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Objective: The aim of the present study was to determine if a three-dimensional (3D)-printed instrument technique would improve lavage removal of plastic beads (guttural pouch [GP] chondroid mimics) through a dorsal pharyngeal recess (DPR) fenestration. We hypothesized that using a 3D-printed instrument placed through the DPR fenestration would remove more beads, reduce lavage time and incur less soft tissue damage than using a lavage tube control or instrument placement through the salpingopharyngeal ostium (SPO)., Study Design: Experimental cadaveric study., Sample Population: A total of 30 cadaveric equine heads., Methods: DPR fenestration was performed using transendoscopic laser and 50 plastic 12 mm beads were placed into one GP of horse heads. Four removal procedures using a 3D-printed instrument or lavage tube control placed through the DPR fenestration or the SPO were compared. Number of beads removed and number of 2-min lavage cycles to recover ≥96% of beads or three consecutive no-yield cycles were recorded. Endoscopic soft tissue damage was graded. Data were compared by generalized estimating equations (GEE) model and Fisher's exact test (p < .05)., Results: More beads (median 48 beads; range 0-49) were removed faster (median 24 beads/cycle; range 12-50) using the 3D-printed instrument compared to control (median 6 beads; range 0-29, 0.66 beads/cycle, range 0-49). There was no difference between total beads removed or removal speed between placement sites. There was no difference in soft tissue damage between procedures., Conclusion: Our 3D-printed instrument enabled efficient plastic bead removal., Clinical Significance: DPR fenestration and use of our 3D-printed instrument represents an alternative to current chondroid removal techniques, warranting investigation in clinical cases., (© 2024 American College of Veterinary Surgeons.)

Ileus is a common life-threatening problem in horses, and currently available treatments may be ineffective. The purpose of this study was to determine whether bit chewing, a form of sham feeding, decreases the gastric emptying time (GET), small intestinal transit time (SITT), and total orocecal transit time (OCTT) in clinically normal horses in a prospective crossover study. Nine healthy horses were acclimated and fed a standardized diet. Following 24 h of fasting, self-contained video endoscopy capsules and acetaminophen were administered into the stomach via a nasogastric tube. Each horse underwent experimental (bit chewing for 20 min every 6 h) or control (no bit chewing) conditions, with a 3-week minimum washout period between conditions. The horses were enrolled in either part of the study until all video capsules were retrieved and/or 30 days lapsed. The video capsules were recovered from manure, and GET, SITT, and OCTT were determined from a video analysis. Bit chewing significantly decreased OCTT ( p = 0.015) compared to the control conditions. Bit chewing decreased GET and SITT, but the differences were not significant. The mean (median) times determined via the video capsule analysis for the bit-chewing conditions were as follows: GET, 2.34 h (2.86 h); SITT, 3.22 h (3.65 h); and OCTT, 5.13 h (6.15 h), and for the control conditions, they were as follows: GET, 3.93 h (5 h); SITT, 3.79 h (4.4 h); and OCTT, 8.02 h (9.92 h). Bit chewing decreased OCTT in healthy horses. Because this segment of the gastrointestinal tract is frequently affected by ileus, bit chewing may be a safe and inexpensive intervention for that condition in horses. Further investigation in clinical patients with ileus is warranted.

