The population dynamics of horses refers to the study of changes in horse populations over time, influenced by factors such as birth rates, death rates, immigration, and emigration. These dynamics are shaped by environmental conditions, resource availability, predation, and human intervention. Understanding population dynamics is essential for managing wild horse populations and ensuring sustainable practices in breeding and conservation efforts. This page compiles peer-reviewed research studies and scholarly articles that explore the factors affecting horse population dynamics, including genetic diversity, habitat utilization, and the impact of management strategies on population stability and growth.
de Villalobos AE, Zalba SM, Peláez DV.We evaluated the mechanisms that determine the increasing abundance of Pinus halepensis in mountain pampean grasslands in Argentina that is associated with the continuous presence of feral horses. We hypothesized that direct and indirect effects of feral horse grazing on grassland may affect the establishment of P. halepensis. We conducted a field experiment to evaluate this hypothesis, studying the response of seedling emergence, survival and growth to herbaceous vegetation defoliation and soil disturbance in sites with contrasting grazing histories. We also evaluated the composition and stru...
Warmuth V, Eriksson A, Bower MA, Cañon J, Cothran G, Distl O, Glowatzki-Mullis ML, Hunt H, Luís C, do Mar Oom M, Yupanqui IT, Ząbek T, Manica A.The role of European wild horses in horse domestication is poorly understood. While the fossil record for wild horses in Europe prior to horse domestication is scarce, there have been suggestions that wild populations from various European regions might have contributed to the gene pool of domestic horses. To distinguish between regions where domestic populations are mainly descended from local wild stock and those where horses were largely imported, we investigated patterns of genetic diversity in 24 European horse breeds typed at 12 microsatellite loci. The distribution of high levels of gen...
Murcia PR, Wood JL, Holmes EC.Equine influenza viruses (EIVs) of the H3N8 and H7N7 subtypes are the causative agents of an important disease of horses. While EIV H7N7 apparently is extinct, H3N8 viruses have circulated for more than 50 years. Like human influenza viruses, EIV H3N8 caused a transcontinental pandemic followed by further outbreaks and epidemics, even in populations with high vaccination coverage. Recently, EIV H3N8 jumped the species barrier to infect dogs. Despite its importance as an agent of infectious disease, the mechanisms that underpin the evolutionary and epidemiological dynamics of EIV are poorly und...
Bömcke E, Gengler N, Cothran EG.In Greece, seven native horse breeds have been identified so far. Among these, the Skyros pony is outstanding through having a distinct phenotype. In the present study, the aim was to assess genetic diversity in this breed, by using different types of genetic loci and available genealogical information. Its relationships with the other Greek, as well as foreign, domestic breeds were also investigated. Through microsatellite and pedigree analysis it appeared that the Skyros presented a similar level of genetic diversity to the other European breeds. Nevertheless, comparisons between DNA-based a...
Goyache F, Alvarez I, Fernández I, Pérez-Pardal L, Royo LJ, Lorenzo L.Empirical evidence of the usefulness of different molecular-based methods to estimate the effective population size (N(e)) for conservation purposes in endangered livestock populations is reported. The black-coated Asturcón pony pedigree (1,981 individuals) was available. Additionally, a total of 267 Asturcón individuals born in 1998, 2002, and 2008 were typed for 15 microsatellites. These yearly cohorts (cohort(1998, 2002, 2008)) included almost all individuals kept for reproduction at the end of the corresponding foaling season. The genealogical realized N(e) was estimated for each cohort ...
Cieslak M, Pruvost M, Benecke N, Hofreiter M, Morales A, Reissmann M, Ludwig A.Domestic horses represent a genetic paradox: although they have the greatest number of maternal lineages (mtDNA) of all domestic species, their paternal lineages are extremely homogeneous on the Y-chromosome. In order to address their huge mtDNA variation and the origin and history of maternal lineages in domestic horses, we analyzed 1961 partial d-loop sequences from 207 ancient remains and 1754 modern horses. The sample set ranged from Alaska and North East Siberia to the Iberian Peninsula and from the Late Pleistocene to modern times. We found a panmictic Late Pleistocene horse population r...
