Analyze Diet

Topic:Pasture

Pasture and horses involve the study and management of grazing environments and their impact on equine health, nutrition, and behavior. Pastures serve as a primary source of forage, providing essential nutrients and contributing to the overall well-being of horses. Factors such as pasture composition, quality, and management practices influence the nutritional intake and health of grazing horses. Research in this area often focuses on optimizing pasture conditions to support equine dietary needs, prevent overgrazing, and manage pasture-related health issues such as laminitis. This page compiles peer-reviewed research studies and scholarly articles that explore the relationship between pasture management and equine health, including topics on forage quality, grazing behavior, and pasture maintenance strategies.
Do different livestock dwellings on single grassland share similar faecal microbial communities?
Applied microbiology and biotechnology    May 4, 2019   Volume 103, Issue 12 5023-5037 doi: 10.1007/s00253-019-09849-1
Yang J, Wang Y, Cui X, Zhang Y, Yu Z.Huge numbers of microorganisms reside in livestock faeces and constitute one of the most complex microbial ecosystems. Here, faecal microbial communities of three typical livestock in Xilingol steppe grassland, i.e. sheep, cattle, and horse, were investigated by Illumina MiSeq sequencing and quantitative real-time polymerase chain reaction (qPCR). Firmicutes and Bacteroidetes comprised the majority of bacterial communities in three livestock faeces. Sordariomycetes, Leotiomycetes, and Dothideomycetes were dominant in fungal communities, as well as Methanobacteria and Methanomicrobia were domin...
Potential new sources of hypoglycin A poisoning for equids kept at pasture in spring: a field pilot study.
The Veterinary record    May 2, 2019   Volume 184, Issue 24 740 doi: 10.1136/vr.104424
Votion DM, Habyarimana JA, Scippo ML, Richard EA, Marcillaud-Pitel C, Erpicum M, Gustin P.Equine atypical myopathy in Europe results from hypoglycin A (HGA) exposure through the ingestion of samaras or seedlings of the sycamore maple tree. This pilot study aimed at better defining sources of HGA intoxication in spring. Samaras fallen on the ground and then seedlings were collected at two-week intervals from sycamore, Norway, and field maple trees over the spring 2016. In early April, rainwater from wet seedlings collected after a rainy night was harvested to be analysed. Mid-May, samaras of the box elder, common ash, and inflorescences of sycamore maples were collected on the tree....
Utilizing the fecal microbiota to understand foal gut transitions from birth to weaning.
PloS one    April 30, 2019   Volume 14, Issue 4 e0216211 doi: 10.1371/journal.pone.0216211
De La Torre U, Henderson JD, Furtado KL, Pedroja M, Elenamarie O, Mora A, Pechanec MY, Maga EA, Mienaltowski MJ.A healthy gastrointestinal (GI) tract with a properly established microbiota is necessary for a foal to develop into a healthy weanling. A foal's health can be critically impacted by aberrations in the microbiome such as with diarrhea which can cause great morbidity and mortality in foals. In this study, we hypothesized that gut establishment in the foal transitioning from a diet of milk to a diet of grain, forage, and pasture would be detectable through analyses of the fecal microbiotas. Fecal samples from 37 sets of foals and mares were collected at multiple time points ranging from birth to...
Equine airway inflammation in loose-housing management compared with pasture and conventional stabling.
The Veterinary record    March 9, 2019   Volume 184, Issue 19 590 doi: 10.1136/vr.104580
Hansen S, Klintoe K, Austevoll M, Baptiste KE, Fjeldborg J.Icelandic horses are often stabled in loose-housing systems, and to date this type of stabling has not been evaluated with regard to its potential impact on respiratory health. The objective was to assess if differences in management systems (eg, conventional stable, loose housing and pasture only) affect the degree of airway inflammation, evaluated by cytology of tracheal aspirate (TA) and bronchoalveolar lavage (BAL) fluid. In total, 84 Icelandic horses (aged 8.1±4.6 years) housed under three different management systems (conventional stables [n=29], loose-house systems [n=29] and pasture [...
Different effects of alpine woody plant expansion on domestic and wild ungulates.
