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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.
Use of remote sensing techniques to determine the effects of grazing on vegetation cover and dune elevation at Assateague Island National Seashore: impact of horses. The effects of grazing by feral horses on vegetation and dune topography at Assateague Island National Seashore were investigated using color-infrared imagery, lidar surveys, and field measurements. Five pairs of fenced and unfenced plots (300 m2) established in 1993 on sand flats and small dunes with similar elevation, topography, and vegetation cover were used for this study. Color-infrared imagery from 1998 and field measurements from 2001 indicated that there was a significant difference in vegetation cover between the fenced and unfenced plot-pairs over the study period. Fenced plots cont...
Eye infections due to Listeria monocytogenes in three cows and one horse. A retrospective study was conducted to determine case histories, microbiological characteristics, and molecular subtypes associated with Listeria monocytogenes infections of the eye in large animals. For selected cases, environmental L. monocytogenes contamination patterns on case farms were also evaluated to probe for potential sources and spread of listerial eye infections. Records of 170 L. monocytogenes isolates from animal infections were reviewed to determine the fraction of isolates associated with eye infections (conjunctivitis, keratitis, and uveitis) of animals and to gather informat...
Lead in blood of urban Indian horses. A cross sectional study recorded the Lead (Pb) concentrations in blood from 288 horses in urban areas. Mean blood Pb concentration was estimated as 0.47 +/- 0.02 and 0.55 +/- 0.02 ppm in horses for industrial and highway-adjacent localities respectively. Mean blood Pb in horses from rural areas was 0.38 +/- 0.03 ppm. The mean Pb in forage samples from these horses was 36.96 +/- 6.23, 52.08 +/- 9.86 and 11.72 +/- 1.34 ppm in industrial, highway-adjacent and rural localities respectively. No overt signs of Pb toxicosis were seen in these animals
Assessment of electrical charge on airborne microorganisms by a new bioaerosol sampling method. Bioaerosol sampling is necessary to monitor and control human exposure to harmful airborne microorganisms. An important parameter affecting the collection of airborne microorganisms is the electrical charge on the microorganisms. Using a new design of an electrostatic precipitator (ESP) for bioaerosol sampling, the polarity and relative strength of the electrical charges on airborne microorganisms were determined in several laboratory and field environments by measuring the overall physical collection efficiency and the biological collection efficiency at specific precipitation voltages and po...
Epistaxis related to exercise-induced pulmonary haemorrhage in south African Thoroughbreds. This study investigated if environmental factors had an effect on the incidence of epistaxis related to exercise-induced pulmonary haemorrhage (EIPH) among racehorses in southern Africa. Data covering the period 1986-2001 and involving 778 532 race runs were analysed. This included the following information: date of race, age, sex, name of breeder, trainer, distance, jockey, state of going, weight carried, racing centre and altitude. Veterinarians employed by the Jockey Club suspended officially entered horses that presented with epistaxis (frank bleeding from the nostrils) after racing. On-co...
Airway mucus in recurrent airway obstruction–short-term response to environmental challenge. Mucus accumulation and neutrophilic inflammation in the airways are hallmarks of heaves. Endoscopically visible mucus accumulations, however, have not been studied during exposure to dusty hay and allergens (ie, environmental challenge). We hypothesized that (1) heaves-affected horses have increased mucus accumulation compared with controls, (2) mucus accumulations increase in heaves-affected horses during environmental challenge, and (3) environmental challenge also induces neutrophilic inflammation and mucus accumulation in control horses. Mucus accumulation was graded endoscopically (mucus ...
Detection of Salmonella organisms and assessment of a protocol for removal of contamination in horse stalls at a veterinary teaching hospital. To assess methods of detecting environmental contamination with Salmonella organisms and evaluate a cleaning and disinfection protocol for horse stalls in a veterinary teaching hospital. Methods: Original study. Methods: 37 horses with diarrhea likely to be caused by Salmonella infection and their stall environments. Methods: Fecal samples were collected from horses daily during hospitalization; samples were obtained from stall sites after cleaning and application of disinfectants. Fecal and environmental samples were cultured for Salmonella spp and tested via polymerase chain reaction (PCR) a...