Tenzin , Sharma B, Dhand NK, Timsina N, Ward MP.From January through July 2008, rabies reemerged in the Chhukha district of southwestern Bhutan. To clarify the distribution and direction of spread of this outbreak, we mapped reported cases and conducted directional tests (mean center and standard deviational ellipse). The outbreak resulted in the death of 97 animals (42 cattle, 52 dogs, and 3 horses). Antirabies vaccine was given free of charge to ≈674 persons suspected to have been exposed. The outbreak spread south to north and appeared to follow road networks, towns, and areas of high human density associated with a large, free-roaming...
Nergadze SG, Lupotto M, Pellanda P, Santagostino M, Vitelli V, Giulotto E.The insertion of mitochondrial DNA in the nuclear genome generates numts, nuclear sequences of mitochondrial origin. In the horse reference genome, we identified 82 numts and showed that the entire horse mitochondrial DNA is represented as numts without gross bias. Numts were inserted in the horse nuclear genome at random sites and were probably generated during the repair of DNA double-strand breaks. We then analysed 12 numt loci in 20 unrelated horses and found that null alleles, lacking the mitochondrial DNA insertion, were present at six of these loci. At some loci, the null allele is prev...
Corbin LJ, Blott SC, Swinburne JE, Vaudin M, Bishop SC, Woolliams JA.Many genomic methodologies rely on the presence and extent of linkage disequilibrium (LD) between markers and genetic variants underlying traits of interest, but the extent of LD in the horse has yet to be comprehensively characterized. In this study, we evaluate the extent and decay of LD in a sample of 817 Thoroughbreds. Horses were genotyped for over 50,000 single nucleotide polymorphism (SNP) markers across the genome, with 34,848 autosomal SNPs used in the final analysis. Linkage disequilibrium, as measured by the squared correlation coefficient (r(2)), was found to be relatively high bet...
Tseng CT, Miller D, Cassano J, Bailey E, Antczak DF.A system for identifying equine major histocompatibility complex (MHC) haplotypes was developed based on five polymorphic microsatellites located within the MHC region on ECA 20. Molecular signatures for 50 microsatellite haplotypes were recognized from typing 353 horses. Of these, 23 microsatellite haplotypes were associated with 12 established equine leucocyte antigen (ELA) haplotypes in Thoroughbreds and Standardbreds. Five ELA serotypes were associated with multiple microsatellite subhaplotypes, expanding the estimates of diversity in the equine MHC. The strong correlations between serolog...
Chauhan M, Gupta AK, Dhillon S.The genetic relationships of three Indian horse breeds-Marwari, Spiti, and Kathiawari were studied by genotyping 96 individuals with 20 polymorphic microsatellite markers. A total of 157 alleles were detected across 20 polymorphic loci. The Marwari population showed the highest allelic diversity (A = 5.7 and Ar = 5.14), followed by Spiti (A = 4.9 and Ar = 4.74) and Kathiawari (A = 4.1 and Ar = 3.82). The gene diversity was highest in the Spiti population (He = 0.67), followed by Marwari (He = 0.66) and Kathiawari (He = 0.59). Within population inbreeding estimates (f) in Marwari, Spiti and Kat...
Nuñez CM, Adelman JS, Rubenstein DI.Although the physiological effects of immunocontraceptive treatment with porcine zona pellucida (PZP) have been well studied, little is known about PZP's effects on the scheduling of reproductive cycling. Recent behavioral research has suggested that recipients of PZP extend the receptive breeding period into what is normally the non-breeding season. Results: To determine if this is the case, we compiled foaling data from wild horses (Equus caballus) living on Shackleford Banks, North Carolina for 4 years pre- and 8 years post-contraception management with PZP (pre-contraception, n = 65 births...
Selvaggi M, Pesce Delfino AR, Dario C.The aim of this study was to assess genetic polymorphism at two loci in the exon 1 of the CSN3 gene in Murgese horse breed by PCR-RFLP analysis. The overall frequencies of alleles A and G at c.-66A > G locus were 0.80 and 0.20, respectively, and no GG animals were found in the population. At the c.-36C > A locus allelic frequencies were 0.74 and 0.26 for allele C and A, respectively, and no AA animals were detected. Population genetic indexes, namely gene heterozygosity, gene homozygosity, effective allele numbers, fixation index, and polymorphism information index were calculated. C...
