Helminth control used by trainers of thoroughbreds in England

A telephone survey was conducted of the methods used to control parasitic worms at 106 thoroughbred training yards. Most of the horses were allowed access to grass and were therefore at risk of infection. The control methods relied primarily on the use of anthelmintics and appeared reasonably successful because only 44 per cent of trainers reported observing clinical signs of nematode infections. They dosed their horses frequently, 40 per cent treating every four to six weeks and 25 per cent treating every seven to eight weeks. New arrivals on yards were usually treated with anthelmintic but the strategies used would be unlikely to prevent the introduction of anthelmintic-resistant nematodes on most yards or to deal with encysted cyathostomes. Trainers were responsible for the design of most control schemes, and only 42 per cent of them based their choice of anthelmintic on veterinary advice.     

Parasite control methods used by horse owners: factors predisposing to the development of anthelmintic resistance in nematodes

One hundred and fifty horse owners, primarily private owners and riding schools, replied to a questionnaire concerning the practices they used to control parasites. Twenty-seven had experienced a parasite problem. Faecal samples from 188 horses selected at random showed that worm control practices were generally successful; however, many owners were not following recommendations for slowing the development of resistant parasites. In 1996, 86 per cent of the owners were using either three or two classes of anthelmintic a year, and they used a median of six doses with a range from one to 11. Approximately half the owners, more commonly owners of up to five horses, picked up their horses' faeces at least once a week, but these owners also used more doses of anthelmintic a year than owners who did not pick up faeces. One-third of the owners manually removed Gasterophilus species eggs from the horses' hairs, but 94 per cent of them also used ivermectin. Many owners treated specifically for Anoplocephala species, cyathostome larvae and Gasterophilus species, and these owners were the most likely to use three classes of anthelmintic a year. One-hundred-and-seven owners replied to a second questionnaire asking for information about the factors that influenced their anthelmintic control practices. Many owners, particularly private owners, were not influenced by the cost of the anthelmintic. For the timing and frequency of treatment, and the choice of drug, owners were most influenced by advertisements, magazine articles and veterinary surgeons. In two magazines aimed at horse owners, the brands of drugs most frequently advertised were the brands most commonly used by the owners, and articles in the magazines recommended the use of three classes of drug per year. These results are discussed in relation to their influence on the development of anthelmintic-resistant nematodes.     

Postal survey of the population of South American camelids in the United Kingdom in 2000/01

The members of the two leading British camelid breeders associations were surveyed by means of a postal questionnaire between December 2000 and January 2001; 696 questionnaires were posted and 218 usable responses were returned. A total of 3520 camelids were recorded, of which 2719 (77.2 per cent) were alpacas (Lama pacos) and 726 (20.6 per cent) were llamas (Lama glama). Ninety-four per cent of the camelid herds were of one species, and 70 per cent of the animals were kept for more than one purpose. Camelids imported from South America were present on 45 per cent of the units surveyed. Husbandry procedures and preventive health measures were uniform; 92.2 per cent of the animals were kept on pasture all year round, 99 per cent were supplemented with hay and 97.7 per cent with concentrate feed; 88.1 per cent were vaccinated against clostridial disease with a multivalent vaccine licensed for sheep, and 96.3 per cent were treated periodically with anthelmintic drugs. During 2000, ill health, other than dermatological conditions, was reported by 24.3 of respondents, and 32 different conditions were described. Skin disease was reported by 51 per cent of breeders. Zinc deficiency was diagnosed presumptively as the cause of skin disease by 31.9 per cent of the respondents, and ectoparasitism by 26.4 per cent. Of those who treated a skin condition, 71.9 per cent reported an improvement, but less than half of them considered the improvement to have been permanent.     

Traumatic injuries involving tendons of the distal limbs in horses: a retrospective study of 55 cases.

Fifty-five horses were presented to Colorado State University Veterinary Teaching Hospital between 1st of January 1980 and 31st of December 1989 for treatment of distal limb lacerations involving flexor tendons (n = 35) or extensor tendons (n = 20). Of the 35 flexor tendon lacerations, 11 horses were killed without treatment and 24 horses were treated. Twenty-two horses were included in determining outcome. Four (18 per cent) returned to their original level of use, nine (41 per cent) returned to limited riding, seven (32 per cent) returned to breeding or pasture soundness and two (9 per cent) were killed. Eighteen of the 20 horses with extensor tendon lacerations underwent treatment and 15 had sufficient follow-up to determine outcome. Seven (47 per cent) returned to their original or intended use, five (33 per cent) returned to limited use, one (7 per cent) was used for breeding and two (13 per cent) were killed. Results for horses with extensor tendon lacerations support previous reports that these injuries can be treated successfully. Results for horses having flexor tendon lacerations were better than in previous reports.     