Global change biology    February 28, 2019   Volume 25, Issue 5 1808-1819 doi: 10.1111/gcb.14587
Espunyes J, Lurgi M, Büntgen U, Bartolomé J, Calleja JA, Gálvez-Cerón A, Peñuelas J, Claramunt-López B, Serrano E.Changes in land-use and climate affect the distribution and diversity of plant and animal species at different spatiotemporal scales. The extent to which species-specific phenotypic plasticity and biotic interactions mediate organismal adaptation to changing environments, however, remains poorly understood. Woody plant expansion is threatening the extent of alpine grasslands worldwide, and evaluating and predicting its effects on herbivores is of crucial importance. Here, we explore the impact of shrubification on the feeding efficiency of Pyrenean chamois (Rupicapra p. pyrenaica), as well as ...
Atypical myopathy-associated hypoglycin A toxin remains in sycamore seedlings despite mowing, herbicidal spraying or storage in hay and silage.
Equine veterinary journal    January 30, 2019   Volume 51, Issue 5 701-704 doi: 10.1111/evj.13070
González-Medina S, Montesso F, Chang YM, Hyde C, Piercy RJ.Several pasture management strategies have been proposed to avoid hypoglycin A (HGA) intoxication in horses, but their efficacy has never been investigated. Objective: To evaluate the effect of mowing and herbicidal spraying on HGA content of sycamore seedlings and the presence of HGA in seeds and seedlings processed within haylage and silage. Methods: Experimental study. Methods: Groups of seedlings were mowed (n = 6), sprayed with a dimethylamine-based (n = 2) or a picolinic acid-based herbicide (n = 1). Seedlings were collected before intervention, and at 48 h, 1 and 2 weeks after. ...
Species distribution and seasonal dynamics of equine tick infestation in two Mediterranean climate niches in Israel.
Parasites & vectors    October 16, 2018   Volume 11, Issue 1 546 doi: 10.1186/s13071-018-3093-0
Tirosh-Levy S, Gottlieb Y, Apanaskevich DA, Mumcuoglu KY, Steinman A.Ticks are important ectoparasites of horses that can affect animal welfare and vector several infectious, including zoonotic, diseases. In order to investigate the species distribution, epidemiology and seasonal dynamics of ticks infesting horses in Israel, 3267 ticks were collected from 396 horses in 24 farms across the country from July 2014 to June 2015. Results: Ticks were found on 50% of the farms and on 25% of the horses, with Hyalomma being the most prevalent genus (70% of ticks). Pasture was the most prominent risk factor for tick infestation (99% of ticks, P < 0.001), and is repres...
Newborn foal with atypical myopathy.
Journal of veterinary internal medicine    September 14, 2018   Volume 32, Issue 5 1768-1772 doi: 10.1111/jvim.15236
Karlíková R, Široká J, Mech M, Friedecký D, Janečková H, Mádrová L, Hrdinová F, Drábková Z, Dobešová O, Adam T, Jahn P.The case of atypical myopathy (AM) in newborn Haflinger foal with clinical signs of depression and weakness appearing 6 hours after birth resulting in recumbency 12 hours after birth is described. The foal's dam was diagnosed with AM in the 6th month of gestation based on clinical signs of a myopathy, elevated serum activity of creatine kinase, metabolomic analysis and the presence of methylenecyclopropyl acetyl carnitine (MCPA-carnitine) in the blood. At the time of delivery, the mare was grazing on a pasture near sycamore trees but was free of clinical signs of AM. Metabolomic analysis of th...
Risk factors associated with strongylid egg count prevalence and abundance in the United States equine population.
Veterinary parasitology    May 31, 2018   Volume 257 58-68 doi: 10.1016/j.vetpar.2018.05.006
Nielsen MK, Branan MA, Wiedenheft AM, Digianantonio R, Scare JA, Bellaw JL, Garber LP, Kopral CA, Phillippi-Taylor AM, Traub-Dargatz JL.Equine strongyle parasites are considered ubiquitous in grazing equids across the world, and cyathostomin parasites are known pathogens causing well-described disease complexes in horses. Decades of intensive anthelmintic treatments have led to anthelmintic resistance in cyathostomins, and current recommendations are to lower treatment intensity and base control strategies on fecal egg count surveillance. Little is known about risk factors associated with strongyle parasite egg shedding patterns in the United States equine population, as the most recent national survey was conducted 20 years a...
