Resolution of chronic regurgitation in an 8 month old Babydoll sheep by thoracoscopic treatment of a vascular ring anomaly.

OBJECTIVE: The objective was to describe the successful thoracoscopic treatment of esophageal entrapment resulting from a vascular ring anomaly (VRA) comprising a persistent right aortic arch (PRAA) and left ligamentum arteriosum (LA) in a Babydoll sheep wether. STUDY DESIGN: Case report. ANIMAL: Eight month old Babydoll sheep wether, 13 kg. METHODS: The patient presented with a weight half that of its sibling, persistent regurgitation following eating, and delayed growth noted from the age of approximately 2 months, coinciding with the introduction of solid feed into the diet. Plain thoracic radiographs were within normal limits but computed tomography angiography (CTA) confirmed multiple congenital vascular anomalies. The primary finding was esophageal and tracheal entrapment by a PRAA and left LA. Thoracoscopic transection of the LA was performed with a bipolar vessel sealing device with the aid of transesophageal endoscopy. RESULTS: Immediate improvement in attitude and absence of regurgitation were observed. The patient was discharged and subsequently reintroduced to grazing and long-stem hay, which were previously not tolerated. By 6 months post discharge, the patient's weight was 36 kg, comparable to an age-matched sibling and considered appropriate for the stage of growth. CONCLUSION: Thoracoscopic transection of the LA in sheep is a feasible treatment for esophageal compression resulting from a VRA. Surgical intervention resolved the clinical signs and allowed normal digestive rumination, restoring bidirectional esophageal function in a ruminant.

Stress response as a contributing factor in horses with laminitis.

BACKGROUND: Laminitis is a complex and debilitating disease of horses. Numerous predisposing factors contribute to laminitis development, however the exact pathogenesis remains undetermined. Serum T4, cortisol, and histamine are components of the innate stress response and could play a causative or contributory role. Stress hormone concentrations in laminitis are largely unknown. OBJECTIVE: To evaluate parameters associated with stress response in horses with laminitis, and compare these to healthy horses and horses with gastrointestinal (GI) disease. METHODS: Thirty-eight adult horses presenting for non-medical conditions, GI abnormalities, or clinical laminitis were prospectively enrolled. Horses were assigned to the appropriate disease group (healthy, GI disease, and laminitis) and had blood drawn on presentation to the hospital. Samples were analyzed for plasma endogenous adrenocorticotrophic hormone (eACTH), serum cortisol, serum thyroid hormone, and plasma histamine. RESULTS: Stress hormone concentrations were significantly different between horses in the laminitis and GI disease groups. Plasma histamine levels were highest in horses with laminitis, compared with GI disease and controls. Both horses with laminitis and GI disease had increased plasma eACTH when compared to healthy horses. Horses with GI disease had higher serum cortisol concentrations than horses with laminitis or controls. Serum T4 was lower in horses with GI disease than in horses with laminitis and controls. CONCLUSIONS: Horses with laminitis had relative increases in both plasma histamine and eACTH concentrations. Serum T4 and cortisol concentrations of horses with laminitis did not differ significantly when compared to healthy horses. The role of stress hormones in equine disease warrants further investigation.

Serial venous lactate measurement following gastrointestinal surgery in horses.

BACKGROUND: Prospective clinical study of blood lactate concentration in horses undergoing colic surgery is needed to determine utility in outcome prediction. OBJECTIVES: To evaluate venous lactate measurements in horses following colic surgery, including immediately after anesthetic recovery and daily throughout hospitalization, as well as to determine if lactate concentrations were significantly higher in horses that developed postoperative complications or did not survive to hospital discharge. METHODS: Horses > 1 year of age undergoing surgery for colic and recovered from general anesthesia were sampled. A portable lactate meter was used to measure venous samples collected immediately following anesthetic recovery and daily throughout hospitalization. Complications arising during hospitalization and survival to hospital discharge were recorded. RESULTS: Fifty one horses were enrolled, ranging in age from 2 to 29 years. Lactate concentration immediately following anesthetic recovery was higher in horses that developed complications during hospitalization (p = 0.046). The odds of developing complications postoperatively were doubled for horses with a venous lactate concentration > 5 mmol/L. Lactate measurements in non-survivors were significantly higher compared to survivors by 96 h postoperatively (p < 0.006). CONCLUSIONS: Higher venous lactate concentrations in the postoperative colic period were associated with an increased risk of complications and death. Results suggest horses with higher venous lactate measurements in recovery are more likely to have postoperative complications, with the odds of developing complications doubled for horses with a venous lactate > 5 mmol/L. Evaluation of venous lactate could provide information on prognosis in the postoperative period for horses with surgical colic.

Ureteropyeloscopic removal of a nephrolith from a 19 year old Hanoverian gelding.

