The influence of weather on horses encompasses various environmental factors such as temperature, humidity, precipitation, and wind, which can affect the physiological and behavioral responses of these animals. Weather conditions can impact hydration, thermoregulation, and overall health, influencing feeding patterns and exercise performance. Horses may exhibit different responses to extreme weather conditions, such as heat stress or cold exposure, which can necessitate management adjustments to maintain their well-being. This page compiles peer-reviewed research studies and scholarly articles that investigate the effects of weather on equine physiology, behavior, and management practices.
Kohn CW, Hinchcliff KW, McKeever KH.Six healthy Thoroughbred mares were trained to run on a high-speed treadmill and were conditioned for approximately 5 weeks. Each horse performed 6 identical standardised exercise tests (SET) 5 to 7 days apart. Each SET was performed under different ambient laboratory conditions: low temperature/low humidity (LL) 20.2 degrees +/- 0.6 degree C, 53.6 +/- 4.1%; low temperature/high humidity (LH) 19.7 +/- 0.6 degrees C, 86.7 +/- 4.2%; medium temperature/low humidity (ML) 24.6 +/- 0.2 degrees C, 58.7 +/- 3.7%; medium temperature/high humidity (MH) 24.7 +/- 0.3 degrees C, 87.5 +/- 1.4%; high tempera...
Henry M, Amaral D, Tavares FF, Santos NR.The aim of the present study was to analyse the effect of hydrocoele of the vaginal cavity of stallions on semen characteristics, libido and fertility, and to contribute to the understanding of the aetiopathology of this condition in stallions. Hydrocoele did not substantially affect either the libido or semen characteristics of affected stallions compared with a control group, and had no effect on fertility. However, the protein content of hydrocoelic fluid was significantly higher than that of peritoneal fluid and was lower than the protein content of blood serum. Electrophoretic profiles of...
Cohen ND, Gibbs PG, Woods AM.To determine whether dietary and other management factors were associated with development of colic in horses. Methods: Prospective matched case-control study. Methods: 2,060 horses examined by veterinarians in private practice in Texas for colic and noncolic emergencies. Methods: Each month for 12 months, participating veterinarians were sent forms to collect information on 1 horse with colic and 1 horse that received emergency treatment for a condition other than colic, information collected included signalment, farm management and characteristics, diet, medical and preventive medical factor...
Duvivier DH, Chiap P, Crommen J, Lekeux P.The aim of this study was to determine the effect of breathing pattern, air humidity and position of the device on the delivery of an aerosol generated by a dry powder inhalation (DPI) device (Inhalator M). The in vitro inhalation study was performed using the cascade impaction method (Andersen Sampler) adapted to imitate nasal breathing. The amount of ipratropium found in the device, the artificial upper airways and the six stages of the Andersen Sampler was measured using high precision liquid chromatography. Stage 1 of the Andersen Sampler was considered to be the respirable fraction and st...
Yeruham I, Elad D, Egozi O.A retrospective study of an outbreak of dermatophilosis in a herd of 18 adult horses and 13 foals, in Israel, is presented. To the best of our knowledge this is the first time such an outbreak has been reported from a country in the Mediterranean climatic zone. This outbreak might be associated with exposure of the horses to water and humidity as a result of excessive rainfall in November 1994, as well as intensive washing of the horses and a long period spent by the animals in a marshy manege.
Harris PA, Marlin DJ, Scott CM, Harris RC, Mills PC, Michell AR, Orme CE, Roberts CA, Schroter RC, Marr CM.Four horses (H, J, N and M) undertook a simulated competition exercise test (CET), designed to simulate physiological and metabolic stresses of the Speed and Endurance (S & E) test of a 3-day-event, under 3 different environmental conditions: 20 degrees C/40% relative humidity (RH) (cool, dry [CD] 2 sessions); 30 degrees C/40% RH (hot, dry [HD]) and 30 degrees C/80% RH (hot, humid [HH]) (Marlin et al. 1995a). Venous blood samples for electrolyte and total protein (TP) determinations were collected from indwelling catheters at predetermined time points throughout each CET and initial 30 min...
Kohn CW, Hinchcliff KW.Physiological data were collected during two 3-day-event competitions: one (H) held in hot and the other (CL) in cool conditions. During H, ambient temperature and relative humidity were 2.5 degrees C-35 degrees C and 74-36% respectively, while during CL, ambient temperature and relative humidity were 7.8 degrees C-8.3 degrees C and 46%-41%, respectively. Rectal temperature, heart and respiratory rates were recorded on arrival at the event, at the end of Phase C and 6 min later, at the end of Phase D and for 30 min at 10 min intervals after each horse finished Phase D (Recovery Period). Becaus...
