Feral horses, also known as free-roaming or wild horses, are equines that live in natural environments without direct human management. They are descendants of domesticated horses that have adapted to living in the wild over generations. These populations are found in various regions worldwide and exhibit behaviors and social structures distinct from domesticated horses. In contrast, domesticated horses are bred and raised under human care, often for specific purposes such as work, recreation, or sport. The study of feral horses involves understanding their ecology, behavior, and genetics, while research on domesticated horses often focuses on health, management, and performance. This page compiles peer-reviewed research studies and scholarly articles that explore the differences and similarities between feral and domesticated horses, including their behavior, physiology, and impact on ecosystems.
Lippold S, Matzke NJ, Reissmann M, Hofreiter M.DNA target enrichment by micro-array capture combined with high throughput sequencing technologies provides the possibility to obtain large amounts of sequence data (e.g. whole mitochondrial DNA genomes) from multiple individuals at relatively low costs. Previously, whole mitochondrial genome data for domestic horses (Equus caballus) were limited to only a few specimens and only short parts of the mtDNA genome (especially the hypervariable region) were investigated for larger sample sets. Results: In this study we investigated whole mitochondrial genomes of 59 domestic horses from 44 breeds an...
Pruvost M, Bellone R, Benecke N, Sandoval-Castellanos E, Cieslak M, Kuznetsova T, Morales-Muñiz A, O'Connor T, Reissmann M, Hofreiter M, Ludwig A.Archaeologists often argue whether Paleolithic works of art, cave paintings in particular, constitute reflections of the natural environment of humans at the time. They also debate the extent to which these paintings actually contain creative artistic expression, reflect the phenotypic variation of the surrounding environment, or focus on rare phenotypes. The famous paintings "The Dappled Horses of Pech-Merle," depicting spotted horses on the walls of a cave in Pech-Merle, France, date back ~25,000 y, but the coat pattern portrayed in these paintings is remarkably similar to a pattern known as...
Hampson BA, Owens E, Watts KA, Mills PC, Pollitt CC, de Laat MA.To determine the impact of a free-choice diet on nutritional intake and body condition of feral horses. Methods: Cadavers of 41 feral horses from 5 Australian locations. Methods: Body condition score (BCS) was determined (scale of 1 to 9), and the stomach was removed from horses during postmortem examination. Stomach contents were analyzed for nutritional variables and macroelement and microelement concentrations. Data were compared among the locations and also compared with recommended daily intakes for horses. Results: Mean BCS varied by location; all horses were judged to be moderately thin...
Gilchrist P, Sergeant ES.Australia has the world's largest population of wild equids and equine influenza (EI) was confirmed on several properties in New South Wales (NSW) close to uncontrolled areas of land during the 2007 outbreak. Likelihood and risk management assessments were carried out to determine the risk of EI infection of the wild horse populations. The likelihood of spread to the wild horse population was determined to be extremely low, but the likelihood of spread from an established wild horse reservoir back to domestic horses was considered high. The most effective mechanism of control was determined to...
Hampson BA, de Laat MA, Mills PC, Pollitt CC.To investigate the density of the primary epidermal lamellae (PEL) around the solar circumference of the forefeet of near-term fetal feral and nonferal (ie, domesticated) horses. Methods: Left forefeet from near-term Australian feral (n = 14) and domesticated (4) horse fetuses. Methods: Near-term feral horse fetuses were obtained from culled mares within 10 minutes of death; fetuses that had died in utero 2 weeks prior to anticipated birth date and were delivered from live Thoroughbred mares were also obtained. Following disarticulation at the carpus, the left forefoot of each fetus was frozen...
Seyfarth RM, Cheney DL.Convergent evidence from many species reveals the evolutionary origins of human friendship. In horses, elephants, hyenas, dolphins, monkeys, and chimpanzees, some individuals form friendships that last for years. Bonds occur among females, among males, or between males and females. Genetic relatedness affects friendships. In species where males disperse, friendships are more likely among females. If females disperse, friendships are more likely among males. Not all friendships, however, depend on kinship; many are formed between unrelated individuals. Friendships often involve cooperative inte...
