Primitive Horses Research Articles

Genetic Diversity and Population Structure of Dülmen Wild, Liebenthal and Polish Konik Horses in Comparison with Przewalski, Sorraia, German Draught and Riding Horses.

The objective of the present study was to analyze the genetic diversity, individual-based assessment of population structure, and admixture in the Dülmen wild horse population in comparison to warmblood, coldblood, and primitive horse populations. The Dülmen wild horse is kept as a unique horse population in the Merfelder Bruch near Dülmen in Westphalia, Germany, and since 1856 has been managed by the Dukes of Croÿ. The Dülmen wild horse population is exposed to the natural conditions of the Merfelder Bruch all year round without human interventions for feeding and veterinary care. In the present study, genetic diversity was estimated for 101 Dülmen wild horses using multilocus genotypic information from a set of 29 autosomal microsatellites and compared with 587 horses from 17 different horse populations. Dülmen wild horses maintained a high degree of genetic diversity, with an average observed heterozygosity of 0.68, a mean number of 6.17 alleles, and heterozygote deficit of -0.035. Pairwise genetic distances (FST, Nei's standard, and Cavalli-Sforza distances) were closest to German coldblood breeds, Polish Konik, and Icelandic horses and most divergent from Sorraia and Przewalski's horses. Neighbor joining dendrogram and PCA plots showed a clear distinction of Dülmen wild horses from other populations, particularly from Przewalski horses. Posterior Bayesian analysis confirmed clear differentiation from other horse populations without an admixture pattern and a high membership index (0.92). It was possible to distinguish Dülmen wild horses from Dülmen and Polish Konik horses. In conclusion, Dülmen wild horses show a notable separation from other German horse breeds and primitive horse populations and may serve as a resource to study evolution of equine domestication.

Ancient Mitochondrial Genomes Provide New Clues in the History of the Akhal-Teke Horse in China.

This study analyzed ancient DNA from the remains of horses unearthed from the Shihuyao tombs. These were found to date from the Han and Tang Dynasties in Xinjiang (approximately 2200 to 1100 years ago). Two high-quality mitochondrial genomes were acquired and analyzed using next-generation sequencing. The genomes were split into two maternal haplogroups, B and D, according to a study that included ancient and contemporary samples from Eurasia. A close genetic affinity was observed between the horse of the Tang Dynasty and Akhal-Teke horses according to the primitive horse haplotype G1. Historical evidence suggests that the ancient Silk Road had a vital role in their dissemination. Additionally, the matrilineal history of the Akhal-Teke horse was accessed and suggested that the early domestication of the breed was for military purposes.

Molecular cytogenetic screening of sex chromosome abnormalities in young horse populations.

Chromosomal abnormalities occur in the equine population at a rate of approximately 2%. The use of molecular cytogenetic techniques allows a more accurate identification of chromosomal abnormalities, especially those with a low rate of abnormal metaphases, demonstrating that the actual incidence in equine populations is higher. Estimation of the number of carriers of karyotypic abnormalities in a sample from a population of young horses of various breeds, using molecular cytogenetic techniques. Cross-sectional. Venous blood samples were collected from 500 young horses representing 5 breeds (Purebred Arabian, Hucul, Polish primitive horse [Konik], Małopolska, Coldblood, Silesian). Chromosomes and DNA were obtained from blood lymphocytes and evaluated by fluorescence in situ hybridisation (FISH) and PCR, using probes and markers for the sex chromosomes and select autosomes. Nineteen horses, 18 mares and 1 stallion, were diagnosed with different chromosomal abnormalities: 17 cases of mosaic forms of sex chromosome aneuploidies with a very low incidence (0.6%-4.7%), one case of a SRY-negative 64,XY sex reversal mare, and one mare with X-autosome translocation. The percentage of sex chromosomal aberrations was established as 3.8% in the whole population, 6.08% in females and 0.49% in males. Limited sample size, confined to horses from Poland. The rate of sex chromosomal abnormalities we identified was almost double that reported in previous population studies that used classical chromosome staining techniques. FISH allowed the detection of aneuploid cell lines which had a very low incidence. The FISH technique is a faster and more precise method for karyotype examination; however, it is usually focused on only one or two chromosomes while banding karyotyping includes the entire chromosome set.