Yamashita J, Oki H, Hasegawa T, Honda T, Nomura T.Genetic contributions of nine historically important ancestors and allelic diversity in the Japanese Thoroughbred population were examined by applying the gene dropping simulation to the foals produced from 1978 to 2005. Full pedigree records traced to ancestors (base animals) born around 1890 were used for the simulation. Alleles originated from some of the historically important ancestors were found to be at risk of future extinction, although their genetic contributions to the foal population have increased during the last three decades. The proportion of surviving alleles to the total alle...
Robin CA, Wylie CE, Wood JL, Newton JR.Detailed knowledge of horse populations can better facilitate effective control of equine diseases. Preliminary studies were undertaken to ascertain the type of information held on the UK's National Equine Database (NED) and to determine the geographical resolution at which mandatorily recorded owner addresses might be a suitable proxy for predicting horse locations. Results indicated that relatively few UK passport-issuing organisations requested details of where horses were kept in addition to owner address details. Examination of data on 1440 horses held on an Animal Health Trust syndromic ...
Holcomb KE, Stull CL, Kass PH.Closure of US equine slaughter facilities in 2007 along with the concomitant economic recession have contributed to a sharp increase in the number of unwanted horses throughout the United States, with estimates totaling 100,000 horses per year. The objective of the study was to obtain comprehensive data regarding nonprofit organizations caring for unwanted horses, along with the characteristics and outcome of horses relinquished to these organizations. Nonprofit organizations that accept relinquished equines were contacted to participate in a 90-question survey. Responding organizations (144 o...
Yamashita J, Oki H, Hasegawa T, Honda T, Nomura T.To investigate the breeding structure in the Japanese Thoroughbred population, we applied a demographic analysis to the populations of foals produced from 1978 to 2005. The migration rate estimated from the proportion of foals produced by imported breeding horses was around 40% over the investigated period. After early 1990s, the migration rate through stallions imported from USA sharply increased. The average generation interval was within range of 10.5-11.5 years. The longer generation interval of Thoroughbred was considered to be a reflection of the fact that Thoroughbred horses begin breed...
Bartolomé E, Goyache F, Molina A, Cervantes I, Valera M, Gutiérrez JP.A method to quantify the contribution of subpopulations to genetic diversity in the whole population was assessed using pedigree information. The standardization of between- and within-subpopulation mean coancestries was developed to account for the different coat colour subpopulation sizes in the Spanish Purebred (SPB) horse population. The data included 166264 horses registered in the SPB Studbook. Animals born in the past 11 years (1996 to 2006) were selected as the 'reference population' and were grouped according to coat colour into eight subpopulations: grey (64 836 animals), bay (33 633...
Ling YH, Ma YH, Guan WJ, Cheng YJ, Wang YP, Han JL, Mang L, Zhao QJ, He XH, Pu YB, Fu BL.We determined the genetic diversity and evolutionary relationships among 26 Chinese indigenous horse breeds and two introduced horse breeds by genotyping these animals for 27 microsatellite loci. The 26 Chinese horse breeds come from 12 different provinces. Two introduced horse breeds were the Mongolia B Horse from Mongolia and the Thoroughbred Horse from the UK. A total of 330 alleles were detected, and the expected heterozygosity ranged from 0.719 (Elenchuns) to 0.780 (Dali). The mean number of alleles among the horse breeds ranged from 6.74 (Hequ) to 8.81 (Debao). Although there were abunda...
Shah W.Medical Usage Rate (MUR) of Galway Races: The Galway Races is the most popular horse-racing festival in Ireland. It takes place for a week starting from the last Monday in July. The races are held at Ballybrit race course in Galway. During the 7 days of racing, about 180,000 people attend. The average temperature in Galway around that time of the year is around 15-200C. The aim of this study is to calculate the MUR of Galway Races and to develop a model to predict the MUR for Galway Races in future. The MUR of Galway Races is calculated by looking retrospectively at the medical records of the ...
Ning T, Xiao H, Li J, Hua S, Zhang YP.Mitochondria play a crucial role in energy metabolism through oxidative phosphorylation. Organisms living at high altitudes are potentially influenced by oxygen deficits and cold temperatures. The severe environmental conditions can impact on metabolism and direct selection of mitochondrial DNA. As a wide-ranging animal, the domestic horse (Equus caballus) has developed various morphological and physiological characteristics for adapting to different altitudes. Thus, this is a good species for studying adaption to high altitudes at a molecular level. We sequenced the complete NADH dehydrogenas...