Hampson BA, Connelley AD, de Laat MA, Mills PC, Pollitt CC.To determine solar load-bearing structures in the feet of feral horses and investigate morphological characteristics of the sole in feral horses and domestic Thoroughbreds. Methods: Forelimbs from cadavers of 70 feral horses and 20 domestic Thoroughbreds in Australia. Methods: Left forefeet were obtained from 3 feral horse populations from habitats of soft substrate (SS [n = 10 horses]), hard substrate (HS [10]), and a combination of SS and HS (10) and loaded in vitro. Pressure distribution was measured with a pressure plate. Sole depth was measured at 12 points across the solar plane in feet ...
Hampson BA, de Laat MA, Mills PC, Pollitt CC.The distance travelled by Australian feral horses in an unrestricted environment has not previously been determined. It is important to investigate horse movement in wilderness environments to establish baseline data against which the movement of domestically managed horses and wild equids can be compared. Objective: To determine the travel dynamics of 2 groups of feral horses in unrestricted but different wilderness environments. Methods: Twelve feral horses living in 2 wilderness environments (2000 vs. 20,000 km(2)) in outback Australia were tracked for 6.5 consecutive days using custom desi...
Conant EK, Juras R, Cothran EG.The domestic horse (Equus caballus) was re-introduced to the Americas by Spanish explorers. Although horses from other parts of Europe were subsequently introduced, some New World populations maintain characteristics ascribed to their Spanish heritage. The southeastern United States has a history of Spanish invasion and settlement, and this influence on local feral horse populations includes two feral-recaptured breeds: the Florida Cracker and the Marsh Tacky, both of which are classified as Colonial Spanish horses. The feral Banker horses found on islands off the coast of North Carolina, whic...
Kirkpatrick JF, Lyda RO, Frank KM.Wildlife, free-ranging and captive, poses and causes serious population problems not unlike those encountered with human overpopulation. Traditional lethal control programs, however, are not always legal, wise, safe, or publicly acceptable; thus, alternative approaches are necessary. Immunocontraception of free-ranging wildlife has reached the management level, with success across a large variety of species. Thus far, the immunocontraceptive research and management applications emphasis have been centered on porcine zona pellucida and gonadotropin-releasing hormone vaccines. Contraceptive succ...
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...
Franson JC, Hofmeister EK, Collins GH, Dusek RJ.We screened 1,397 feral horses (Equus caballus) on Sheldon National Wildlife Refuge, Nevada, United States, for IgM and IgG against flavivirus during 2004-2006, 2008, and 2009. Positive serum samples were tested for neutralizing antibodies to West Nile virus (WNV) and St. Louis encephalitis virus (SLEV). One animal was positive for antibody against WNV in 2004, but all others tested in 2004-2006 were negative. In 2008 and 2009, we found evidence of increasing seropositive horses with age, whereas seroprevalence of WNV decreased from 19% in 2008 to 7.2% in 2009. No horses were positive for anti...
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...
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...
Opałka M, Kamińska B, Jaworski Z.Blood and feces samples were collected from Polish Konik stallions kept under conventional stable conditions and in the forest reserve during a 1-year study period. Levels of testosterone (T) and androstenedione (A(4)) were measured using radioimmunoassay. Positive correlation between fecal and plasma concentrations of androgens was observed. Fecal T concentrations increased in April and May reaching peak value mid-April in the stallions from the reserve group and 2 weeks later in the stallions from the stable group. Comparatively, concentrations of T were higher in the stable group. Levels of...
Hampson BA, Morton JM, Mills PC, Trotter MG, Lamb DW, Pollitt CC.The aims of this work were to (1) develop a low-cost equine movement tracking collar based on readily available components, (2) conduct preliminary studies assessing the effects of both paddock size and internal fence design on the movements of domestic horses, with and without foals at foot, and (3) describe distances moved by mares and their foals. Additional monitoring of free-ranging feral horses was conducted to allow preliminary comparisons with the movement of confined domestic horses. Methods: A lightweight global positioning system (GPS) data logger modified from a personal/vehicle tr...
