Analyze Diet

Topic:Environmental Stressors

Environmental stressors encompass a range of external factors that can impact the health and well-being of horses. These stressors include temperature extremes, humidity, air quality, noise, and changes in habitat or management practices. Horses may exhibit physiological and behavioral responses to these stressors, which can affect their overall health, performance, and welfare. Research in this area focuses on understanding how environmental variables influence equine physiology and behavior, as well as identifying management strategies to mitigate negative effects. This page compiles peer-reviewed research studies and scholarly articles that explore the effects of environmental stressors on horses, examining their impact on health, performance, and welfare.
Environmental stress and 3-day eventing: effects of altitude.
Equine veterinary journal. Supplement    February 5, 2000   Issue 30 394-397 doi: 10.1111/j.2042-3306.1999.tb05254.x
Foreman JH, Waldsmith JK, Lalum RB.Three-day event horses are subject to various external environmental stresses including changes in ambient temperature, humidity, altitude, and test severity. Considerable research on the adverse effects of increased heat and humidity preceded the 1996 Olympic Summer Games in Atlanta, Georgia USA, but no research has been done previously on the effects of altitude on 3-day eventing. Physical and venous blood gas data were collected on horses (n = 24) competing in the High Prairie Preliminary (CCN*) and Intermediate (CCN**) 3-day events and Preliminary Horse Trials in Parker, Colorado (1900 m a...
Effect of ambient temperature and humidity on pulmonary artery temperature of exercising horses.
Equine veterinary journal. Supplement    February 5, 2000   Issue 30 404-411 doi: 10.1111/j.2042-3306.1999.tb05256.x
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...
Secular sperm trends in stallions between 1981 and 1996.
Journal of andrology    December 11, 1999   Volume 20, Issue 6 763-768 
Multigner L, Magistrini M, Ducot B, Spira A.Several reports have suggested that human semen quality has declined throughout the world over the last few decades. Chemicals in the environment acting as endocrine disrupters have been implicated as a possible cause. If this is indeed the case, then similar effects may be observed in animals. We analyzed 1489 ejaculates collected from 390 Breton draught stallions between 1981 and 1996. Semen was collected from all the stallions at a single center, according to standardized semen collection protocols and laboratory methods. Semen volume decreased slightly but significantly and there was an in...
Ambient temperature and relative humidity influenced packed cell volume, total plasma protein and other variables in horses during an incremental submaximal field exercise test.
Equine veterinary journal    August 24, 1999   Volume 31, Issue 4 314-318 doi: 10.1111/j.2042-3306.1999.tb03823.x
Hargreaves BJ, Kronfeld DS, Naylor JR.Thermoregulation may limit exercise performance under hot and humid conditions. This study compared heart rate (HR), respiratory rate (RR), rectal temperature (Tr), packed cell volume (PCV) and total plasma protein concentration (TPP) during a submaximal incremental field exercise test under high vs. low ambient temperature and relative humidity. Ten horses were tested 3 times in summer (July) and 3 times in autumn (September). Heart rate was measured continuously, the other variables at rest and immediately after 4 min at 3.5, 4.5 and 7.0 m/s, separated by 3 min rest intervals, and after 5 an...
Animals and man: a complex relationship examined.
The Veterinary record    December 5, 1998   Volume 143, Issue 19 515-517 
No abstract available
Acclimation and acclimatisation of the equine athlete.
International journal of sports medicine    August 7, 1998   Volume 19 Suppl 2 S164-S166 doi: 10.1055/s-2007-971987
Marlin DJ.A number of studies have clearly shown that the ability of both man and horses to perform a standardised exercise test in hot humid conditions is reduced compared to that in hot dry or cool conditions (see reviews by Maughan and Lindinger, 1995; Lindinger and Marlin, 1995). In man it is clear that a period of acclimation or acclimatisation is beneficial. A search of the literature prior to 1995 indicates no published information relating to the acclimation or acclimatisation of the horse to hot or hot humid environmental conditions. Concerns for the appropriate preparation for and welfare of h...
