Investigation of single and paired measurements of adrenocorticotropic hormone for the diagnosis of pituitary pars intermedia dysfunction in horses.

Background: Paired measurement of ACTH concentration may be more reliable than a single measurement.

Hypothesis/objectives: To determine whether the mean of 2 measurements of ACTH concentration is more reliable in assessing pituitary pars intermedia dysfunction (PPID) than a single measurement.

Animals: Paired ACTH measurements were performed on (1) 148 occasions from 124 horses being investigated for PPID, (2) 90 occasions from 76 horses with PPID that were receiving treatment with pergolide, and (3) 63 occasions from 50 horses in which there was no clinical suspicion of PPID.

Viraemic frequencies and seroprevalence of non-primate hepacivirus and equine pegiviruses in horses and other mammalian species.

Non-primate hepacivirus (NPHV), equine pegivirus (EPgV) and Theiler's disease associated virus (TDAV) are newly discovered members of two genera in the Flaviviridae family, Hepacivirus and Pegivirus respectively, that include human hepatitis C virus (HCV) and human pegivirus (HPgV). To investigate their epidemiology, persistence and clinical features of infection, large cohorts of horses and other mammalian species were screened for NPHV, EPgV and TDAV viraemia and for past exposure through serological assays for NPHV and EPgV-specific antibodies. NPHV antibodies were detected in 43% of 328 horses screened for antibodies to NS3 and core antibodies, of which three were viraemic by PCR.

Effects of metformin hydrochloride on blood glucose and insulin responses to oral dextrose in horses.

Reasons For Performing Study: Metformin is a potential therapeutic agent for the treatment of insulin resistance (IR). In laboratory animals, orally administered metformin reduces intestinal glucose absorption and may therefore affect insulinaemic responses to oral carbohydrate ingestion.

Objectives: To determine whether pretreatment with metformin reduces plasma glucose concentration and insulin responses following consumption of dextrose in horses.

In equine grass sickness, serum amyloid A and fibrinogen are elevated, and can aid differential diagnosis from non-inflammatory causes of colic.

Equine grass sickness (EGS) is a debilitating and often fatal neurodegenerative disease. A presumptive diagnosis of EGS may be made on the basis of clinical signs and subjective ancillary tests, but a definitive antemortem diagnosis can only be made following histopathological examination of intestinal biopsies. It has previously been reported that horses with EGS may show clinical and clinicopathological signs of systemic inflammation.

Circannual variation in plasma adrenocorticotropic hormone concentrations in the UK in normal horses and ponies, and those with pituitary pars intermedia dysfunction.

Reasons For Performing Study: Pituitary pars intermedia dysfunction (PPID) is a common endocrinopathy, frequently diagnosed via plasma adrenocorticotropic hormone (ACTH) concentrations. Seasonal variation in plasma ACTH concentrations has been described in normal horses prompting caution in diagnosing PPID at certain times of the year. The aims of this study were to determine appropriate reference intervals for equine plasma ACTH throughout the year; and to examine the circannual variation of plasma ACTH concentrations in PPID cases.

The pharmacologic basis for the treatment of endocrinopathic laminitis.

Although the treatment and management of laminitis in the horse requires a holistic and often multidisciplinary approach from the veterinarian, farrier, and nutritionist, this review focuses on pharmacologic interventions that might have prophylactic benefit, specifically in the horse with laminitis as a result of pituitary pars intermedia dysfunction and equine metabolic syndrome.

Type 2 diabetes mellitus with pancreatic beta cell dysfunction in 3 horses confirmed with minimal model analysis.

Reasons For Performing Study: Type 2 diabetes mellitus (T2DM) is diagnosed rarely in equine practice although it may be under-recognised. A greater awareness of the condition and therapeutic considerations would be to the benefit of such cases presenting in practice. More investigation into the pharmacological management of these cases is needed.

Stability of common biochemistry analytes in equine blood stored at room temperature.

Reasons For Performing Study: Time delays between collection of blood samples and biochemical analysis of equine blood are unavoidably common in equine practice. The effect that delays may have on the accuracy of results of blood biochemical analyses is not well established.

Hypothesis: Delays in processing of blood of up to 72 h results in alterations in measured levels of common biochemical analytes that are of potential clinical relevance.

The role of nutrition in colic.

Nutritional intolerances manifesting as colic in the horse may be largely explained by divergence from the diet and ingestive behaviors to which the feral ancestors of modern domesticated equids had become accustomed and adapted. High-starch diets and abrupt dietary changes are probably foremost in the risk factors for diet-associated colic in the horse and have their basis in disruption of the stability of microbial populations resident within the equine hindgut. Although some general associations between colic and diet may be inferred from several epidemiologic studies, data derived from studies of single and specific disease processes associated with colic allow more effective practical application of corrective dietary management strategies in situations where colic risk is judged to be increased.

Long-term management of sabulous cystitis in five horses.

Five horses with sabulous cystitis were managed for up to three years. They were treated by emptying the bladder through a urinary catheter and saline lavage with cytoscopic guidance to remove residual sabulous material. The cystitis was treated with antimicrobial and anti-inflammatory medications, and bethanechol chloride was also administered.

The effect of metformin on measurements of insulin sensitivity and beta cell response in 18 horses and ponies with insulin resistance.

Reasons For Performing Study: Laminitis in equids is a very common debilitating disease, and insulin resistance (IR) and hyperinsulinaemia are increasingly recognised as important predisposing factors. Pharmacological modification of IR and hyperinsulinaemia might reduce the risk of laminitis.

Hypothesis: Metformin, a drug commonly prescribed for treatment of human IR, may also decrease IR in equids.

