Seasonal variation in horses refers to the physiological and behavioral changes that occur in response to different seasons. These changes can affect various aspects of equine biology, including coat growth, reproductive cycles, and metabolic processes. Horses may exhibit alterations in their feeding patterns, activity levels, and thermoregulation as they adapt to environmental shifts such as temperature fluctuations and daylight length. Understanding these seasonal adaptations is important for managing horse health and welfare. This page aggregates peer-reviewed research studies and scholarly articles that explore the mechanisms, effects, and implications of seasonal variation on equine physiology and behavior.
Viviani P, Ragno VM, Parker S, Montgomery JB.Endocrine disorders in horses, such as pituitary pars intermedia dysfunction and equine metabolic syndrome, rely on hormone testing for diagnosis, but seasonal and regional variabilities highlight the need for locally generated data. Objective: To characterize monthly blood concentrations of ACTH and insulin over 1 year in healthy horses in Saskatchewan. A secondary objective was to assess the association between these outcomes and the following factors: sex, age, breed, pregnancy status, level of exercise, body condition score, and cresty neck score. Methods: Sixty-eight clinically healthy, c...
Wunderlich G, Bull M, McGilchrist N, Zhao C, Ross T, Rose M, Chapman B.The equine gut microbiome is a complex and dynamic ecosystem, housing a diverse consortium of bacteria and anaerobic fungi (AF) capable of breaking down complex plant matter and converting it into vital energy sources for their host. The aim of this study was to broaden our current understanding of bacterial and AF diversity in the equine hindgut and how it differs between cohorts and responds to dietary shifts. Results: Faecal samples were collected from 48 horses and the bacteriome and anaerobic mycobiome analysed using long-read amplicon sequencing. Samples were collected from racehorses (R...
Pinn-Woodcock TL, Llanos-Soto SG, Ivanek R, Goodrich E, Frye E, Wells A, Mullen K, Arbittier E, Hughes L, Berryhill E, Brosnahan P, Buslinger L....To determine whether seasonal variation in equine plasma ACTH concentrations is affected by latitude between 29.7°N and 45.0°N in the US. Unassigned: A cohort study was performed between June 2019 and May 2020 in which plasma ACTH was measured monthly by chemiluminescence immunoassay. The study involved 201 apparently healthy horses from 9 locations within the US classified into northern, central, and southern latitude cohorts. Data analysis was performed with 3 major objectives: (1) identify outlier ACTH concentrations and horses; (2) estimate ACTH upper reference limits to define expected ...
Rabei ȘO, Cârstolovean AS, Culda CA, Mihalca AD.This is the first study that targets the epidemiology of Gasterophilus spp. in slaughtered horses from Romania. Previously to our research, there were five recorded species: Gasterophilus haemorrhoidalis, Gasterophilus inermis, Gasterophilus intestinalis, Gasterophilus nasalis, and Gasterophilus pecorum with a dispersed distribution throughout the country, the data being recorded more than 73 years ago. The collection of Gasterophilus larvae was carried out from the digestive system (stomach, duodenum, and rectum) of horses in three abattoirs, monthly between January 2023 and December 2023. Fo...
Mahmood K, Hassan M, Channa AA, Ghafoor A, Riaz A.The present study aimed to evaluate and compare the overall and breed-specific seasonal breeding patterns, fertility rates, cyclicity, and follicular dynamics of Arab, Thoroughbred, and Percheron mares under the subtropical conditions of Pakistan. Methods: A retrospective analysis of climatic data and breeding records of eleven breeding studs spanning four years (2020-2023) was made to find out the overall seasonality in the breeding pattern of mares. Fifty mares of each breed (n = 150 in total) were scanned by ultrasonography for a calendar year to find the cyclicity pattern and follicular ...
Calomeno SS, Freitas Santi T, Barbosa B, Weber SH, Oliveira TM, Machado GF, Michelotto PV.Horses maintained outdoors may experience a lower-allergenic environment compared to their stabled counterparts. This study hypothesizes that climatic changes in southern Brazil can influence respiratory status. To test this hypothesis, we evaluated the lower airways of 17 horses from a teaching herd in southern Brazil, maintained outdoors, during winter, spring, and summer. Except for one mare with a history of severe asthma, all horses were considered healthy and underwent a physical examination. Airway endoscopic evaluation included scoring for tracheal mucus (0-5) and bronchial septum thic...