Hampson BA, Ramsey G, Macintosh AM, Mills PC, de Laat MA, Pollitt CC.The present study investigated the foot health of the Kaimanawa feral horse population and tested the hypotheses that horses would have a large range of foot morphology and that the incidence of foot abnormality would be significantly high. Methods: Abnormality was defined as a variation from what the two veterinarian assessors considered as optimal morphology and which was considered to impact negatively on the structure and/or function of the foot. Fifteen morphometric variables were measured on four calibrated photographic views of all four feet of 20 adult Kaimanawa feral horses. Four morp...
Michalski G, Earman S, Dahman C, Hershey RL, Mihevc T.Multiple stable isotope analysis can be a powerful technique in forensic sciences. Oxygen and nitrogen isotopes were used to determine the source of nitrate that was responsible for the poisoning deaths of 71 wild horses in the Nevada desert. The nitrate was present in a water-filled hole known as 'the Main Lake depression.' Nitrate from the Main Lake depression had delta(18)O and delta(15)N values that were very positive (+32 per thousand, +37 per thousand), and Delta(17)O values of approximately +2 per thousand. The isotopic data suggested that the most probable source of the nitrate was nit...
Ostermann-Kelm SD, Atwill EA, Rubin ES, Hendrickson LE, Boyce WM.Free-ranging horses (Equus caballus) in North America are considered to be feral animals since they are descendents of non-native domestic horses introduced to the continent. We conducted a study in a southern California desert to understand how feral horse movements and horse feces impacted this arid ecosystem. We evaluated five parameters susceptible to horse trampling: soil strength, vegetation cover, percent of nonnative vegetation, plant species diversity, and macroinvertebrate abundance. We also tested whether or not plant cover and species diversity were affected by the presence of hors...
Khalil AM, Nakahara K, Tokuriki M, Kaseda Y, Murakami N.On Misaki peninsula, Japan, fecal samples were collected from 14 Misaki stallions at monthly intervals for 12 consecutive months. The fecal testosterone concentration was measured by radioimmunoassay. We examined monthly fecal testosterone hormone patterns and the relationship between fecal testosterone concentration and breeding season and later harem size. Marked monthly variations in fecal testosterone concentration were observed. The fecal testosterone concentration began rising in March; the highest mean monthly concentration, 2.87 +/- 0.18 ng/g, was found in April, and the level remained...
Cameron EZ, Setsaas TH, Linklater WL.In many mammals, females form close social bonds with members of their group, usually between kin. Studies of social bonds and their fitness benefits have not been investigated outside primates, and are confounded by the relatedness between individuals in primate groups. Bonds may arise from kin selection and inclusive fitness rather than through direct benefits of association. However, female equids live in long-term social groups with unrelated members. We present 4 years of behavioral data, which demonstrate that social integration between unrelated females increases both foal birth rates a...
Ludwig A, Pruvost M, Reissmann M, Benecke N, Brockmann GA, Castaños P, Cieslak M, Lippold S, Llorente L, Malaspinas AS, Slatkin M, Hofreiter M.The transformation of wild animals into domestic ones available for human nutrition was a key prerequisite for modern human societies. However, no other domestic species has had such a substantial impact on the warfare, transportation, and communication capabilities of human societies as the horse. Here, we show that the analysis of ancient DNA targeting nuclear genes responsible for coat coloration allows us to shed light on the timing and place of horse domestication. We conclude that it is unlikely that horse domestication substantially predates the occurrence of coat color variation, which...