[Fluorescence spectroscopic study of interaction between Fe-protoporphyrin in myoglobin and Cu(II) ions]. In this paper, the interaction between Cu(II) ions and Fe-protoporphyrin in horse-heart myoglobin (FePP-Mb) was studied. As a result, some of the Fe(II) ions in FePP-Mb were found to be replaced by Cu(II) ions forming CuPP-Mb, by adding Cu(II) ions into the myoglobin solution. The interaction became stronger when adding more Cu(II) ions into the myoglobin solution. By studying the metal ions' interaction with myoglobin proteins as macromolecules and discussing the interaction mechanism, this work provides a theoretical basis for the further study of hazardous metal ions' interaction with the h...
California state Mosquito-Borne Virus Surveillance and Response Plan: a retrospective evaluation using conditional simulations. The California Mosquito-Borne Virus Surveillance and Response Plan recently was developed to provide a semi-quantitative means for assessing risk for western equine encephalomyelitis (WEE) or St. Louis encephalitis (SLE) viruses and to provide intervention guidelines for mosquito control and public health agencies during periods of heightened risk for human infection. West Nile virus recently has arrived in California, and the response plan also will provide a baseline for assessing the risk for human and equine infection with this virus. In the response plan, overall risk is calculated by ave...
The toxicokinetics of cyanide and mandelonitrile in the horse and their relevance to the mare reproductive loss syndrome. The epidemiological association between black cherry trees and mare reproductive loss syndrome has focused attention on cyanide and environmental cyanogens. This article describes the toxicokinetics of cyanide in horses and the relationships between blood cyanide concentrations and potentially adverse responses to cyanide. To identify safe and humane blood concentration limits for cyanide experiments, mares were infused with increasing doses (1-12 mg/min) of sodium cyanide for 1 h. Infusion at 12 mg/min produced clinical signs of cyanide toxicity at 38 min; these signs included increased heart...
A simple and highly sensitive spectrophotometric method for the determination of cyanide in equine blood. An epidemiological association among black cherry trees (Prunus serotina), eastern tent caterpillars (Malacosoma americana), and the spring 2001 episode of mare reproductive loss syndrome in central Kentucky focused attention on the potential role of environmental cyanogens in the causes of this syndrome. To evaluate the role of cyanide (CN (-)) in this syndrome, a simple, rapid, and highly sensitive method for determination of low parts per billion concentrations of CN (-) in equine blood and other biological fluids was developed. The analytical method is an adaptation of methods commonly in ...
Chloride/bromide ratios in leachate derived from farm-animal waste. Ratios of conservative chemicals have been used to identify sources of groundwater contamination. While chloride/bromide ratios have been reported for several common sources of groundwater contamination, little work has been done on leachate derived from farm-animal waste. In this study, chloride/bromide ratios were measured in leachate derived from longhorn-cattle, quarterhorse, and pygme-goat waste at a farm in Abilene, Texas, USA. (Minimum, median, and maximum) chloride/bromide ratios of (66.5, 85.6, and 167), (119, 146, and 156), and (35.4, 57.8, and 165) were observed for cattle, horses, ...
[Prevalence of behavioral disorders in the Swiss horse population]. In the Swiss horse population, the prevalence of conspicuous behaviours (behavioural disorders and stable vices) was recorded with a written questionnaire in a representative survey among 1861 horse yards, and the occurrence of the stereotypic behavioural disorders crib-biting, weaving and boxwalking was analysed with emphasis on their association with horse specific (breed, age, sex) and environmental factors (e.g. housing system, nutrition, management and utilisation). 622 horse yards with a total number of 2536 horses answered to the questionnaire, and conspicuous behaviours were described ...
Geographic variability of Escherichia coli ribotypes from animals in Idaho and Georgia. Several genotypic methods have been developed for determining the host origin of fecal bacteria in contaminated waters. Some of these methods rely on a host origin database to identify environmental isolates. It is not well understood to what degree these host origin isolates are geographically variable (i.e., cosmopolitan or endemic). This is important because a geographically limited host origin database may or may not be universally applicable. The objective of our study was to use one genotypic method, ribotyping, to determine the geographic variability of the fecal bacterium, Escherichia ...