Monzón CM, Hoyos CB, Jara GA.Tests on 257 blood samples from 21 herds of horses in Formosa Province of Argentina, using the technique of centrifuging microhaematocrit capillary tubes, revealed Trypanosoma evansi in 90 of 137 animals in eight herds. Application of the direct agglutination test to serum samples from the same animals revealed antibodies to T. evansi in 107 horses. Antibody was also detected in nine horses from two herds where the parasite was not detected. Outbreaks of 'mal de caderas' occurred in the humid (eastern) and sub-humid (central) zones of Formosa. More than 95% of the equine population of the prov...
Lapointe JM, Vrins A, McCarvill E.Sixty Standardbred horses, aged 3 to 10 years, were examined endoscopically for exercise-induced pulmonary haemorrhage (EIPH) 1 h after racing, on at least 3 occasions. Racing time, finishing position and post exercise venous lactate concentrations were also recorded. Horses positive for tracheal blood on endoscopy were classified as having either grade 1 EIPH (one or a few spots of blood in the trachea), or grade 2 (stream of blood). Air temperature, relative humidity and air pollutant levels were recorded on each examination day. Of the 60 horses, 52 (87%) were EIPH-positive on at least one ...
Letson GW, Bailey RE, Pearson J, Tsai TF.An Eastern equine encephalitis (EEE) outbreak in 1989 led to nine human and 196 equine cases, chiefly in coastal Atlantic and Gulf Coast counties. In the past two decades, EEE age-specific incidence and mortality rates have declined compared with earlier years. Analysis of rainfall patterns in areas where human EEE cases occurred between 1983 and 1989 revealed an association between occurrence of human cases and excess rainfall. The association was stronger with data from local weather stations than from statewide rainfall averages and the predictive models were best when applied to northern s...
Sellers RF, Maarouf AR.Cases of western equine encephalitis in horses in 1987 in western USA and Manitoba, Canada were examined by backward trajectory analysis of winds. Culex tarsalis mosquitoes infected with western equine encephalitis virus could have been carried on southerly winds from Texas and Oklahoma to northern USA and from there to Manitoba. The presence of the Polar front over North Dakota and Minnesota at the end of July would have led to the landing of Cx. tarsalis in Montana and Wisconsin and prevented further carriage into Manitoba. Temperatures in southern Texas during the winter months (average dai...
Doxey DL, Gilmour JS, Milne EM.Local weather patterns associated with 15 outbreaks of equine grass sickness in eastern Scotland were studied. The majority showed a trend toward cooler drier weather associated with irregular ground frosts. This would not preclude the hypothesis that fungi might be connected with the aetiology of grass sickness.
Clanton C, Kobluk C, Robinson RA, Gordon B.During a pilot study at a Thoroughbred racetrack, information was collected to include weather conditions and track surface properties (moisture content, composition, strength, and coefficient of friction between surface and hoof). Measured weather variables did not correlate to any pattern of horse injuries of breakdowns. Surface moisture content was variable, whereas the moisture content of the compacted cushion was constant. Track surfaces around the starting chutes were more compacted than were other areas of the track. Next to the rail, track surface was softer than the surface toward the...
Flisińska-Bojanowska A, Gill J, Komosa M.1. The diurnal changes in the levels of lactic (LA) and pyruvic (PA) acids and values of pH were studied in standard-bred mares and their foals, for 13 weeks of foal life, throughout 2 years. 2. The studies began when a foal was 7 days old and were repeated every 2 weeks until foals reached 13 weeks of age. 3. Blood samples were taken every 4 hr for one day, each second week. 4. In the LA, PA levels and pH values no diurnal rhythm was stated in lactating mares during study periods. 5. In foals the diurnal rhythm in LA and PA occurred in the 3rd month of their life, with the acrophase at night ...
Cymbaluk NF, Christison GI.Horses are reared in all types of weather. Temperatures as diverse as -40 degrees C to 40 degrees C are tolerated by horses. The nutrient requirement most influenced by cold weather is energy. In cold weather, feeding good quality hays free-choice is usually sufficient for mature horses in good body condition. Grain may have to be fed when poor quality hays are used. Hot weather (greater than 30 degrees C) necessitates heat loss to maintain body core temperature. Horses sweat to reduce body heat. Heat stress can be minimized by feeding diets that reduce the heat increment. Use of grain and fat...
