Prevalence of owner-reported ocular problems and veterinary ocular findings in a population of horses aged ≥15 years.

BACKGROUND: Previous studies suggest that ocular disease is common among aged horses but owners may fail to identify or underestimate their clinical relevance. OBJECTIVES: To document the prevalence of owner-reported ocular disease in horses aged ≥15 years. In a subset of these horses, to document ophthalmic findings from veterinary examination and compare with owner-reported ocular disease, and to determine risk factors for veterinary ophthalmic findings. STUDY DESIGN: Cross-sectional study. METHODS: Owners of aged horses completed a survey on management, clinical signs and medical history. Risk factors for the presence of ocular disease as reported by the owner were determined. A subset of these horses underwent an ophthalmological examination. Risk factors for the presence of ocular disease detected during this examination were determined. Agreement between owner-reported data and veterinary ophthalmic findings was assessed. RESULTS: Abnormal ocular findings were detected in 287/327 horses aged ≥15 years that underwent a complete ophthalmic examination, whereas the presence of ocular disease as reported by the horse-owners was only 3.3%. Agreement between owner-reported ocular disease and results of the veterinary examination was low for all categories analysed. An owner-reported history of ocular discharge was associated with increased odds of veterinary-reported diminished vision. Increasing age was associated with increased odds of the presence of an eye abnormality (any) and cataracts. Appaloosa horses had increased odds of cataract compared with other breeds. Horses in work were less likely to have an eye abnormality. MAIN LIMITATIONS: Volunteer bias may have influenced our results with owners of sick horses or those more concerned about their horses more likely to volunteer at the initial recruitment phase. CONCLUSIONS: This study showed a high prevalence of ocular lesions in aged horses which was not reflected in owner-reported disease. This has highlighted problems in obtaining information on ocular conditions from horse-owners.

Prevalence and risk factors for hyperinsulinaemia in ponies in Queensland, Australia.

OBJECTIVES: To determine the prevalence of hyperinsulinaemia in a population of ponies in Queensland, Australia, and identify associated factors. METHODS: Breeders or traders of ponies within a 100 km radius of Gatton, Queensland, were recruited for study using an internet database. Clinical and management details were obtained, including body condition score, fat deposition and history or evidence of laminitis. Blood samples were analysed for serum insulin and triglyceride concentrations and plasma adrenocorticotrophic hormone (ACTH) and leptin concentrations following short-term removal from pasture and withholding of supplementary food for at least 12 h. RESULTS: Of 23 pony studs identified, 22 were available for visit. The study population consisted of 208 ponies: 70 Australian Ponies; 67 Welsh Mountain Ponies or Cobs; 51 Connemara Ponies; 20 Shetland ponies. We excluded 20 with suspected pituitary pars intermedia dysfunction (>15 years, ACTH >50 pg/mL). In total, 27% of the ponies (51/188) were hyperinsulinaemic (insulin >20 µIU/mL). The final multivariable model revealed increasing age, supplementary feeding and increased leptin and triglyceride concentrations to be associated with hyperinsulinaemia. CONCLUSIONS: Hyperinsulinaemia was prevalent and associated with age and evidence of metabolic disturbance, including elevated leptin and triglyceride concentrations, in this population. A significant number of ponies were at risk of hyperinsulinaemia, which has implications for strategies to reduce the risk of laminitis in this population.

Prevalence, risk factors and clinical signs predictive for equine pituitary pars intermedia dysfunction in aged horses.

