An epidemiological study of summer eczema in Icelandic horses in Norway

A survey of summer eczema was conducted on 391 Icelandic horses in Norway. The study showed a prevalence of summer eczema of 17.6 per cent in the horses investigated. Icelandic horses born in Norway where shown to be less affected with summer eczema than imported horses, 8.2 per cent and 26.9 per cent respectively (P less than 0.001). There was no difference in the prevalence of summer eczema relative to gender or colour of the horse. The number of horses affected with summer eczema rose with increasing age and the number of years which had elapsed since importation. On average, Icelandic horses born in Norway developed summer eczema at the age of 5.3 years. The onset of disease for imported horses was, on average, 4.1 years after importation. The study also revealed that a significantly greater number of horses imported from Iceland to Norway during the period October to April, which has a minimal or low activity of insects (32.3 per cent), had developed summer eczema, compared with horses imported during the period May to September, when insects are more active (16.7 per cent), (P = 0.044). Horses with summer eczema were shown to be significantly more affected by respiratory disease than non-affected horses (P = 0.0086). The most common sites and clinical signs of summer eczema are also described.     

Investigation of the prevalence of summer eczema in Icelandic horses in northern Germany

An epidemiological study on summer eczema (SE) was performed in 490 Icelandic horses from 24 stud farms located in Lower Saxony and Westphalia. The study revealed a prevalence of summer eczema of 29.8 %. Horses imported from Iceland were affected with a frequency of 71.9 %, whereas horses born in Germany and other countries had a prevalence of 15.6 % and 27.3 %. Mares (33.1 %) and geldings (29.1 %) were more often affected by summer eczema than stallions with 15.5 %. The most common sites of summer eczema were mane and tail. Five to eight years old horses were more severely affected by SE than younger or older horses. Piebald horses showed higher degrees of SE than grey horses. The high prevalence of SE in Icelandic horses kept in Germany was due to imported horses from Iceland particularly horses imported at an age of seven to 15 years were at an extremely high risk to SE (96.4 %). The prevalence of SE significantly increased with higher age. Chestnut and grey horses born in Germany were prone to a lower risk to SE than bay, black or piebald horses. In horses imported from Iceland, a higher inbreeding coefficient was significantly related to a lower prevalence of SE. The most efficient measure recommended for reduction of SE in Germany would be to abandon imports of Icelandic horse from Iceland.     

Report of the 3rd Havemeyer workshop on allergic diseases of the Horse, Hólar, Iceland, June 2007

Allergic diseases occur in most mammals, although some species such as humans, dogs and horses seem to be more prone to develop allergies than others. In horses, insect bite hypersensitivity (IBH), an allergic dermatitis caused by bites of midges, and recurrent airway obstruction (RAO), a hyperreactivity to stable born dust and allergens, are the two most prevalent allergic diseases. Allergic diseases involve the interaction of three major factors: (i) genetic constitution, (ii) exposure to allergens, and (iii) a dysregulation of the immune response determined by (i) and (ii). However, other environmental factors such as infectious diseases, contact with endotoxin and degree of infestation with endoparasites have been shown to influence the prevalence of allergic diseases in humans. How these factors may impact upon allergic disease in the horse is unknown at this time. The 3rd workshop on Allergic Diseases of the Horse, with major sponsorship from the Havemeyer Foundation, was held in Hólar, Iceland, in June 2007 and focussed on immunological and genetic aspects of IBH and RAO. This particular venue was chosen because of the prevalence of IBH in exported Icelandic horses. The incidence of IBH is significantly different between Icelandic horses born in Europe or North America and those born in Iceland and exported as adults. Although the genetic factors and allergens are the same, exported adult horses show a greater incidence of IBH. This suggests that environmental or epigenetic factors may contribute to this response. This report summarizes the present state of knowledge and summarizes important issues discussed at the workshop.     