Dewes HF, Townsend KG.Two horses repeatedly underwent episodes of frenzy characterised by extreme discomfort and hyperactivity. Within 2 days of an attack the lower extremities of both hind legs of one subject were uniformly swollen, while on the second subject skin lesions erupted 3-4 days after an attack and swelling persisted for 2-3 weeks. Filariform larvae of Strongyloides westeri were cultured from soil and sawdust where the subjects were kept. Larvae were cultured from soil of low pH (4.5-5.8) but were absent from neutral or alkaline soils. Larvae were found in sawdust with a wide pH range. It is thought tha...
Slocombe JO, Valenzuela J, Lake MC.The transmission of strongyles among 54 Shetland-cross mature ponies was examined from May 30 to November 22, 1983 when the ponies were on pasture and over the ensuing winter when they were in loose housing. Fecal and pasture herbage samples were taken fortnightly through the pasture season and periodically thereafter. Three foals born and reared on pasture were weaned and removed from pasture, two in early August and one in mid-September, and housed for a period before necropsy. Daily maximum and minimum air temperature and total precipitation were recorded. The mean fecal strongyle egg count...
Grady GF, Maxfield HK, Hildreth SW, Timperi RJ, Gilfillan RF, Rosenau BJ, Francy DB, Calisher CH, Marcus LC, Madoff MA.Reappearance of eastern equine encephalitis (EEE) in Massachusetts residents in the 1970's provided an opportunity to assess the predictive value of data on rainfall, EEE in horses, and carriage of EEE virus (EEEV) by mosquitoes, factors which had been studied annually since the last EEE outbreak in 1955-1956. The cycle of multiple cases during 1973-1975 started in a second consecutive year of rainfall that exceeded the annual mean by more than 20 cm, conditions recapitulating the 1955-1956 experience. In 1973, widespread EEE fatalities in horses presaged human cases, another recapitulation of...
Honstein RN, Monty DE.Field investigations were conducted under natural environmental conditions to determine the physiologic responses of rested, hydrated horses (Equus caballus) to the very hot, dry weather characteristic of the summer season in southern Arizona. The emphasis of the investigation was placed on those thermoregulatory mechanisms which are involved in the maintenance of homoiothermy. Rectal temperature of the horses studied remained relatively stable throughout the day, during both cool and hot weather seasons. However, when horses were exposed to hot summer temperatures, rectal temperature (heat st...
Simms JG, Rosser WW.A case of Farmer's Lung in a city dweller who rides horses for recreation is reported. A survey of the members of an urban riding club found that 13% of the persons surveyed had antibodies to T. polyspora in their circulation.Comparing the average rainfall in the area of the riding club to average rainfall throughout regions across the country, it is likely that Farmer's Lung is more prevalent than previously thought.More information about the incidence of this preventable respiratory disease in Canada is needed.
Honstein RN, Monty DE.Field investigations were conducted under natural environmental conditions to determine the physiologic responses of rested, hydrated horses (Equus caballus) to the very hot, dry weather characteristic of the summer season in southern Arizona. The emphasis of the investigation was placed on those thermoregulatory mechanisms which are involved in the maintenance of homoiothermy. Rectal temperature of the horses studied remained relatively stable throughout the day, during both cool and hot weather seasons. However, when horses were exposed to hot summer temperatures, rectal temperature (heat st...
Murase H, Matsui A, Endo Y, Sato F, Hada T.The lying behavior of Thoroughbred foals on breeding farms was continuously measured using triaxial accelerometers. Accelerometers were attached on the side of the hind limb cannon and under the halter of six foals to record triaxial angle data every 10 sec for a period of 24 hr. Lying behavior was divided into sternal lying and lateral lying based on head angle. Sampling was performed for two consecutive days each week until weaning. Sampling periods were divided into two periods on the basis of pasturing time: daytime pasturing (period A: 7-hr pasturing period, 2-60 days of age) and overnigh...
Hammer C, Gunkelman M.The objective of this study was to examine changes in surface temperature of blanketed horses during cold weather. Four mature stock-type horses were used in a 4 × 4 Latin square design. Treatments included 3 different blanket weights (based on g of fiberfill): light weight (LW; 0 g), medium weight (MW; 200 g), heavy weight (HW; 400 g), and a nonblanketed control (CON). Thermographic images were obtained from a standardized lumbar location before blanketing and immediately after cold exposure. During cold exposure, horses were outside with ad libitum access to grass hay and water for 1 h...