Siede C, Komainda M, Tonn B, Wolter SMC, Schmitz A, Isselstein J.Horses can contribute to the maintenance of grassland. To determine the potential contribution of grassland to horse nutrition, we investigated the seasonal variation of herbage on offer and its nutritional quality in an inventory on six practical horse farms in Central Germany during 2019. On all horse-grazed pastures compressed sward height (CSH) was measured monthly and converted into aboveground herbage (AGH) to allocated short and tall grass sward areas (area-specific) via calibration cuts. In addition, four focus pastures were selected for monthly obtained area-specific herbage quality s...
Newcombe JR, Wilsher S, Silva ESM, Sala-Ayala L, Cuervo-Arango J.Two experiments were conducted in the Northern (UK) and Southern (Brazil) hemispheres to determine the effect of season (month of conception) on the development of supplementary CL (SCL) and the relationship with pregnancy loss. In experiment 1, 199 pregnancies were followed between Day 14 and term, to determine the number of SCL and pregnancy viability (Northern Hemisphere). From the 199 pregnancies, 178 were obtained from inseminations during the breeding season (March-September), while the rest, 21 pregnancies resulted from conceptions in the non-breeding season (October to February). Pregn...
Ugulu I, Khan ZI, Ahmad K, Bashir H, Mehmood N, Zafar A.The present study aimed to determine the accumulation levels of arsenic in pasture soil, forage and animals. An atomic absorption spectrophotometer was used to determine the concentration of metals in the samples of soil, forage and blood plasma of horses. The level of arsenic ranged between 4.26 mg/kg (summer) and 4.66 mg/kg (winter) in soil samples and 2.67 mg/kg (summer) and 2.94 mg/kg (winter) in forage samples. In blood plasma samples, the mean arsenic (As) values varied between 1.38 and 1.52 mg/L. In the blood plasma samples, the mean As values varied between 1.38 and 1.52 mg/L. No...
Knowles EJ, Harris PA, Elliott J, Chang YM, Menzies-Gow NJ.Serum insulin concentration at 60 min (InsulinT60) during an oral sugar test (OST) indicates future laminitis risk and insulin dysregulation (ID). Associations between InsulinT60 and physical and owner-reported variables may help clinicians select individuals for ID testing. Associations between InsulinT60 and other metabolic markers may help elucidate ID pathophysiology. Objective: To describe associations between (A) season, physically-apparent and owner-reported factors and binary InsulinT60 interpretation (initial models) and (B) variables included in the initial models, other metabolic ...
Zaitseva S, Dagurova O, Radnagurueva A, Kozlova A, Izotova A, Krylova A, Noskov S, Begmatov S, Patutina E, Barkhutova DD.The Buryatian horse is an ancient breed and, as an indigenous breed, they have unique adaptive abilities to use scarce pastures, graze in winter, and survive in harsh conditions with minimal human care. In this study, fecal microbiota of Buryatian horses grazing in the warm and cold seasons were investigated using NGS technology on the Illumina MiSeq platform. We hypothesized that the composition of microbial communities in the feces of horses maintained on pasture would change in the different seasons, depending on the grass availability and different plant diets. We conducted microhistologic...
Zahradnik E, Sander I, Lotz A, Liebers V, Thullner I, Tacke S, Raulf M.The study aimed to determine the allergen, endotoxin and β-(1,3)-glucan concentrations at various areas on a university campus of veterinary medicine. Methods: Dust samples were collected four times a year for three years using electrostatic dust collectors (EDC) at 25 different locations on a campus of veterinary medicine and in laboratories of inorganic chemistry as a control area representing animal-free environment. Major animal allergens from dog, cat, horse, cattle and mouse, domestic mite (DM) allergens, and β-(1,3)-glucan were measured using enzyme immunoassays and endotoxin using th...
Bamford NJ, Stewart AJ, El-Hage CM, Bertin FR, Bailey SR.Plasma adrenocorticotropic hormone (ACTH) concentration is commonly measured to diagnose pituitary pars intermedia dysfunction (PPID). Several intrinsic and extrinsic factors affect ACTH concentrations, including breed. The objective of this study was to prospectively compare plasma ACTH concentrations among different breeds of mature horses and ponies. Three breed groups comprised Thoroughbred horses (n = 127), Shetland ponies (n = 131) and ponies of non-Shetland breeds (n = 141). Enrolled animals did not show any signs of illness, lameness or clinical signs consistent with PPID. Blood ...
Freitas ML, Viana JHM, Dode MAN, Maggiotto SR, Pivato I, Braga TRC, Lim AIPG, de Oliveira RA.The effects of seasonality on the reproduction of stallions vary based on the latitude. Although previous studies have shown the influence of seasonality in raw semen quality in south-eastern Brazil, data regarding the influence of seasonality in cooled and frozen stored semen in Brazil is limited. Therefore, in this study, we have analysed if seasonality influences the hormone production (i.e., cortisol and testosterone), spermatogenesis, and quality of fresh, cooled, and frozen semen of stallions in central Brazil, and established the season most suitable for semen cryopreservation in a lati...