Equine insect bite hypersensitivity: immunoblot analysis of IgE and IgG subclass responses to Culicoides nubeculosus salivary gland extract

Insect bite hypersensitivity (IBH) is an allergic dermatitis of horses caused by IgE-mediated reactions to bites of Culicoides and sometimes Simulium spp. The allergens causing IBH are probably salivary gland proteins from these insects, but they have not yet been identified. The aim of our study was to identify the number and molecular weight of salivary gland extract (SGE) proteins derived from Culicoides nubeculosus which are able to bind IgE antibodies (ab) from the sera of IBH-affected horses. Additionally, we sought to investigate the IgG subclass (IgGa, IgGb and IgGT) reactivity to these proteins. Individual IgE and IgG subclass responses to proteins of C. nubeculosus SGE were evaluated by immunoblot in 42 IBH-affected and 26 healthy horses belonging to different groups (Icelandic horses born in Iceland, Icelandic horses and horses from different breeds born in mainland Europe). Additionally, the specific antibody response was studied before exposure to bites of Culicoides spp. and over a period of 3 years in a cohort of 10 Icelandic horses born in Iceland and imported to Switzerland. Ten IgE-binding protein bands with approximate molecular weights of 75, 66, 52, 48, 47, 32, 22/21, 19, 15, 13/12 kDa were found in the SGE. Five of these bands bound IgE from 50% or more of the horse sera. Thirty-nine of the 42 IBH-affected horses but only 2 of the 26 healthy horses showed IgE-binding to the SGE (p<0.000001). Similarly, more IBH-affected than healthy horses had IgGa ab binding to the Culicoides SGE (19/22 and 9/22, respectively, p<0.01). Sera of IBH-affected horses contained IgE, IgGa and IgGT but not IgGb ab against significantly more protein bands than the sera of the healthy horses. The cohort of 10 Icelandic horses confirmed these results and showed that Culicoides SGE specific IgE correlates with onset of IBH. IBH-affected horses that were born in Iceland had IgGa and IgGT ab (p< or =0.01) as well as IgE ab (p=0.06) against a significantly higher number of SGE proteins than IBH-affected horses born in mainland Europe. The present study shows that Culicoides SGE contains at least 10 potential allergens for IBH and that IBH-affected horses show a large variety of IgE-binding patterns in immunoblots. These findings are important for the future development of a specific immunotherapy with recombinant salivary gland allergens.     

Characteristics of equine summer eczema with emphasis on differences between Finnhorses and Icelandic horses in a 11-year study

Summer eczema, allergic dermatitis of the horse, was studied on 275 affected horses in Finland in 1997–2007. Features of the horses, clinical signs of the disease and owners'' opinions of aggravating factors were recorded. Differences, especially, between two of the native Scandinavian horse breeds, the Finnhorse and the Icelandic horse, were evaluated. The study was based on clinical examination and information from the owners. Of the horses, 50% were Finnhorses, 26% Icelandic horses and 24% consisted of different breeds of ponies and other horses. Of the Finnhorses, 76% had summer eczema by the age of 5 years, but in the Icelandic horses born in Finland the average age at onset was 7 years. The vast majority of the horses, 75%, had moderate clinical signs, while 16% showed severe and 9% mild. The severity of clinical signs did not depend on the duration of the disease nor was it related to the age at onset. The only linkage to severity was the breed of the horse or import from Iceland; New Forest ponies and imported Icelandic horses showed severe clinical signs significantly more often than Finnhorses. Of the owners, 38% regarded insects as the only aggravating factor, 24% mentioned several simultaneous factors, including grass fodder and sunlight, while 22% could not specify any. In Finland, a typical horse breed suffering from summer eczema is the Finnhorse and the characteristics of the disease are mainly uniform with the other breeds affected. Equine summer eczema seems to be aggravated by various combinations of environmental factors.     

Various Circumstances Regarding Initial Allergen Exposure and Their Influence on Development of Insect Bite Hypersensitivity in Horses

Insect bite hypersensitivity (IBH), an allergic reaction to the saliva of Culicoides, occurs in all horse breeds and is a severe problem. In this study, we aimed at exploring whether exterior conditions, such as duration of allergenic exposure during the first summer and age of the horses at the time of import, influence the development of IBH. Additionally, data were analyzed regarding the period IBH started after birth and after import. Datasets for 582 horses were collected. The horses were locally born Icelandic horses and horses of other breeds with IBH, as well as imported Icelandic horses, both affected and nonaffected. For locally born horses, time of birth and duration of allergen exposure during the first summer had no influence on the prevalence of IBH. The disease started mostly in their third year of life. The majority of the imported horses affected caught IBH during their first year in Central Europe. Older imported horses seemed to develop IBH quicker than younger animals. Animals imported in their first winter are exposed to the allergen when they are at least 7 months old. They experienced approximately the same low risk of developing IBH as locally bred horses. The risk of IBH increased with the horses’ age at import. From our data, we conclude that the period to develop successful immune tolerance goes beyond the perinatal phase and is longer than formerly supposed.     