Prevalence of benzimidazole-resistance in equine cyathostome populations in south east England.

In order to study the prevalence of benzimidazole-resistance in equine cyathostomes, 30 stables in south east England were selected according to strict criteria but with minimum bias to provide three matched groups of 100 horses. One group was treated with fenbendazole, one with pyrantel embonate and the third was left untreated. The overall efficacies of fenbendazole and pyrantel embonate, as judged by the faecal egg-count reduction test, were 56.3 and 95.8 per cent, respectively. The numbers of horses at individual stables were too small to draw conclusions at each stable, but whereas efficacies greater than 85 per cent were recorded for pyrantel at 26 of 27 stables, the corresponding figure for fenbendazole was five of 27. Cyathostomes accounted for more than 90 per cent of the larvae cultured from faeces before and after treatment. Trichostrongylus axei was detected on 20 sites, but Strongylus species were present on only five. In the area of the survey, benzimidazole-resistance was very widespread in stables which used benzimidazole anthelmintics regularly and had more than nine horses per stable, but the benzimidazole-resistant cyathostome strains were adequately controlled with the non-benzimidazole anthelmintic pyrantel embonate.     

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.     

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.     

Survey of the current use of pharmacokinetic model-driven drug delivery in small animal anaesthesia and analgesia in Italy

Veterinary surgeons in Italy were surveyed about their current practice with regard to the use of propofol and intravenous opioids during anaesthesia and for treatment of acute pain in small animals. Questionnaires were e-mailed to all 171 members of the Italian Society of Veterinary Regional Anaesthesia and Pain Medicine. Information was requested on the type of practice the veterinarians worked in, the administration techniques used and the perceived benefit of pumps with target-controlled infusion (TCI) capability implementing small animal pharmacokinetic models. A total of 168 responses were received (response rate 98.2 per cent). Of the respondents, 121 (72.0 per cent) worked in a first-opinion private practice, 25 (14.9 per cent) worked in a 24/7 private practice, 11 (6.5 per cent) worked in a referral private practice, eight (4.8 per cent) worked in a university hospital, two (1.2 per cent) were not currently practising with small animals and one (0.6 per cent) had retired. Of the 130 (78.8 per cent) practising respondents who reported using a syringe pump, eight (4.8 per cent) used a TCI system, 31 (18.8 per cent) used manual TCI, 40 (24.2 per cent) used a bolus-elimination-transfer scheme and 51 (31 per cent) used a constant-rate infusion. As a result, 79 of 165 (47.9 per cent) practising respondents used a pharmacokinetic model-driven method of drug delivery. The majority of respondents (81.2 per cent) believed that the use of pumps with TCI capability would improve practice and patient care.     

Prevalence and some clinical characteristics of equine cheek teeth diastemata in 471 horses examined in a UK first-opinion equine practice (2008 to 2009)

Cheek teeth (CT) diastemata are now recognised as a clinically significant equine disorder, but their prevalence in the general equine population is unknown. There is also limited information on the signalment of affected horses; the more commonly affected Triadan sites; and the shape and clinical characteristics of CT diastemata. During the 12-month study period (2008 to 2009), standardised records were obtained during routine dental examinations performed by five veterinarians in a first-opinion equine practice. Cheek teeth diastemata were identified in 49.9 per cent of all horses (n=471) of mean age 11 years (range one to 30 years), with 83.5 per cent of all diastemata affecting mandibular CT and 16.5 per cent affecting maxillary CT. The mean number of diastemata per case was 1.7 (range one to 20) and the mandibular 07 to 08 position was most commonly affected. Valve diastemata were more common (72.1 per cent prevalence) than open diastemata (27.9 per cent). Food trapping was present in 91.4 per cent of diastemata, with gingivitis and periodontal pockets adjacent to 34.2 per cent and 43.7 per cent, respectively. Halitosis was present in 45.5 per cent of affected horses. There was an age-related increase in both the prevalence of diastemata, and in the numbers of diastemata per affected horse, and horses over 15 years old had a significantly increased proportion of open diastemata.     