Elghryani N, McOwan T, Mincher C, Duggan V, de Waal T.Gastrointestinal helminths are ubiquitous in horse populations across the world. Intensive anthelmintic treatments have succeeded in controlling some of the pathogenic effects of these parasites. However, the success of anthelmintic drugs has been threatened by the development of widespread resistance to those most commonly used. To develop improved control strategies, information on helminth distribution patterns is needed, which can be obtained by identifying animals regarded as high egg shedders and taking age, gender, and other risk factors into account. The aim of this study was to determ...
Thomassen EE, Sigsgaard EE, Jensen MR, Olsen K, Hansen MDD, Svenning JC, Thomsen PF.Trophic rewilding is increasingly applied in restoration efforts, with the aim of reintroducing the ecological functions provided by large-bodied mammals and thereby promote self-regulating, biodiverse ecosystems. However, empirical evidence for the effects of megafauna introductions on the abundance and richness of other organisms such as plants and invertebrates, and the mechanisms involved still need strengthening. In this study, we use environmental DNA (eDNA) metabarcoding of dung from co-existing feral cattle and horses to assess the seasonal variation in plant diet and dung-associated a...
Boelow H, Krücken J, von Samson-Himmelstjerna G.Gastrointestinal nematodes are ubiquitous parasites of grazing equines with Parascaris spp., and strongyles being the most relevant ones regarding the prevalence and potential disease severity. Despite their importance, epidemiological data regarding the presence and egg-shedding intensities of these parasites are scarce. Data from 1067 horse samples collected on German horse farms initially to compare diagnostic methods were used for epidemiological analyses. Due to its higher sensitivity, presence/absence data were based on a combined sedimentation/flotation technique while faecal egg counts...
Dirikolu L, Waller P, Malveaux K, Lucas CH, Lomnicka I, Pourciau A, Bennadji H, Liu CC.The TCO (total carbon dioxide) test is performed on the blood of racehorses as a means of combatting the practice of administering alkalizing agents. This study evaluated serum TCO concentrations and factors influencing concentration of TCO in Thoroughbred and Quarter Horses. The normality of data were evaluated with a Shapiro-Wilk test. Mann-Whitney tests and Kruskal-Wallis tests were used against different effects. When a fixed effect was detected, Dunn's post-hoc comparisons were performed. The median pre-race serum TCO concentration (32.20 mmol/L (interquartile range (IQR): 30.80-33.50)) w...
Ake AS, Ayo JO.This study aimed to evaluate the effects of packing (load carrying) on the diurnal rhythms of respiratory and heart rates in donkeys during the hot-dry season. Twenty 2- to 3-years-old donkeys weighing 93 ± 2.7 kg were divided into two groups to serve as subjects: Group 1 was subjected to packing + trekking, while group 2 was subjected to trekking only. All donkeys trekked 20 km on each experimental day. The procedure was repeated three times at one-day intervals. Thermal environmental parameters were recorded. Respiratory rate (RR) and heart rate (HR) were measured before and immediately (15...
DeBoer M, Konop A, Fisher B.Horses are often blanketed during cold weather for numerous reasons including assisting thermoregulation, cleanliness, and anecdotally to decrease hair coat length. However, the impact of blanketing on the hair coat has yet to be evaluated. The objective of this study was to evaluate changes in hair coat length and diameter over time in blanketed and nonblanketed horses during winter. In October 2019, 16 mature adult horses were blocked by breed and BCS and randomly assigned to a blanketed (n = 8) or nonblanketed (n = 8) treatment; blankets were placed. Data was collected between October 2...
Schusser GF, Köller G, Recknagel S, Lindner A.The hay producing plants, concentrate, straw and meadows could be contaminated by the aerosols of glyphosate based herbicide during spraying process of crops and pre-harvest desiccation treatment of cereals. The aim of this study is to investigate the concentration of glyphosate in the duodenal fluid of horses with gastric ulcer syndrome. The stomach and duodenum of referred untreated horse patients (n=92) with colic, weight loss, diarrhoea, anemia or performance intolerance were endoscopically examined right after the admission. Duodenal fluid (40 ml) was collected from the duodenal region ...