Reduced incidence of insect-bite hypersensitivity in Icelandic horses is associated with a down-regulation of interleukin-4 by interleukin-10 and transforming growth factor-beta1

Insect bite hypersensitivity (IBH) is an allergic dermatitis of horses caused by IgE-mediated reactions to bites of insects of the genus Culicoides. IBH does not occur in Iceland due to the absence of Culicoides. However, Icelandic horses exported to mainland Europe as adults (1st generation) have a > or =50% incidence of developing IBH. In contrast, their progeny (2nd generation) has a <10% incidence of IBH. Here we show that peripheral blood mononuclear cells (PBMC) from Icelandic horses born in mainland Europe and belonging either to the IBH or healthy subgroup produce less interleukin (IL)-4 after polyclonal or allergen-specific stimulation when compared with counterparts from horses born in Iceland. We examined a role of IL-10 and transforming growth factor (TGF)-beta1 in down-regulation of IL-4 in healthy 2nd generation Icelandic horses. Supernatants of PBMC from 2nd generation healthy horses down-regulated the proportion of IL-4-producing cells and IL-4 production in stimulated cultures of PBMC from 1st generation IBH. This inhibition was mimicked by a combination of IL-10 and TGF-beta1 but not by the single cytokines. Cultures of stimulated PBMC of healthy 2nd generation horses produced a low level of IL-4, but IL-4 production was increased by anti-equine IL-10 and anti-human TGF-beta1. This shows for the first time that in horses, IL-10 and TGF-beta1 combined regulate IL-4 production in vitro. It is suggested that in this naturally occurring IgE-mediated allergy, IL-10 and TGF-beta1 have a role in the down-regulation of IL-4-induced allergen-specific Th2 cells, thereby reducing the incidence of IBH.     

Production of monoclonal antibodies specific for native equine IgE and their application to monitor total serum IgE responses in Icelandic and non-Icelandic horses with insect bite dermal hypersensitivity

Immunoglobulin E forms a minor component of serum antibody in mammals. In tissues IgE is bound by FcvarepsilonRI receptors on the surface of mast cells and mediates their release of inflammatory substances in response to antigen. IgE and mast cells have a central role in immunity to parasites and the pathogenesis of allergic diseases in horses and other mammals. This paper describes the production of several novel monoclonal antibodies that detect native equine IgE in immunohistology, ELISA and Western blotting. An antigen capture ELISA to quantify equine IgE in serum has been developed using two of these antibodies. The mean serum IgE concentration of a group of 122 adult horses was 23,523ng/ml with a range of 425-82,610ng/ml. Total serum IgE of healthy horses was compared with that of horses with insect bite dermal hypersensitivity (IBDH) an allergic reaction to the bites of blood feeding insects of Culicoides or Simulium spp. IBDH does not occur in Iceland where Culicoides spp. are absent, but following importation into mainland Europe native Icelandic horses have an exceptionally high incidence of this condition. In the present study Icelandic horses with IBDH had significantly higher total IgE than healthy Icelandic horse controls (P<0.05). By contrast in horses of other breeds the difference in total serum IgE between those affected with IBDH and healthy controls was not statistically significant. Total serum IgE was also monitored in a cohort of Icelandic horses prior to import into Switzerland and for a period of 3 years thereafter. High levels of serum IgE were present in all horses at the start of the study but dropped in the first year after import. Thereafter the total serum IgE remained low in Icelandic horses that remained healthy but rose significantly (P<0.05) in those that developed IBDH. These results support the conclusion that IBDH is a type I hypersensitivity response to insect allergens but indicate that IBDH in Icelandic horses may have a different pathogenesis from the same condition in other breeds.     

Effects of integrated genetic evaluations for Icelandic horses on predictive ability, accuracy and selection bias

The genetic evaluation of Icelandic horses is currently based on results from breeding field tests of riding ability and conformation. The effect of integrating competition traits and/or test status into the genetic evaluation was studied concerning estimation bias, predictive ability, accuracy, correlations between breeding values and ranking of sires. Breeding field test data included 19 954 records from horses assessed in 11 countries during 1994-2008. Competition data included 44 160 records from 7687 horses competing in Iceland and Sweden in 1998-2008. Test status was defined as attendance of horses born in Iceland at breeding field tests and/or in competition. Overall, there were trivial differences between different genetic evaluation models regarding estimation bias and predictive ability. Very strong correlations were estimated between breeding values for combined indexes of conformation, riding ability and total score from different models. Higher accuracy was achieved for most of the traits when competition traits and/or test status were added to the model. Sires ranked differently when the new traits were added to the genetic evaluation model. It was concluded that competition traits should be integrated into the genetic evaluation. Further analyses on genetic parameters for test status and its relationship with the other traits are needed for future inclusion of test status in the genetic evaluation.     