REASONS FOR PERFORMING STUDY: Equine pituitary pars intermedia dysfunction (PPID) is an ageing-related neurodegenerative disorder. The prevalence and risk factors for PPID using seasonally adjusted basal adrenocorticotropic hormone (ACTH) concentrations in aged horses have not been previously reported. OBJECTIVES: To determine the prevalence, risk factors and clinical signs predictive for PPID in a population of horses aged ≥ 15 years in Queensland, Australia. METHODS: Owner-reported data was obtained using a postal questionnaire distributed to an equestrian group. A subgroup of surveyed owners were visited and a veterinary physical examination performed on all horses aged ≥ 15 years. Blood samples were analysed for basal plasma alpha melanocyte-stimulating hormone (α-MSH) and ACTH concentrations, routine haematology and selected biochemistry. Aged horses with elevations above seasonally adjusted cut-off values for basal plasma ACTH were considered positive for PPID. Positive horses were compared with their aged counterparts to determine risk factors and clinical signs associated with PPID. RESULTS: Pituitary pars intermedia dysfunction was prevalent in aged horses (21.2%) despite owners infrequently reporting it as a known or diagnosed disease or disorder. Numerous clinical or historical signs were associated with an increased risk of PPID in the univariable model, but only age (odds ratio (OR) 1.18; 95% confidence interval (CI) 1.11-1.25, P<0.001) and owner-reported history of hirsutism (OR 7.80; 95% CI 3.67-16.57, P<0.001) remained in the final multivariable model. There were no routine haematological or biochemical variables supportive of a diagnosis of PPID. CONCLUSIONS AND POTENTIAL RELEVANCE: Pituitary pars intermedia dysfunction occurs commonly in aged horses despite under-recognition by owners. The increased risk of PPID with age supports that this is an ageing associated condition. Aged horses with clinical or historical signs consistent with PPID, especially owner-reported hirsutism (delayed shedding and/or long hair coat), should be tested and appropriate treatment instituted.

The prevalence of endocrinopathic laminitis among horses presented for laminitis at a first-opinion/referral equine hospital.

Endocrinopathic causes of laminitis may be a common underlying causative pathogenesis in first-opinion or field cases presenting with laminitis, as opposed to laminitis produced in inflammatory research models. This study aimed to determine whether evidence of an underlying endocrinopathy was present in horses presented for laminitis to a first-opinion/referral veterinary teaching hospital. A second aim was to compare the signalment of horses and ponies with laminitis with the equine hospital population during the same period. All horses presenting for laminitis at Helsinki University Equine Teaching Hospital, Finland, over a 16-month period were examined for an underlying endocrinopathy. Horses presenting for laminitis were compared with the hospitalized population over the same period. There were 36 horses presented for laminitis, and evidence of endocrinopathy was present in 89%. Of the horses showing an underlying endocrinopathy, one-third had a diagnosis of pituitary pars intermedia dysfunction, and two-thirds showed basal hyperinsulinemia indicative of insulin resistance, without evidence of hirsutism. Phenotypic indicators of obesity were present in 95% of horses with basal hyperinsulinemia without hirsutism. Compared with the hospital population during the same period, horses with laminitis associated with an underlying endocrinopathy were significantly older and more likely to be pony breeds. Our data support that endocrine testing should be performed on all cases of laminitis that do not have a clear inflammatory or gastrointestinal origin.

A survey of aged horses in Queensland, Australia. Part 2: Clinical signs and owners' perceptions of health and welfare.

OBJECTIVE: To describe the prevalence and risk factors for clinical signs of disease and owner-reported health or welfare issues of aged horses in Queensland, Australia. METHODS: Owners of horses were contacted via an equestrian organisation in Queensland and asked to complete a questionnaire about their horses aged 15 years and older, to gain information about clinical signs observed in the horse and disease history. Owners were asked to identify health or welfare issues they felt were important in aged horses. RESULTS: Owners were able to identify many clinical signs of disease, with 83% of horses having at least one reported clinical sign of disease. Muscle stiffness (33%), lameness (28%), ocular discharge (22%), change in hair coat (22%) and skin problems (21%) were the most commonly reported signs. Increasing age was a risk factor for the presence of clinical signs of disease. Ponies had an increased risk of both laminitis and hirsutism, whereas Thoroughbreds had an increased risk of stereotypies, wounds, weight loss and musculoskeletal signs. Owners reported a known disease or disorder in their horses less frequently than the clinical signs of disease. Owners reported weight loss (28%), arthritis/lameness (24%) and teeth/dental care (18%) as the most important health issues, followed by welfare issues (8%). CONCLUSION: Owners demonstrated concern for the health and welfare of their aged horses, but the lack of appropriate recognition of the significance of clinical signs and limited veterinary care suggest a need for increased client communication and veterinarian-client interaction.

A survey of aged horses in Queensland, Australia. Part 1: management and preventive health care.