An evidence‐based approach to equine parasite control: It ain't the 60s anymore

Most veterinarians continue to recommend anthelmintic treatment programmes for horses that derive from knowledge and concepts more than 40 years old. However, much has changed since these recommendations were first introduced and current approaches routinely fail to provide optimal or even adequate levels of parasite control. There are many reasons for this. Recent studies demonstrate that anthelmintic resistance in equine parasites is highly prevalent and multiple‐drug resistance is common in some countries, but few veterinarians take this into account when making treatment decisions or when recommending rotation of anthelmintics. Furthermore, the current approach of treating all horses at frequent intervals was designed specifically to control the highly pathogenic large strongyle, Strongylus vulgaris. But this parasite is now quite uncommon in managed horses in most of the world. Presently, the cyathostomins (small strongyles) are the principal parasitic pathogens of mature horses. The biology and pathogenesis of cyathostomins and S. vulgaris are very different and therefore require an entirely different approach. Furthermore, it is known that parasites are highly over‐dispersed in hosts, such that a small percentage of hosts harbour most of the parasites. The common practices of recommending the same treatment programme for all horses despite great differences in parasite burdens, recommending prophylactic treatment of all horses without indication of parasitic disease or knowing what species of parasites are infecting the horses, recommending use of drugs without knowledge of their efficacy and failing to perform diagnostic (faecal egg count) surveillance for estimating parasite burdens and determining treatment efficacy, are all incompatible with current standards of veterinary practice. Consequently, it is necessary that attitudes and approaches to parasite control in horses undergo a complete overhaul. This is best achieved by following an evidence‐based approach that takes into account all of these issues and is based on science, not tradition.     

Training and growth induced changes in the middle gluteal muscle of young Standardbred trotters

The middle gluteal muscle of five, two-year-old untrained trotters was investigated by repeated needle biopsy sampling over a training period of six months. A second group of five, three-year-old untrained horses was included to examine the effect of growth. After the training period increases were found in the relative distribution of slow twitch (ST) fibres from 18 per cent to 25 per cent and fast twitch (FTa) fibres from 36 per cent to 45 per cent, and a decrease in FTb fibres from 46 per cent to 30 per cent. A proportionally equal reduction (approximately 18 per cent) in the cross sectional area of all fibre types was observed after the first two months of training succeeded by an increase to approximately pretraining levels at the end of the period. The number of capillaries per fibre was enhanced from 1.7 to 2.4. Proliferation of capillaries occurred around fibres of all types. The metabolic adaptations showed increases in the activities of 3-hydroxy-acyl-CoA dehydrogenase (HAD) (50 per cent) and citrate synthase (31 per cent). Growth had no effect on the relative fibre type distribution nor the capillary per fibre ratio, but as the mean fibre area increased 36 per cent (primarily because of increases in FT fibres) the number of capillaries/mm2 was lower in the older untrained horses (350 capillaries/mm2) compared with the younger untrained ones (460 capillaries/mm2). Increase with growth was found in the activity of phosphorylase and HAD and a decrease was seen in the activity of hexokinase. It is concluded that the training programme exclusively induced alterations which improved the aerobic capacity of the muscle.     

A survey by questionnaire of parasitic worm control in cattle and sheep at the Glasgow University Lanark practice

The results of a questionnaire circulated in 1984 concerning parasitic worm control on cattle and sheep farms in a veterinary practice in the west of Scotland are reported. Control by grazing management or anthelmintic treatment was used in 92 per cent of the cattle herds and in all the sheep flocks. The use of anthelmintic drugs was greatest on farms where grazing control was also practised. Benzimidazoles were the most frequently used anthelmintic drugs.     

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.     

Factors associated with the wastage and achievements in competition of event horses registered in the United Kingdom

The aims of this study were to estimate the wastage of horses registered for eventing in Britain, to investigate the reasons for this wastage and to evaluate factors affecting the horses' achievement of grade I status (at least 61 points) while registered. An analysis of the database of the British Eventing register found that 33.7 per cent of horses registered for the first time in 1999 were not re-registered for eventing in subsequent years. By using multivariable logistic regression analysis, it was shown that horses that were kept at an event yard were more likely to be re-registered than those kept on other premises (odds ratio [or] 2.0, 95 per cent confidence interval [ci] 1.2 to 3.2), and those that took part in showjumping while registered were also more likely to be re-registered (or 1.5, 95 per cent ci 1.1 to 2.2). Horses that took part in unaffiliated eventing while registered were less likely to be re-registered the following year (or 0.7, 95 per cent ci 0.5 to 0.9), as were those that were not insured (or 0.7, 95 per cent ci 0.5 to 1.0) and those from outside the British Isles (or 0.6, 95 per cent ci 0.3 to 1.0). Veterinary problems were the most commonly cited explanation (35.1 per cent) why horses that remained in their original ownership were not re-registered with British Eventing the following year. Horses from Australia were more likely to achieve grade I status than horses from the British Isles (or 9.7, 95 per cent ci 7.1 to 13.2), as were horses from New Zealand (or 6.4, 95 per cent ci 5.0 to 8.2), the usa (or 5.2, 95 per cent ci 3.8 to 7.2) and France (or 2.8, 95 per cent ci 2.1 to 3.7), but horses from the Netherlands (or 0.5, 95 per cent ci 0.3 to 0.9) and Belgium (or 0.3, 95 per cent ci 0.1 to 0.9) were less likely to achieve grade I status. Mares were less likely to achieve grade I status than geldings (or 0.4, 95 per cent ci 0.4 to 0.5).     