Effect of exercise on fluid balance and renal function in horses.
The Veterinary clinics of North America. Equine practice    April 30, 1998   Volume 14, Issue 1 23-44 doi: 10.1016/s0749-0739(17)30210-9
McKeever KH.Exercise places large demands on the equine cardiovascular system which are further complicated by environmental factors. In many respects, performance is limited by fluid and electrolyte stores and the ability to maintain cardiovascular and thermoregulatory stability in the face of severe sweat losses. Studies in the exercising horse have been primarily descriptive or associative, with only a limited number seeking to identify physiologic mechanisms associated with the control of fluid and electrolyte balance. More mechanistic studies are needed to fully understand the integration of the card...
Environmental control to maintain stabled COPD horses in clinical remission: effects on pulmonary function.
Equine veterinary journal    April 16, 1998   Volume 30, Issue 2 93-96 doi: 10.1111/j.2042-3306.1998.tb04466.x
Vandenput S, Duvivier DH, Votion D, Art T, Lekeux P.The objective of this study was to test the hypothesis that stabled COPD horses can be maintained in clinical remission by replacing hay by grass silage and bedding made of wood shavings (Period B) and of wheat straw (Period C) during 6 weeks, respectively. At the end of these different periods, the pulmonary function of the horses was assessed by mechanics of breathing and arterial blood analyses. These results were compared to those measured in clinical remission obtained after 2 months in pasture (Period A). No significant difference was observed between these 3 periods neither to values ob...
Comments on chronic environmental cadmium toxicosis in horses and cattle.
Journal of the American Veterinary Medical Association    February 21, 1998   Volume 212, Issue 3 340-341 
Smith RM.No abstract available
Some factors governing the entry of Culicoides spp. (Diptera: Ceratopogonidae) into stables.
The Onderstepoort journal of veterinary research    February 19, 1998   Volume 64, Issue 3 227-233 
Barnard BJ.The entry of Culicoides species into stables was examined by comparing the numbers of midges caught with identical light-traps under different conditions. The comparison was made between collections made inside an empty stable, a regularly cleaned stable and a dirty stable and those made outside the stables in a sleeping space open on two sides. The work was first done in the presence of cattle and sheep in adjoining paddocks and then repeated in their absence. A positive correlation was found between the numbers of C. imicola females caught out of doors and inside a clean stable. Removal of t...
Influence of Llamas, Horses, and Hikers on Soil Erosion from Established Recreation Trails in Western Montana, USA.
Environmental management    February 18, 1998   Volume 22, Issue 2 255-262 doi: 10.1007/s002679900101
Deluca TH, Patterson Iv WA , Freimund WA, Cole DN./ Various types of recreational traffic impact hiking trails uniquely and cause different levels of trail degradation; however, trail head restrictions are applied similarly across all types of packstock. The purpose of this study was to assess the relative physical impact of hikers, llamas, and horses on recreational trails. Horse, llama, and hiker traffic were applied to 56 separate plots on an existing trail at Lubrecht Experimental Forest in western Montana. The traffic was applied to plots at intensities of 250 and 1000 passes along with a no-traffic control under both prewetted and dry t...
Chronic environmental cadmium toxicosis in horses and cattle.
Journal of the American Veterinary Medical Association    November 28, 1997   Volume 211, Issue 10 1229-1230 
Swerczek TW.No abstract available
Small airway disease as a vanguard for chronic obstructive pulmonary disease.
The Veterinary clinics of North America. Equine practice    November 22, 1997   Volume 13, Issue 3 549-560 doi: 10.1016/s0749-0739(17)30230-4
Viel L.Equine allergic small airway disease is a highly prevalent respiratory condition among the stabled horse population. With the assistance of new diagnostic tools such as bronchoalveolar lavage, the condition can be recognized in young performing horses. The pathophysiological and clinical features resemble an earlier stage of chronic obstructive pulmonary disease as determined by the appearance of specific inflammatory cells. Although environmental management is paramount in controlling the disease, proper selective therapeutic regimens are as important to reduce the concurrent inflammation and...