Marín Navas C, Delgado Bermejo JV, McLean AK, León Jurado JM, Camacho Vallejo ME, Navas González FJ.The historical increase in the occurrence of extreme weather events in Spain during the last thirty years makes it a perfect location for the evaluation of climate change. Modeling the effects of climate change on domestic animals' genetic diversity may help to anticipate challenging situations. However, animal populations' short life cycle and patent lack of historical information during extended periods of time drastically compromise the evaluation of climate change effects. Locally adapted breeds' gene pool is the base for their improved resilience and plasticity in response to climate chan...
Hormones and behaviorMarch 18, 2024
Volume 161 105526 doi: 10.1016/j.yhbeh.2024.105526
Granweiler J, Cristóbal-Azkarate J, Morton N, Palme R, Shultz S.In seasonal environments, maintaining a constant body temperature poses challenges for endotherms. Cold winters at high latitudes, with limited food availability, create opposing demands on metabolism: upregulation preserves body temperature but depletes energy reserves. Examining endocrine profiles, such as thyroid hormone triiodothyronine (T3) and glucocorticoids (GCs), proxies for changes in metabolic rate and acute stressors, offer insights into physiological trade-offs. We evaluated how environmental conditions and gestation impact on faecal hormone metabolites (fT3Ms and fGCMs) from late...
Stoff M, Baumgärtner W, Wohlsein P.During summer, permanent or temporary pasture keeping carries an increased risk of death caused by lightning strikes. Although - due to their body structure and pasture grazing - large animals are particularly susceptible to step voltage effects in consequence to a lightning strike to the ground there are only few published cases in the veterinary literature. Frequently in lightning-related accidents, a current flow through the heart occurs resulting in acute cardiac and circulatory failure. In the vast majority of cases, this is accompanied either by very unspecific lesions or even lacks any ...
Simms JG, Rosser WW.A case of Farmer's Lung in a city dweller who rides horses for recreation is reported. A survey of the members of an urban riding club found that 13% of the persons surveyed had antibodies to T. polyspora in their circulation.Comparing the average rainfall in the area of the riding club to average rainfall throughout regions across the country, it is likely that Farmer's Lung is more prevalent than previously thought.More information about the incidence of this preventable respiratory disease in Canada is needed.
Harris PA, Marlin DJ, Scott CM, Harris RC, Mills PC, Michell AR, Orme CE, Roberts CA, Schroter RC, Marr CM.Four horses (H, J, N and M) undertook a simulated competition exercise test (CET), designed to simulate physiological and metabolic stresses of the Speed and Endurance (S & E) test of a 3-day-event, under 3 different environmental conditions: 20 degrees C/40% relative humidity (RH) (cool, dry [CD] 2 sessions); 30 degrees C/40% RH (hot, dry [HD]) and 30 degrees C/80% RH (hot, humid [HH]) (Marlin et al. 1995a). Venous blood samples for electrolyte and total protein (TP) determinations were collected from indwelling catheters at predetermined time points throughout each CET and initial 30 min...
Danek J, Flosadóttir S.The purpose of this work was to assess the impact of a specific equestrian training, conducted in winter weather conditions, on the thermovision temperature distribution of a rider's body surface. The study included a riding pair with 12 years of experience (female rider, aged 25, sports active and 16-year-old horse, Trakehner breed). Methods: The study included the temperature distribution of selected parts of the rider's body (the area of the right and left shoulder blade, chest and lumbar section, and the region of the left and right cross) was carried out before and after recreational, jum...
Domange C, Casteignau A, Collignon G, Pumarola M, Priymenko N.Seventy horses with clinical evidence of Australian stringhalt were studied in France from 2003 to 2008. All horses but one had history of bilateral stringhalt and grazed pastures infested with Hypochoeris radicata (L.). They displayed hind limbs hyperflexion and an abnormal gait because of a distal axonopathy with a skeletal muscle denervation and atrophy. Fifty percentage of them recovered spontaneously in 8 months, and only the more affected horses were unable to recover even if they looked healthy on dry and hot days. Clinical troubles revealed also depression or aggressive behaviour, sugg...
de Jesús Tello-Pasos A, González-Pech PG, Blanco-Molina JM.The aim of this observational study was to describe the characteristics of circuits performed by horses used in carriage tourism in a tropical city and discuss their implications as a challenge for animal welfare. The tourism circuit of 33 Criollo horses (400 ± 50 kg) was followed by using the GPS from August 31 to December 2nd, 2018, in the rainfall summer season. The environmental temperature, humidity, and accumulated rainfall were obtained from a local meteorological station. The distance and number of trips, the number of people transported, and the time taken for working and resting ac...