Selective use of forest habitat by Biłgoraj horses

Primitive horses are quite often kept in nature reserves with access to the forest, which they sometimes penetrate to use the vegetation. Horses, as grazers, use specific foraging and anti-predator strategies that differ from typical browsers. The aim of the study was to assess the factors influencing the pattern of forest use by Bilgoraj horses. We hypothesized that the essential factors influencing their pattern of foraging are: browse abundance, distance to pasture, and openness of the habitat. Data were collected at the Biłgoraj Horse-Breeding Centre near Janów Lubelski, Poland. The horses browsed significantly more on woody vegetation in parts of the forest more exposed to sunlight and more abundant in browse material (especially containing preferred species). Distance to the main pasture had a significant effect upon browsing intensity only when an interaction with the abundance of preferred browse was considered.

Mitochondrial DNA sequencing illuminates genetic diversity and origin of Hunagrian Nonius horse breed and his relatives – Danubian horse and Serbian Nonius

From a historical perspective, horse breeding in Bulgaria has been very well developed since the time of the Thracians (early Bronze Age c. 3000 BCE). Archaeological discoveries from this era present us with an extremely rich type diversity, including wild and local primitive horses, the prototype of heavy draft horses, and fine riding horses. The objective of this study was to investigate the genetic structure of unexamined populations of three closely related horse breeds – the Danubian Nonius Hungarian Nonius and Serbian Nonius horses. A 608 bp long fragment of the mtDNA D-loop region was amplified and sequenced. The obtained results showed completely different genetic profiles between the investigated breeds. We identified nine of the 17 haplogroups described in modern horses. Most of the obtained sequences fell into M, L, G, and O’P lineages, which reflects the genetic profiles of the ancestral mares that were probably used at the initial stages of formation of the breeds. The population of the Danubian horse was characterized by a high prevalence of Central Asian specific haplogroup G (45%), followed by Western Eurasian specific haplogroups L and M (both about 21%). In contrast to the Danubian horse, in the Nonius breed the highest frequency of Western Eurasian haplogroup M (43.5%) was found, followed by Middle Eastern haplogroups O’P (26.1%) Central Asian specific E (13.0%) and G (13.1%). The Serbian Nonius horse showed a completely different genetic profile with a prevalence of the rare for Europe haplogroup D (66.7%), followed by Central Asian specific G (16.7%). The high mitochondrial haplotype diversity (Hd = 0.886) found in the investigated samples is evidence for multiple maternal origins in all populations. In conclusion, the obtained results demonstrated a high percentage of haplogroup sharing especially in the Danubian and Hungarian Nonius horse breeds, which reflects the possible common origins of the two breeds. In contrast to these breeds, the Serbian Nonius, despite the small number of investigated animals, showed a specific genetic profile, which could be explained by different and independent origins.

Effect of fearfulness and cortisol reactivity to stress on the spatial learning performance in mountain primitive horses

This study aimed to determine whether the level of fearfulness and cortisol reactivity influenced spatial learning performance in primitive mountain Hucul horses. The Huculs had to overcome particularly difficult, sometimes dangerous conditions to survive over centuries. We hypothesized that they were familiar with danger and should learn easily. The study involved 22 mares. They were divided into groups of different fearfulness levels according to behavioral score and cortisol concentration increase in the saliva, both of which were determined in a test of a novel object. In the next step, the mares were subjected to a spatial learning test in a maze with food reward at the end, conducted in two trials, on consecutive days. Their spatial learning performance was assessed with an error score and time taken to complete the maze. The study found that both the level of fearfulness and cortisol concentration increase varied in the mares. The spatial learning performance of mares that had low, medium and high levels of fearfulness and cortisol increase was similar within a trial, although animals displaying a medium fearfulness level or moderate cortisol change achieved better results in the second trial than in the first trial. These results indicate a weak influence of the fearfulness and cortisol reactivity on spatial learning performance in Huculs which may suggest an effect of the origin and historical environment of the breed.