Treatment of medial condylar fractures of the third metatarsus in three horses with fibreglass casts under standing neuroleptanalgesia.

Minimally displaced condylar fractures propagating into the third metatarsal diaphysis were treated conservatively in one thoroughbred and two Arabian racehorses. In each case a neuroleptanalgesic protocol provided adequate pain relief for a rigid fibreglass cast to be applied in a weight-bearing position. The fractures healed completely and the three horses recovered uneventfully.

Clinical, immunophenotypic and functional characterisation of T-cell leukaemia in six horses.

Reason For Performing Study: Lymphoid leukaemia (LL) is rare in equids. In man, immunophenotypic classification identifies distinct leukaemic types with different treatment strategies. Improved understanding and classification of equine LL may allow similar advances.

Electrosurgery as the sole means of haemostasis during the laparoscopic removal of pathologically enlarged ovaries in mares: a report of 55 cases.

Reasons For Performing Study: There is little published clinical evidence on the use of a laparoscopic approach for the removal of pathologically enlarged ovaries in standing mares.

Objectives: To show the orders of success and complication rates that can be expected if pathologically enlarged ovaries are removed from standing, sedated mares under laparoscopic guidance using only electrosurgical means of haemostasis.

Methods: A retrospective analysis was made of 55 mares in which the removal of an enlarged ovary was attempted by applying a standard laparoscopic procedure for routine ovariectomy in standing mares including a reliance solely on one of 2 types of electrosurgical bipolar forceps with an integrated guillotine for haemostasis and transection of the ovarian pedicle.

Clinical application of parenteral nutrition in the treatment of five ponies and one donkey with hyperlipaemia.

Five ponies and one donkey with hyperlipaemia that occurred secondarily to a variety of primary clinical conditions were treated with lipid-free partial parenteral nutrition comprising equal volumes of 50 per cent glucose and 15 per cent amino acids. The infusion supplied energy and protein at rates of 2.6 kJ/kg per hour and 34.

Diagnosis and treatment of ligamentous and meniscal injuries in the equine stifle.

The accuracy of the diagnosis of ligamentous and meniscal injuries in the equine stifle has improved significantly in the last 20 years. There are, however, significant limitations in the diagnosis of stifle injuries because of the size and anatomy of the equine stifle. Treatment of soft tissue injuries to the equine stifle has been empirical,with only a few large case studies for specific conditions of stifle ligaments and menisci and only retrospective case studies of the outcome of treatment.

End-to-end jejuno-ileal anastomosis following resection of strangulated small intestine in horses: a comparative study.

Reasons For Performing Study: Small intestinal resection and anastomosis is a relatively common procedure in equine surgical practice. This study was designed to test objectively the subjective opinions of surgeons at the Liphook Equine Hospital that an end-to-end jejuno-ileal anastomosis (JIA) is an effective and clinically justifiable procedure, contrary to conventional recommendations.

Hypothesis: An end-to-end JIA carries no greater risk of morbidity and mortality than an end-to-end jejunojejunal anastomosis (JJA).

Nutritional and clinicopathological effects of post operative parenteral nutrition following small intestinal resection and anastomosis in the mature horse.

Reasons For Performing Study: There is an absence of data describing the nutritional requirements and nutritional status of horses following surgery for colic; furthermore, the potential effect of parenteral nutrition (PN) on improving nutritional status in such cases is unknown.

Hypothesis: Post operative colic cases suffer from a potentially detrimental negative energy balance and the PN formulation developed in this study would lead to clinicopathologically detectable improvements in the subjects' nutritional status.

Methods: Several clinicopathological variables, some known to be associated with nutritional status, were compared in 2 groups of horses in the post operative period following colic surgery; Group N (n = 15) were treated with PN and Group C (n = 15) were starved routinely.

Study of the clinical effects of postoperative parenteral nutrition in 15 horses.

Several clinical variables were compared in two groups of 15 horses recovering from resection and anastomosis of a strangulated small intestine; 15 were treated with parenteral nutrition and 15 were starved routinely. There was some evidence that parenteral nutrition had a short-lived adverse effect on both the catheter sites and gastric emptying, but there were no marked adverse clinical effects and no evidence of any improvement in the horses' condition.

An evaluation of diagnostic data in comparison to the results of liver biopsies in mature horses.

Reasons For Performing Study: The diagnostic value of several investigative procedures commonly used during the evaluation of suspected equine hepatopathy cases has not been specifically quantified in previous studies.

Hypothesis: No noninvasive procedures would clearly discriminate between horses with and without significant liver disease.

Methods: Histopathology of biopsy samples was used as the 'gold standard' technique for definitive diagnosis of the presence or absence of significant liver disease.

Retrospective analysis of historical, clinical, ultrasonographic, serum biochemical and haematological data in prognostic evaluation of equine liver disease.

Reasons For Performing Study: Results of noninvasive tests of liver disease do not always correlate with the degree of hepatic disease nor outcome of the case.

Objective: To investigate the prognostic value of data collected using noninvasive tests during the investigation of cases of suspected liver disease in mature horses.

Hypothesis: Much of the data gathered during the investigation of suspected hepatopathy cases offers little prognostic guidance and interpretation of such data can be misleading.

Development and application of a scoring system for prognostic evaluation of equine liver biopsies.

Reasons For Performing Study: The study was designed to investigate the prognostic value of liver biopsy during investigation of cases of suspected liver disease in mature horses.

Hypothesis: That liver biopsy is the most prognostically useful technique in common usage in the investigation of suspected liver disease.

Methods: This study examined the prognostic value of liver biopsy during the investigation of suspected liver disease in 73 mature horses.