DeAssis JB, DeLaat DM, Peixoto MG, Bergmann JA, Fonseca CG, Carvalho MR.One hundred and fifteen unrelated Mangalarga Marchador horses were sampled from three geographically distinct regions of Minas Gerais State, Brazil (South, Southeast, and Northeast) and tested for 10 microsatellite loci. Genetic diversity and population structure parameters were estimated with ARLEQUIN 3.0, CERVUS 2.0, POPGENE 1.31, GENEPOP on the web, STRUCTURE 2.0, and SPAGEDI 1.2 software packages. Under Hardy-Weinberg assumptions, seven markers were at equilibrium (LEX014, LEX017, LEX019, SGCV23, TKY321, VHL20, and VIASH39), while two (ASB3 and LEX031) presented significant homozygote exce...
The Journal of heredityNovember 27, 2009
Volume 101, Issue 2 133-143 doi: 10.1093/jhered/esp101
Gonzales E, Hamrick JL, Smouse PE, Trapnell DW, Peakall R.We examined spatial genetic structure (SGS) in Enterolobium cyclocarpum (the Guanacaste tree), a dominant tree of Central American dry forests in 4 sites in Guanacaste Province, Costa Rica. In disturbed dry forest sites (e.g., pastures), E. cyclocarpum is primarily dispersed by cattle and horses, whose movements are restricted by pasture boundaries. The study sites varied in tree densities and disturbance. Allozyme analyses of adult trees demonstrated significant levels of SGS in 3 of 4 sites. SGS was primarily due to clusters of young adults located along seasonal streams, rocky areas, and in...
Traversa D, Milillo P, Barnes H, von Samson-Himmelstjerna G, Schurmann S, Demeler J, Otranto D, Lia RP, Perrucci S, Frangipane di Regalbono A....A broad scale study was carried out in 2008 to evaluate the distribution and species-specific occurrence of cyathostomin populations in horse yards from Europe. In total 102 properties and 3123 horses were included in Italy (60 yards and 1646 animals), United Kingdom (22 yards and 737 animals) and Germany (20 yards and 740 animals). Individual faecal samples were examined with a McMaster technique while pooled samples were subjected to the microscopic examination of in vitro cultured larvae and to a Reverse Line Blot (RLB) assay able to molecularly identify the most diffused 13 species of cyat...
Burocziova M, Riha J.Genetic relationships and population structure of 8 horse breeds in the Czech and Slovak Republics were investigated using classification methods for breed discrimination. To demonstrate genetic differences among these breeds, we used genetic information - genotype data of microsatellite markers and classification algorithms - to perform a probabilistic prediction of an individual's breed. In total, 932 unrelated animals were genotyped for 17 microsatellite markers recommended by the ISAG for parentage testing (AHT4, AHT5, ASB2, HMS3, HMS6, HMS7, HTG4, HTG10, VHL20, HTG6, HMS2, HTG7, ASB17, AS...
Priskin K, Szabó K, Tömöry G, Bogácsi-Szabó E, Csányi B, Eördögh R, Downes CS, Raskó I.Movements of human populations leave their traces in the genetic makeup of the areas affected; the same applies to the horses that move with their owners This study is concerned with the mitochondrial control region genotypes of 31 archaeological horse remains, excavated from pre-conquest Avar and post-conquest Hungarian burial sites in the Carpathian Basin dating from the sixth to the tenth century. To investigate relationships to other ancient and recent breeds, modern Hucul and Akhal Teke samples were also collected, and mtDNA control region (CR) sequences from 76 breeds representing 921 in...
Cervantes I, Gutiérrez JP, Molina A, Goyache F, Valera M.This research assesses the genetic composition of three Arab-derived Spanish horse breeds as an example to highlight the major shortcomings related to genealogical analyses in open populations and to propose approaches useful to deal with this task. The studbooks of three Spanish Arab (SA)-derived horse breeds, Spanish Anglo-Arab (dAA), Hispano-Arab (dHA) and Spanish Sport Horse (dSSH) and those of their parental breeds SA, Spanish Purebred (SPB) and Thoroughbred (TB), totalling 211 754 individuals, were available. The genealogies of the dAA, dHA and dSSH were analysed not only using the corre...
