation in shape describing the type (heavy–light) was also fairly heritable (h2 = 0.36–0.37). Furthermore, the shape of the FM stallions has clearly evolved towards a lighter type from 1940 to 2018 without stabilisation in recent years, risking the loss of the light draught horse type. Phenotyping based on photographs allowed us to improve the accuracy of certain joint angle traits, and to monitor the conformational development of the FM breed. Conformation traits such as joint angles are important selection criteria in equine breeding, but mainly consist of subjective evaluation scores given by breeding judges, showing limited variation. The horse shape space model extracts shape data from 246 landmarks (LM) and objective joint angle measurements from triplets of LM on standardized horse photographs. The heritability was estimated for 10 joint angles (seven were measured twice with different LM placements), and relative warp components of the whole shape, in 608 Franches-Montagnes (FM) horses (480 stallions, 68 mares and 60 geldings born 1940–2018, 3–25 years old). The pedigree data comprised 6986 horses. Genetic variances and covariances were estimated by restricted maximum likelihood model (REML), including the fixed effects birth year, age (linear and quadratic), height at withers (linear and quadratic), as well as postural effects (head, neck, limb position and body alignment), together with a random additive genetic animal component and the residual effect. Estimated heritability varied from 0.08 (stifle joint) to 0.37 (poll). For the shape, the type was most heritable (0.36 to 0.37) and evolved from heavy to light over time. Image-based phenotyping can improve the selection of horses for conformation traits with moderate heritability (e.g., poll, shoulder and fetlock). [ABSTRACT FROM AUTHOR]

Maternal aging has negative influences on the development and racing performance of their offspring in racehorses. However, the mechanism by which pregnancy at old age reduces the race performance of the offspring is unknown. Here, two hypotheses were posited: 1) Foals born to older mares are more likely to have muscular, skeletal, and cognitive disadvantages (direct effects). 2) Foals born to older mares are more likely to be affected by non-physiological factors correlating with the mare's age, such as the quality of sires (e.g. low-quality sires are likely to be chosen as partners of older broodmares). To test these hypotheses, the effect of the broodmare's age on the offspring's racing performance was examined, while controlling for the effects of the stallion's quality, age, and ID, offspring's sex, trainer, and the location of the training center. Information of racehorses registered to the Japan Racing Association were collected from the Japan Bloodhorse Breeders' Association website. Overall, results showed that the racing performance of horses born from older mares was lower than that of horses born from younger mares. However, generalized linear mixed models (GLMM) indicated that the quality of sires was significantly associated with the offspring's racing performance, rather than the broodmare's age itself. Furthermore, the age of broodmares was negatively correlated with the quality of sires, although the variance inflation factor was low. Therefore, the effect of maternal aging was negligible or only limited, and rather, the sire's quality had an important influence on the offspring's racing performance. Low quality sires, or cheap stallions in other words, are likely to be chosen as partners of older blood-mares, which may have reproductive risks such as lower fertility and higher rate of miscarriages. The present study suggests that the conventional belief that racehorses born from older mares show lower performance may not always be accurate. [ABSTRACT FROM AUTHOR]

The study covers data from the DNA-card for determining the identity of 90 horses born after 2010, belonging to 6 genealogical lines of the East Bulgarian Horse breed. Nucleotide polymorphism (SSRs) data in 15 loci were analyzed. High genetic diversity in the ASB23 and ASB2 loci has been established for lines found by Thoroughbred stallions. Above average for the respective line was the polymorphism in HTG10 and HMS3 in the Tihany line, and ASB17 in the lines of Vusterhir, Da Kapo, Eistanzer and Ladykiller. The diversity in the HMS2, HMS7 and HMS3 loci was also noticeable in the Da Kapo and Eistanzer lines, descended from Hanoverian stallions. There were specifics regarding to degrees of certain alleles fixation by loci and the type and frequency of alleles belonging to the “rare” category for each of the studied genealogical units. Later set lines were characterized by higher polymorphism in the conditions of medium level of differentiation between the lines. Close distances have been established between the Tihany and Zenger lines, followed by Da Kapo and Eistanzer, and between the Da Kapo line and the Zenger and Vusterhir lines. The highest number of migrated alleles per generation in the genealogical lines was observed in the loci HMS2 (6.954), AHT4 (5.565) and HMS1 (4.080). Carrying out possible monitoring of the change of the microsatellite DNA profile of the formed lines would give the breeders information on the deviation from the population averages of the above mentioned parameters and at what stage of their development a new components of heredity should be introduced. [ABSTRACT FROM AUTHOR]