Serological surveillance of equine viral arteritis in the United Kingdom since the outbreak in 1993

Serological analysis of blood samples submitted to the Animal Health Trust showed that during 1995, 185 of 9203 unvaccinated horses (2.0 per cent) tested positive for antibodies to equine arteritis virus (EAV), and that during 1996, 46 of 8851 unvaccinated horses (0.52 per cent) tested positive. During both years thoroughbreds were the predominant breed tested and only a small proportion of these (<0.3 per cent), consisting predominantly of imported mares, were seropositive. In contrast, among standardbred horses, from which samples were actively solicited in 1995, 84 of 454 (18.5 per cent) were seropositive. Among standardbreds there was a difference in prevalence between types of horses, with 3.7 per cent of racing horses, 25 per cent of non-racing horses and 41 per cent of stallions testing seropositive. Investigations of seropositive stallions identified during 1994 and 1995 demonstrated that clinically inapparent equine viral arteritis (EVA) had occurred previously in the UK. Of 50 seropositive stallions, nearly half were standardbreds and nearly all had been imported from either North America or the European Union. Whether 34 seropositive stallions were shedding virus in their semen was established either by test mating, by the serology of the covered mares, or by investigation by MAFF following the introduction of the Equine Viral Arteritis Order 1995. Nine of the stallions (26.5 per cent) were identified as presumptive shedders of EAV in semen and among specific breeds, viral shedding was identified in six of 15 (40 per cent) standardbreds and three of nine (33 per cent) warmbloods. In contrast with the outbreak of EVA in the UK in 1993, no signs of disease typical of EAV infection were reported during these investigations, even in mares test mated to stallions shedding the virus.     

Prevalence and epidemiology of the major gastrointestinal parasites of horses in Perth, Western Australia

A survey was conducted on the prevalence of the major gastrointestinal parasites in 140 horses necropsied in Perth, Western Australia, during 1979 to 1982. Adult Strongylus vulgaris were found in 22.5 per cent of horses and verminous arteritis in 62.9 per cent. The peak worm prevalence was in November to January (summer). S edentatus had a similar prevalence and seasonality but S equinus was not found in this survey. Draschia megastoma and Habronema muscae were found in 66.2 per cent and 35.3 per cent of horses respectively. Infection is probably acquired in summer when 8 per cent of the Musca domestica in the vicinity of the stables carried third stage spiruroid larvae. Gasterophilus intestinalis and G nasalis occurred in 36.4 per cent and 22.1 per cent of the horses respectively and 52.1 per cent of horses were infected with one or both species. The peak prevalence of G intestinalis larvae occurred in December with a trough in February-April; the peak prevalence of G nasalis was in May with a trough in November-December. Parascaris equorum was found in 9.9 per cent of the horses and in 21.3 per cent of those less than three years old. Anoplocephala perfoliata was found in 4.9 per cent of the horses and most of these were in older horses.     

Evaluation of fipronil spot-on in the treatment of flea allergic dermatitis in dogs

The purpose of this study was to evaluate the effectiveness of treatment with 10 per cent fipronil solution for controlling signs of flea allergic dermatitis in dogs under field conditions. Thirty-one client-owned dogs with flea allergic dermatitis were treated with three monthly applications of 10 per cent fipronil solution. Flea counts and pruritus were significantly reduced at all post-treatment visits. At the final visit, on day 90, flea counts were reduced by 98 per cent, and pruritus was reduced or eliminated in 84 per cent of the study dogs. Dermatological lesion scores for erythema, crusts, scales and papules were also significantly improved by the final visit. The overall assessment of efficacy on day 90 was 'excellent' to 'good' for 87 per cent of the study dogs. The results demonstrate that treatment with monthly topical applications of 10 per cent fipronil solution is effective in reducing the prevalence and severity of signs of flea allergic dermatitis in dogs.     