Weight loss occurs when the supply of energy is insufficient to meet the energy needs of an individual. The energy supply may be reduced by inadequate provision of feed, inadequate consumption, reduced digestion and absorption, or disruption in metabolic processing. Increased energy expenditure occurs with exercise and during cold temperatures, pregnancy, and lactation. Underlying clinical disease, particularly chronic inflammation, neoplasia, and protein-losing conditions, can cause weight loss or exacerbate existing weight loss. A methodical approach to weight-loss investigation and treatment is necessary, because of the often multifactorial nature of this condition., Competing Interests: Disclosures N. Jarvis and H. McKenzie have no commercial or financial conflicts of interest and no active external funding relevant to this article., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis occurs in horses with systemic inflammatory response syndrome (SIRS). Peripheral resistance to glucocorticoids has not been investigated in horses., Objective: To determine if glucocorticoid receptor (GR) function in horses can be measured using flow cytometry, and to use this information to evaluate HPA axis dynamics., Animals: Eleven healthy adult horses in parts 1 and 2. Ten horses with SIRS and 10 age and sex matched controls in part 3., Methods: Flow cytometry was used to evaluate GR density and binding affinity (BA) in 3 healthy horses in part 1. In part 2, exogenous ACTH was administered to eight healthy horses. Their cortisol response and GR properties were measured. In part 3, CBC, serum biochemistry, cortisol and ACTH, and GR properties were compared between controls without SIRS (n = 10) and horses with SIRS (n = 10), and between survivors and nonsurvivors (n = 4 and n = 6 respectively)., Results: Flow cytometry can be used to measure GR properties in equine PBMCs. No correlation was observed between plasma cortisol concentration and GR density or BA in healthy horses (r = -0.145, P = .428 and r = 0.046, P = .802 respectively). Nonsurvivors with SIRS had significantly decreased GR BA (P = .008). Horses with triglyceride concentration > 28.5 mg/dL had increased odds of nonsurvival (OR=117; 95% CI, 1.94-7,060). GR BA <35.79% was associated with nonsurvival (OR = 30.33; 95% CI, 0.96-960.5)., Conclusions and Clinical Importance: Tissue resistance to glucocorticoids contributes to HPA axis dysfunction in adult horses with SIRS. These horses might benefit from treatment with exogenous glucocorticoids., (Copyright © 2015 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.)

The purpose of this study was to determine the pharmacokinetics and safety profile of firocoxib in neonatal foals. Seven healthy foals were administered 0.1 mg/kg firocoxib orally q24 h for nine consecutive days, commencing at 36 h of age. Blood was collected for firocoxib analysis using high-pressure liquid chromatography with fluorescence detection at 0 (dose #1 only), 0.25, 0.5, 1, 2, 4, 8, 16, and 24 h after doses 1, 5, and 9. For all other doses (2, 3, 4, 6, 7, and 8), blood was collected immediately prior to the next dose (24 h trough). Elimination samples (36, 48, 72, 96, 120, and 144 h) were collected after dose 9. Safety was assessed via physical examinations, body weight measurements, gastroscopy, complete blood count, plasma biochemistry and urinalysis. Firocoxib was rapidly absorbed following oral administration with minimal accumulation after repeat dosing. After the final dose, the terminal half-life was approximately 11 h. Firocoxib was below the limit of detection (<2.5 ng/mL) in plasma 72 h after the final dose. No significant abnormalities were found on blood analyses, urinalysis, or gastroscopy. This study demonstrated that firocoxib is absorbed in neonatal foals with no demonstrable adverse effects after repeated doses of 0.1 mg/kg., (© 2013 John Wiley & Sons Ltd.)

Hyperlipidemia is the presence of elevated lipid concentrations in the blood and is associated with periods of negative energy balance and physiologic stress. In increased concentrations, circulating lipids typically occur in the triglyceride form, which may interfere with numerous normal physiologic functions, particularly by reducing insulin sensitivity. Although the hyperlipidemia risk is greatest in ponies, miniature horses, and donkeys, all equids are at risk if they are in a situation involving negative energy balance. The sedentary lifestyle of many modern horses and the frequent feeding of high-carbohydrate diets contribute substantially to the risk of excessive fat mobilization and the development of hyperlipidemias., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Nutritional support of the foal can be challenging because of the constant changes in nutritional requirements and dietary composition during the transition from neonate to weanling. Additional complexity arises because of dilemmas regarding the means and route of delivery of nutrition to the foal, and the possibility that metabolic dysfunction may impair the ability of the foal to use nutrients appropriately. This article provides practical information on enteral and parenteral nutritional support of sick neonatal foals. The potential benefits of a conservative, hypocaloric feeding strategy, particularly in the very sick patient, are also discussed.