Senra RL, Ramírez-López CJ, Magalhães-Júnior MJ, Neves JGDS, Barros E, Waddington B, Guimarães SEF, Guimarães JD, Baracat-Pereira MC.Horses are seasonal polyoestrous animals, and the photoperiod is the main factor modulating their reproductive activity. There is no consensus on the andrological and biochemical factors that influence breeding seasonality. To assess the involvement of climate in reproduction, Mangalarga Marchador stallions were monitored over 1 year regarding semen quality and seminal plasma proteome. Here, we show that kallikrein (KLKs) proteoforms in seminal plasma are involved in climate conditioning of reproduction. During the breeding season, greater abundance and different types of KLKs occurred simult...
Waheed MM, Meligy A, Alhaider AK, Ghoneim IM.Seminal plasma contains several microelements like Zn, Fe, Se, and Cu that affect sperm motility and male fertility. Biochemical evaluation of seminal plasma trace elements is important for assessing fertility and diagnosing male infertility. Unassigned: The present study was designed to evaluate the effect of seminal fluid trace elements on sperm parameters and fertility in Arabian horses. Unassigned: Ninety-four ejaculates from 25 Arabian stallions (4-27 years old) were used to investigate the effect of seminal fluid trace elements on semen parameters and fertility. Data divided according to...
Jachimowicz-Rogowska K, Topczewska J, Krupa W, Bajcar M, Kwiecień M, Winiarska-Mieczan A.The purpose of the study was to evaluate seasonal changes in selected trace elements such as Fe, Cu, Mn, Zn, and Al in the coat of healthy Hucul horses kept in south-eastern Poland in two different facilities and fed with locally sourced feed. The coat for the study was collected from 24 individuals in autumn, winter, and spring. The concentration of elements in the feed was also determined. The date of collection had a significant effect on the concentration of the micronutrients analysed in the coat of Hucul horses. The highest concentration of Zn was found in the coat taken in summer. The c...
Newcombe JR, Wilsher S, Cuervo-Arango J.Mares are seasonally polyoestrous breeders. Therefore, the first ovulation of the season, following winter anoestrus, is the only cycle in which mares ovulate without the presence of an old CL from the previous cycle. The objective of this study was to compare the length of oestrous behaviour, and plasma progesterone concentrations during the early post-ovulatory period between mares after the first and second ovulation of the breeding season. Overall, 38 mares and 167 oestrous periods were used in the study. From those, 11 mares were used during the first and subsequent oestrous period to mea...
Pomorska-Zniszczyńska A, Szczepanik MP, Kalisz G, Adamczyk N, Tarach M, Sobuś M, Abramowicz B.Videodermoscopic examinations have only recently started to be used in veterinary medicine and usually involve a small group of animals. The aim of this study was to compare specific dermoscopic parameters in selected areas of the body of Arabian horses in the summer and winter seasons. The research was conducted between 2018-2019. The procedure was performed on the left side of the horse's body in seven areas: head, neck, chest, flank, rump, mane, and tail. 42 purebred Arabian horses aged 1-25 (median), 39 mares and 3 stallions were qualified for the study. An Italian Video-Dermascope 7 (Medi...
Soma LR, Stefonovski D, Robinson MA, Tsang DS, Haughan J, Boston RC.A retrospective study was conducted to establish the prerace venous acid-base and blood gas values of Standardbred horses at rest using big data analytics. Methods: Venous blood samples (73,382) were collected during seven racing seasons from 3 regional tracks in the Commonwealth of Pennsylvania. Horses were detained 2 hours prior to race time. Methods: A mixed-effects linear regression model was used for estimating the marginal model adjusted mean (marginal mean) for all major outcomes. The interaction between age and gender, track, and the interaction between month, treatment (furosemide), a...
Dosi MCMC, McGorum BC, Kirton RD, Cillán-García E, Mellanby RJ, Keen JA, Hurst EA, Morgan RA.Vitamin D deficiency is common in humans and is increasingly linked to the pathogenesis of a multitude of diseases including obesity and metabolic syndrome. The biology of vitamin D in horses is poorly described; the relative contribution of the diet and skin synthesis to circulating concentrations is unclear and associations with the endocrine disease have not been explored. Objective: To determine the relationship between management, season and endocrine disease and vitamin D status in horses. Methods: Cross-sectional cohort study. Methods: Plasma concentrations of 25-hydroxyvitamin D2 (25(O...
The objective of the current study was to determine the photoperiod-induced variations and the impact of exercise on oxidative stress biomarkers [2-thiobarbituric acid reactive substances (TBARS), aldehydic (AD) and ketonic (KD) derivatives of oxidatively modified proteins (OMP), total antioxidant capacity (TAC), and activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx)] and biomarkers of metabolic alterations [glucose, urea, and uric acid and the activity of lactate dehydrogenase (LDH)] in the blood of Shetland pony mares and stallions involved in recreati...