Field study of the prevalence of lameness in horses with back problems

A population of 805 horses (70 per cent dressage, 20 per cent show jumpers and 10 per cent trotters) with orthopaedic problems was examined for signs of lameness and back problems, irrespective of their original complaints. In the horses with a back problem the prevalence of lameness was 74 per cent, and back problems were diagnosed in 32 per cent of the lame horses. These percentages were significantly higher than those recorded in a control population of 399 horses, of which 20 per cent were lame and 12 per cent had back problems. In the group of horses with orthopaedic problems there was a strong association between lameness and back problems and, in particular, there was a high prevalence of lameness among the horses with back problems.     

Intradermal skin testing in Icelandic horses in Austria

Icelandic horses in Austria are commonly affected by an allergic inflammatory skin disease recurring during the summer seasons, which shares characteristic features with Culicoides hypersensitivity. However, the causative agents have not yet been identified. Therefore, intradermal skin testing (IDST) with a standardised extract of Culicoides variipennis and 21 other allergens relevant within Austria was performed in 81 Icelandic horses. All horses included into the study were treated regularly with ivermectin and had no history of administration of anti-inflammatory drugs. Forty-three of these horses were affected by summer seasonal recurrent dermatitis (SSRD). No history or signs of any other disease were evident in any horse. Pruritic dermatitis due to ectoparasites, bacteria and dermatophytes were ruled out by means of fungal culture, skin scraping and biopsy. Culicoides variipennis antigens evoked a positive cutaneous reaction in 1 of 38 normal and 3 of 43 SSRD horses at the proposed dilution of 1:50,000 or 1:25,000, and in 24 of 38 normal and 13 of 43 SSRD horses at a dilution of 1:10,000. Furthermore, no significant differences in onset or intensity of skin reactions to the 21 other allergens, including pollens, moulds, mites and insects, except deerfly and horsefly, were obvious between the 2 groups. Efficiency (percentage of correct results) for the used antigens in the skin test was 0.47-0.60. Maximal sensitivity was 0.51. Altogether, 38 of 43 SSRD horses and 28 of 38 normal horses were positive 4 h after allergen administration. The divergence between IDST results and manifestation of clinical signs found in this study underlines the difficulties associated with establishing a skin test protocol in horses within a geographic area. Whether the outcome of this study would have been influenced significantly by using Culicoides spp. present in Austria has to be clarified in future research.     

Incidence of exertional rhabdomyolysis in polo horses in the USA and the United Kingdom in the 1999/2000 season

A questionnaire was used to determine the incidence of exertional rhabdomyolysis and the factors that might have contributed to its occurrence among 423 polo horses in 11 yards. The yards were selected at random, six of them with 111 horses, in north-eastern USA, and five with 312 horses in south-east England. During the 1999/2000 season the incidence of the condition was 7.3 per cent (9 per cent in the USA and 6.7 per cent in England). The incidence in mares was similar in the two countries, 8.4 per cent in the USA and 8.0 per cent in England, but the incidence in geldings in the USA (10 per cent) was much higher than in England (1.5 per cent). A more excitable than average temperament was reported in 71 per cent of the horses with the condition, and most cases occurred after a game (chukka) in which the horse was perceived to be not fit enough for the level of play demanded. Sixty-four per cent of the cases occurred early in the season and on average each episode resulted in the loss of 7.6 training days.     

Influence of imported sport horses on the genetic evaluation of Swedish Warmblood stallions

There is substantial international influence on the Swedish Warmblood (SWB) sport horse population. The SWB Association suspects that imported horses are pre-selected based on their anticipated performance level, which could lead to biased estimated breeding values (EBVs) for stallions. This study examined different strategies to handle records for imported horses in the genetic evaluation. The stallions were evaluated for 10 traits using 3 different EBV estimation methods that were compared based on ranking comparisons of stallions, accuracy, correlations and absolute differences between EBVs. The results showed that the stallions’ EBVs were affected by imported offspring which, as a group, had higher average scores than horses born in Sweden. Sire EBVs differed by up to 0.6 genetic standard deviation of the trait between methods for stallions with >50% imported offspring. Excluding imported offspring lowered the accuracies and caused larger re-ranking compared with including a fixed effect of origin in the model.     

Equine parascarosis under the tropical weather conditions of Ethiopia: a coprological and postmortem study

A cross-sectional coprological survey in the regions of Ada, Akaki, Bereh and Boset, and a retrospective postmortem investigation were conducted to study the epidemiology of Parascaris equorum in donkeys and horses in Ethiopia. Faecal samples from 803 working donkeys and 402 horses were collected, and the numbers of worms recovered from 112 donkeys examined postmortem between 1995 and 2004 were analysed. There was a high prevalence of infection and faecal egg output of P equorum in both donkeys and horses, and the severity of the infection in donkeys was increased irrespective of their age. The prevalence of the infection in the donkeys was 51.1 per cent and in the horses 16.2 per cent, and the prevalence in the donkeys examined postmortem was 55 per cent. There was no significant difference between different age groups of donkeys in either the prevalence or the intensity of the infection. The prevalence of the infection was significantly higher in the Ada and Akaki regions than in the Bereh and Boset regions.     