Durham AE.Nutritional intolerances manifesting as colic in the horse may be largely explained by divergence from the diet and ingestive behaviors to which the feral ancestors of modern domesticated equids had become accustomed and adapted. High-starch diets and abrupt dietary changes are probably foremost in the risk factors for diet-associated colic in the horse and have their basis in disruption of the stability of microbial populations resident within the equine hindgut. Although some general associations between colic and diet may be inferred from several epidemiologic studies, data derived from stu...
Bourjade M, de Boyer des Roches A, Hausberger M.Adults play an important role in regulating the social behaviour of young individuals. However, a few pioneer studies suggest that, more than the mere presence of adults, their proportions in social groups affect the social development of young. Here, we hypothesized that aggression rates and social cohesion were correlated to adult-young ratios. Our biological model was naturally-formed groups of Przewalski horses, Equus f. przewalskii, varying in composition. Results: We investigated the social interactions and spatial relationships of 12 one- and two-year-old Przewalski horses belonging to ...
Grange S, Duncan P, Gaillard JM.We investigated density dependence on the demographic parameters of a population of Camargue horses (Equus caballus), individually monitored and unmanaged for eight years. We also analysed the contributions of individual demographic parameters to changes in the population growth rates. The decrease in resources caused a loss of body condition. Adult male survival was not affected, but the survival of foals and adult females decreased with increasing density. Prime-aged females maintained high reproductive performance at high density, and their survival decreased. The higher survival of adult m...
Seal US, Siniff DB, Tester JR, Williams TD.Combinations of etorphine hydrochloride and xylazine hydrochloride in different dosages were tested for their efficacy as immobilizing agents on 16 recently captured feral mares in corrals. The results of these trials led to the utilization of a standard combination of 5.5 mg of etorphine hydrochloride, 150 mg of xylazine hydrochloride, and 3 mg of atropine sulfate in a 7-ml dart syringe for field capture. This combination was used, administered by dart gun from helicopters, to capture 87 free-ranging feral horses from about 80 bands. Five mares died at the time of capture and the remains of t...
Sneddon JC, van der Walt JG, Mitchell G.This study set out to investigate tolerance of the body water pool to short-term water deprivation in horses and, in particular, to assess whether feral horses from the Namib Desert showed tolerance to dehydration superior to Transvaal. Hydration status was compared in six feral horses from the Namib Desert and in six Boerperd farm horses under conditions of normal hydration and after 72 h of dehydration. Under normal hydration, the two groups did not differ significantly in water intake, plasma sodium and potassium concentrations, plasma osmolality, hematocrit, total plasma protein, body wate...
De Stoppelaire GH, Gillespie TW, Brock JC, Tobin GA.The effects of grazing by feral horses on vegetation and dune topography at Assateague Island National Seashore were investigated using color-infrared imagery, lidar surveys, and field measurements. Five pairs of fenced and unfenced plots (300 m2) established in 1993 on sand flats and small dunes with similar elevation, topography, and vegetation cover were used for this study. Color-infrared imagery from 1998 and field measurements from 2001 indicated that there was a significant difference in vegetation cover between the fenced and unfenced plot-pairs over the study period. Fenced plots cont...
Lucas Z, Raeside JI, Betteridge KJ.Field observations of 400 totally unmanaged feral horses on Sable Island, Nova Scotia, were complemented by oestrogen determinations in faecal samples from 154 identified females over a 4-year period (454 mare-years). Of mares that were sampled throughout the year and subsequently produced foals, 92.1% exhibited elevated faecal oestrogens between 15 October and 30 March. The results confirm that faecal oestrogens are a useful indicator of pregnancy after approximately 120 days gestation. Distribution of foaling resembled that seen in other feral populations, with 95% of births occurring from A...
Mask TA, Schoenecker KA, Kane AJ, Ransom JI, Bruemmer JE.Immunocontraception with porcine ZP (pZP) can be an effective means of fertility control in feral horses. Previous studies suggest that antibodies produced after pZP vaccination may both inhibit fertilization and cause follicular dysgenesis. Zonastat-H, PZP-22, and SpayVac are three pZP vaccines proposed for use in horses. Although all these vaccines contain the pZP antigen, variations in antigen preparation and vaccine formulation lead to differences in antigenic properties among them. Likewise, despite numerous efficacy and safety studies of Zonastat-H and PZP-22, the contraceptive mechanism...
