Stud management involves the systematic and strategic breeding of horses to enhance desirable traits, maintain genetic diversity, and ensure the health and welfare of both mares and stallions. This practice encompasses a range of activities, including the selection of breeding pairs, monitoring of reproductive health, and management of breeding cycles. Key aspects of stud management include assessing genetic compatibility, managing nutrition and health care, and implementing breeding technologies such as artificial insemination or embryo transfer. Effective stud management requires a comprehensive understanding of equine genetics, reproductive physiology, and husbandry practices. This page gathers peer-reviewed research studies and scholarly articles that explore various facets of stud management, including genetic evaluation, reproductive technologies, and the impact of management practices on breeding outcomes.
Gilkerson JR, Whalley JM, Drummer HE, Studdert MJ, Love DN.The prevalence of EHV-1 and EHV-4 antibody-positive horses was determined using a type specific ELISA on serum samples collected from 229 mares and their foals resident on a large Thoroughbred stud farm in the Hunter Valley of New South Wales in February 1995. More than 99% of all mares and foals tested were EHV-4 antibody positive, while the prevalence of EHV-1 antibody positive mares and foals were 26.2 and 11.4%, respectively. Examination of the ELISA absorbance data for the individual mares and foals suggested that the EHV-1 antibody positive foals had been infected recently with EHV-1 and...
Gilkerson JR, Whalley JM, Drummer HE, Studdert MJ, Love DN.Sero-epidemiological studies conducted between 1995 and 1997 on two large Thoroughbred stud farms in the Hunter Valley of NSW showed clear evidence of EHV-1 infection in foals as young as 30 days of age. Similarly, serological evidence suggested that these foals were infected with EHV-1 from their dams or from other lactating mares in the group, with subsequent foal to foal spread of infection prior to weaning. These studies also provided evidence of EHV-1 infection of foals at and subsequent to weaning, with foal to foal spread of EHV-1 amongst the weanlings. These data indicated that the mar...
Gilkerson JR, Love DN, Drummer HE, Studdert MJ, Whalley JM.To investigate the seroprevalence of equine herpesvirus 1 in foals around weaning and after weaning on two large Thoroughbred farms using a type-specific enzyme-linked immunosorbent assay to determine exposure to infection. Methods: A longitudinal population study in groups of Thoroughbred weanling foals. Methods: Two hundred weanling Thoroughbred foals from a population of about 380 foals were enrolled on two adjacent stud farms in the Hunter Valley of New South Wales. Foals on both farms were weaned from February to May 1995 into randomly selected groups of 10 to 15 foals. Farms were selecte...
van Buiten A, Remmen JL, Colenbrander B.In horses reproductive performance is usually expressed as the foaling rate. This rate ranges from 40% to 80%. Three major factors contribute to this variation namely, the stallion, the mare and management. In this study, the performance of Shetland ponies kept in three different breeding systems was investigated retrospectively. In one breeding system, the stud farmer travelled with his stallion (n = 9) to the mare (system 1) while in another system, the stallion (n = 3) stayed at the stud farm and the mares came to the stallion (system 2). The last system was pasture breeding (system 3; n = ...
Höglund J, Nilsson O, Ljungström BL, Hellander J, Lind EO, Uggla A.The egg output and humoral antibody response to scolex antigens of the equine tapeworm Anoplocephala perfoliata were monitored in naturally infected foals by an egg flotation/centrifugation method and an indirect enzyme-linked immunosorbent assay (ELISA). The study was performed on a stud farm in south-western Sweden between May 1994 and April 1995. Sequential blood and faecal samples were taken from 21 foals during their first summer on pasture and until tapeworm eggs were detected. Results were expressed separately for 10 and 11 foals born before and after the end of April 1994, respectively...
van Schaik AM, van der Pol BA, van der Linde-Sipman JS.A healthy, 10-day-old Welsh A pony colt was totally blind 1 day after arrival at a studfarm. Both eyes appeared normal on external inspection. The young animal had been very distressed during the 40-km journey to the studfarm. Intravenous corticosteroids were administered for 2 days, but did not result in any observable improvement. The animal was euthanized at the owner's request. Both eyes with the optic nerves were removed for histological examination. Both optic nerves showed Wallerian degeneration, a well-known response of peripheral nerves to trauma. The foal, which was not tethered duri...