Technical note: Comparing 4 techniques for estimating desired grass species composition in horse pastures.
Journal of animal science    April 19, 2018   Volume 96, Issue 6 2219-2225 doi: 10.1093/jas/sky111
Kenny LB, Ward D, Robson MG, Williams CA.Many methods exist for estimating species composition, but few studies compare those useful in improved horse pastures. The objective of this study was to examine 4 techniques for estimating desirable forage species composition in 2 cool-season horse pastures based on prevalence estimates, repeatability, bias, and practicality, and to select a method for use in a subsequent grazing study. The techniques included Equine Pasture Evaluation Disc (EPED), Line-Point Intercept with 3 transects of 50 observations each (LPI 3-50), LPI with 5 transects of 30 observations each (LPI 5-30), and Step Point...
Grass greenness flush can influence breeding phenology and fertility in equatorial thoroughbred mares in the absence of photoperiod variation.
Animal science journal = Nihon chikusan Gakkaiho    April 17, 2018   Volume 89, Issue 6 919-924 doi: 10.1111/asj.12964
Carranza J, Yoong WA, Vergara BC, Briones A, Mateos C.Reproductive phenology is an important trait subjected to natural selection. Current horses in America belong to the Palearctic original populations after being introduced by European colonizers. Photoperiod variation is the main environmental factor for the adjustment of reproductive timing in horses, but is absent in equatorial areas. Here we hypothesize that seasonality of green-grass availability may influence breeding phenology in equatorial regions. We used data of 929 services to mares from 2006 to 2011 in a thoroughbred equine exploitation in Ecuador that experienced strong grass seaso...
How grazing affects soil quality of soils formed in the glaciated northeastern United States.
Environmental monitoring and assessment    February 21, 2018   Volume 190, Issue 3 159 doi: 10.1007/s10661-018-6550-5
Cox AH, Amador JA.Historically, much of the New England landscape was converted to pasture for grazing animals and harvesting hay. Both consumer demand for local sustainably produced food, and the number of small farms is increasing in RI, highlighting the importance of characterizing the effects livestock have on the quality of pasture soils. To assess how livestock affect pasture on Charlton and Canton soils series in RI, we examined soil quality in farms raising beef cattle (Bos taurus), sheep (Ovis aries), and horses (Equus ferus caballus), using hayed pastures as a control. We sampled three pastures per li...
Enzootic calcinosis in horses grazing Solanum glaucophyllum in Argentina. Odriozola ER, Rodríguez AM, Micheloud JF, Cantón GJ, Caffarena RD, Gimeno EJ, Bodega JJ, Gardey P, Iseas FB, Giannitti F.Solanum glaucophyllum, a toxic plant known for its calcinogenic effects, causes enzootic calcinosis in ruminant and monogastric animals. We describe an outbreak of enzootic calcinosis that occurred in a herd of 110 horses grazing pastureland heavily contaminated with S. glaucophyllum in Buenos Aires province, Argentina. Ten horses developed clinical signs, and 6 horses died. Clinical signs included abnormal gait (stiff-legged action, short strides), stiffness, thoracolumbar kyphosis, reluctance to move, wide stance, chronic weight loss, weakness, recumbency, and difficulty standing. Autopsy of...
Stable isotopes reveal diet shift from pre-extinction to reintroduced Przewalski’s horses.
Scientific reports    July 20, 2017   Volume 7, Issue 1 5950 doi: 10.1038/s41598-017-05329-6
Kaczensky P, Burnik Šturm M, Sablin MV, Voigt CC, Smith S, Ganbaatar O, Balint B, Walzer C, Spasskaya NN.The Przewalski's horse (Equus ferus przewalskii), the only remaining wild horse within the equid family, is one of only a handful of species worldwide that went extinct in the wild, was saved by captive breeding, and has been successfully returned to the wild. However, concerns remain that after multiple generations in captivity the ecology of the Przewalski's horse and / or the ecological conditions in its former range have changed in a way compromising the species' long term survival. We analyzed stable isotope chronologies from tail hair of pre-extinction and reintroduced Przewalski's horse...
Application of a wearable GPS unit for examining interindividual distances in a herd of Thoroughbred dams and their foals.