Seong HS, Kim NY, Kim DC, Hwang NH, Son DH, Shin JS, Lee JH, Chung WH, Choi JW.The Jeju horse is an indigenous horse breed in Korea. However, there is a severe lack of genomic studies on Korean horse breeds. The objective of this study was to report genomic characteristics of domestic horse populations that inhabit South Korea (Jeju, Jeju crossbred, and Thoroughbred) and a wild horse breed (Przewalski's horse). Using the equine reference genome assembly (EquCab 2.0), more than ~ 6.5 billion sequence reads were successfully mapped, which generated an average of 40.87-fold coverage throughout the genome. Using these data, we detected a total of 12.88 million SNPs, of w...
Nakamura K, Tozaki T, Kakoi H, Owada S, Takasu M.Kiso horse is a breed of Japanese native horses. In this study, to clarify coat color gene variation in Kiso horses, we used SNaPshot™ genotyping to evaluate variation in MC1R, ASIP, and MATP genes at the Extension (E), Agouti (A), and Cream dilution (C) loci. The coat color of 149 horses was documented. The coat color of 140, 3, and 6 horses was bay, chestnut, and buckskin, respectively. Furthermore, the frequency of alleles E, e, A, a, C, and Cr was 0.80, 0.20, 0.86, 0.14, 0.98, and 0.02, respectively. Current status of coat color genes in Kiso horses was clarified, and this information wi...
Sonali , Giri SK, Unnati , Nayan V, Legha RA, Pal Y, Bhardwaj A.India has well documented horse and pony breeds; however, the population is well diversified in different geographical regions. The Myostatin gene is one of the most profoundly studied genetic components for the detection of SNP's for the performance analysis in horses. In the present study, the MSTN exon 2 partial cds were amplified, sequenced and characterized in about 60 samples of eight different breeds of Indian horses. The results indicated the transition of Thymine to Cytosine (T>C) as single nucleotide polymorphisms in the partial sequence of exon 2 of the MSTN gene at two different...
Fenu G, Melis A, Pinna MS, Loi MC, Calderisi G, Cogoni D. (SWEs), despite their pivotal ecological role due to their participation in hydrogeological processes and their richness in biodiversity, seem to be often overlooked by the scientific community. In this study, the vascular plant diversity in some representative SWEs, that host a peculiar assemblage of plant and animal species, was investigated in relation to the disturbance effects of a wild horse population. A total of 50 plots, equally distributed in small and large SWEs, were surveyed and a level of disturbance was attributed to each plot. We found greater species richness in small and und...
Heath TJ.To define and describe the population of Australian veterinarians who work with horses. Methods: Questionnaires were mailed to 866 veterinarians who had been identified as working with horses, and 87% were completed and returned. Data were entered onto an Excel spreadsheet, and analysed using the SAS System for Windows. Results: About 12% of Australia's veterinarians were doing all the veterinary work with horses, and about 3% worked exclusively (> 90%) with horses, but did more than half (58%) of the horse work. Veterinarians working with horses included more males (80%) than the veterinar...
Atsenova N, Palova N, Mehandjyiski I, Neov B, Radoslavov G, Hristov P.The question about the time and the place of horse domestication, a process which had a profound impact on the progress of mankind, is disputable. According to the most widely accepted hypothesis, the earliest domestication of the horse happened in the western parts of the Eurasian steppes, between the Northern Black Sea region and present-day Kazakhstan and Turkmenistan. It seems that it occurred not earlier than the first half and most probably during the middle (even the last third) of the fourth millennium BC (from ∼ 5.5 kya). The next steps of large-scale horse breeding occurred almost ...
Sutton GJ, Cawley A, Murphy C, Lau ML, Hibbert DB.Horse racing authorities impose a limit on the concentration of plasma 'total carbon dioxide' (TCO2), typically 36 mM with action taken above 37 mM, as measured by an electrochemical gas analyzer. It is of interest to understand the distribution of TCO2 in a 'normal' population of racehorses and determine probabilities of members of this population exceeding these current regulatory and action limits. TCO2 levels in equine plasma samples have been modelled for 12 months (2011-2012) of thoroughbred (3076 measurements) and standardbred (3788 measurements) data in Australia. The two populations h...
Hall SE, Nixon B, Aitken RJ.Feral horses are a significant pest species in many parts of the world, contributing to land erosion, weed dispersal and the loss of native flora and fauna. There is an urgent need to modify feral horse management strategies to achieve public acceptance and long-term population control. One way to achieve this is by using non-surgical methods of sterilisation, which are suitable in the context of this mobile and long-lived species. In this review we consider the benefits of implementing novel mechanisms designed to elicit a state of permanent sterility (including redox cycling to generate oxid...