Shakeel M, Jung H, Yoon D, Yoon M.The economic impacts of infertility and subfertility of stallions greatly influence the horse breeding industry. Self-renewal and differentiation of spermatogonial stem cells are the initial processes to maintain an adequate sperm population. Thus, understanding these processes may provide useful information to reveal the causes and remedies of subfertile and infertile stallions. Stallions are seasonal breeders. About 50% of the sperm population is reduced during the non-breeding season (NBS) in stallions. The seasonal regulation of spermatogenesis renders stallions as ideal models to understa...
Salem SE, Maddox TW, Berg A, Antczak P, Ketley JM, Williams NJ, Archer DC.Colic (abdominal pain) is a common cause of mortality in horses. Change in management of horses is associated with increased colic risk and seasonal patterns of increased risk have been identified. Shifts in gut microbiota composition in response to management change have been proposed as one potential underlying mechanism for colic. However, the intestinal microbiota in normal horses and how this varies over different seasons has not previously been investigated. In this study the faecal microbiota composition was studied over 12 months in a population of horses managed at pasture with minima...
Ali A, Khan MA, Zahid H, Yaseen PM, Qayash Khan M, Nawab J, Ur Rehman Z, Ateeq M, Khan S, Ibrahim M.Although ticks prevalent in various agro-systems of Pakistan are associated with economic losses, information is still missing about the tick's diversity, hosts they infest, seasonal dynamics and molecular phylogeny of in Khyber Pakhtunkhwa (KP) Pakistan. This study for the first time enlisted ticks infesting diverse hosts including humans in various regions of KP. A total of 8,641 ticks were collected across the northern, southern and central regions of KP and were morpho-taxonomically categorized into six genera comprising 17 species, ( = 3,584, 42%), ( = 2,253, 27%) ( = 1,342, 16%), ( =...
Johnson L, Thompson DL, Varner DD.Testicular function is under the control of expression and repression of several genes and gene products, and many of these works through Sertoli cells. The capability of Sertoli cells to regulate spermatogenesis is dependent on Sertoli cell functions and Sertoli cell number. Sertoli cell number has long been thought to be stable in adults with no proliferation of Sertoli cells once adult numbers have been reached. However, adult horses do not have stable Sertoli cell numbers, and new studies indicate that adult Sertoli cells can be made to re-enter mitotic phase under certain experimental con...
Giles SL, Rands SA, Nicol CJ, Harris PA.Reasons for performing study. The prevalence of obesity in companion animals, including horses and ponies has risen drastically in recent years and risk factors have been little investigated. Horses are unique amongst companion animals in that many are outdoor-living and forage independently on pasture; they also have a dual utility and companionship role. The body condition of wild and free-living equines is known to vary seasonally, yet previous estimates of the prevalence of obesity and associated risk factors in domestic animals do not consider this. Most previous studies were conducted du...
Bucknell DG, Gasser RB, Beveridge I.A quantitative post mortem study of 150 horses from Victoria was conducted to determine the prevalence and epidemiology of gastrointestinal parasites. A total of 42 species of metazoan parasite was found. The following species of non-cyathostome parasite were found (% prevalence): Trichostrongylus axei (51%); Habronema muscae (13%); H. majus (2%); Draschia megastoma (5%); Gastreophilus intestinalis (81%); G. nasalis (29%); Parascaris equorum (5%); Anoplocephala perfoliata (29%); Fasciola hepatica (0.7%); Oxyuris equi (7%); Strongylu vulgaris (23%); S. edentatus (23%); S. equinus (3%); Crateros...
Thatcher CD, Pleasant RS, Geor RJ, Elvinger F.The prevalence of obesity in horses in the eastern United States is not well documented. Objective: To determine body condition and risk factors for obesity in horses in Southwest Virginia during summer. Methods: A sample of 300 mature (4-20 years old), light breed horses (140 mares, 151 geldings, and 9 stallions) from the VMRCVM Equine Field Service practice equine database. The horses were from 114 farms and 138 owners. Methods: Horses were evaluated over a 60-day period in this cross-sectional, prospective study. A questionnaire was completed for each horse. Body condition score (BCS) was a...
Goehring LS, van Winden SC, van Maanen C, Sloet van Oldruitenborgh-Oosterbaan MM.Equine herpesvirus type 1(EHV-1)-associated myeloencephalopathy (EHM) is a rare disease affecting the central nervous system and, in particular, the spinal cord of horses. Epidemiologic data are limited, and usually are restricted to the description of a single outbreak. During an observational period of 4 years, we evaluated 9 outbreaks of EHM in The Netherlands. A risk factor analysis was done on the data from 6 outbreaks. Findings were: regular appearance of EHM outbreaks in The Netherlands (2-3/y); strong association of EHM with season; and risk factors, such as breed, sex, age, and fever....