Journal of equine science    March 28, 2017   Volume 28, Issue 1 13-17 doi: 10.1294/jes.28.13
Sato F, Tanabe T, Murase H, Tominari M, Kawai M.Global positioning system (GPS) units are now lightweight and compact. They have proven useful for analyzing the behavioral characteristics of horses in pastures. Because the GPS records data in latitude and longitude, it may be feasible to calculate the distance between GPS units. The present study aimed to confirm the applicability of GPS units in behavioral studies on horses. For this, we analyzed the accuracy of the distances calculated from GPS units using Hubeny's distance formula and of the monthly changes in interindividual distances obtained from GPS units worn by Thoroughbred dams an...
Pathological changes seen in horses in New Zealand grazing Mediterranean tall fescue (Lolium arundinaceum) infected with selected endophytes (Epichloë coenophiala) causing equine fescue oedema.
New Zealand veterinary journal    November 6, 2016   Volume 65, Issue 3 147-151 doi: 10.1080/00480169.2016.1248516
Munday JS, Finch SC, Vlaming JB, Sutherland BL, Fletcher LR.To investigate whether Mediterranean tall fescue (Lolium arundinaceum (Schreb.) Darbysh. (syn Festuca arundinacea)) infected with selected fungal endophytes (Epichloë coenophiala (formerly Neotyphodium coenophialum)) caused equine fescue oedema when grown in New Zealand, and to examine the pathological changes associated with this intoxication. Methods: Horses were grazed on Mediterranean tall fescue that was infected with the endophytes AR542 (n=2), or AR584 (n=3), or Mediterranean tall fescue that was endophyte-free (n=2). Blood samples were taken up to 7 days after the start of feeding to ...
Prospective cohort study evaluating risk factors for the development of pasture-associated laminitis in the United Kingdom.
Equine veterinary journal    August 25, 2016   Volume 49, Issue 3 300-306 doi: 10.1111/evj.12606
Menzies-Gow NJ, Harris PA, Elliott J.Certain individuals appear to be predisposed to recurrent pasture-associated laminitis. Previous studies have predominantly investigated risk factors only after disease occurrence. Objective: To investigate risk factors for pasture-associated laminitis prior to disease occurrence. Methods: Prospective cohort study. Methods: Non-laminitic ponies aged ≥7 years were recruited. Body condition score (BCS), height, weight, crest height and thickness were measured and an overnight dexamethasone suppression test performed. Plasma or serum adiponectin, leptin, triglyceride, basal insulin, insulin pos...
Acquired multiple acyl-CoA dehydrogenase deficiency and marked selenium deficiency causing severe rhabdomyolysis in a horse.
The Canadian veterinary journal = La revue veterinaire canadienne    November 6, 2015   Volume 56, Issue 11 1166-1171 
Gomez DE, Valberg SJ, Magdesian KG, Hanna PE, Lofstedt J.This report describes a case of severe rhabdomyolysis in a pregnant mare associated with histopathologic and biochemical features of both selenium deficiency and acquired multiple acyl-CoA dehydrogenase deficiency (MADD) due to seasonal pasture myopathy (SPM). This case highlights the importance of assessing plasma selenium levels in horses with clinical signs of pasture myopathy as this deficiency may be a contributing or exacerbating factor. Déficience multiple acquise de déshydrogénase acyl-CoA et carence en sélénium marquée causant une rhabdomyolyse grave chez un cheval. Ce rapport d...
[Yellow oat grass intoxication in horses: Pitfalls by producing hay from extensive landscapes? A case report].
Tierarztliche Praxis. Ausgabe G, Grosstiere/Nutztiere    September 8, 2015   Volume 43, Issue 5 296-304 doi: 10.15653/TPG-150106
Bockisch F, Aboling S, Coenen M, Vervuert I.Vitamin-D intoxication by yellow oat grass is often reported under the syndrome of enzootic calcinosis in ruminants in the upper regions of the Alps. The intake of Trisetum flavescens in ruminants and horses induces calcification of soft tissue, including vessels, tendons and ligaments, lung, heart and kidneys. Clinical symptoms, including a reluctance to move, inappetence, body-weight loss and impaired organ function, are frequently observed. To date, there are only a very few case reports about yellow-oat-grass intoxication in horses. The present case report describes Vitamin-D intoxication ...