OBJECTIVE: To describe management practices and routine preventive care of aged horses in Queensland, Australia, including effects of owner characteristics, affiliation to an equestrian group and retirement of the horse. METHODS: Owners of horses were contacted via Equestrian Australia (EA) and asked to complete a questionnaire about their aged horses (e.g. age, breed, sex and colour); their use and management, including preventive health care; and use of equine healthcare providers. RESULTS: Horses aged 15 years or greater represented one-third of the total horses owned in the population sample. The median age of the horses was 20.7 years (range 15-44 years). Basic husbandry and preventive health care varied depending on demographic region, age of the horse and its use. Affiliation with EA was associated with the breed and use of the horse, but not with management or preventive health care other than frequency of hoof care visits. Retired horses had reduced basic husbandry and preventive health care compared with non-retired horses. There was reduced preventive health care in rural compared with urban areas. The majority (61%) of horses in the current study had not been visited by a veterinarian in the previous 12 months. CONCLUSION: Aged horses constitute a large subgroup of the Australian horse population. Although basic management is at a high level for most aged horses, it appears to be reduced following the horse's retirement and in the more rural areas. There was limited veterinary involvement in preventive healthcare strategies for aged horses, especially in rural areas.

Prevalence of equine polysaccharide storage myopathy and other myopathies in two equine populations in the United Kingdom.

The aim of this study was to determine the prevalence of equine polysaccharide storage myopathy (EPSM) in two populations of horses in the UK. Biopsy specimens from 94 horses presented to an abattoir (population 1), and 46 horses with neuromuscular disorders presented to a university referral hospital (population 2) were obtained over a period of 4years. Histological sections were examined by a veterinary pathologist for lesions including abnormal polysaccharide inclusions in myofibres. In population 1, a diagnosis of EPSM was made in 8% and non-specific myopathy in 33% of horses. In population 2, a diagnosis of EPSM was made in 22%, equine motor neurone disease (EMND) in 15% and non-specific myopathy in 37%. Within each population there was no difference in age, sex or breed distribution and muscle disease diagnosis. However, populations differed from each other in age and breed distributions and muscle disease diagnosis. EPSM was found in draft, Warmblood and related breeds and was diagnosed for the first time in cob-types. EMND was reported in 7/46 horses presented for neuromuscular disease and weakness, representing an important diagnosis in the UK. This study showed a high prevalence of EPSM and other myopathies in typical breeds of horses in the UK.

Movement between the equine ilium and sacrum: in vivo and in vitro studies.

REASONS FOR PERFORMING STUDY: Sacroiliac disease (SID) is an important cause of loss of performance in horses, yet little is known about the biomechanics of movement of the sacroiliac joint (SIJ). OBJECTIVES: (a) To document the presence of equine SIJ motion by measuring the change in cross-sectional area (CSA) of the dorsal portion of the dorsal sacroiliac ligament (DSIL) during application of manual forces to the pelvis, and to ascertain if this varied between horses with SID and normal horses; (b) To determine the amount and direction of motion available at the equine SIJ using 3-D orientation sensors, and how motion is limited by the DSIL and sacrotuberous ligament. METHODS: Study 1: CSA obtained ultrasonographically was compared before and during manual force application to the ilium, on a group of 10 horses, 5 with SID and 5 clinically normal. Study 2: direction and degrees of motion between sacrum and ilium were measured in 8 cadaveric SIJs. 3D orientation sensors were mounted to the fixated sacrum and the moveable ilium, and relative motion recorded between the 2 bones when manual forces were applied to the ilium. RESULTS: Study 1 showed a significant decrease in the CSA of the equine DSIL during application of manual forces to both tuber coxae (TC) (P<0.001) and tuber sacrale (TS) (P<0.001) when compared to at rest. Study 2 described range of motion to be greatest in the transverse or coronal plane, when lateral and oblique forces were applied to the pelvis, and recorded significant increases (P<0.05) in range of motion in the sagittal plane following resection of both the DSIL and sacrotuberous ligament. CONCLUSION AND POTENTIAL RELEVANCE: The change in DSIL CSA with application of manual force may be due to a lengthening of the ligament, reflecting equine SIJ motion in vivo. The motion recorded between ilium and sacrum in vitro suggests that greatest sacroiliac motion may occur in the transverse plane. Increases in range of motion following resection of ligaments give some indication of the role of each ligament.