Meier HP, Gertsch U, Kohler S.Twin pregnancies are a serious problem in stud medicine as they terminate in most cases in abortion, stillbirth or the delivery of dead or weak and deformed foals. In recent years, the introduction of sonography has greatly improved the management of mares with twin conceptuses, in particular monitoring the phenomenon of spontaneous embryo reduction to a single vesicle. This allows supervision of pregnancy with relatively little expenditure and loss of time. We document the spontaneous reduction to single vesicles of unilateral twin pregnancies in a draught- and a warmblood-mare. In both mares...
Merkt H.A stallion got fatal injuries by kicks of a maiden mare because a so called "panic hook" untied spontaneously. The use of such hooks to secure mares during mating should therefore not be recommended.
Gawor JJ.Autopsies and analyses of faecal samples from working horses have shown common occurrence of ascarids in foals, whereas 19.6% of adult horses have been found infected. No influence of season on EPG in adult horses has been found. Study based on faecal samples from stud horses has shown that 5-6-month old animals were most susceptible to the infection. 50% of foals have been found infected in spite of deworming with the use of bezimidazole compounds. It has been stated that the proper dose of an anthelminthic is a basic problem in the control of ascarids.
Allen WR, Mathias S, Lennard SN, Greenwood RE.Rapid enzyme-based immunoassays were used to measure concentrations of oestradiol-17 beta and progesterone in daily blood samples recovered throughout oestrus and for a few days after ovulation from 34 Thoroughbred and 8 pony-type maiden, barren and foaling mares. The first detectable fall in oestradiol-17 beta levels occurred in 88% of the mares within the interval -72 to 0 h with respect to ovulation and in 65% of mares within the interval of -48 to 0 h. The results indicated that serial daily hormone assays of this type could, in a high proportion of animals, predict a correct time for a si...
Egri B, Sárközy P, Bánhidy G.From 14 to 17 April 1990 and from 12 to 21 May 1993 a total of 136 Caucasian (Donish, Karabakh, Kabardin, local halfbred) and 26 thoroughbred stud-horses were examined for ectoparasites in studs of Stawropol County, Russia. A total of 4054 botfly larvae were identified from 9700 faecal samples collected during a period of 3-4 days after oral treatment with Eqvalan (MSD), Strongid Plus (Pfizer) and Vermitan Plus (Sanofi-Chinoin). The species distribution was: Gasterophilus intestinalis 84.53%, G. nasalis 10.41%, G. haemorrhoidalis 3.62%, G. inermis 1.41%. Gasterophilus nasalis and G. inermis ha...
The Journal of heredityMay 1, 1994
Volume 85, Issue 3 222-224 doi: 10.1093/oxfordjournals.jhered.a111439
Bowling AT.Analysis of selected studbook records of the American Paint Horse Association, consisting of 687 foals sired by 13 overo stallions from non-overo mares, supports the inheritance of overo spotting as an autosomal dominant gene. More than one gene may control patterns registered as overo. Additional studies are necessary to explain the sporadic occurrence of overo spotting from nonspotted quarter horse parents and to confirm the inheritance of overo spotting in other breeds.
Tekin N, Yurdaydin N, Klug E, Daskin A, Keskin O, Kücük H.Within a German-Turkish university partnership deep freezing preservation of stallion semen was performed as a part project of the cooperation contract. In this study a modification of the introduced Makrotüb method was used for semen freezing. The investigated characteristics of fresh semen of the Arab stallions were in the normal range cited in the international literature. However, the semen data obtained from the Haflinger stallions were markedly and partially significantly in lower range than measured for the Arab stallions. This may reflect an incomplete adaptation process of the import...
Yurdaydin N, Tekin N, Gülyüz F, Aksu A, Klug E.An Arab broodmare herd of 30 mares age ranging from 4 to 12 years was grouped into 3 groups (group A, B, C) with 10 mares each and exposed to three different methods of cycle synchronisation. Group A mares received two PGF2 alpha injections 14 days apart. Group B mares got additionally 2,500 IU of hCG 5 days after second prostaglandin application. Group C consisted of mares which had foaled in a synchrony of one week and got a PGF2 alpha injection 3 weeks after parturition. All the mares responding to synchronisation were inseminated closely to ovulation detected by serial rectal palpations wi...