Occurrence of Hippobosca equina in Polish primitive horses during the grazing season.
Annals of parasitology    September 8, 2015   Volume 61, Issue 2 119-124 
Sokół R, Michalski MM.The presence of Hippobosca equina strongly influences the behaviour and health status of horses. The aim of the study was to analyse the invasion dynamics of the forest fly in Polish primitive horses (Equus caballus gmelini) in the Popielno Forest Reserve (northeastern Poland). Observations were carried out from May to September, every two weeks for two consecutive years (2012 and 2013) in five study groups: in 11-12-year-old mares with foals, 6-7-year-old leading stallions, 1.5-year-old fillies, 1.5-year-old colts and 9-10-year-old working geldings. Adult H. equina were counted in the preferr...
Assessing the seasonal prevalence and risk factors for nuchal crest adiposity in domestic horses and ponies using the Cresty Neck Score.
BMC veterinary research    January 31, 2015   Volume 11 13 doi: 10.1186/s12917-015-0327-7
Giles SL, Nicol CJ, Rands SA, Harris PA.Nuchal crest adiposity in horses and ponies has been associated with an enhanced risk of metabolic health problems. However, there is no current information on the prevalence of, and risk factors specific to, nuchal crest adiposity in horses and ponies. In addition, the cresty neck score has not previously been utilised across different seasons within a UK leisure population, it is not know whether nuchal crest adiposity shows the same seasonal trends as general obesity. Results: A Cresty Neck Score (CNS, 0-5) was given to 96 horses with access to pasture (>6 h per day) at the end of winte...
A field investigation into a suspected outbreak of pyrrolizidine alkaloid toxicosis in horses in western Queensland.
Preventive veterinary medicine    January 9, 2015   Volume 118, Issue 4 378-386 doi: 10.1016/j.prevetmed.2014.12.019
Robinson B, Gummow B.A disease outbreak investigation was conducted in western Queensland to investigate a rare suspected outbreak of pyrrolizidine alkaloid (PA) toxicosis in horses. Thirty five of 132 horses depastured on five properties on the Mitchell grass plains of western Queensland died in the first six months of 2010. Clinical-pathological findings were consistent with PA toxicosis. A local variety of Crotalaria medicaginea was the only hepatotoxic plant found growing on affected properties. Pathology reports and departure and arrival dates of two brood mares provided evidence of a pre wet season exposure ...
Effects of daily pyrantel tartrate on strongylid population dynamics and performance parameters of young horses repeatedly infected with cyathostomins and Strongylus vulgaris.
Veterinary parasitology    May 27, 2014   Volume 204, Issue 3-4 229-237 doi: 10.1016/j.vetpar.2014.05.034
Reinemeyer CR, Prado JC, Andersen UV, Nielsen MK, Schricker B, Kennedy T.Strongylid infections are ubiquitous in grazing horse populations. Infections with cyathostomin (small strongyle) and strongylin (large strongyle) nematodes have long been associated with clinical disease in horses, but little is known about their subclinical impact. A masked, randomized, controlled study was conducted to evaluate the effects of daily administration of pyrantel tartrate on body condition scores, weight gain, fecal egg counts, and total worm counts of young horses repeatedly inoculated with strongylid larvae. Twenty eight immature horses were treated with larvicidal anthelminti...
Obesity prevalence and associated risk factors in outdoor living domestic horses and ponies.
PeerJ    March 20, 2014   Volume 2 e299 doi: 10.7717/peerj.299
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...
Equine grazing in managed subalpine wetlands: effects on arthropods and plant structure as a function of habitat.
Environmental management    September 3, 2013   Volume 52, Issue 6 1474-1486 doi: 10.1007/s00267-013-0154-1
Holmquist JG, Schmidt-Gengenbach J, Haultain SA.Grazing management necessarily emphasizes the most spatially extensive vegetation assemblages, but landscapes are mosaics, often with more mesic vegetation types embedded within a matrix of drier vegetation. Our primary objective was to contrast effects of equine grazing on both subalpine vegetation structure and associated arthropods in a drier reed grass (Calamagrostis muiriana) dominated habitat versus a wetter, more productive sedge habitat (Carex utriculata). A second objective was to compare reed grass and sedge as habitats for fauna, irrespective of grazing. All work was done in Sequoia...