Tezuka A, Takasu M, Tozaki T, Nagano AJ.Taishu horses are a native Japanese breed, of which only 41 individuals remained on Tsushima Island in 2018. Their genetic diversity is considered lower than that of other Japanese native horse breeds; thus, it needs to be investigated for sustainable conservation of this breed. Historical records revealed that several Taishu individuals were released areas off-Tsushima Island in mid-1980s. At present, Taishu horses living outside of Tsushima Island, hereafter referred to as Non-Tsushima Taishus (NTTs), are tagged. However, the genetic structure of the NTT individuals remains unclear, and such...
Bowling AT.The genetic make-up of Great Basin wild (feral) horses was investigated by blood typing studies. Blood samples of 975 feral horses from seven trap sites in Nevada and Oregon were tested by serological and electrophoretic techniques for genetic markers at 19 polymorphic loci. The average number of variants for the seven feral populations [72.1 +/- 3.2 (SEM), range 62-85] was not significantly different from that of 16 domestic breeds (75.0 +/- 11.5, range 58-105). The expected average frequency of heterozygotes per locus (average heterozygosity) for the feral populations (0.402 +/- 0.009, range...
An J, Tseveen K, Oyungerel B, Kong HS.Mongolian horses are one of the oldest horse breeds, and are very important livestock in Mongolia as they are used in various fields such as transportation, food (milk, meat), and horse racing. In addition, research and preservation on pure Mongolian breeds are being promoted under the implementation of the new Genetics of Livestock Resources' act in Mongolia. However, despite the implementation of this act, genetic research on Mongolian horses using microsatellites (MS) has not progressed enough. Therefore, this study was conducted to analyze the genetic polymorphism of five breeds (Gobi shan...
Aberle K, Wrede J, Distl O.Gene contributions of foreign populations as well as coefficients of inbreeding and relationship were evaluated in 699 Black Forest Draught horses of Baden-Württemberg actually registered in the year 2002. Based on nearly complete 5-generation-pedigrees and after taking into account the remaining incompleteness, the mean coefficient of inbreeding for the total population was 6.5%. The recently by incrossing with different breeds newly established lines of stallions showed significantly lower mean coefficients of inbreeding. High rates of inbreeding of about 1.6% in the last five generations c...
Viklund Å, Furre S, Eriksson S, Vangen O, Philipsson J.Breeding programmes for warmblood sport horses are similar in the Nordic countries Sweden, Denmark, Finland and Norway, and stallions of same origin are used. The aim was to investigate whether a joint Nordic genetic evaluation based on lifetime competition performance is feasible and beneficial for breeding competitive sport horses in the Nordic countries. Results for almost 45,000 horses in show jumping and 30,000 horses in dressage were available. The larger populations in Sweden and Denmark contributed with 85% of the results. Heritabilities and genetic correlations between performances in...
Dovc P, Susnik S, Snoj A.Management of breeding- and free-living populations, traditionally based on phenotypic traits, relays more and more on availability of reliable information about the basic population genetic parameters as heterozygosity, mean number of alleles per locus, percentage of polymorphic loci, population structuring, genetic distances and others. Therefore, the application of molecular markers, revealing a great deal of phenotypically hidden information, becomes inevitable for population analysis. Conservation geneticists use this information for implementation of appropriate management policies. Appl...
Amano T, Tozaki T, Takasu M, Onogi A, Yamada F, Kawai M, Ueda J.We investigated whether regular changes of the sire in a breeding farm of Hokkaido Native Horses (HKDs) enables the DNA-level genetic variation of the produced animals to be maintained. The genotypes of 31 microsatellite markers were identified and analyzed in 207 animals produced in a breeding farm in which the sire was replaced every 3 to 5 years. The mean allele number indicating the degree of genetic variation was 5.97 and was similar to those reported previously. The mean observed heterozygosity was 0.74 and was higher than the expected heterozygosity, 0.69; F was -0.07, indicating that ...
