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.
Fescue-associated oedema of horses grazing on endophyte-inoculated tall fescue grass (Festuca arundinacea) pastures. A new form of toxicity called equine fescue oedema is described. The clinical signs included inappetence, depression, and subcutaneous oedema of the head, neck, chest and abdomen. Affected horses had very low plasma albumin values. The toxicity affected 48 of 56 horses on six farms in different states of Australia, and 4 horses have died. All horses were grazing pastures that had been sown with varieties of Mediterranean tall fescue (Festuca arundinacea) that carry the endophyte known as Max P or Max Q. It is proposed that a pyrrolizidine alkaloid, N-acetyl norloline, which is produced by the ...
Effect of selenium supplementation and plane of nutrition on mares and their foals: selenium concentrations and glutathione peroxidase. To investigate the maternal plane of nutrition and role of Se yeast on muscle Se concentration, plasma glutathione peroxidase (Gsh-Px) activity, and colostrum Se concentration in mares and their foals, 28 Quarter Horse mares (465 to 612 kg of BW, and 6 to 19 yr of age) were used in a study with a randomized complete block design. Mares were blocked by expected foaling date and randomly assigned to dietary treatments within blocks. Dietary treatments were arranged as a 2 x 2 factorial with 2 planes of nutrition, pasture or pasture + grain mix (fed at 0.75% of BW on an as-fed basis) and 2 concen...
Parasitism and colic. Equids are hosts to dozens of species of internal parasites that infect no other domestic animals. Virtually all horses, especially those exposed to pasture, experience some level of parasitism continuously. Despite pathologic evidence of parasitic damage in various organs and tissues, few parasitisms are manifested systemically in well-managed horses. Contrary to conventional wisdom, only three common parasitisms of horses are likely to be manifested as colic: Strongylus vulgaris, Parascaris equorum, and Anoplocephala perfoliata. This article discusses the life cycles, pathophysiology, manife...
Comparative long-term efficacy of ivermectin and moxidectin over winter in Canadian horses treated at removal from pastures for winter housing. The impact of a late fall treatment on the spring rise of fecal egg counts was evaluated in a controlled study with Canadian horses treated with 2 different dewormers immediately after removal from pasture for winter housing. The horses were stabled until the end of the trial period. Seventeen weanlings, 20 yearlings, and 15 2-year-old horses located in Ontario, which were presumed to be naturally infected with cyathostomins after pasture grazing, were randomly allocated to either a group treated with 0.4 mg/kg of moxidectin and 2.5 mg/kg of praziquantel or a group treated with 0.2 mg/kg of iv...
Clinical assessment of nutritional status and feeding programs in horses. Veterinarians are a primary source of nutritional information and advice for horse owners. This article reviews methods for clinical assessment of nutritional status and feeding programs that can be applied to an individual horse or group of horses. Physical examination, including measurement of body weight and evaluation of body condition score, estimation of nutrient requirements and the nutrient content of the horse's diet, and evaluation of the feeding method are important components of the assessment. Ongoing clinical assessment of health and body condition will gauge the need for reasses...
Mineral content of hay harvested in Bavarian and Swiss horse farms. Predictive value of cutting time, number of cut, botanical composition, origin and fertilization. Hay samples from 29 horse farms in Southern Upper Bavaria and 31 horse farms in Switzerland were taken and analysed for minerals such as calcium, magnesium, phosphorus and potassium. The content of herbs and legumes in the hay was determined and the Weende analysis was performed. Comparison between Bavaria and Switzerland resulted in comparable calcium contents of approximately 4 g Ca/kg dry matter (DM) in grass hay. Hay with more than 10% of herbs and legumes found only in Switzerland showed higher Ca contents of >7 g Ca/kg DM in hay. The mineral contents of phosphorus and potassium were l...
Atypical myopathy in grazing horses: a first exploratory data analysis. Over the last decade, atypical myopathy (AM) in grazing horses has emerged in several European countries. An exploratory analysis was conducted to determine horse- and pasture-level indicators or factors associated with AM in Belgium. Belgian cases of AM confirmed by histology (n=57) were compared to their healthy co-grazing horses (n=77) and to pastured horses not involved with AM as controls (n=386). The pastures where confirmed cases were grazing (42 pastures; 38 sites; 44 incidences of AM) were compared with those of the controls (216 pastures; 96 sites; no incidence of AM). Statistically ...