Aurich C, Kaps M.The behaviour of mares is often detrimental to their performance resulting in frequent demand for methods to suppress gonadal function. In addition, prevention of unintended reproduction especially in feral horse populations may require methods for suppression of gonadal function. Surgical ovariectomy is a safe method but not an acceptable approach in feral mares and undesired in mares where future breeding is considered. There are different approaches for artificial prolongation of the luteal phase resulting in transient inhibition of oestrus and ovulation. Among those, treatment with natural...
Franson JC, Hofmeister EK, Collins GH, Dusek RJ.We screened 1,397 feral horses (Equus caballus) on Sheldon National Wildlife Refuge, Nevada, United States, for IgM and IgG against flavivirus during 2004-2006, 2008, and 2009. Positive serum samples were tested for neutralizing antibodies to West Nile virus (WNV) and St. Louis encephalitis virus (SLEV). One animal was positive for antibody against WNV in 2004, but all others tested in 2004-2006 were negative. In 2008 and 2009, we found evidence of increasing seropositive horses with age, whereas seroprevalence of WNV decreased from 19% in 2008 to 7.2% in 2009. No horses were positive for anti...
Bowling AT, Gordon L, Penedo MC, Wictum E, Beebout J.We describe a method for agarose IEF under acid conditions in which a single gel can be used to diagnose from equine red cell lysates genetic variants for carbonic anhydrase (CA) and catalase (Cat). Family and population data for 4801 horses of 27 breeds and seven trap sites of Great Basin feral horses are presented to support the presence of a sixth CA allele, CAE, which has been recognized previously, but not described by published data. Allelic frequencies for the two systems suggest it may be appropriate to use this gel for parentage verification programmes or to obtain population data for...
Turner JW, Liu IK, Flanagan DR, Bynum KS, Rutberg AT.Porcine zona pellucida (PZP) immunocontraception was investigated for possible use in free-roaming wild horses in the western USA. A protocol of two injections (3-4 weeks apart) of vaccine lasting 1 year was first used and a single-injection controlled-release vaccine of 1 year duration was developed and tested in the field. Studies of a presumptive vaccine of 2 year duration were initiated. The parameters of anti-PZP antibody titre response, pregnancy testing and offspring production were used, and PZP vaccine was found to provide up to 94% infertility in free-roaming wild mares. In addition,...
St-Pierre B, de la Fuente G, O'Neill S, Wright AD, Al Jassim R.We investigated the community structure of bacteria that populate the stomach of the Brumby, a breed of feral horses from the Australian outback. Using a 16S rRNA gene clone library, we identified 155 clones that were assigned to 26 OTUs based on a 99.0 % sequence identity cutoff. Two OTUs represented 73.5 % of clones, while 18 OTUs were each assigned only a single clone. Four major bacterial types were identified in the Brumby stomach: Lactobacillaceae, Streptococcaceae, Veillonellaceae and Pasteurellaceae. The first three groups, which represented 98.1 % of the Brumby stomach library clones,...
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...
Medill SA, Janz DM, McLoughlin PD.Cortisol is a glucocorticoid hormone produced during activation of the hypothalamic-pituitary-adrenal axis (HPA) in response to psychological or physiological demands. High amounts of circulating cortisol can be found in individuals experiencing energetically demanding physiological events, such as pregnancy, lactation, injury, or starvation, but, also, in individuals who may have less obvious HPA activation from social situations. The feral horse population on Sable Island (Nova Scotia, Canada) provides an opportunity to look at hair cortisol concentration (HCC) as a proxy for circulating cor...
Wiesner H, von Hegel G.Successful immobilisation of Przewalski's horses and zebras was obtained by using a combination of STH 2130 (Boehringer) and Tiletamin/Zolazepam.