Radiation hazards from horses undergoing scintigraphy using technetium-99m.
Equine veterinary journal    January 1, 1997   Volume 29, Issue 1 26-30 doi: 10.1111/j.2042-3306.1997.tb01632.x
Whitelock RG.This paper quantifies the extent of the radiation hazard to personnel from horses undergoing scintigraphy using technetium99m methylene diphosphonate (99Tcm-MDP). From the data produced it is possible to derive safe working protocols which are comfortably within the legislated limits for whole body doses as set out in the Ionising Radiations Regulations 1985. Measurements were made of the surface and environmental activities which result from individuals undergoing scintigraphic evaluation and also from urine contaminated bedding. The use of both high and low activities in the assessment of th...
The prevalence of shedding of Cryptosporidium and Giardia spp. based on a single fecal sample collection from each of 91 horses used for backcountry recreation. Johnson E, Atwill ER, Filkins ME, Kalush J.Cryptosporidium parvum and Giardia duodenalis are now recognized as primary enteric pathogens in animals and humans. Regulatory agencies, such as the Environmental Protection Agency are under increasing pressure to reduce the concentration of these protozoa in surface waters. Given the popularity of recreational riding of horses on public land in California backcountry, concerns have been raised by various regulatory agencies as to whether horses used for backcountry recreation are a significant source of C. parvum and G. duodenalis for the environment. The prevalence of fecal shedding of Cryp...
Methanogenesis in monogastric animals.
Environmental monitoring and assessment    September 1, 1996   Volume 42, Issue 1-2 99-112 doi: 10.1007/BF00394044
Jensen BB.Studies of methanogenic bacteria present in monogastric animals are still scarce. Methanogens have been isolated from faeces of rat, horse, pig, monkey, baboon, rhinoceros, hippopotamus, giant panda, goose, turkey and chicken. The predominant methanogen in all except the chicken and turkey is species of Methanobrevibacterium. The chicken and turkey harbour species of Methanogenium. In pig the population of methanogenic bacteria is more than 30 times as dense in the distal colon as in the caecum. This finding is in agreement with the finding that the rate of methane production is much higher in...
Pulmonary function measurements during repeated environmental challenge of horses with recurrent airway obstruction (heaves).
American journal of veterinary research    August 1, 1996   Volume 57, Issue 8 1214-1219 
Tesarowski DB, Viel L, McDonell WN.To evaluate the degree of reproducibility in clinical variables, blood gas measurements, and lung function variables, and the changes in these variables caused by exposure to moldy hay in naturally sensitized and control horses. Methods: The magnitude of variation in arterial blood gas and pulmonary function measurements were evaluated in a model of naturally acquired heaves. Horses with heaves and similarly aged control horses were studied prior to moldy hay challenge and again after the horses with heaves manifested clinical signs of airway obstruction. This cycle of testing was repeated 3 t...
Use of the Wet Bulb Globe Temperature (WBGT) index to quantify environmental heat loads during three-day-event competitions.
Equine veterinary journal. Supplement    July 1, 1996   Issue 22 3-6 doi: 10.1111/j.2042-3306.1996.tb05025.x
Schroter RC, Marlin DJ, Jeffcott LB.No abstract available
Physiological responses in nonheat acclimated horses performing treadmill exercise in cool (20 degrees C/40% RH), hot dry (30 degrees C/40% RH) and hot humid (30 degrees C/80% RH) conditions.