Brück I, Anderson GA, Hyland JH.The records of 1630 mare years from 6 Thoroughbred stud farms in south eastern Australia were analysed for the years 1981 to 1986. Overall pregnancy and foaling rates were 83.9% and 69.3%, respectively. When calculated per served oestrous cycle, pregnancy and foaling rates were 54.7% and 43.1%, respectively. Pregnancy and foaling rates were higher (P < 0.001) for mares 3 to 10 years of age than for older mares. There was no difference in the pregnancy rates of maiden, barren and foaling mares. The foaling rate was significantly higher (P < 0.001) in mares that became pregnant during the ...
Van Wyk JA, Van Wijk EF.This paper is apparently the first report of resistance of helminths of equids to anthelmintics in South Africa. While a strain of Cyathostominae from an Arab horse stud near Pretoria showed greatly reduced susceptibility to benzimidazoles in faecal egg reduction tests, ivermectin was apparently still unaffected. It is suggested that integrated methods of control such as alternation of horses and ruminants on pasture and mechanical removal of faeces should be used in addition to anthelmintics.
O'Donohue DD, Smith FH, Strickland KL.A two part survey was carried out in Irish Thoroughbred horses in 1988 and 1989 to establish the incidence and prevalence of developmental skeletal problems, particularly possible manifestations of developmental orthopaedic disease (DOD). Survey One was a retrospective study based on a questionnaire involving the foal crops of 46 stud farms for 3 successive seasons; the 1711 animals initially documented represented 10.46% of Irish foal registrations. The second survey involved repeated monitoring of the 1988 foal crop from birth to 18 months of age on 17 stud farms. The 248 foals initially exa...
Martin RG, McMeniman NP, Dowsett KF.Intakes of milk and milk nutrients were determined for 8 foals at 11-18 days of age and for 10 foals at 30-44 days and 60-74 days of age while sucking grazing mares. Water intakes (sources other than milk) of the foals were determined at 30-44 days and 60-74 days of age. Five of the 10 mares were fed a protein supplement (24% crude protein) in addition to grazing during the stud season. The protein supplement did not influence foal intakes of milk and milk nutrients, milk composition, weight gains of the mares or the growth rate of the foals. Foal milk intakes increased (P less than 0.05) from...
Nowotny N, Bürki F.Three cases of abortions were diagnosed as caused by Equine Arteritis Virus (EAV) by isolation and typing of this virus from the respective fetuses. All 3 abortions were single cases, one occurring on a stud with Iceland Ponies, one with Warmbloods, one with Lipizzaner horses. On each stud horses of the respective breed were kept exclusively, therefore there existed no epidemiologic link. By means of seroneutralization tests performed on in contact horses it could be shown, that EAV had only been introduced recently into the stud with the Iceland Ponies. An extraneous mare stabled temporarily ...
Höglund J, Nilsson O, Ljungström BL, Hellander J, Lind EO, Uggla A.The egg output and humoral antibody response to scolex antigens of the equine tapeworm Anoplocephala perfoliata were monitored in naturally infected foals by an egg flotation/centrifugation method and an indirect enzyme-linked immunosorbent assay (ELISA). The study was performed on a stud farm in south-western Sweden between May 1994 and April 1995. Sequential blood and faecal samples were taken from 21 foals during their first summer on pasture and until tapeworm eggs were detected. Results were expressed separately for 10 and 11 foals born before and after the end of April 1994, respectively...
Salem SE, Sinnott A, Roach JM, Verheyen KLP, de Mestre AM.Multiple pregnancies (MPs) are commonly diagnosed during breeding management of mares. Whilst some studies have reported on factors associated with the risk of MPs, few have utilised multivariable data analysis to control for confounding variables. A prospective cohort study of Thoroughbred broodmares was conducted with information collected on 27 factors. Mixed-effects logistic regression was used to determine risk factors for MPs. Mare, stallion, stud, and veterinarian were evaluated as random effects. The prevalence of MPs in 1754 mares and 2245 pregnancies was 16.06% (95% confidence interv...
Schulman ML, Marlow CH, Nurton JP.The data and an analysis of the statistical summaries from the 'Return of Mares' of the General Stud Book of The Jockey Club of Southern Africa from 1975-1999 are presented. The total number of mares covered per season ranged from 7393 (1992) to 5180 (1995). The total living produce in the period surveyed was 95 317 foals. The categories of data examined include: the total number of mares covered per season; the total numbers and percentage of their living produce; the total numbers and percentage dead produce, 'slips' and foals born dead, barren and 'no return' mares; and the total number of ...