Arnold W, Ruf T, Kuntz R.Many large mammals show pronounced seasonal fluctuations of metabolic rate (MR). It has been argued, based on studies in ruminants, that this variation merely results from different levels of locomotor activity (LA), and heat increment of feeding (HI). However, a recent study in red deer (Cervus elaphus) identified a previously unknown mechanism in ungulates--nocturnal hypometabolism--that contributed significantly to reduced energy expenditure, mainly during late winter. The relative contribution of these different mechanisms to seasonal adjustments of MR is still unknown, however. Therefore,...
Chemineau P, Guillaume D, Migaud M, Thiéry JC, Pellicer-Rubio MT, Malpaux B.Farm mammals generally express seasonal variations in their production traits, thus inducing changing availability of fresh derived animal products (meat, milk and cheese) or performances (horses). This is due to a more or less marked seasonal birth distribution in sheep and goats, in horses but not cattle. Birth peak occurs at the end of winter-early spring, the most favourable period for the progeny to survive. Most species show seasonal variations in their ovulation frequency (presence or absence of ovulation), spermatogenic activity (from moderate decrease to complete absence of sperm prod...
Luthersson N, Nielsen KH, Harris P, Parkin TD.The prevalence (up to 93% in Thoroughbred racehorses) and severity of equine gastric ulceration syndrome (EGUS) has been associated with type of training and differing management practices. However, there have been few studies to confirm these findings in nonracehorses in Europe. Objective: To investigate the prevalence of EGUS in a population of Danish horses, during winter when the horses had been housed and fed for at least 8 weeks and to analyse the influence of feed, work level and environment on the risk of EGUS of > or = grade 2 in severity. Methods: A total of 201 horses, not in active...
Bailey SR, Habershon-Butcher JL, Ransom KJ, Elliott J, Menzies-Gow NJ.To determine the metabolic phenotype of a group of laminitis-prone ponies when at pasture in summer, compared with when at pasture in winter. Methods: 40 ponies of various breeds predisposed to recurrent pasture-associated laminitis and 40 unaffected control ponies. Methods: Body condition score and size of the crest of the neck were assessed, blood samples obtained, and blood pressure measured by use of an indirect oscillometric technique, while ponies were kept on winter pasture (last week of November or beginning of December) and again on summer pasture (June). Serum insulin concentration a...
Wood EL, Matthews JB, Stephenson S, Slote M, Nussey DH.Cyathostomins are the most prevalent equine intestinal parasites and resistance has been reported in these nematodes against all 3 licensed anthelmintic classes. Strategies need to be developed that are less dependent upon drugs and more reliant on management-based control. To develop these we need to understand natural transmission patterns better. Here, we analysed longitudinal fecal egg count (FEC) data from 5 pony populations used for conservation purposes. We tested how egg excretion varied amongst populations and individuals, and how this was affected by age and climate. There was eviden...
Donaldson MT, McDonnell SM, Schanbacher BJ, Lamb SV, McFarlane D, Beech J.The purpose of this study was to evaluate the variation in plasma adrenocorticotropic hormone (ACTH) concentration and dexamethasone suppression test (DST) results with season, age, and sex in healthy, pony mares (n=15) and pony stallions (n=14) living under semiferal conditions and horse mares (n=10) living at pasture. Plasma ACTH concentrations were measured in September 2002, and in January, May, and September 2003. DSTs were performed in January and September 2003. Plasma ACTH concentrations in September 2002 and September 2003 were similar and were significantly greater than in January an...
Papas M, Arroyo L, Bassols A, Catalán J, Bonilla-Correal S, Gacem S, Yeste M, Miró J.This study compared the activities of four antioxidant enzymes (superoxide dismutase, SOD; catalase, CAT; glutathione peroxidase, GPX; and glutathione reductase, GSR) in the seminal plasma of stallions and jackasses. Eighteen stallion ejaculates and 24 jack ejaculates were collected through an artificial vagina. Seminal plasma was obtained by several centrifugations at 3000×g and 4 °C for 10 min, and activities of SOD, CAT, GPX and GSR were subsequently determined. We also evaluated whether the collecting season had any influence on the activities of these four enzymes in both stallions ...