[Nutritional laminitis–preventive measures for the obese horse].
Tierarztliche Praxis. Ausgabe G, Grosstiere/Nutztiere    August 21, 2013   Volume 41, Issue 4 257-265 
Kienzle E, Fritz J.Nutrition-induced laminitis is often caused by i) fermentation of large amounts of carbohydrates in the hindgut (usually fructans from grass or starch from cereals), which cause the release and absorption of microbial toxins and ii) insulin resistance induced by being overweight (equine metabolic syndrome). Both causes can act together. Overweight horses with a history of laminitis need to reduce body weight to prevent further incidences of laminitis. Weight reduction occurs normally on a diet of late-cut hay, a hay-straw mixture (maximally one third straw to prevent constipation) or grass see...
Epidemiology of intoxication of domestic animals by plants in Europe.
Veterinary journal (London, England : 1997)    April 6, 2013   Volume 197, Issue 2 163-168 doi: 10.1016/j.tvjl.2013.03.007
Cortinovis C, Caloni F.This review focuses on some of the most important poisonous plants in Europe and provides an overview of the poisoning episodes that have occurred in European countries. Poisoning of livestock and companion animals by plants is a relatively common occurrence. In Europe livestock and horses are commonly poisoned by Datura stramonium (Jimson weed), Senecio spp. (ragworts and groundsels), Quercus spp. (oak), Taxus baccata (European yew), Nerium oleander (oleander), Pteridium aquilinum (bracken fern), Robinia pseudoacacia (black locust) and Rhododendron spp. (rhododendrons and azaleas). Poisoning ...
Seasonal pasture myopathy/atypical myopathy in North America associated with ingestion of hypoglycin A within seeds of the box elder tree.
Equine veterinary journal    November 20, 2012   Volume 45, Issue 4 419-426 doi: 10.1111/j.2042-3306.2012.00684.x
Valberg SJ, Sponseller BT, Hegeman AD, Earing J, Bender JB, Martinson KL, Patterson SE, Sweetman L.We hypothesised that seasonal pasture myopathy (SPM), which closely resembles atypical myopathy (AM), was caused by ingestion of a seed-bearing plant abundant in autumn pastures. Objective: To identify a common seed-bearing plant among autumn pastures of horses with SPM, and to determine whether the toxic amino acid hypoglycin A was present in the seeds and whether hypoglycin metabolites were present in SPM horse serum or urine. Methods: Twelve SPM cases, 11 SPM pastures and 23 control farms were visited to identify a plant common to all SPM farms in autumn. A common seed was analysed for amin...
A survey on the feeding of eventing horses during competition.
Journal of animal physiology and animal nutrition    July 19, 2012   Volume 96, Issue 5 878-884 doi: 10.1111/j.1439-0396.2012.01324.x
Brunner J, Wichert B, Burger D, von Peinen K, Liesegang A.This study aims at the comparison of the actual feeding of horses with the recommendations from the literature, and it studies the effects of feeding and exercise on several blood metabolic parameters before and after exercise. Blood samples were collected from 25 horses during one-star eventing competitions and evaluated for blood glucose, insulin, lactate, free fatty acids and triglyceride levels. Questionnaires on the feeding practices of the horses were evaluated. The questionnaires revealed that during training, and on tournament days, horses received on average 4.3 kg of concentrate per ...
Poisoning by Indigofera lespedezioides in horses.
Toxicon : official journal of the International Society on Toxinology    April 25, 2012   Volume 60, Issue 3 324-328 doi: 10.1016/j.toxicon.2012.04.341
Lima EF, Riet-Correa F, Gardner DR, Barros SS, Medeiros RM, Soares MP, Riet-Correa G.Poisoning by Indigofera lespedezioides is reported in horses in the state of Roraima, northern Brazil. The main clinical signs are anorexia, sleepiness, unsteady gait, severe ataxia, weakness, stumbling, and progressive weight loss. To induce the disease experimentally, a 7-year-old horse was introduced in a small paddock invaded by the plant. The first nervous signs were observed 44 days from the start of grazing. The animal was euthanized on day 59. No significant gross lesions were observed upon necropsies of the experimental horse as well as one spontaneously affected horse. Upon histologi...