Mouncey R, Arango-Sabogal JC, de Mestre AM, Verheyen KL.Up-to-date estimates of early-life morbidity and mortality in Thoroughbreds are lacking. Methods: A birth cohort was established on Thoroughbred stud farms across the UK and Ireland. All veterinary interventions for disease or injury between birth and 18 months of age or leaving the study were recorded. Multilevel Poisson regression models with farm and foal as random effects were fitted to estimate incidence rates. Results: Data were available for 3328 foal-months at risk for 275 foals on seven farms. The overall rates of disease and injury requiring veterinary intervention and mortality were...
Malmgren L.The storage and transport of cooled, liquid semen is an effective way of facilitating the use of desirable stallions for breeding mares located on distant farms. The Equitainer System is the most widely used transport container and it has been shown that it is possible to ship semen in this container and obtain good conception rates. However, the cost of Equitainers is high, and stud-farms that ship large quantities of semen have tended to rely on cheaper alternatives, even though little documentation exists concerning their reliability, especially under extreme temperature conditions. Two dif...
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...
Dărăbuş G, Badea C, Oprescu I, Morariu S, Mederle N, Ilie M, Suici T, Imre M.Resistance of cyathostomins to benzimidazole (BZ) anthelmintics is widespread in horses in many parts of the world. This study compared three methods for the determination of benzimidazole resistance of Cyathostominae in 18 horses from a stud farm in Romania. The horses were treated with Fenbendazole. The resistance test was performed by FECRT, ERP and PCR. On Day 0, larvae of species belonging to the Cyathostominae subfamily, types A, B, C, D and Gyalocephalus, as well as Strongylus vulgaris species of the Strongylinae subfamily, were identified. At 42 days post treatment with fenbendazole on...
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...
Lowis TC, Hyland JH.This project surveys the reproductive performance of 154 foaling Thoroughbred mares on a commercial stud in southern Victoria. Of these, 96 were served on foal heat (FHS) and 58 were served at a subsequent prostaglandin-induced oestrus (PGS). The PGS group of mares performed more favourably in all aspects except the foaling-to-conception interval where there was a 9.4 day advantage to the FHS group. The first service conception rate in the FHS group was 47.9% compared with 55.2% in PGS mares. Second heat period conception rates were 46% vs 57.7% for FHS and PGS mares, respectively. Overall con...
Praud A, Dufour B, Robert C, Valette JP, Denoix JM, Crevier-Denoix N.Several studies have demonstrated a statistical association between management practices and juvenile osteochondral conditions (JOCC) in foals from birth to 6months of age, but this association has not been investigated in yearlings. The purpose of the current study was to determine the adjusted effects of management practices on the onset and evolution of JOCC in French yearlings. The study sample consisted of 259 yearlings born on 20 stud farms in Normandy. The breeding conditions of these horses were monitored from 6 to 17months. They were radiographed at 6 and 17months to determine their r...
Lepeule J, Seegers H, Rondeau V, Robert C, Denoix JM, Bareille N.Developmental Orthopaedic Disease (DOD) in limb joints is frequent, can cause lameness and is a major cause of economic losses for the horse breeding industry. Studies on risk factors for DOD usually dichotomise the outcome to presence/absence without considering the extent of the disease, which can be appreciated by the number or the severity of the lesions. The aim of this study was to assess the effects of growth, exercise conditions and feeding practices on the number of radiographic findings (RF) of DOD in a cohort of horses, assuming that the risk factors associated with the presence of ...
Stoneham SJ, Digby NJ, Ricketts SW.The importance of colostrum for the passive transfer of maternal immunity to foals is well recognised. This survey reports the incidence of the failure of passive transfer of colostral immunity in thoroughbred foals in the United Kingdom during 1988 to 1990, and the effect of plasma transfusions on IgG levels in a group of them. The incidence of disease in these foals first month of life is also recorded.
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...
Tanner JC, Barrell GK.Despite being a large commercial breeding industry, there is little published data on the reproductive success of Standardbred mares. Objective: To quantify the reproductive performance of Standardbred mares under artificial breeding systems in a commercial setting and determine the incidence of early embryonic and other pre-partum losses. Methods: Retrospective cohort study. Methods: Data from four commercial farms were collected across four breeding years, and all mares were bred via artificial insemination. A total of 3995 mares contributed 7229 mare years. First-cycle pregnancy rate (FCPR)...
