Analysis of volatiles from feces of released Przewalski’s horse (Equus przewalskii) in Gasterophilus pecorum (Diptera: Gasterophilidae) spawning habitat

The absolute dominant species that infests wild population of Przewalski’s horse (Equus przewalskii) is Gasterophilus pecorum, and feces of released Przewalski’s horse, a habitat odor, plays an important role in mating and ovipositing locations of G. pecorum. To screen out unique volatiles for attracting G. pecorum, volatiles from fresh feces of released horses at stages of pre-oviposition (PREO), oviposition (OVIP), and post-oviposition (POSO) of G. pecorum, and feces with three different freshness states (i.e., Fresh, Semi-fresh, and Dry) at OVIP were collected by dynamic headspace adsorption and determined by automatic thermal desorption GC–MS. Results show that there were significant differences in fecal volatiles within both test conditions. Of the five most abundant volatiles from the five individual samples, the most important volatile was ammonium acetate at OVIP/Fresh, followed by acetophenone (Semi-fresh), toluene (PREO, OVIP and POSO), butanoic acid (OVIP and Semi-fresh), acetic acid (PREO, POSO and Semi-fresh), 1,6-octadiene,3,7-dimethyl-,(S)- (PREO, OVIP and POSO), 1,5,9-undecatriene,2,6,10-trimethyl-,(Z)- (PREO and Semi-fresh) and caprolactam (all conditions), which seem to be critical substances in oviposition process of G. pecorum. The findings may be beneficial to development of G. pecorum attractants, facilitating prevention and control of infection by G. pecorum to released Przewalski’s horse.

Andrological and cytogenetic investigations of an infertile Przewalski’s stallion

The case of an 8-year-old, sexually active but infertile Przewalski’s stallion (Equus ferus przewalskii) was studied. Besides the infertility, the stallion also showed permanent problems with its body condition, being obviously weaker than all the other group members. The horse was kept in a separate place for two years with 12 mares in its harem group (six mares had foals earlier); however, none of the mares covered got pregnant. Andrological and cytogenetic investigations revealed underdeveloped testes, arrested spermatogenesis, azoospermia, and XY/XXY/X0 mosaicism. We classify the case as a mosaic Klinefelter syndrome, the first reported case in Przewalski’s horse.

Genetic diversity of the free-living population of Przewalski's horses in the Chernobyl Exclusion Zone

The present study is aimed at evaluating the genetic diversity, genetic status and the extent of hybridization with the domestic horse for the Przhevalski’s horse (Equus ferus przewalskii Poliakov 1881) population free-ranging in the territory of the Chernobyl Exclusion Zone (CEZ) in Belarus and Ukraine. The sample size included 12 individuals (10 sampled in the Belarusian part of the CEZ and 2 from the Ukrainian part of the CEZ). Ten microsatellites recommended by the International Society for Animal Genetics (ISAG) for horse genetic status and pedigree determination were used as markers in this study. The fragment analysis data obtained utilising this microsatellite panel determined that two individuals from Belarus possess no allelic variants typical for Przhevalski’s horse. Most of the other individuals presented diagnostically valuable allelic variants. Demographic history analysis for the population did not indicate any drastic population shrinkage events in the population’s recent history. The studied population is characterised by heterogeneous population structure with signs of inbreeding (0.21 %), intermediate level of genetic diversity (He = 0.63) and allelic richness (5.15), possesses 16 unique alleles among 2 microsatellite loci and valuable alleles for loci HMS3 and HMS7 (46.4 and 67.9 % specific alleles for Przhevalski’s horse, respectively). Genetic structure evaluation for the population was performed via Bayesian population structure analysis and factorial correspondence analysis (FCA), which indicated the presence of intrapopulation genetic subdivision. Taking into account the obtained indicators of genetic diversity, we may conclude on the relatively favourable status of Przewalski’s horse in the exclusion zone with good potential for the long-term existence of the species population in the wild. In order to minimise inbreeding effects and the risk of a decline in genetic diversity in the population of Przewalski’s horse of the exclusion zone, as well as to increase the value of this free-living group to preserve the gene pool of the species as a whole, it is necessary to provide detailed genetic monitoring of the livestock’s state, as well as develop a regional population management plan, including measures aimed to minimise the possibility of further hybridisation of wild horses with domestic ones.

Hormone-responsive organoids from domestic mare and endangered Przewalski’s horse endometrium

The endometrium, the inner uterine lining, is composed of cell layers that come in direct contact with an embryo during early pregnancy and later with the fetal placenta. The endometrium is responsible for signals associated with normal reproductive cyclicity as well as maintenance of pregnancy. In the mare, functionally competent in vitro models of the endometrium have not been successful. Furthermore, the ability to study various reproductive processes in vitro may allow critical evaluation of signaling pathways involved in the reproductive diseases of animals that cannot be handled frequently, such as various wildlife species. Here we report the establishment of organoids, 3D structures, derived from fresh and frozen–thawed equine endometrium (Equus ferus caballus and E. f. przewalskii). Although organoids from domestic mares responded to exogenous hormonal stimuli, organoids from Przewalski’s horse failed to respond to exogenous hormones. The present study represents a ‘first’ for any large animal model or endangered species. These physiologically functional organoids may facilitate improved understanding of normal reproductive mechanisms, uterine pathologies, and signaling mechanisms between the conceptus and endometrium and may lead to the development of novel bioassays for drug discovery.