Brinkmann L, Gerken M, Riek A.Recent results suggest that the wild ancestor of the horse, the Przewalski horse, exhibits signs of a hypometabolism. However, there are speculations that domestic animals lost the ability to reduce energy expenditure during food shortage and adverse environmental conditions. Therefore, we investigated physiological and behavioural strategies employed by a robust domesticated horse breed, the Shetland pony, over the course of a year under temperate conditions by measuring ambient temperature (T(a)), subcutaneous temperature (T(s)), locomotor activity (LA), lying time, resting heart rate, body ...
Rehbein S, Visser M, Winter R.Prevalence and intensity of gastrointestinal parasites were studied through a longitudinal survey in 400 horses over a 17-month period in an abattoir in Germany. Three hundred and ten horses (77.5 %) were demonstrated harbouring endoparasites either by direct recovery of parasites from the digestive tract and/or in terms of faecal egg counts (strongyles). The following parasites were found (percentage prevalence, range of counts): Gasterophilus intestinalis larvae (2.25 %, 1-154), Gasterophilus nasalis larvae (0.25 %, 44), Trichostrongylus axei (11.0 %, 1-3,620), Habronema majus (8.0 %; 1...
Copas VE, Durham AE.Pituitary pars intermedia dysfunction (PPID) is a common endocrinopathy, frequently diagnosed via plasma adrenocorticotropic hormone (ACTH) concentrations. Seasonal variation in plasma ACTH concentrations has been described in normal horses prompting caution in diagnosing PPID at certain times of the year. The aims of this study were to determine appropriate reference intervals for equine plasma ACTH throughout the year; and to examine the circannual variation of plasma ACTH concentrations in PPID cases. Objective: Plasma ACTH can be used as a test for PPID throughout the year with the use of ...
Wylie CE, Ireland JL, Collins SN, Verheyen KL, Newton JR.The objectives of this study were to describe the demographic characteristics and management practices undertaken by owners of horses/ponies within GB and assess seasonal and geographical variations in management practices. A cross-sectional study was conducted, surveying a random sample of veterinary-registered owners in GB, using a self-administered postal questionnaire. A total of 797 useable responses were received. Only 4.0% of animals were stabled 24h/day, this proportion being greater in winter compared to other seasons (p<0.001). Shavings (45.7%) and straw (35.3%) were the most freq...
Stull CL, Rodiek AV.Fifteen mature horses (mares, n = 6); geldings, n = 9) were used to assess the physiological responses of 24 h of transport in a commercial van under California summer conditions. The study was conducted on four consecutive days, and data were collected on d 1 and d 2 to obtain baseline values and to determine any diurnal variation in the individual measurements. Travel commenced on d 3 at 0800 for 24 h, with a total of 1,622 km traveled. Blood samples were collected at 0800, 1100, 1400, 2000, and 0200 each day. Horses were weighed and rectal temperatures recorded at 0800 each day and at 2000 ...
Sturdee AP, Bodley-Tickell AT, Archer A, Chalmers RM.A longitudinal sample survey testing for Cryptosporidium in livestock and small wild mammals conducted over 6 years (1992-1997) on a lowland farm in Warwickshire, England, has shown the parasite to be endemic and persistently present in all mammalian categories. Faecal samples were taken throughout the year and oocysts concentrated by a formal ether sedimentation method for detection by immunofluorescence staining using a commercially available genus specific monoclonal antibody. Cryptosporidium parvum was identified by morphology and measurement of modified Ziehl-Neelsen stained oocysts. C. m...
Hillyer MH, Taylor FG, French NP.The aim of this study was to estimate the incidence of colic in horses in Thoroughbred training premises in 1997 in the British Isles. The seasonal pattern and outcome of colic episodes were also investigated, together with any association between premises level variables and colic. Data were collected by a postal questionnaire. The results showed a colic incidence density of 7.19/100 horse years (s.e. 0.42) and a cumulative incidence of colic of 5.80% (s.e. 0.30). Premises were grouped according to whether they had more Flat than National Hunt horses (Flat premises) or more National Hunt than...
Cordero M, Brorsen BW, McFarlane D.Cosinor analysis was used to evaluate whether pituitary and adrenal hormones exhibit circadian rhythmicity in horses. The effect of season and animal age on their respective rhythms was also determined. In addition, the usefulness of evaluating cortisol rhythmicity for the diagnosis of pituitary pars intermedia dysfunction (PPID) was assessed. Serum cortisol concentrations (P < 0.01), but not plasma ACTH or α-melanocyte-stimulating hormone (α-MSH), showed a significant circadian periodicity in horses. An effect of season on hormone concentration was observed with plasma ACTH and α-MSH co...
de Paula LGF, do Nascimento RM, Franco AO, Szabó MPJ, Labruna MB, Monteiro C, Krawczak FDS.Amblyomma sculptum is a hard tick that is associated with domestic animals and the transmission of Brazilian spotted fever. This association has motivated several field studies on this ixodid tick within its distribution area in South America. Thorough knowledge of the seasonal dynamics of A. sculptum in different ecological scenarios is required in order to better understand the biological characteristics of this tick and develop techniques for the control and prevention of diseases transmitted by this vector. In this article, we systematically review the seasonal dynamics of A. sculptum and ...