Effect of paddock vs. stall housing on 24 hour gastric pH within the proximal and ventral equine stomach. Stall housing has been suggested as a risk factor for ulcer development in the equine stomach; however, the exact pathogenesis for this has not been established. Objective: To investigate the effect of 3 environmental situations (grass paddock, stall alone or stall with adjacent companion) on pH in the proximal and the ventral stomach. Methods: Six horses with permanently implanted gastric cannulae were used in a randomised, cross-over, block design. Each horse rotated through each of three 24 h environmental situations. Horses remained on their normal diet (grass hay ad libitum and grain b.i....
Occurrence of Anoplocephala perfoliata infection in horses in Ontario, Canada and associations with colic and management practices. Infection with the tapeworm Anoplocephala perfoliata has been found to be associated with equine colic in horses in the United Kingdom. Using a matched case-control study design, data collected from 117 pairs of horses in Ontario were examined for evidence of associations between risk of colic and A. perfoliata infection, and between seropositivity to infection and management practices. Cases were horses in southern Ontario diagnosed with colic by local veterinarians, and control horses were from the same stables as cases and were matched by age, breed and gender where possible. Infection stat...
History and clinical features of atypical myopathy in horses in Belgium (2000-2005). The emergent nature of atypical myopathy or atypical myoglobinuria (AM) necessitates precise description of its clinical and epidemiologic features. Objective: To define key features of AM to help practitioners recognize the disease and to advise owners to take preventive measures. Methods: Belgian cases of AM confirmed by histology (CC horses; n = 57) from autumn 2000 to spring 2005 were included in the study. Co-grazing horses (Co-G horses; n = 77) that remained free of any abnormal clinical signs constituted a control group. Methods: History, environmental characteristics, clinical signs, a...
Dietary fructan carbohydrate increases amine production in the equine large intestine: implications for pasture-associated laminitis. Pasture-induced laminitis in the horse is associated with the overconsumption of fermentable carbohydrate, in the form of simple sugars, fructans, or starch. The fermentation of carbohydrate in the cecum and large intestine results in the production of lactic acid and other toxins or "laminitis trigger factors." Vasoactive amines have been suggested as possible initiating factors. The aim of this study was to feed a commercially available form of fructan carbohydrate (inulin, 3 g/kg of BW per day) to normal ponies and to ponies predisposed to laminitis, to mimic a change from a basal hay diet ...
Pimelea trichostachya poisoning (St George disease) in horses. A dense population of Pimelea trichostachya plants (Family Thymelaeaceae) in pasture poisoned a horse herd in southern inland Queensland in October-November 2005. Plant density was 2 to 45 g wet weight/m(2) (mean 16 g/m(2)) from 5 to 69 plants/m(2) (mean 38 plants/m(2)) representing 3 to 20% (mean 9%) of the volume of pasture on offer. Ten of 35 mares, fillies and geldings were affected. Clinical signs were loss of body weight, profound lethargy, serous nasal discharge, severe watery diarrhoea and subcutaneous oedema of the intermandibular space, chest and ventral midline. Pathological finding...
Effect of detraining on cardiorespiratory variables in young thoroughbred horses. Thoroughbred racehorses often experience interruptions to their training. Identifying the effects of these changes and how they alter athletic performance might provide an insight on to how to prevent these changes from occurring. Objective: Training and detraining young Thoroughbreds alters their aerobic capacities with correlated changes in circulatory capacities; if horses remained spontaneously active in a pasture during their detraining period, their decreases in aerobic capacity during detraining would be reduced. Methods: We trained 6 Thoroughbred yearlings for 6 months using a conventi...
The prevalence of gastric ulceration in racehorses in New Zealand. To establish the prevalence and factors influencing the prevalence and severity of gastric ulceration in racehorses in New Zealand. Methods: Horses (n=171) in active training for racing by trainers (n=24) located throughout New Zealand were examined using gastroscopy during 2003 and 2004. Images of the examination were recorded and reviewed, and an ordinal grade based on the severity of gastric ulceration present was assigned, using the grading system proposed by the Equine Gastric Ulcer Council (EGUC). Information about the horses such as age, breed, sex, stabling, time at pasture, pasture qu...
A study on the seasonal epidemiology of Anoplocephala spp.-infection in horses and the appropriate treatment using a praziquantel gel (Droncit 9% oral gel). In a study on the seasonal dynamics of the gastro-intestinal nematode egg production in horses, one breeding farm also revealed a particularly high prevalence of Anoplocephala spp. infection. Consequently, this farm was chosen for analysing the seasonal pattern of the tapeworm egg excretion over a one year period in order to establish the most favourable periods for an appropriate and successful cestocidal treatment. The seasonal analysis showed a significantly higher (p < 0.05) Anoplocephala spp. egg excretion between July and October, i.e. during the second part of the grazing period. This r...