Ho EN, Kwok WH, Leung DK, Riggs CM, Sidlow G, Stewart BD, Wong AS, Wan TS.Testosterone is an endogenous steroid produced primarily in the testes. Trace levels of testosterone are found in urine samples from geldings, as testosterone is also secreted by the adrenal. An international threshold of free and conjugated testosterone in urine (20 ng/mL) was adopted by the International Federation of Horseracing Authorities (IFHA) in 1996 for controlling testosterone misuse in geldings. In view of the recent popularity of using blood in doping control testing, it is necessary to establish a threshold for testosterone in gelding plasma. A liquid chromatography-mass spectro...
Klein R, Oláh J, Mihók S, Posta J.The Mezőhegyes Stud was founded in 1784 where three different horse breeds were developed: the Furioso-North Star, the Gidran, and the Nonius. These breeds were based on the same mare population, but each breed had different utilization purposes. Our aim was to analyze the pedigree information of these three indigenous breeds. The genealogical information was traced back from the actual breeding population back to the founder animals, and the final database contained more than 47,000 horses. The reference populations were defined as the registered breeding animals in 2019. The complete genera...
Houston T, Chay S, Woods WE, Combs G, Kamerling S, Blake JW, Edmundson AG, Vessiney R, Tobin T.A survey of plasma and urinary concentrations of phenylbutazone and its metabolites in thoroughbred horses racing in Kentucky was carried out. Post-race blood samples from more than 200 horses running at Latonia Racetrack and Keeneland in the Spring of 1983 were analysed. The modal plasma concentration of phenylbutazone was between 1 and 2 micrograms/ml, the mean concentration was 3.5 micrograms/ml and the range was up to 15 micrograms/ml. Oxyphenbutazone had a modal plasma concentration between 1 and 2 micrograms/ml, a mean concentration of 2.07 micrograms/ml and a range of up to 13 microgram...
Sitzenstock F, Rathke I, Ytournel F, Simianer H.A reference horse-breeding programme with 13500 foals each year was modelled with ZPLAN+. This new software for the optimization of the structures in breeding programmes is based on ZPLAN. In two scenarios, the implementation of a rigorous selection of mares was implemented. In scenario I, the mare performance test was the point of selection, while in scenario II, further information on 20 competitions in two more years is available. These selected mares were used for embryo transfer (ET), partly in combination with multiple ovulation (MOET). The selection intensity and the number of foals out...
Grewar JD, Sergeant ES, Weyer CT, van Helden LS, Parker BJ, Anthony T, Thompson PN.An African horse sickness (AHS) outbreak occurred in South Africa's AHS controlled area in autumn 2016. A freedom from disease survey was performed to establish the likelihood of ongoing circulation of the associated virus during the same period the following year. A single-stage surveillance strategy was employed with a population-level design prevalence of 1% to establish a survey population sensitivity of 95% (probability that one or more positive horses would be detected if AHS was present at a prevalence greater than or equal to the design prevalence). In March 2017, a total of 262 random...
Scully CM, Lee RL, Pielstick L, Medlock J, Patton KM, Collins GH, Kutzler MA.Free-roaming horse (Equus caballus) management is a complex issue incorporating social, economic, emotional, political, and environmental factors. Currently, few proven field techniques exist for managing free-roaming horse population growth, which can reach 20-25% annually. Although there are several strategies available for sterilizing mares when managing free-roaming horse populations, surgical vasectomy is the only method used in the field for stallions. Some managers believe that surgically vasectomizing dominant stallions would have significant effects on reducing horse populations. Howe...
Lyons ET, Drudge JH, Tolliver SC, Swerczek TW, Stamper S, Granstrom DE.Studies in a band of ponies harboring Population S benzimidazole-resistant small strongyles were initiated in 1974 and have continued for 18 years. Treatment (bimonthly) was with cambendazole for the first 4 years and with oxibendazole (OBZ) for the next 14 years. Data on the first 10 years have been published. The present investigation includes the last 8 years (4 October 1984-11 September 1992), which are the seventh through fourteenth years, of treatment with OBZ. Pre- and posttreatment mean counts of strongyle eggs (epg) and larvae (lpg) per gram of feces were determined biweekly during th...
Lyman CC, Baldrighi JM, Anderson CO, Germaine SS, Kane AJ, Holyoak GR.A significant welfare concern for those within the horse industry is that of the overpopulation in free-roaming horses in the western US. The goal of the present study was to identify a humane and inexpensive means of providing contraception and reducing pregnancy rates in a way that could be applied to free-roaming horses on the western U.S. open range lands. A series of studies was conducted utilizing the previously-described silastic O-ring intrauterine devices (IUDs). Throughout these studies pregnancy was successfully prevented in mares with an O-ring IUD, but collective retention rates f...