Reasons for Performing Study: Continuous-rate infusions (CRI) of lidocaine are often used for prolonged duration but, to date, only limited time/concentration relationships administered as a short term (24 h) CRI have been reported., Objective: To determine the time/concentration profile of lidocaine and its active metabolites glycinexylidide (GX) and monoethylglycinexylidide (MEGX) during a 96 h lidocaine infusion., Methods: Lidocaine was administered to 8 mature healthy horses as a continuous rate infusion (0.05 mg/kg bwt/min) for 96 h. Blood concentrations of lidocaine, GX and MEGX were determined using high performance liquid chromatography during and after discontinuation of the infusion., Results: Serum lidocaine concentrations reached steady state by 3 h and did not accumulate thereafter. Concentrations were above the target therapeutic concentration (980 ng/ml) only at 6 and 48 h, and did not reach the range described as potentially causing toxicity (>1850 ng/ml) at any time. MEGX did not accumulate over time, while the GX accumulated significantly up to 48 h and then remained constant. The serum concentrations of lidocaine, MEGX and GX were below the limit of detection within 24 h of discontinuation of the infusion. None of the horses developed any signs of lidocaine toxicity during the study., Conclusions: The metabolism of lidocaine was not significantly impaired by prolonged infusion and no adverse effects were observed. Prolonged infusions appear to be safe in normal horses but the accumulation of GX, a potentially toxic active metabolite, is cause for concern.

Reasons for Performing Study: Adequate nutritional support of sick foals in critical care is an important aspect of treatment. When enteral feeding is contraindicated, parenteral nutrition (PN) provides a source of energy and protein. However, no study has critically assessed the use of PN in a large group of foals., Objective: The administration of PN to clinically ill foals was examined retrospectively to determine the effects of PN formulation and variables on the incidence of PN-associated complications and outcome., Hypotheses: There was no effect of PN formula on 1) the occurrence or type of complications; 2) of PN formula on outcome; 3) of disease severity on the occurrence or type of complications; and 4) of disease severity on outcome., Methods: Medical records of 45 foals, presented to the Marion duPont Scott Equine Medical Center, which received PN, were reviewed for the years 2000-2004., Results: The indications for PN were recumbency, depression or gastrointestinal conditions. Formulation of PN was not associated with the development of complications, and there was no association of PN formula with patient survival. Disease severity was positively associated with the development of PN complications and the occurrence of PN complications was associated with an increased risk of nonsurvival., Conclusion and Potential Relevance: The use of lipid-containing PN solutions facilitates the delivery of energy to the critically-ill foal without increasing the risk of deleterious side effects. Severely ill foals are more prone to develop complications associated with PN and to have a poor outcome.

Objective: To assess gentamicin concentrations in serum and bronchial lavage fluid (BLF) of horses during a 24-hour period after once-daily aerosol administration of gentamicin (GAER) for 7 days and the pattern and degree of bronchial tree inflammation associated with repeated GAER., Animals: 13 healthy adult horses (9 geldings and 4 mares)., Procedure: The treatment group comprised 8 horses, and 5 horses were untreated control animals. Gentamicin (20 mL of gentamicin [50 mg/mL]) was administered via aerosol once daily for 7 days. Samples of serum and BLF were obtained from all horses before GAER and 0.5, 4, 8, and 24 hours after the final day of GAER. Gentamicin concentrations were determined for all samples from treated horses, and cytologic examinations were performed on all BLF samples., Results: Peak median BLF gentamicin concentration detected at 0.5 hours was 2.50 microg/mL. Median serum gentamicin concentration was < 0.50 microg/mL at all time points. Significant differences were not observed in total nucleated cell counts or differential cell counts in BLF between groups at any time point. Neutrophil count in BLF for all horses was increased over baseline at 4 and 24 hours., Conclusions and Clinical Relevance: We did not detect evidence of gentamicin accumulation or respiratory inflammation after once-daily GAER for 7 days. This protocol appears unlikely to result in local or systemic toxicosis. Repeated daily GAER to horses appears to be a safe procedure and may have clinical use in the treatment of horses with bacterial infections of the airways.

