Abstract: OBJECTIVE: To record the prevalence and document the types of eye disease in population of Thoroughbred racehorses in Victoria, Australia. DESIGN: Prospective study. ANIMALS: Two hundred four Thoroughbred racehorses. PROCEDURE: All horses and both eyes were examined at four metropolitan and two country racing stable complexes. Ophthalmic exam was performed following dark adaptation with a transilluminator, biomicroscope, and direct ophthalmoscope. Intraocular pressures were measured when indicated. Both pupils were dilated with tropicamide when indicated. RESULTS: One hundred eighty-two (89.2%) flat-racing and 22 (10.8%) jump-racing (hurdle or steeple) horses were examined. Age range: 2-9 years (mean 3.7 years, median 3); 97 (47.5%) male-neuter, 74 (36. 3%) female, 33 (16.2%) male. Potential vision-threatening eye disease was present in 15 (7.4%) different horses: complete lenticular cataracts 3, posterior lens luxation and cataract 1, large peripapillary 'butterfly' inactive lesions 3, large peripapillary 'butterfly' active lesions 2, peripapillary focal inactive 'bullet hole' chorioretinal lesions (> 20) 5, optic nerve atrophy 1. Non-vision threatening eye disease was present in 117 (57.4%) different horses, involving one or more ocular structures: lower eyelid scars 3; periocular fibropapillomatous disease 1; third eyelid squamous cell carcinoma 1; corneal scars 6; corneal band opacity 2; anterior iris synechia 1; developmental cataracts 36 (17.2%); peripapillary focal inactive 'bullet hole' chorioretinal lesions (< 20) 103 (50.0%); linear peripapillary hyperpigmentation bands 16 (7.9%). Unusual variations of normal ocular anatomy and colobomata was recorded in 11 (5.4%) different horses: granular iridica hypoplasia 3, granular iridica hyperplasia 2, multilobular granular iridica cyst 1, microcornea 1, hyaloid remnant 1, rotated optic nerve head 1, coloboma of the lens 1, atypical coloboma of the retina 1. CONCLUSIONS: This survey demonstrates that the prevalence of vision-threatening eye disease in racing horses may be greater than previously perceived, and highlights the importance of ocular examination within any routine physical examination of horses.

Abstract: REASONS FOR PERFORMING STUDY: There has been no large study of horses with suspected sacroiliac (SI) joint region pain in which the clinical diagnosis has been supported by either abnormal radiopharmaceutical activity in the SI joint region or by periarticular infiltration of local anaesthetic solution. OBJECTIVES: To describe the clinical features of horses with SI joint region pain, to document the age, breed, sex, discipline, size and conformation of affected horses and to compare these with the author's (SD) normal case population and to document the results of infiltration of local anaesthetic solution around the SI joint region. METHODS: Horses were selected for inclusion in the study based upon the exclusion of other causes of lameness or poor performance, together with clinical signs suggestive of SI joint pain and abnormal radiopharmaceutical activity in the SI joint region and/or a positive response to periarticular infiltration of local anaesthetic solution. RESULTS: Sacroiliac joint region disease was identified in 74 horses between November 1997 and March 2002. Dressage and showjumping horses appeared to be at particular risk (P < 0.001). Affected horses were generally slightly older than the normal clinic population (P < 0.0001), taller at the withers (P < 0.0001) and of greater bodyweight (P < 0.01). There was a significant effect of breed (P < 0.001), with a substantially higher proportion of Warmblood horses (51%) in the SI pain group compared to the normal clinic population (29%). There was no correlation between conformation and the presence of SI joint region pain. The tubera sacrale appeared grossly symmetrical in most (95%) horses. Poor development of the epaxial muscles in the thoracolumbar region and asymmetry of the hindquarter musculature were common. Twenty-six horses (35%) showed restricted flexibility of the thoracolumbar region and 10 (16%) had an exaggerated response to pressure applied over the tubera sacrale. Fourteen horses (19%) were reluctant to stand on one hindlimb for prolonged periods. The majority of horses (75%) had a straight hindlimb flight and only 18% moved closely behind or plaited. In all horses restricted hindlimb impulsion was the predominant feature; invariably this was most obvious when the horse was ridden. Stiffness, unwillingness to work on the bit and poor quality canter were common. Sacroiliac joint region pain was seen alone (47%), or in conjunction with thoracolumbar pain (16%), hindlimb lameness (20%), forelimb lameness (7%) or a combination of problems (10%). Seventy-three horses (99%) had abnormalities of the SI joint region identified using nuclear scintigraphy. Infiltration of local anaesthetic solution around the SI joint region produced profound improvement in gait in all 34 horses in which it was performed. CONCLUSIONS AND POTENTIAL RELEVANCE: Careful clinical examination combined with scintigraphic evaluation of the SI joint region and local analgesia can enable a more definitive diagnosis of SI joint region pain than has previously been possible.