Occurrence of Equine Foamy Virus Infection in Horses from Poland

Equine foamy virus (EFVeca) is a foamy virus of non-primate origin and among the least-studied members of this retroviral subfamily. By sequence comparison, EFVeca shows the highest similarity to bovine foamy virus. In contrast to simian, bovine or feline foamy viruses, knowledge about the epidemiology of EFVeca is still limited. Since preliminary studies suggested EFVeca infections among horses in Poland, we aimed to expand the diagnostics of EFVeca infections by developing specific diagnostic tools and apply them to investigate its prevalence. An ELISA test based on recombinant EFVeca Gag protein was developed for serological investigation, while semi-nested PCR for the detection of EFVeca DNA was established. 248 DNA and serum samples from purebred horses, livestock and saddle horses, Hucul horses and semi-feral Polish primitive horses were analyzed in this study. ELISA was standardized, and cut off value, sensitivity and specificity of the test were calculated using Receiver Operating Characteristic and Bayesian estimation. Based on the calculated cut off, 135 horses were seropositive to EFVeca Gag protein, while EFVeca proviral DNA was detected in 85 animals. The rate of infected individuals varied among the horse groups studied; this is the first report confirming the existence of EFVeca infections in horses from Poland using virus-specific tools.

Genetic Background of the Polish Primitive Horse (Konik) Coat Color Variation-New Insight into Dun Dilution Phenotypic Effect.

Only the blue dun coat color, produced by the action of the dun allele on the background of a black base coat, is officially permitted in the Polish primitive horse (PPH, Konik) breed, yet the population is not visually homogenous and various coat color shades occur. Herein, the molecular background of PPH coat color was studied based on genotyping of known causative variants in equine coat color-related genes (ASIP, MC1R, TBX3, SLC36A1, SLC45A2, PMEL17, and RALY). Additionally, screening for the new polymorphisms was conducted for the ASIP gene coding sequence and the TBX3 1.6-kb insert (associated with the dun dilution). We did not observe the champagne, silver, or cream color dilution variants in the PPH breed. A significant association (P < 0.01) was recorded for the genotype in TBX3 gene 1.6 kb in/del and the degree of dun coat dilution, demonstrating that the dominant action of the dun mutation is not fully penetrant. In addition to the effect of the 1.6 kb in/del zygosity, variants within the TBX3 insert were significantly associated with PPH coat color variability (P < 0.01), suggesting the presence of an additional allele at this locus. Finally, we identified a high frequency (35%) of genetically bay dun-colored PPH individuals that are officially recorded as blue (black base coat) duns. We propose that the difficulty in distinguishing these 2 phenotypes visually is due to an independent locus upstream of the ASIP gene, which was recently described as darkening the typical bay pigmentation shade.

Some Genetic and Environmental Effects on Equine Asthma in Polish Konik Horses.

Simple SummaryEquine Asthma (EA) is a blanket term covering inflammatory diseases of the lower airways in horses. It includes mild-to-moderate equine asthma, which affects horses of any age, and severe equine asthma, which is typically seen in horses older than 7 years of. Relationships of the disease’s occurrence with sex or breed have been proven. However, some authors consider genetic background a predisposing factor, due to the fact that in some bloodlines a clinical form of asthma is more frequently observed. This indicates serious breeding and economic consequences. This study aimed to identify the factors affecting predisposition to severe equine asthma in the population of Polish Konik horses and some environmental and inbreeding effects on the disease. Generally, in the observed population, EA is negligibly affected by the factors analysed. Individual inbreeding effects on asthma were not confirmed by various statistical approaches, but significant maternal inbreeding effects were observed. These results are very important from the perspective of the currently implemented genetic resource conservation programme.Current knowledge of the genetic and environmental backgrounds of equine asthma seems to be insufficient, especially for primitive horse breeds. The main objectives of this study were to estimate the effects of sex, birth period, stud, parentage line and inbreeding on asthma morbidity in Polish Konik horses. Records of 274 horses (housed in two studs) were analysed. These animals were allocated to maternal and paternal lines. Individual inbreeding coefficients were extracted from the additive relationship matrix. Horses underwent diagnosis based on observation of the basic symptoms (high frequency of coughing and excessive nasal discharge). Subsequently, some horses (28 individuals) were clinically examined to confirm the earlier observations. Generally, no significant effects of parentage line on heaves morbidity were identified by the use of logistic regression, although the Pearson’s chi-squared test had shown that individuals of some maternal and paternal lines had a predisposition to severe equine asthma. It was concluded that the individual inbreeding level is not associated with the incidence of EA, but a significant effect of the maternal inbreeding coefficient may be observed. It was also found that there is some variability in the incidence of this disease between studs.