Ainsworth CG, Hyland JH.Continuous infusion of gonadotrophin releasing hormone (GnRH) has been shown to induce oestrus and ovulation in experimental mares in seasonal anoestrus. The present study sought to apply this form of treatment to anoestrous mares subjected to normal management procedures on 15 commercial Thoroughbred studfarms in Australia. The GnRH was delivered via subcutaneously implanted osmotic minipumps (OMP) at dose rates of 100 ng/kg/h and 200 ng/kg/h. The ovaries of treated mares were palpated on the day of OMP insertion (Day 0) and blood samples were collected twice weekly from a proportion of mares...
Noue P, Bernabé J, Rampin O, Vidament M, Dumas T, Palmer E, Magistrini M.The sexual behavior of 42 stallions from French national and private studs was examined in two contexts: semen collection for artificial insemination (AI) and in-hand natural service (NS). Each stallion was observed twice in the same context. Erection and ejaculation latencies, the number of mounts leading to ejaculation, dismount latency and total breeding time were measured and compared between AI and NS. Mount without erection was rare (6/83 observations). Erection latency was 89+/-11s, and was not different between NS (62+/-22s) and AI (100+/-13s, P=0.128). Stallions ejaculated after eithe...
Ewert M, Böröcz J, Uphaus H, Oldenhof H, Distl O, Sieme H.The aim of this study was to evaluate factors affecting pregnancy rates in the German Thoroughbred Breed with particular emphasis on optimisation of fertility rates for breeding stallions of older ages. Methods: Data from the studbooks of the German Thoroughbred Breeding Association from 1996 to 2009 analysed. This analysis included the records of 319 stallions and 6622 brood mares, resulting in 21,372 pregnancies at the end of the season. Results: Pregnancy rates were significantly affected by the age of the stallion and mare as well as the season (month in the breeding season in which coveri...
Fawcett JA, Innan H, Tsuchiya T, Sato F.Many studies have reported that advancing age in broodmares has a negative impact on the reproductive performance of horses. However, although the ages at first and last mating vary among broodmares, it is unknown how this variation affects the correlation between age and reproductive performance in mares. Here, in order to examine the effects of the ages at first and last mating, we analyzed all recorded mating events for Thoroughbreds in Japan from 1997 to 2017. We found that the live foal birth rate of mares with a younger age at first mating indeed declined at an earlier age than those wit...
Gilkerson JR, Love DN, Drummer HE, Studdert MJ, Whalley JM.To investigate the seroprevalence of equine herpesvirus 1 in foals around weaning and after weaning on two large Thoroughbred farms using a type-specific enzyme-linked immunosorbent assay to determine exposure to infection. Methods: A longitudinal population study in groups of Thoroughbred weanling foals. Methods: Two hundred weanling Thoroughbred foals from a population of about 380 foals were enrolled on two adjacent stud farms in the Hunter Valley of New South Wales. Foals on both farms were weaned from February to May 1995 into randomly selected groups of 10 to 15 foals. Farms were selecte...
Steensma MJ, Doekes HP, Pook T, Derks MFL, Bakker N, Ducro BJ.In the past, small population sizes and unequal ancestor contributions have resulted in high inbreeding rates (ΔF) in the Friesian horse. Two decades ago, the studbook implemented a mating quota and started publishing individual kinships and reduced ΔF below 1% per generation. However, since then, the breeding population size has decreased and this raises the question whether current breeding strategies are sufficient to keep ΔF below desired rates. The aim of this study was to (1) reflect on past inbreeding trends and their main determinants, using pedigree analysis and (2) evaluate the ef...
Sullivan JJ, Pickett BW.Approximately 1 week was required to stabilize the extragonadal sperm reserves in stallions ejaculated daily for 10 weeks. The true daily sperm output of a stallion was equal to the mean daily sperm output of seven ejaculates +/- 1-35 X 10(9) spermatozoa. Mean concentrations of spermatozoa/ml and number of spermatozoa/ejaculate were higher (P less than 0-01) for X1 and X3/week ejaculation frequencies than for a X6/week frequency. Sperm output/week was nearly identical for a X6/week frequency. Sperm output/week was nearly identical for the X3 and X6 frequencies and higher (P less than 0-01) tha...