Reasons for Performing Study: Sporadic measurement of serum triglycerides in depressed and inappetant clinically ill horses revealed severe hypertriglyceridaemia without visible evidence of lipaemia on several occasions, leading to the inclusion of serum triglyceride concentrations in the routine serum biochemistry evaluation of our hospital. Since then, more cases have been identified and treated for hypertriglyceridaemia, raising questions about the prevalence, predisposing factors and significance of these findings., Hypotheses: 1) Severe hypertriglyceridaemia without visible opacity of the serum occurs more commonly in clinically ill and inappetant horses than previously described and 2) appropriate treatment using i.v. dextrose and/or partial parenteral nutrition would decrease serum triglycerides to normal limits and might result in improved appetite and attitude of the patient., Methods: The laboratory computer database from 2000 and 2001 was searched for increased serum triglycerides (> 5.65 mmol/l) in any horse breed, ponies and miniature breeds excluded. Data analysed included subject details, diagnosis, clinical and laboratory parameters, treatment, response to treatment and outcome., Results: Severe hypertriglyceridaemia was identified in 13 horses, with serum triglyceride concentrations 6.17-18.29 mmol/l, while none showed visible lipaemia. All horses had clinical and laboratory findings consistent with systemic inflammatory response syndrome and all but one had an increased serum creatinine concentration. Treatment with i.v. dextrose and/or partial parenteral nutrition resulted in decrease of the serum triglycerides to normal limits., Conclusions: Severe hypertriglyceridaemia occurs in inappetant and clinically ill horses without evidence of serum opacity more commonly than previously described. The presence of systemic inflammatory response syndrome might predispose horses to hypertriglyceridaemia, while the increased creatinine concentration might be a predisposing factor or result of the condition. Horses identified in our study readily responded to treatment and appetite and attitude improved coincident with decrease of the serum triglycerides to normal limits., Potential Relevance: Hypertriglyceridaemia could perpetuate inappetance and depression in clinically ill horses and potentially predispose to fatty infiltration of the liver and other organ systems.

Objective: To compare concentrations of gentamicin in serum and bronchial lavage fluid after IV and aerosol administration of gentamicin to horses., Animals: 9 healthy adult horses., Procedure: Gentamicin was administered by aerosolization (20 ml of gentamicin solution [50 mg/ml]) and IV injection (6.6 mg of gentamicin/kg of body weight) to each horse, with a minimum of 2 weeks between treatments. Samples of pulmonary epithelial lining fluid were collected by small volume (30 ml) bronchial lavage 0.5, 4, 8, and 24 hours after gentamicin administration. Serum samples were obtained at the same times. All samples were analyzed for gentamicin concentration, and cytologic examinations were performed on aliquots of bronchial lavage fluid collected at 0.5, 8, and 24 hours., Results: Gentamicin concentrations in bronchial lavage fluid were significantly greater 0.5, 4, and 8 hours after aerosol administration, whereas serum concentrations were significantly less at all times after aerosol administration, compared with IV administration. Neutrophil counts in bronchial lavage fluid increased from 0.5 to 24 hours, regardless of route of gentamicin administration., Conclusions and Clinical Relevance: Aerosol administration of gentamicin to healthy horses resulted in gentamicin concentrations in bronchial fluid that were significantly greater than those obtained after IV administration. A mild inflammatory cell response was associated with aerosol delivery of gentamicin and repeated bronchial lavage. Aerosol administration of gentamicin may have clinical use in the treatment of bacterial bronchopneumonia in horses.