Serological Evidence of Common Equine Viral Infections in a Semi-Isolated, Unvaccinated Population of Hucul Horses.

Simple SummaryThe aim of the following research was an analysis of the occurrence of common equine viral infections in a Hucul herd, based on serological studies. This study provides epidemiological data concerning animals representing a semi-isolated herd, devoid of any specific prophylaxis. The obtained results provide a source of information on a primitive breed of horses, as well as giving an insight into viruses (among them, arboviruses) circulating within a local ecosystem.Huculs (Equus caballus) are an old breed of primitive mountain horses, originating from the Carpathian Mountains. To the best of our knowledge, data concerning the epidemiology of viral infections observed within this breed are sparse. The objective of this study was to estimate the serological status of a semi-isolated, unvaccinated Hucul herd, with respect to both common equine viral infections and horse-infecting arboviruses, the presence of which was previously reported in Poland. Twenty horses of the Hucul breed, living in a remote area in Poland, were studied in 2018 from March to May. Using nasal secretion swabs as a specimen source, isolation attempts were negative regarding ERAV, EHV-1, EAV, and EIV. According to the virus neutralisation method, in the sera obtained from the animals, antibodies against the following viruses were detected: EHV-1 in 12 horses (60%; with titres from 1:8 to 1:64), EIV A/H7N7 in 13 (65%; titres from 1:20 to 1:80), EIV A /H3N8 in 12 (60%; titres from 1:20 to 1:80), USUV in 5 (25%; titres from 1:10 to 1:80), and ERAV in 1 (5%; titre 1:32). Antibodies against EAV, EIAV, and WNV were not present in the tested sera. The detected presence of specific antibodies associated with five out of the eight equine viruses investigated indicates that the Hucul herd, due to its partial separation and lack of specific prophylaxis, could serve as a sentinel animal group for the detection of equine viruses/arboviruses present within the local ecosystem. The detection of common equine viral infections within the herd provides additional epidemiological data concerning the breed.

The examination of biophysical parameters of the skin in Polish Konik horses.

This study aimed to assess the biophysical parameters of the skin in Polish Konik horses (Polish primitive horses). According to the authors, this is the first assessment performed on such a wide scale in this group of animals. The evaluation carried out is innovative both with regards to the breed of the animals and the wide scope of the physicochemical skin assessment. The study group comprised mares, stallions and geldings, and the evaluations concerned transepidermal water loss, corneometry, pH, skin temperature assessment and mexametry. These parameters were assessed in five skin regions: the lips, the right ear, the prosternum, the right side of the neck and the chest. The measurements were taken after spreading the hair apart, with the use of a Multiprobe Adapter System (MPA®) and dedicated probes (Courage + Khazaka electronic GmbH, Cologne, Germany). The measurements revealed statistically significant differences in the values of transepidermal water loss in the lips in mares compared with stallions (P = 0.023) and also in stallions compared with geldings (P = 0.009). Corneometry showed significantly higher results in the neck region in mares compared with stallions (P = 0.037) and the prosternum areas in mares and geldings compared with stallions (P = 0.037 and P = 0.018). Skin pH measurement on the right side of the neck rendered significantly higher values in stallions than in mares (P = 0.037). In geldings, the skin temperature was significantly higher than in stallions (P = 0.049). Once the appropriate physicochemical values for specific animal species and breeds are determined, non-invasive methods of skin examination in many diseases and also methods of evaluation of the efficacy and/or adverse effects of applied medications can be established.