Risk factors for high endoparasitic burden and the efficiency of a single anthelmintic treatment of Danish horses

A questionnaire survey regarding endoparasite control practices in Danish horse herds was carried out in 1995. The participating veterinarians and herd owners were sampled using convenience and purposive sampling. In the analysis of risk factors for development of a high endoparasitic burden (> 200 eggs per gram faeces) 903 horses were sampled and the analysis of the efficiency of a single anthelmintic treatment was based on 605 horses. The following factors had a significant effect on the endoparasitic burden: herd type, age of the horses, use of pasture rotation, anthelmintic treatment of horses visiting the herd, use of an adviser in the planning of endoparasite control and advice regarding pasture rotation. An interaction between pasture rotation and advice regarding pasture rotation was found, but due to high colinearity this was not reported. The factors influencing significantly on the reduction of the faecal egg count after a single anthelmintic treatment were the type of herd, the age of the horse, the drug used, and the anthelmintic-resistance-status of the herd. A negative effect of permanent pastures was observed. If pasture hygiene was performed on the advice of the veterinarian, the effect of a single anthelmintic treatment was less compared to a single anthelmintic treatment without any advice. An interaction between the treatment group and the resistance-status of the herd was found. Additional factors, normally accounted for, when endoparasites and anthelmintic resistance is discussed, were investigated, but not found significant in this study.     

Characteristics of commercial pig farms in Great Britain and their use of antimicrobials

A mail survey of 1889 pig producers in Great Britain with more than 100 sows or more than 1000 pigs was carried out to investigate their use of antimicrobials and other health-related management practices. The response rate was 25.5 per cent. Antimicrobials were most commonly administered in feed. Depending on the production system, between 60 and 75 per cent of the farms had used antimicrobials in their weaner rations and 20 to 62 per cent had used them in their grower rations. Antimicrobial injections had been used on 59 per cent of the farms. The use of antimicrobials in pigs of different age groups was variously associated with the scale of production, membership of a quality assurance scheme, the use of vaccination and whether the farmer thought the farm environment could be improved. Half the respondents (49 per cent) indicated that they used growth promoters in their weaners, but fewer used these in their growers (45 per cent) and finishers (34 per cent). Although 63 per cent of the farmers felt that the continued use of antimicrobials for disease prevention was justified, only 21 per cent felt that their continued use as growth promoters was justified.     

Use of height-specific weigh tapes to estimate the bodyweight of horses

Two thousand horses of different ages, heights and breeds were divided into two height groups of up to 14.2 hands high (hh) and more than 14.2 hh, and weighed on a weighbridge; each horse then had its weight estimated by three weigh tapes, one height specific (tape 1 or 2, depending on the animal's height) and two for general use (tapes 3 and 4). For horses up to 14.2 hh, weigh tape 1 provided the most accurate estimate of mean (sd) bodyweight (100.5 [6.2] per cent), and weigh tapes 3 and 4 were 112 (6.8) and 97-0 (6.1) per cent accurate, respectively. For horses more than 14.2 hh, weigh tape 2 provided the most accurate estimate of bodyweight (98.6 [18.4] per cent), with weigh tapes 3 and 4 being 102.6 (17.4) and 90.8 (15.2) per cent accurate, respectively.     

An investigation of the incidence of chronic obstructive pulmonary disease (COPD) in random populations of Swiss horses

The incidence of Chronic Obstructive Pulmonary Disease (COPD) in Switzerland was determined in three groups of horses selected at random. Group A (97 horses) and Group B (93 horses) had no history of respiratory disease, but Group C (113 horses) had a history of lower respiratory tract disease. All horses were examined by auscultation of the respiratory tract under forced breathing, endoscopic examination of the upper and lower respiratory tract, arterial blood gas analysis at rest and cytological examination of respiratory secretions (RS). Fifty-four per cent of the horses in Group A and 54.8 per cent of Group B were diagnosed as suffering clinical COPD and only 12.4 per cent of horses in Group A and 8.6 per cent in Group B had no detectable abnormalities in their lower respiratory tracts. In Group B, 19.4 per cent were considered to be suffering from parasitic pulmonary disease indicated by elevated numbers of eosinophils in their RS. Pharyngeal lymphoid hyperplasia was exhibited in 70.1 per cent of Group A and 74.2 per cent of Group B. Cytological examination of RS was useful to determine if the secretions found in the trachea originated from the upper or lower respiratory tract. Arterial blood gas analysis revealed no significant differences between healthy horses and those with subclinical or mild COPD.     

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.