Equine veterinary journal. Supplement    July 1, 1996   Issue 22 70-84 
Marlin DJ, Scott CM, Schroter RC, Mills PC, Harris RC, Harris PA, Orme CE, Roberts CA, Marr CM, Dyson SJ, Barrelet F.The aim of the present study was to determine the effect of different environmental conditions on physiological response to exercise. Four winter acclimatised, nonheat acclimated horses of different breeds were exercised at 20 degrees C/40% RH (CD), 30 degrees C/40% RH (HD) and 30 degrees C/80% RH (HH). The exercise test was designed to represent the structure and intensity of a One star Speed and Endurance test (competition exercise test [CET]). All 4 horses were able to complete the full CET (60 min + 30 min active recovery) in CD and HD, but only one horse completed the CET in HH. Two horse...
Effects of exercise intensity and environmental stress on indices of oxidative stress and iron homeostasis during exercise in the horse.
European journal of applied physiology and occupational physiology    January 1, 1996   Volume 74, Issue 1-2 60-66 doi: 10.1007/BF00376495
Mills PC, Smith NC, Casas I, Harris P, Harris RC, Marlin DJ.The effects of prolonged variable-intensity and short-term high-intensity exercise on indices of oxidative stress and iron homeostasis were compared in six fit horses under cool [20 degrees C, 40% relative humidity (RH)] or hot/humid (30 degrees C, 80% RH) environmental conditions. The exercise protocols were designed to simulate equine competition, including racing (intense exercise) or the speed and endurance phase of a 3-day event (prolonged exercise). Increased plasma concentrations of lipid hydroperoxides and haemolysate concentrations of oxidised glutathione (GSSG) were measured within 3...
Recent acute and subacute mycotoxicoses recognized in France.
Veterinary research    January 1, 1996   Volume 27, Issue 4-5 383-394 
Le Bars J, Le Bars P.Successful investigation and prevention of mycotoxic problems requires close collaboration between scientists from several disciplines ranging from agronomists and technologists required during production of food and feeds, to toxicologists and pathologists examining the effects of mycotoxins on animals and man. Zootoxic metabolites following fungal infection result from four general mechanisms: (i) secondary fungal metabolism (mycotoxins, eg, aflatoxins); (ii) bioconversion of vegetal compounds (eg, dicoumarol); (iii) plant reactions (phytoalexins, eg, coumestrol); and (iv) plant-fungus assoc...
Invited editorial on “Selective brain cooling in the horse during exercise and environmental heat stress”.
Journal of applied physiology (Bethesda, Md. : 1985)    December 1, 1995   Volume 79, Issue 6 1847-1848 doi: 10.1152/jappl.1995.79.6.1847
Baker MA.No abstract available
Selective brain cooling in the horse during exercise and environmental heat stress.
Journal of applied physiology (Bethesda, Md. : 1985)    December 1, 1995   Volume 79, Issue 6 1849-1854 doi: 10.1152/jappl.1995.79.6.1849
McConaghy FF, Hales JR, Rose RJ, Hodgson DR.Five horses were exercised on a treadmill [to central blood temperature (Tcore) approximately 42.5 degrees C]. Three of those horses were heated at rest in a climate room (53 degrees C, 90% relative humidity) (to Tcore approximately 41.5 degrees C). Temperatures were measured in the rectum, hypothalamus (Thyp), cerebrum, and cavernous sinus (Tsinus), on the skin of the head and midside, and Tcore. When Tcore increased above 38.5 degrees C, Thyp remained 0.6 +/- 0.1 degree C (SE) lower during heat exposure and 1 +/- 0.2 degrees C lower during exercise. During heat exposure, Tsinus was 2.2 +/- 0...
Electrolyte and total protein changes in nonheat acclimated horses performing treadmill exercise in cool (20 degrees C/40%RH), hot, dry (30 degrees C/40%RH) or hot, humid (30 degrees C/80%RH) conditions.
Equine veterinary journal. Supplement    November 1, 1995   Issue 20 85-96 
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...
Heart rate response and plasma lactate concentrations of horses competing in the speed and endurance phase of 3-day combined training events.