Allergen-specific IgE in Icelandic horses with insect bite hypersensitivity and healthy controls, assessed by FcepsilonR1alpha-based serology

Insect bite hypersensitivity (IBH) and atopy can both be causes of pruritus in horses and are associated with allergen-specific IgE to biting insects and environmental allergens respectively. Information with respect to differences in IgE levels in diseased and healthy animals is crucial in enabling an understanding of the clinical relevance of results of allergen-specific IgE tests. The aim of this study was (i) to evaluate and compare levels of allergen-specific IgE, using an ELISA method, in Icelandic horses, with and without IBH, from Iceland and Sweden respectively; (ii) to investigate patterns of allergen-specific IgE to insects, pollens, moulds and mites in those groups of horses; and (iii) to investigate the clinical significance of employing two different cut-off levels for the ELISA. The study compromised a total number of 99 horses from Iceland and Sweden, with and without IBH, divided in 5 groups. Sera from the horses were analysed blindly with the use of Allercept , a non-competitive, solid-phase ELISA-test, designed to detect the presence of allergen-specific IgE in sera using the recombinant alpha chain of the high-affinity IgE receptor (FcepsilonR1alpha). The distribution of the ELISA values was shown for each insect, mould, mite and pollen allergen, in the different groups using 10th, 50th and 90th percentiles. The use of two cut-off levels, 150 EA and 300 EA, did not eliminate the false positives. Horses with IBH had a higher number of positive reactions, counting all the 29 allergens, than healthy controls and this was borderline significant (P=0.053). In this study it was shown that serological testing with an ELISA that uses the high-affinity IgE receptor (FcepsilonR1alpha) is presently not suitable as a tool for establishing a diagnosis of IBH or equine atopy. The importance of establishing a correct cut-off level for the ELISA for the different allergens is emphasised.     

Presence of the glycogen synthase 1 (GYS1) mutation causing type 1 polysaccharide storage myopathy in continental European draught horse breeds

The purpose of this study was to determine which continental European draught horse breeds harbour a mutation in the glycogen synthase 1 gene (GYS1) that is known to be responsible for type 1 polysaccharide storage myopathy in quarter horses and North American draught horses. Of a non-random selection of continental European draught horses belonging to 13 breeds, 62 per cent (250 of 403) tested were found to carry the mutant allele. The horses were located in Belgium, France, Germany, The Netherlands, Spain and Sweden. The mutation was identified in animals from each of the breeds examined. In the breeds in which more than 15 animals were available for testing, the highest percentages of GYS1-positive horses were found in the Belgian trekpaard (92 per cent; 35 of 38 horses tested), Comtois (80 per cent; 70 of 88), Netherlands trekpaard (74 per cent; 17 of 23), Rheinisch-Deutsches kaltblut (68 per cent; 30 of 44) and Breton (64 per cent; 32 of 51).     

Sentinel practice-based survey of the management and health of horses in northern Britain.

Details of the management, feeding, level of activity and routine health care of horses in Scotland and the five northernmost counties in England were recorded through a stratified random sample of horse owners who had responded to a previous survey. Sixty-eight per cent of the horses were kept where their owners resided, and 32 per cent were kept away from the owner's home. More than 99 per cent were turned out to grazing for at least part of the year and 81 per cent were stabled for at least part of the time, most commonly bedded on straw (50 per cent) or shavings (34 per cent). Hay was fed to 87 per cent, sugar beet pulp to 64 per cent and commercially prepared concentrate mixes to 60 per cent of the horses. Hacking was the most popular activity (52 per cent of horses) followed by riding/pony club events (28 per cent) and showing (21 per cent). The majority of the horses were involved in more than one activity. There were an estimated 0.88 veterinary visits per horse per year and 29 per cent of the horses were reported to suffer from at least one permanent or recurrent health disorder. The median annual numbers of administrations of vaccines (influenza and tetanus) and anthelmintics were one and seven respectively per horse, and each horse was shod a median seven times. There were significant differences in the management of horses kept in different types of premises and in areas of different human population density.