Genes encoding equine β-lactoglobulin (LGB1 and LGB2): Polymorphism, expression, and impact on milk composition.

β-lactoglobulin is one of the most abundant milk whey proteins in many mammal species, including the domestic horse. The aim of this study was to screen for polymorphism in the equine LGB1 and LGB2 gene sequences (all exons, introns, and 5’-flanking region) and to assess potential relationship of particular genotypes with gene expression levels (measured in milk somatic cells) and milk composition traits (protein, fat, lactose, and total β-lactoglobulin content). Direct DNA sequencing analysis was performed for twelve horse breeds: Polish Primitive Horse (PPH), Polish Coldblood Horse (PCH), Polish Warmblood Horse (PWH), Silesian, Hucul, Fjording, Haflinger, Shetland Pony, Welsh Pony, Arabian, Thoroughbred, and Percheron—and revealed the presence of 83 polymorphic sites (47 and 36 for LGB1 and LGB2 genes, respectively), including eight that were previously unknown. Association analysis of the selected polymorphisms, gene expression, and milk composition traits (conducted for the PPH, PCH, and PWH breeds) showed several statistically significant relationships; for example, the two linked LGB1 SNPs (rs1143515669 and rs1144647991) were associated with total milk protein content (p < 0.01). Our study also confirmed that horse breed had significant impact on both gene transcript levels (p < 0.01) and on milk LGB content (p < 0.05), whereas an influence of lactation period was seen only for gene relative mRNA abundances (p < 0.01).

Inter- and intrabreed diversity of the major histocompatibility complex (MHC) in primitive and draft horse breeds.

BackgroundPolymorphism of major histocompatibility complex (MHC) genes ensures effective immune responses against a wide array of pathogens. However, artificial selection, as performed in the case of domestic animals, may influence MHC diversity. Here, we investigate and compare the MHC diversity of three populations of horses, for which different breeding policies were applied, to evaluate the impact of artificial selection and the environment on MHC polymorphism.MethodsSamples of DNA were taken from 100 Polish draft horses, 38 stabled Konik Polski horses and 32 semiferal Konik Polski horses. MHC alleles and haplotype diversity within and between these populations of horses was estimated from 11 MHC microsatellite loci.ResultsMHC diversity measured based on allelic richness, observed heterozygosity, expected heterozygosity and polymorphism content was similar across the MHC microsatellite loci in all three populations. The highest expected heterozygosity was detected in semiferal primitive horses (He = 0.74), while the lowest was calculated for draft horses (He = 0.65). In total, 203 haplotypes were determined (111 in Polish draft horses, 43 in semiferal Konik Polski horses and 49 in stabled Konik Polski horses), and four haplotypes were shared between the two populations of Koniks. None of these haplotypes were present in any of the previously investigated horse breeds. Intra-MHC recombination events were detected in all three populations. However, the population of semiferal Konik horses showed the highest recombination frequency among the three horse populations. In addition, three recombination events were detected.ConclusionsThese results showed that despite the different breeding policies, the MHC allele and haplotype diversity was similarly high in all three horse populations. Nevertheless, the proportion of new haplotypes in the offspring was the highest in semiferal Konik Polski horses, which indicates the influence of the environment on MHC diversity in horses. Thus, we speculate that the genetic makeup of the domestic horse MHC might be more strongly influenced by the environment than by artificial selection. Moreover, intra-MHC conversion, insertion, and deletion and intra-MHC recombination may be proposed as mechanisms underlying the generation of new MHC haplotypes in horses.