Equine veterinary journal. Supplement    November 1, 1995   Issue 20 52-56 doi: 10.1111/j.2042-3306.1995.tb05008.x
White SL, Williamson LH, Maykuth PL, Cole SP, Andrews FM.The exercise intensity of horses competing in 3-day combined training events at 3 different levels of competition (CCI, n = 7; CCI, n = 11; CCI, n = 23) was investigated. Environmental conditions during all events were cool with 100% cloud cover. Heart rates were continuously recorded at 5 s intervals by a heart rate monitor. Mean +/- s.d. heart rate for all horses during each phase were: Phase A = 118 +/- 11 beats/min, Phase B = 179 +/- 22.7 beats/min, Phase C = 129 +/- 13.9 beats/min and Phase D = 174 +/- 19.6 beats/min. Mean +/- s.d. heart rates on Phase A and C were significantly different...
An index of the environmental thermal load imposed on exercising horses and riders by hot weather conditions.
Equine veterinary journal. Supplement    November 1, 1995   Issue 20 16-22 doi: 10.1111/j.2042-3306.1995.tb05003.x
Schroter RC, Marlin DJ.There is a need to determine objectively the environmental heat load imposed on horses competing to an international standard in 3-day-events in environments where there is likely to be a high level of radiation added to high ambient temperatures and relative humidity; the presently used FEI 'Comfort Index' is severely limited in its applicability. It is proposed that the Wet Bulb Globe Temperature (WBGT) Index be used. This index was originally established for man exercising strenuously under harsh climatic conditions with high solar radiation levels. It may be defined as: WBGT = 0.7Twb + 0.3...
‘No hoof no horse?’.
Equine veterinary journal    May 1, 1995   Volume 27, Issue 3 166-168 doi: 10.1111/j.2042-3306.1995.tb03058.x
Reilly JD.No abstract available
Copper deficiency in cattle, sheep and horses caused by excess molybdenum from fly ash: a case report.
Veterinary and human toxicology    February 1, 1995   Volume 37, Issue 1 63-65 
Ladefoged O, Stürup S.A case of copper deficiency or molybdenum toxicosis in cattle, sheep and horses after heavy pollution of a pasture with fly ash is described. If the pastures had not been grazed by cattle and sheep as well as the horses, it would have been difficult to identify the reason for the intoxication in the horses. It is argued that molybdenum intoxication, although seldom seen in non-ruminants, was the cause of the deaths of the horses. It is suggested that the bioavailability of molybdenum in fly ash is high and therefore can cause equine intoxication.
Emergence of eastern encephalitis in Massachusetts.
Annals of the New York Academy of Sciences    December 15, 1994   Volume 740 157-168 doi: 10.1111/j.1749-6632.1994.tb19866.x
Komar N, Spielman A.The 20th century emergence in Massachusetts of zoonotic eastern encephalitis was interpreted in terms of recorded environmental change. The main mosquito vector of the infection, Cs. melanura, appears to have been scarce in eastern North America before the 1930s. Its relative scarcity resulted from destruction of the swamps that had been lumbered or drained for farming in the 18th and 19th centuries. When swamps matured once again early in the 1900s, the formation of subsurface pools of water beneath mature trees would have increased the availability of breeding sites for this mosquito. Transm...
Application of PCR to a clinical and environmental investigation of a case of equine botulism.
Journal of clinical microbiology    August 1, 1994   Volume 32, Issue 8 1986-1991 doi: 10.1128/jcm.32.8.1986-1991.1994
Szabo EA, Pemberton JM, Gibson AM, Thomas RJ, Pascoe RR, Desmarchelier PM.PCR for the detection of botulinum neurotoxin gene types A to E was used in the investigation of a case of equine botulism. Samples from a foal diagnosed with toxicoinfectious botulism in 1985 were reanalyzed by PCR and the mouse bioassay in conjunction with an environmental survey. Neurotoxin B was detected by mouse bioassay in culture enrichments of serum, spleen, feces, and intestinal contents. PCR results compared well with mouse bioassay results, detecting type B neurotoxin genes in these samples and also in a liver sample. Other neurotoxin types were not detected by either test. Clostrid...