[Pilot study to evaluate the efficiency of insecticide-treated mosquito net fences for the protection of horses against nuisance insects in northern Brandenburg]. A fence of black mosquito netting of 100 cm height, pre-treated with 80 mg/m2 of deltamethrin and UV-protected, was used to shelter horses from nuisance and biting insects on pasture in northern Brandenburg. The netting material was attached to the surrounding poles of the existing fences at a height of 15 cm above ground. Three trial groups were selected grazing in spatially separated areas with comparable densities of insect populations. One paddock was completely fenced apart from a wall of 170 cm height and 70 m length. The second pasture had only partial protection with 126 m (13.4%) of f...
Airway inflammation in Michigan pleasure horses: prevalence and risk factors. Although subclinical airway inflammation is thought to be common in horses, there is little information on its prevalence and none on risk factors. Objective: To determine the prevalence and risk factors for an increased number of inflammatory cells and for mucus accumulation in the trachea of pleasure horses. Methods: Horses (n = 266) in stables (n = 21) in Michigan were examined endoscopically, once in winter and once in summer 2004. Visible tracheal mucoid secretions were graded 0-5 and inflammatory cell numbers counted in a tracheal lavage sample. Information collected about each horse inc...
Quantification of spontaneous locomotion activity in foals kept in pastures under various management conditions. To describe spontaneous locomotion activity of foals kept under various management conditions and assess the suitability of global positioning system (GPS) technology for recording foal activity. Animals-59 foals. Methods: During the foals' first 4 months of life, 921 observation periods (15 minutes each) were collected and analyzed for locomotion activities. The GPS system was evaluated by simultaneously carrying out field observations with a handheld computer. Results: Foals spent 0.5% of total observed time cantering, 0.2% trotting, 10.7% walking, 32.0% grazing, 34.8% standing, and 21.6% ly...
10.1093/jn/136.7.2090S. Treatment of clinical laminitis usually fails to prevent some degree of persistent disability; thus, intervention should aim at avoiding risk factors and preventing the disease. Efficiency of intervention would be improved by identifying predisposed horses and ponies. A herd of 160 healthy ponies included 54 previously laminitic (PL) and 106 never laminitic (NL). Pedigree analysis was consistent with dominant inheritance partially suppressed in males. Blood analysis revealed higher plasma concentrations of insulin and triglycerides but not cortisol, glucose, or free fatty acids in the PL group...
Countermeasures for pasture-associated laminitis in ponies and horses. Laminitis occurs throughout the world in horses and ponies and has major welfare implications. It is obviously important to be able to recognize and treat the condition in its early stages so that pain and suffering are kept to a minimum. However, ideally it would be preferred to be able to recommend certain interventions/countermeasures that avoid or prevent the condition from occurring in the first place. Because pasture-associated laminitis occurs with grass consumption, one obvious way to avoid the condition is to prevent access to pasture and to feed forage alternatives that are known to ...
Evaluation of the risk of motor neuron disease in horses fed a diet low in vitamin E and high in copper and iron. To determine whether equine motor neuron disease (EMND) could be induced in adult horses fed a diet low in vitamin E and high in copper and iron. Methods: 59 healthy adult horses. Methods: Horses in the experimental group (n = 8) were confined to a dirt lot and fed a concentrate low in vitamin E and high in iron and copper in addition to free-choice grass hay that had been stored for 1 year. Control horses (n = 51) were fed a concentrate containing National Research Council-recommended amounts of copper, iron, and vitamin E. The hay fed to control horses was the same as that fed to experimenta...
Horses on pasture may be affected by equine motor neuron disease. Equine motor neuron disease (EMND) was diagnosed in 3 horses maintained on lush, grass-based pasture. This contrasted with North American studies which identified limited or no access to green herbage as an important risk factor for EMND. Objective: Grazing horses that have an apparently adequate intake of pasture herbage to meet normal equine vitamin E requirements can develop EMND. Methods: Owners of 32 European horses diagnosed with EMND completed a questionnaire regarding intrinsic, managemental, nutritional and environmental factors that could potentially be risk factors for EMND, and als...
Bodyweights and growth rates of spring- and autumn-born Thoroughbred horses raised on pasture. To examine the growth of spring- and autumn-born Thoroughbred foals raised on pasture. Methods: Bodyweight and growth rates were measured in pasture-raised Thoroughbred horses, born in either spring (n=56) or autumn (n=7), from birth to approximately 13 and 17 months of age. Results: Birthweight tended to be lower in autumn- than spring-born foals (54.4, SD 7.92 kg vs 57.3, SD 5.90 kg; p=0.08). Between birth and 6 months of age, there was no difference in growth rate at equivalent ages between horses born in spring and autumn. Spring-born horses, which were weaned in the autumn, had lower post...