Polish Pony Changes Lower Layer Biodiversity in Old Growth Scots Pine Stands

The study examines the influence of Polish primitive horse grazing on vegetation in deciduous and coniferous old forest stands in north-east Poland. It was conducted in both forest sites in two complexes located in: (i) the fenced area of the Popielno Research Station of the Polish Academy of Sciences, with free-living Polish pony [Polish primitive horse (Equus ferus caballus Linnaeus, 1758)] in 130-year-old stands, and (ii) in the open 116-year-old managed (harvested) Maskulińskie Forest District, without horses. In both areas the stands are inhabited by free-living red and roe deer. The impact of forest animals on ground cover layer as well as on understory shrub layer and undergrowth was compared. Very significant differences in the structure of the understory and undergrowth (above 0.5 m) layer vegetation communities between both areas and type of stands were found. The results suggest that the presence of the Polish horse substantially changed the species composition and increased the species diversity of the ground layer and shrub layer both in the coniferous forest and deciduous forest habitats. The height of the shrub layer trees was lower by 30% in the area with the Polish horse. The level of biodiversity of forest plants was dependent on the presence of the Polish horse, which in the past was one of the natural inhabitants of forests in the area of research.

A genome-wide scan for diversifying selection signatures in selected horse breeds.

The genetic differentiation of the current horse population was evolutionarily created by natural or artificial selection which shaped the genomes of individual breeds in several unique ways. The availability of high throughput genotyping methods created the opportunity to study this genetic variation on a genome-wide level allowing detection of genome regions divergently selected between separate breeds as well as among different horse types sharing similar phenotypic features. In this study, we used the population differentiation index (FST) that is generally used for measuring locus-specific allele frequencies variation between populations, to detect selection signatures among six horse breeds maintained in Poland. These breeds can be classified into three major categories, including light, draft and primitive horses, selected mainly in terms of type (utility), exterior, performance, size, coat color and appearance. The analysis of the most pronounced selection signals found in this study allowed us to detect several genomic regions and genes connected with processes potentially important for breed phenotypic differentiation and associated with energy homeostasis during physical effort, heart functioning, fertility, disease resistance and motor coordination. Our results also confirmed previously described association of loci on ECA3 (spanning LCORL and NCAPG genes) and ECA11 (spanning LASP1 gene) with the regulation of body size in our draft and primitive (small size) horses. The efficiency of the applied FST-based approach was also confirmed by the identification of a robust selection signal in the blue dun colored Polish Konik horses at the locus of TBX3 gene, which was previously shown to be responsible for dun coat color dilution in other horse breeds. FST-based method showed to be efficient in detection of diversifying selection signatures in the analyzed horse breeds. Especially pronounced signals were observed at the loci responsible for fixed breed-specific features. Several candidate genes under selection were proposed in this study for traits selected in separate breeds and horse types, however, further functional and comparative studies are needed to confirm and explain their effect on the observed genetic diversity of the horse breeds.

5\u2019-flanking variants of equine casein genes (CSN1S1, CSN1S2, CSN2, CSN3) and their relationship with gene expression and milk composition

Genes encoding casein proteins are important candidates for milk composition traits in mammals. In the case of the domestic horse, our knowledge of casein genes is limited mainly to coding sequence variants. This study involved screening for polymorphism in 5’-flanking regions of four genes encoding equine caseins (CSN1S1, CSN1S2, CSN2, and CSN3) and making a preliminary assessment of their effect on the gene expression (on the mRNA and protein levels) and milk composition traits in selected horse breeds. Altogether, 23 polymorphisms (21 described previously SNPs and two novel InDels) were found in the studied sequences, the majority of which are common in various horse breeds. Statistical analysis revealed that some are putatively associated with gene expression or milk composition — for example, the c.-2047_-2048insAT polymorphism (CSN1S1) turns out to be related to the total milk protein content in Polish Primitive Horse (p < 0.05), whereas c.-2105C>G SNP (CSN2) is related to beta-casein relative mRNA level and milk lactose concentration in the Polish Coldblood Horse breed (p < 0.05). We have also found significant effects of horse breed and lactation time-point on gene expression and mare’s milk composition. Our study indicates that the 5’-regulatory regions of genes encoding casein proteins are interesting targets for functional studies of their expression and the composition traits of mare’s milk.