Evans PM, Armour MD, Dubielzig RR. To describe the gross and histopathological ocular findings in a horse following suspected lightning injury. Methods: The eyes of a 2-year-old thoroughbred gelding were clinically and histopathologically evaluated following a severe lightning storm following euthanasia because of visual impairment. Results: Severe corneal edema and hydrops were noted clinically oculus dexter. Indirect ophthalmoscopy revealed bilateral symmetrical raised hyporeflective peripapillary geographic lesions. Histopathologic evaluation revealed corneal edema in the right eye with normal corneal endothelium...
Pain R, Sneddon JC, Cochrane CA.Franz diffusion cells containing uniformly dehydrated equine blood clots to simulate fibrinous eschar were used to measure the rate of debridement of fibrin by novel and traditional wound dressings, under standardised conditions of temperature, pH and humidity. Significant increases in protein breakdown occurred within 24 hours with all the dressings, but not thereafter. In general, dressings hydrated in normal saline were better as debriding agents than dressings hydrated in water. Autolytic debriding agents were 47 per cent more effective than chemical debriding agents; specifically, hydrofi...
Flisińska-Bojanowska A, Gill J, Komosa M.1. The diurnal changes in the levels of lactic (LA) and pyruvic (PA) acids and values of pH were studied in standard-bred mares and their foals, for 13 weeks of foal life, throughout 2 years. 2. The studies began when a foal was 7 days old and were repeated every 2 weeks until foals reached 13 weeks of age. 3. Blood samples were taken every 4 hr for one day, each second week. 4. In the LA, PA levels and pH values no diurnal rhythm was stated in lactating mares during study periods. 5. In foals the diurnal rhythm in LA and PA occurred in the 3rd month of their life, with the acrophase at night ...
Duvivier DH, Chiap P, Crommen J, Lekeux P.The aim of this study was to determine the effect of breathing pattern, air humidity and position of the device on the delivery of an aerosol generated by a dry powder inhalation (DPI) device (Inhalator M). The in vitro inhalation study was performed using the cascade impaction method (Andersen Sampler) adapted to imitate nasal breathing. The amount of ipratropium found in the device, the artificial upper airways and the six stages of the Andersen Sampler was measured using high precision liquid chromatography. Stage 1 of the Andersen Sampler was considered to be the respirable fraction and st...
Kraouchi DE, Meradi S, Bentounsi B.The composition, prevalence, and seasonal dynamic of species were studied at the slaughterhouse of Constantine region (East Algeria) in 128 horses over an 18 months period. Our survey revealed that 124 (96.9%) horses were infected with a mean intensity of 161 larvae of spp. Four species of were identified; and were by far the predominant species with 95.3% and 77.3% respectively, followed by (14.0%) and (10.1%). The age, sex, and breed of horses did not affect the distribution of the infection. Second-stage larvae (L2) of were absent between April and July and present in higher numbers...
Thomas BA, Saylor RK, Taylor ZP, Rhodes DVL.Strangles is a highly contagious upper respiratory infection of equids that is globally distributed. The causative agent of strangles, subspecies , can be spread through indirect contact with infected fomites, and studies have shown this microbe to live well in varying environmental conditions. The purpose of this study was to analyze strangles case numbers across the United States of America from 2018 to 2022 to investigate potential temporal or weather patterns associated with outbreaks. Diagnosed case records were obtained from the Equine Disease Communication Center, university databases,...
Son V, Penagos-Tabares F, Hollmann M, Khiaosa-Ard R, Sulyok M, Krska R, Zebeli Q.Pastures are used for grazing and the production of conserved roughage in horses. Yet, the nutritional profile of the forage varies from spring to late summer, affecting equine nutrient supply and health. In addition, environmental factors may also favor plant contaminants such as mycotoxins. This study aimed to determine the nutritional profile and contaminant load of selected horse pastures from early spring till late summer. The nutrient composition (main macronutrients, macro elements and trace elements), as well as mycotoxins, metabolites, pesticides, and plant-derived compounds of seven ...
Katz LM, Gough K, McGivney CL, McGivney B, Sides RH, Hill EW, Bayly WM.Sex effects on ventilatory and oxygen consumption (V̇O) measurements during exercise have been identified in humans. This study's aim was to evaluate the hypothesis that there are sex effects on ventilatory and V̇O measurements in exercising, untrained yearling Thoroughbreds (Tb). Forty-one Tbs (16 colts, 25 fillies; 19.8 ± 1.4 months old) were recruited. Physiological, ventilatory and exercise data were gathered from horses exercising unridden at high intensity on an all-weather track from a global positioning-heart rate unit and a portable ergospirometry system. Data were analysed with an...