An analysis of human pathogens found in horse/mule manure along the John Muir Trail in Kings Canyon and Sequoia and Yosemite National Parks. To determine the prevalence of microorganisms that are potentially pathogenic for humans in horse/mule manure along the John Muir Trail (JMT). Methods: Random samples of horse/mule manure were collected along sections of the JMT in Yosemite, Kings Canyon, and Sequoia national parks (NP), as well as in portions of the Pacific Crest Trail (PCT) and selected JMT/PCT access trails. Convenience samples of wild animal scat found within I mile of trails were also collected. The fresh specimens were individually preserved both in 0.9% saline and polyvinyl alcohol (PVA)-containing tubes and stored at 4...
The use of cardboard bedding material as part of an environmental control regime for heaves-affected horses: in vitro assessment of airborne dust and aeroallergen concentration and in vivo effects on lung function. This study aimed to test whether shredded cardboard is an appropriate minimum-dust bedding material for heaves-affected horses. Results of standardized in vitro measurement of airborne dust and aeroallergen concentrations of cardboard bedding were significantly lower than those of common bedding materials. Six heaves-affected horses in clinical remission after pasturing were stabled for two months on cardboard bedding and fed grass silage. Pulmonary function tests (PFT: ventilatory mechanics, arterial blood gases, airway inflammation scoring, bronchoalveolar cytology) were performed before, du...
Lead poisoning of horses in the vicinity of a battery recycling plant. The diagnosis of lead poisoning in horses living on farmland in the vicinity of a battery recycling plant was based on clinical signs as well as on laboratory findings. Chemical analysis of six surface soils (0-15 cm) and herbage samples taken at different distances to the recycling plant showed very high total lead levels in the closest sites to the facility and a clear decrease with distance. Total lead levels in soil samples ranged from 127 to 5657 mg kg(-1), with more than 70% of lead extractable by EDTA in the most polluted soils. Lead levels in the aerial part of herbage samples were in ...
Industrial chemicals and the horse. Poisoning resulting from exposure to a wide variety of industrial chemicals is not a common occurrence in horses, but it does happen on occasion. A wide range of toxicosis can occur from a wide range of industrial pollutants, such as dioxin, carbon tetrachloride, and tetrachloroethylene, to heavy metals, such as cadmium and zinc. The equine practitioner must consider industrial chemical toxicosis in differential diagnoses and work with a reputable veterinary diagnostic laboratory to confirm or rule out industrial chemical poisoning.
Metal toxicosis in horses. The ubiquity and stability of metals in the environment make them unique as a pollutant or an essential dietary component. Metals are neither created nor destroyed by chemical processes but are redistributed in the environment. In combination with other elements, metal compounds and alloys are essential materials of the contemporary world. Inappropriate use or distribution in the environment leads to adverse health effects on all biologic systems, including horses. Gastrointestinal upset is a common feature of acute toxicosis with metals in general. Among the metals discussed, arsenic and inor...
Application of polymerase chain reaction (PCR) and TaqMan PCR techniques to the detection and identification of Rhodococcus coprophilus in faecal samples. Rhodococcus coprophilus, a natural inhabitant of herbivore faeces, has been suggested as a good indicator of animal (as opposed to human) faecal contamination of aquatic environments. However, conventional detection methods limit its use for this as they require up to 21 days to obtain a result. In this paper an optimised method for extracting R. coprophilus DNA from faecal samples is described. PCR and 5'-nuclease (TaqMan) PCR methods were developed to allow the detection and enumeration of R. coprophilus in faecal samples within 2-3 days. Both PCR methods targeted the 16S rRNA gene, producin...
Chemical, physical, and environmental properties of pelleted newspaper compared to wheat straw and wood shavings as bedding for horses. Two experiments were conducted comparing pelleted recycled newspaper (PN) to wheat straw (S) and kiln-dried pine wood shavings (WS) as an animal bedding material. Adult horses housed 20 to 21 h/d in boxstalls served as the animal model for comparisons. In Exp. 1 eight boxstalls, each housing one horse, were each bedded with two types of PN (0.32 and 0.64 x 2.54 cm), S, and WS over four 5-d periods (replicated 4 x 4 Latin square). Initial amounts of bedding materials surpassed most commercial conditions, but stalls were cleaned daily of feces only and additional clean bedding was added as neede...