Theelen MJP, Luiken REC, Wagenaar JA, Sloet van Oldruitenborgh-Oosterbaan MM, Rossen JWA, Zomer AL.Several studies have described the faecal microbiota of horses and the factors that influence its composition, but the variation in results is substantial. This study aimed to investigate the microbiota composition in healthy equids in The Netherlands under standard housing and management conditions and to evaluate the effect of age, gender, horse type, diet, pasture access, the season of sampling and location on it. Spontaneously produced faecal samples were collected from the stall floor of 79 healthy horses and ponies at two farms. The validity of this sampling technique was evaluated in a ...
Robinson NE, Karmaus W, Holcombe SJ, Carr EA, Derksen FJ.Although subclinical airway inflammation is thought to be common in horses, there is little information on its prevalence and none on risk factors. Objective: To determine the prevalence and risk factors for an increased number of inflammatory cells and for mucus accumulation in the trachea of pleasure horses. Methods: Horses (n = 266) in stables (n = 21) in Michigan were examined endoscopically, once in winter and once in summer 2004. Visible tracheal mucoid secretions were graded 0-5 and inflammatory cell numbers counted in a tracheal lavage sample. Information collected about each horse inc...
Davis KU, Sheats MK.Equine asthma syndrome (EAS) is a common problem that affects horses of any age. Severe EAS is reported to affect 10-20% of adult horses in the northern hemisphere, while mild/moderate EAS is reported to affect 60-100% of adult horses, depending on the population and geographic region. For both severe and mild/moderate EAS, the presence of lower airway inflammation is attributed to airborne "triggers" such as dust, mold, and bacterial components that horses encounter in hay and stable-environments; and treatment recommendations for horses with EAS often include full-time pasture turnout. The c...
Riihimäki M, Raine A, Elfman L, Pringle J.Airborne factors in a conventionally managed racing stable and markers of pulmonary inflammation in the stabled horses were investigated on 3 occasions at 6-month intervals, including 2 winter periods and the intervening summer period. The stable measurements included inside and outside ambient temperature and relative humidity, levels of total and respirable dust, endotoxin, and 1,3-beta-glucan. Horses (n = 12) were examined in detail clinically as well as by endoscopy, bronchoalveolar lavage (BAL) cytology, and real-time polymerase chain reaction (RT-PCR) analysis of BAL-cells for IL-6 and I...
Kuntz R, Kubalek C, Ruf T, Tataruch F, Arnold W.Large ruminants respond to changing plant phenology during winter by decreasing voluntary food intake, increasing gut passage time and utilizing body fat reserves. It is uncertain, however, how other large mammals with a non-ruminant digestive physiology cope with winter forage conditions. Therefore, we investigated seasonality of energy intake in a large herbivorous wild mammal, the Przewalski horse (Equus ferus przewalskii). Throughout all seasons we used the n-alkane method to measure daily dry matter intake (DMI), diet composition and digestion, and determined an index of gut passage time ...
Lyle CH, Blissitt KJ, Kennedy RN, Mc Gorum BC, Newton JR, Parkin TD, Stirk A, Boden LA.Sudden death adversely affects racehorse welfare, jockey safety and the public perception of horseracing. Objective: To describe the risk of racing-associated sudden death in Thoroughbred racehorses in the UK from 2000 to 2007, to identify whether there were risk factors uniquely associated with sudden death and to improve the understanding of the pathogenesis of racing-associated sudden death by identification of risk factors for such cases. Methods: A sudden death was defined as an acute collapse and death, in an apparently healthy Thoroughbred racehorse, during or immediately after racing, ...
Osthaus B, Proops L, Long S, Bell N, Hayday K, Burden F.There are clear differences between donkeys and horses in their evolutionary history, physiology, behaviour and husbandry needs. Donkeys are often kept in climates that they are not adapted to and as such may suffer impaired welfare unless protection from the elements is provided. Objective: To compare some of the hair coat properties of donkeys, mules and horses living outside, throughout the year, in the temperate climate of the UK. Methods: Longitudinal study. Methods: Hair samples were taken from 42 animals: 18 donkeys (4 females, 14 males), 16 horses (6 females, 10 males) and eight mules ...