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...
Plotka ED, Seal US, Eagle TC, Asa CS, Tester JR, Siniff DB.Forty-eight newly captured free-ranging feral stallions (Equus caballus) from two different locations and six captive stallions were immobilized using combinations of etorphine hydrochloride, xylazine hydrochloride and atropine sulfate with or without acepromazine. Six animals were immobilized twice, 1 mo apart. The drugs were administered either intramuscularly (n = 13) or intravenously (n = 44). Mean immobilization time (+/- SE) after intravenous (i.v.) injection of etorphine, xylazine and atropine was 55 +/- 4 sec (range 20 to 185 sec) compared to 708 +/- 131 sec (range 390 to 1,140 sec) fo...
Hampson BA, de Laat MA, Mills PC, Pollitt CC.To investigate the density of the primary epidermal lamellae (PEL) around the solar circumference of the forefeet of near-term fetal feral and nonferal (ie, domesticated) horses. Methods: Left forefeet from near-term Australian feral (n = 14) and domesticated (4) horse fetuses. Methods: Near-term feral horse fetuses were obtained from culled mares within 10 minutes of death; fetuses that had died in utero 2 weeks prior to anticipated birth date and were delivered from live Thoroughbred mares were also obtained. Following disarticulation at the carpus, the left forefoot of each fetus was frozen...
Goldstein DM, Engiles JB, Rezabek GB, Ruff CB.The elongated, distally tapered limbs of horses are adapted for high-speed locomotion. Because these traits are artificially selected for in modern racehorses, they operate at a morphological extreme with a high risk of fracture. Racehorses are subject to different training and racing regimes depending on their breed and gait, and are therefore an interesting model to examine bone functional adaptation under variable biomechanically intense conditions. This study compares bone structural properties in the third metacarpal (MCIII) of Thoroughbred (n = 9) and Quarter Horse (n = 11) racehorses, u...
Malacarne BD, Martins RR, Paz CFR, Alves JVA, Dias LA, Cavalcante MA, Santos AM, Silva AGM, Leise BS, Carvalho AM, Faleiros RR.Although the external conformation of wild horse hooves has been proposed as an ideal model for domesticated modern horses, histological signs of laminitis have been reported among them. With the hypothesis that the lamellar tissue of horses of Iberian origin raised in semi-feral is healthier than those raised in an intensive management system (stall confinement and high-calorie diet intake), the objective was to compare their lamellar tissues. Lamellar tissue samples were taken from the forelimb hoof of eight domesticated Mangalarga Marchador (MM) horses and from six semi-feral Marajoara (MJ)...
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...
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...
Kirkpatrick JF, Liu IM, Turner JW, Bernoco M.Twenty-six free-roaming feral mares were immunized against porcine zonae pellucidae (PZP) between February and May, 1988. Eight sexually mature mares received 2 inoculations 2 weeks apart, and 18 mares received 3 inoculations at intervals of 2 and 4 weeks. Analysis of urinary oestrone conjugates (E1C) and non-specific progesterone metabolites (iPdG) in samples collected in October, 1988, revealed that none of the 18 mares that received 3 and only 1 of the 6 mares that received two inoculations were pregnant, whereas 3 of 6 sham-injected control mares and 5 of 11 untreated mares were pregnant. ...
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...
Górecka-Bruzda A, Jaworska J, Siemieniuch M, Jaworski Z, Stanley CR, Wocławek-Potocka I, Lansade L.Equine reproductive behavior is affected by many factors, some remaining poorly understood. This study tested the hypothesis that a period of captivity during the juvenile period and human-controlled reproduction may potentially be involved in the disruption of the development of incestuous mating avoidance behavior in sanctuary-reintroduced male Konik polski horses. Between 1986 and 2000, cases of incestuous behavior in harem stallions born and reared until weaning in the sanctuary were studied. Eight males lived in the sanctuary's feral herd for the rest of their lives (the non-captive group...
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...