Dynamic averaging and foraging decisions in horses (Equus callabus). The variability of most environments taxes foraging decisions by increasing the uncertainty of the information available. One solution to the problem is to use dynamic averaging, as do some granivores and carnivores. Arguably, the same strategy could be useful for grazing herbivores, even though their food renews and is more homogeneously distributed. Horses (Equus callabus) were given choices between variable patches after short or long delays. When patch information was current, horses returned to the patch that was recently best, whereas those without current information matched choices to ...
Digestible energy intake, dry matter digestibility and mineral status of grazing New Zealand Thoroughbred yearlings. To measure the nutritive value of pasture in terms of digestible energy intake (DEI) and dry matter (DM) digestibility, and to determine the effect of Ca, P, Cu, Zn, and Se supplementation on growth rate and degree of physeal swelling in Thoroughbred yearlings grazed on pasture. Methods: Fourteen yearling horses were randomly allocated to 1 of 2 groups and rotationally grazed on a ryegrass/white clover pasture for 7 months. One group was supplemented daily with a mineral mix. Liveweight changes were recorded at fortnightly intervals and pasture mineral composition determined at monthly interva...
Digestible energy intake, dry matter digestibility and effect of increased calcium intake on bone parameters of grazing Thoroughbred weanlings in New Zealand. To measure the nutritive value of pasture in terms of digestible energy intake (DEI) and dry matter (DM) digestibility, and the effects of increased calcium (Ca) intakes on apparent mineral absorption and bone characteristics in grazing weanling Thoroughbreds. Methods: DM intake (DMI) and DEI were determined in 16 weanling Thoroughbreds grazing pasture from their daily faecal DM output, measured over 8 days, divided by the DM indigestible fraction (1-digestible DM) determined in a 6-day digestibility trial. The DM, gross energy content, crude protein, soluble carbohydrate, acid detergent fibre...
Fluorescence spectra and measurement of phylloerythrin (phytoporphyrin) in plasma from clinically healthy sheep, goats, cattle and horses. To measure the background concentration of phylloerythrin in plasma from clinically healthy sheep, goats, cattle and horses on pasture. Methods: Blood samples were taken from 34 sheep of the Dala breed, 20 female Norwegian dairy goats, 35 Norwegian Red cows and 34 horses of different breeds. All animals were grazing green pasture when blood samples were taken. Blood samples were collected from each of four clinically healthy newborn lambs, goats, calves and foals, and pooled into one sample per species. Plasma samples were analysed for phylloerythrin by fluorescence spectroscopy, using a Perki...
The effect of injectable barium selenate on the selenium status of horses on pasture. To examine the effect of intramuscular barium selenate on the blood selenium concentration of horses with marginal selenium status. Methods: Eighteen mares were assigned to one of six groups. The mares in groups 1-4 received barium selenate at 0.5, 0.75, 1.0 and 1.5 mg Se/kg, respectively, injected into the right pectoral muscle mass. The mares in group 5 received sodium selenate at 0.05 mg Se/kg orally at 8-week intervals. The mares in group 6 were left untreated. Blood samples were collected at 0, 1, 2, 5, 10, 30, 60, 90, 120, 180, 240, 300 and 360 days after the initial treatment for assay ...
Antiparasitic activity of an ivermectin and praziquantel combination paste in horses. Modern anthelmintic use in horses has decreased the prevalence of the large strongyles, which has in turn shifted the focus of parasitologists to the pathogenic importance of the small strongyles, tapeworms, and other parasites. These studies show that a combination product containing ivermectin and praziquantel allowed efficacious treatment of horses for nematode, cestode, and bot infections. The use of this combination product may be of special benefit to horses that are mainly kept outdoors and on grazing pastures.
Shedding consistency of strongyle-type eggs in Dutch boarding horses. Faeces of 484 horses were sampled twice with an interval of 6 weeks while anthelmintic therapy was halted. Faecal eggs counts revealed that 267 (55.2%) horses had consistently low numbers of eggs per gram faeces (EPG) (EPG 100). Horses with consistently high EPGs were more often mares with access to pasture, aged less than 6 or more than 23 years, that were dewormed at intervals longer than 6 months, and were treated for the last time more than 3 months before the start of the study. Horses with consistently low EPGs were more often male horses with no or limited access to pasture, that were ...