Blazyczek I, Hamann H, Ohnesorge B, Deegen E, Distl O.The objective of the present study was to analyse the importance of the influences of the sex, inbreeding coefficient and the additive genetic contribution to the occurrence of guttural pouch tympany in Arabian foals. Horses affected by guttural pouch tympany were ascertained in the Clinic for Horses, School of Veterinary Medicine Hannover. The data comprised 27 Arabian purebred foals with guttural pouch tympany. Of these 27 animals 22 were patients of the Clinic for Horses between 1994 and 2001 and 5 Arabian foals were sampled on the studs. Information on the pedigrees of these patients allow...
Lubow BC, Ransom JI.Reliably estimating wildlife abundance is fundamental to effective management. Aerial surveys are one of the only spatially robust tools for estimating large mammal populations, but statistical sampling methods are required to address detection biases that affect accuracy and precision of the estimates. Although various methods for correcting aerial survey bias are employed on large mammal species around the world, these have rarely been rigorously validated. Several populations of feral horses (Equus caballus) in the western United States have been intensively studied, resulting in identifica...
Kaneene JB, Saffell M, Fedewa DJ, Gallagher K, Chaddock HM.The Michigan equine monitoring system (MEMS) was designed and implemented in the State of Michigan, starting in 1991. The program was designed systematically to track the State's equine population, its health, and its economic implications to the equine industry. The MEMS was designed as a two-phase program. Phase I (the population and economic survey; the subject of this paper) was designed to provide new and statistically valid information describing the size, composition, location and economic characteristics of the Michigan equine industry. A standardized questionnaire was used to collect ...
McGree JM, Noble G, Schneiders F, Dunstan AJ, McKinney AR, Boston R, Sillence M.We describe the population pharmacokinetics of an acepromazine (ACP) metabolite (2-(1-hydroxyethyl)promazine) (HEPS) in horses for the estimation of likely detection times in plasma and urine. ACP (30 mg) was administered to 12 horses, and blood and urine samples were taken at frequent intervals for chemical analysis. A bayesian hierarchical model was fitted to describe concentration-time data and cumulative urine amounts for HEPS. The metabolite HEPS was modelled separately from the parent ACP as the half-life of the parent was considerably less than that of the metabolite. The clearance (Cl/...
Cozzi MC, Valiati P, Longeri M, Ferreira C, Abreu Ferreira S.The Lusitano Horse (LH) originates from Portugal, but is reared worldwide. Since 1994, the University of Milan has routinely tested the LHs bred in Italy for parentage control. This study aims to assess the genetic variability of the LH reared in Italy using 16 microsatellites markers. Moreover, the genetic variability changes over the years in the total population (n.384) and in unrelated horses (n.47) were evaluated. Horses were grouped according to their date of birth (1975-1990, 1991-2000, 2001-2010, 2010-2019). Standard genetic diversity parameters, including observed (Ho) and expected (H...
Yamashita J, Oki H, Hasegawa T, Honda T, Nomura T.To investigate the breeding structure in the Japanese Thoroughbred population, we applied a demographic analysis to the populations of foals produced from 1978 to 2005. The migration rate estimated from the proportion of foals produced by imported breeding horses was around 40% over the investigated period. After early 1990s, the migration rate through stallions imported from USA sharply increased. The average generation interval was within range of 10.5-11.5 years. The longer generation interval of Thoroughbred was considered to be a reflection of the fact that Thoroughbred horses begin breed...
Juneja RK, Andersson L, Sandberg K, Gahne B, Adalsteinsson S, Gunnarsson E.Two-dimensional agarose gel (pH 8.6)-horizontal polyacrylamide gel (pH 9.0) electrophoresis of horse serum proteins revealed genetic polymorphism of ceruloplasmin (Cp) and two unidentified serum proteins tentatively designated serum protein 1 (SP1) and serum protein 2 (SP2). Family data were consistent with the hypothesis that the observed Cp and SP1 phenotypes were each controlled by two codominant, autosomal alleles. The three common SP2 phenotypes were shown to be controlled by two codominant, autosomal alleles. Population data and limited family data indicated the occurrence of two additio...