Identification of sources of Salmonella organisms in a veterinary teaching hospital and evaluation of the effects of disinfectants on detection of Salmonella organisms on surface materials. To determine sources of Salmonella organisms in a veterinary teaching hospital, compare bacterial culture with polymerase chain reaction (PCR) testing for detection of Salmonella organisms in environmental samples, and evaluate the effects of various disinfectants on detection of Salmonella organisms on surface materials. Methods: Prospective study. Methods: Fecal samples from 638 hospitalized horses and 783 environmental samples. Methods: Standard bacterial culture techniques were used; the PCR test amplified a segment of the Salmonella DNA. Five disinfectants were mixed with Salmonella suspe...
Tracheobronchial mucus viscoelasticity during environmental challenge in horses with recurrent airway obstruction. The goal of this study was to compare the rheological properties of mucus from horses with recurrent airway obstruction (RAO) to that from healthy controls during environmental challenge by stabling in stalls with straw as bedding and hay as feed. We determined viscoelasticity (log G* dyn/cm2, at 10 radian/s) and calculated mucociliary clearability index (MCI) and cough clearability index (CCI), which are derivative parameters of G* and the ratio of viscosity and elasticity measured at 1 and 100 radian/s, respectively. We also investigated the solids content of mucus, and cytology of bronchoal...
Isolation of environmental Clostridium difficile from a veterinary teaching hospital. An environmental survey of a veterinary teaching hospital for the presence of Clostridium difficile was performed using contact plates and cycloserine-cefoxitin-fructose with 0.1% sodium taurocholate agar. Clostridium difficile was isolated from 24 of 381 sites (6.3%). Growth was obtained from 4.5% (9/202) of sites sampled in the Large Animal Clinic, from 8.1% (13/160) of sites within the Small Animal Clinic, and from 20% (2/10) of sites sampled elsewhere. Fourteen of 21 strains tested produced toxins in vitro. A geographic association was found with areas in the large animal clinic where noso...
Effect of daily floor treatment with sodium bisulfate on the fly population of horse stalls. To determine application rate and effectiveness of sodium bisulfate to decrease the fly population in a horse barn environment. Methods: 12 privately owned farms in southeastern Pennsylvania. Methods: Application rates of sodium bisulfate were approximately 2.3 kg/stall, 1.1 kg/stall, and 0.5 kg/stall. Two or 3 stalls were treated, and 1 or 2 stalls were not treated (control stalls) at each farm. Farm personnel applied sodium bisulfate in treated stalls daily for 7 days. Fly tapes were hung from the same site in treated and control stalls. After 24 hours, the fly tape was removed, flies adheri...
Concentrations of cadmium, lead and zinc in livestock feed and organs around a metal production centre in eastern Kazakhstan. This paper presents results of analysis of animal feed and meat (cattle, horse and sheep) products from a metal processing region (Oskemen) in east Kazakhstan. Samples were collected from a range of districts of differing distances from the main source of anthropogenic pollution and with differing underlying metal-containing geologies. Analyses for cadmium, lead and zinc revealed high concentrations in many feed and meat samples. Horse (an important food animal) samples had higher levels of contamination than cattle, which were higher than sheep. For example, mean cadmium concentrations in hor...
The effect of increasing visual horizons on stereotypic weaving: implications for the social housing of stabled horses. Stabled horses commonly perform stereotypic patterns of weaving, where the horse shifts its weight from side to side often swinging its head. Ten warm-blood types, of which five were known to reliably weave, were housed in similar 12x12 ft wooden loose boxes in a single stable block surrounding a courtyard. Each horse was exposed to each of five stable designs. These were: the conventional front top-half of the door open only with a view of the stable courtyard (F); front half-door open and a similar half-door open at the back of the stable with a view to the surrounding fields (FB); back open...