Taste Preferences of Horses in Relation to Their Breed and Sex

The aim of this study was to determine the taste preferences of horses in relation to their breed and sex. Forty-eight adult purebred Arabian, Anglo-Arabian, Polish Konik, and Polish cold-blooded horses—stallions and mares in equal numbers—were examined in the study. During the experiment, five types of industrially processed feeds based on oats and natural dried products commonly regarded as horse treats (i.e., sour and sweet apples, carrots, sugar beet molasses, and barley with salt) were given to horses in buckets on three consecutive days. The behavior of the horses during the experiment was evaluated, as was the way in which they expressed their taste preferences, the sequence in which they consumed the pellets, the time they took to become interested in the pellets, and the time they took to consume each kind of pellet. The taste preferences of the horses were found to depend on their breed and sex. Pellets containing molasses were consumed more willingly by mares than stallions. Feeds with the addition of apples or carrots were the favorite treats of all tested breeds. The greatest variety in pellet taste preferences was found in purebred Arabian horses. Pellets with a distinct sweet taste or slightly salty cereals should be given to horses if other options are not available. In most cases, these two additions were chosen last by the horses in the experiment. Primitive horses had a distinct manner of expressing taste sensations. Horse behavior indicating an interest in a feed should not be taken as a proof of its tastiness. The first food chosen is not necessarily the one consumed most quickly.

A Novel Non-Invasive Selection Criterion for the Preservation of Primitive Dutch Konik Horses.

The Dutch Konik is valued from a genetic conservation perspective and also for its role in preservation of natural landscapes. The primary management objective for the captive breeding of this primitive horse is to maintain its genetic purity, whilst also maintaining the nature reserves on which they graze. Breeding selection has traditionally been based on phenotypic characteristics consistent with the breed description, and the selection of animals for removal from the breeding program is problematic at times due to high uniformity within the breed, particularly in height at the wither, colour (mouse to grey dun) and presence of primitive markings. With the objective of identifying an additional non-invasive selection criterion with potential uniqueness to the Dutch Konik, this study investigates the anatomic parameters of the distal equine limb, with a specific focus on the relative lengths of the individual splint bones. Post-mortem dissections performed on distal limbs of Dutch Konik (n = 47) and modern domesticated horses (n = 120) revealed significant differences in relation to the length and symmetry of the 2nd and 4th Metacarpals and Metatarsals. Distal limb characteristics with apparent uniqueness to the Dutch Konik are described which could be an important tool in the selection and preservation of the breed.

Influence of primitive Biłgoraj horses on the glossy buckthorn (Frangula alnus)-dominated understory in a mixed coniferous forest

Changes in the understory dominated by glossy buckthorn Frangula alnus via the influence of primitive horses were analyzed in a 28-year-old enclosure in the village of Szklarnia at the Biłgoraj Horse-Breeding Centre near Janów Lubelski (eastern Poland). The analysis was conducted in 20 circular plots (30 m2) defined in adjacent, similar forest stands (enclosed and control). Disturbance by the horses, mainly through trampling, caused numerous paths to form within the glossy buckthorn-dominated understory and led to a decrease in density of stems of lower height classes (30–80 and 81–130 cm, respectively). An increase in species diversity at the expense of glossy buckthorn density was also observed. The horses' trampling caused an increase in Padus avium density and the encroachment of other woody plant species that were less shade-tolerant and grew well in soils rich in nutrients. An increase in the density of woody plants over 180 cm above ground was observed within the enclosure, which was probably the result of the horses’ excretion of feces. The results presented here provide new insight into the ecological role that horses play in forest-meadow landscape mosaics, which, via altering the development of vegetation, may contribute to an increase in biodiversity within forest habitats.

Coat cover hair density is a symptom of primitive horse adaptation to the environment

Coat cover hair density is a symptom of primitive horse adaptation to the environment