Identification of volatile components from oviposition and non-oviposition plants of Gasterophilus pecorum (Diptera: Gasterophilidae)

Oviposition by Gasterophilus pecorum on shoot tips of Stipa caucasica is a key determinant of its severe infection of the reintroduced Przewalski’s horse (Equus przewalskii). Volatiles in shoots of grasses on which Przewalski’s horse feeds, including S. caucasica at preoviposition, oviposition, and postoviposition stages of G. pecorum, S. caucasica, Stipa orientalis, and Ceratoides latens at the oviposition stage, and S. caucasica in various growth periods, were collected by dynamic headspace adsorption and analyzed by automatic thermal desorption gas chromatography-mass spectrometry. Among five volatiles with highest relative contents under three sets of conditions, caprolactam and 3-hexen-1-ol,(Z)- were common to all samples. Caprolactam was highest in C. latens at oviposition stage of G. pecorum and lowest in S. caucasica at postoviposition stage, and that of 3-hexen-1-ol,(Z)- was lowest in C. latens and highest in S. caucasica at its oviposition stage. Particularly, in S. caucasica during the three oviposition phenological stages of G. pecorum, 3-hexen-1-ol,acetate,(Z)-, 2(5H)-furanone,5-ethyl-, and 3-hexen-1-ol,acetate,(E)- were unique, respectively, to the preoviposition, oviposition, and postoviposition stages; in three plant species during the oviposition stage of G. pecorum, 3-hexen-1-ol,acetate,(Z)-, 3-hexenal, and 1-hexanol were unique to S. orientalis, acetic acid, hexanal, and 2(5H)-furanone,5-ethyl- to S. caucasica, and 1,3,6-octatriene,3,7-dimethyl-, cis-3-hexenyl isovalerate, and acetic acid hexyl ester to C. latens; in S. caucasica, 2-undecanone,6,10-dimethyl- was unique to the early growth period, acetic acid and 2(5H)-furanone,5-ethyl- to the flourishing growth period, and 3-hexen-1-ol,acetate,(Z)- and 1,3,6-octatriene,3,7-dimethyl- to the late growth period. Furthermore, substances specific to S. orientalis and C. latens were also present in S. caucasica, except at oviposition stage. Our findings will facilitate studies on G. pecorum’s adaptation to the arid desert steppe and its future control.

Paratrichophaea boudieri. [Descriptions of Fungi and Bacteria].

A description is provided for Paratrichophaea boudieri, found on dung of of Przewalski's horse (Equus ferus F. przewalskii). Some information on its associated organisms and substrata, dispersal and transmission, habitats and conservation status is given, along with details of its geographical distribution (Africa (Morocco), North America (Canada (Alberta)), Mexico, USA (California, Idaho, Michigan, Wyoming)), Asia (Israel), Atlantic Ocean (Spain (Canary Islands), Europe (Austria, Belgium, Denmark, France, Germany, Netherlands, Norway, Poland, Portugal, Russia (Leningrad Oblast, Tula Oblast), Slovakia, Spain, Switzerland, Ukraine, UK)).

Basic Reproductive Parameters in the Population of Przewalski’s Horse

The present study’s objectives were to determine basic reproductive parameters in the population of Przewalski’s horse and to identify and assess factors of potential relevance to these parameters. Input data were obtained from the worldwide online Przewalski’s Horse Studbook and comprised information from 1899 until 2016.

Drug efficacy of ivermectin against primary nematodes parasitizing captive Przewalski’s horse (Equus ferus przewalskii) after ten years of annually treatment

SummaryReintroduction of endangered species to natural habitat is considered as an important tool for conservation. The effect of drug management on captive population of reintroduced species is largely neglected. Decreased drug efficacy could pose a substantial threat to health of animals. More importantly, captive population without proper drug administration could act as transmission medium of resistance nematodes to wild population, making it important to delay the occurrence of drug resistance in captive population. Ivermectin have been used in captive Przewalski’s horse (Equus ferus przewalskii) to eradicate intestinal parasitic nematodes annually, while no available studies describing the drug efficacy in the recent ten years. Here, fecal egg counts pre- and post-treatment were performed with ivermectin through individual trace. Both large and small strongyles were identifi ed by larval culture. The fecal egg count reduction was almost 100% based on egg counting data of 448 samples from 13 Przewalski’s horses. Feces of two Przewalski’s horses were sampled for successive 20 days. Eggs per gram feces usually increased dramatically at the period of 1 – 2 post-treatment days and declined persistently to 0.0 within 15 days. A sustained high ivermectin efficacy against neither Parascaris equorum nor strongyles was indicated, which can be partly explained by the low deworm frequency.