Abstract: Seven horses with headshaking are described. No physical abnormalities were detected in any of the cases. Six of these horses had onset of clinical signs in the spring. The role of light was assessed by application of a blindfold or dark grey lens to the eyes, covering the eyes with a face mask and observing the horse in total darkness outdoors. Cessation of headshaking was observed with blindfolding (5/5 horses), night darkness outdoors (4/4 horses) and use of grey lenses (2/3 horses). Outdoor behaviour suggested efforts to avoid light in 4/4 cases. The photic sneeze in man is suggested as a putative mechanism for equine headshaking. Five of 7 horses had improvement with cyproheptadine treatment (0.3 mg/kg bwt b.i.d.). Headshaking developed within 2 calendar weeks of the same date for 3 consecutive years in one horse. Neuropharmacological alterations associated with photoperiod mechanisms leading to optic trigeminal summation are suggested as possible reasons for spring onset of headshaking.

Abstract: REASONS FOR PERFORMING STUDY: There is little information on the prevalence of, and risk factors associated with, post anaesthetic colic (PAC) in horses undergoing nonabdominal operations. OBJECTIVES: To undertake the first prospective study of prevalence of PAC and identify risk factors in its development in nonabdominal procedures. METHODS: A multicentre prospective case-control study was conducted, on every horse undergoing anaesthesia for a nonabdominal procedure between April 2004 and June 2005. Colic cases were defined as any horse with recognised signs of abdominal pain within 72 h of general anaesthesia that could not be attributed to any concurrent disease. Five control horses per case were selected randomly from the study population at all hospitals. Multivariable logistic regression analysis was used to examine the relationship between predictor variables and the risk of developing PAC. RESULTS: The estimated mean prevalence of PAC in the study population was 5.2% (95% CI, 2.8, 8.0). However, the prevalence of colic varied between each centre. The most commonly diagnosed cause of colic was impaction. Multivariable analyses showed that the centre involved and the type of surgery performed were associated with an increased risk of PAC. Preoperative food deprivation and the use of opioid drugs were confounding factors. CONCLUSIONS: Prevalence of PAC varied significantly between the 4 hospitals studied; there may be hospital-related covariates that account for this. The type of surgery performed influenced the risk of PAC. POTENTIAL RELEVANCE: Identifying the risk factors for PAC is a prerequisite for its prevention. This study indicates horses at increased risk of PAC that might benefit from a more critical evaluation of post anaesthetic gastrointestinal function and/or the provision of preventative measures. Further investigation is required to explain the variation in prevalence of PAC between centres.

Abstract: To quantify some components of prepurchase evaluations in horses, records from 134 evaluations performed during a 2-year period were reviewed and the outcome was determined via telephone follow-up interview. Sixty-two percent of the prepurchase evaluations had been performed at the clinic and 38% had been performed in the field by the ambulatory service. All evaluations included physical and lameness examinations, whereas radiography (49%), endoscopy (15%), nerve blocking (5%), transrectal palpation (3%), hematologic analysis (2%), electrocardiography (2%), drug testing for analgesic agents (2%), and ultrasonography of the flexor tendons (1%) were not always performed. Fifty-nine percent of horses evaluated at the clinic were radiographed, compared with 33% of horses evaluated in the field (P less than 0.05). Thirty-seven percent of horses evaluated were judged serviceable for their intended use. Thirty-five percent of horses evaluated at the clinic were assessed to be serviceable, compared with 41% of those evaluated in the field (P less than 0.05). Horses used for pleasure riding (48%) tended to be considered serviceable more often than horses used for more athletic endeavors (3-day eventing, 33%; hunter/jumper, 24%; show, 31%; dressage, 30%). The most common basis for finding a horse unserviceable was lameness (88%).(ABSTRACT TRUNCATED AT 250 WORDS)