OBJECTIVE: To describe the ureteropyeloscopic removal of a nephrolith in a horse. ANIMALS: A 19 year old Hanoverian gelding with history of urolithiasis requiring surgical intervention. STUDY DESIGN: Case report METHODS: The horse presented with signs of abdominal straining and stranguria. A proximal urethral calculus was palpable externally within the perineal urethra. Perineal urethrostomy (PU) at the location of the urethral calculi was performed to remove the urethral obstruction. Left nephrolithiasis was then treated by endoscopic retrieval, inserting the endoscope through the PU. The procedures were performed over 2 consecutive days, with the horse standing and sedated. Medical therapy included antimicrobial and anti-inflammatory treatment. RESULTS: The ureteropyeloscopic removal of a nephrolith from the left renal pelvis was completed. No complications were appreciated following the procedure, and the horse was able to return to athletic activity within 2 weeks. The horse had no further clinical signs referable to urinary dysfunction 7 months later. CONCLUSION: Ureteropyeloscopic removal of a nephrolith from the renal pelvis is technically feasible in the equine patient and preserves function of the affected kidney. The availability of a treatment that maintains renal function is a distinct benefit over unilateral nephrectomy, particularly when treating a condition that frequently involves both kidneys.

Clinical outcome of horses with guttural pouch infection following transpharyngeal fenestration.

OBJECTIVE: To report the clinical outcomes of horses with chronic guttural pouch infection characterized by accumulation of mucopurulent material following transpharyngeal diode laser fenestration. ANIMALS: 13 client-owned horses. PROCEDURES: Horses undergoing diode laser fenestration for chronic guttural pouch infection were identified by medical record search. Signalment, disease history, presence of mucopurulent empyema or chondroids, and pre- and postoperative therapy were recorded. Owners were contacted for follow-up information at a minimum of 6 months following surgery. RESULTS: 13 horses underwent laser fenestration for chronic guttural pouch infection. Thirteen had mucopurulent nasal discharge on presentation, and 3 were coughing. At follow-up, 12 horses treated with transpharyngeal diode laser fenestration had complete resolution of nasal discharge and coughing. One horse, despite resolution of guttural pouch infection on endoscopy, continued to have nasal discharge and coughing attributed to concurrent equine asthma syndrome. All owners expressed satisfaction with the surgical procedure and clinical resolution of guttural pouch infection. CLINICAL RELEVANCE: This surgical technique for transpharyngeal diode laser fenestration of the guttural pouch was uncomplicated to perform and well tolerated in sedated horses and attributed to resolution of clinical signs associated with guttural pouch infection, and owners reported a high satisfaction with the clinical outcome. Implementing this surgical technique could be considered to hasten resolution of chronic guttural pouch disease in horses with few technique-related complications.

Complications and Comorbidities in Foals Undergoing Surgical Repair for Uroperitoneum.

Surgical repair is frequently effective at resolving uroperitoneum in foals, though complications occur. Despite their occurrence, management strategies used to address these complications, and their impact on survival are not clearly defined. To better describe the complications following surgical correction of uroperitoneum and to document treatment strategies and outcomes after intervention, a multi-center retrospective case series was performed. Medical record data of foals undergoing surgical treatment for uroperitoneum were retrieved from three surgical centers, and cases identified with complications or comorbidities were reviewed. Long-term follow-up was obtained through owner contact. Of 45 foals with uroperitoneum, 13 (29%) had complications or comorbidities following surgical repair. Uroperitoneum recurred in 9 (20%) foals 12-264 hours after surgery. Foals with recurrence were managed medically with an indwelling urinary catheter, repeat celiotomy, or were euthanized. Other comorbidities following repair included sepsis and persistent azotemia. One horse developed cystic calculi 14 months later. Urinary catheters maintained for 3-7 days in combination with medical and surgical interventions successfully resolved uroperitoneum. The decision to debride bladder tear edges or the selection of suture material or pattern did not impact recurrence or survival. Six (67%) foals with recurrent uroperitoneum survived to hospital discharge; 86% survived if treatment was attempted. Four (80%) of cases treated for recurrent uroperitoneum were alive without active medical problems >2 years later. Despite recurrence, medical or surgical treatment of recurrent uroperitoneum enables short-term survival, and maintenance of long-term health. Indwelling urinary catheters should be considered in select cases with recurrent uroperitoneum.

Rotator cuff repair using a bioresorbable nanofiber interposition scaffold: a biomechanical and histologic analysis in sheep.

BACKGROUND: The purpose of this study was to evaluate the mechanical, structural, and histologic quality of rotator cuff repairs augmented with an interposition electrospun nanofiber scaffold composed of polyglycolic acid (PGA) and poly-L-lactide-co-ε-caprolactone (PLCL) in an acute sheep model. METHODS: Forty acute infraspinatus tendon detachment and repair procedures were performed in a sheep infraspinatus model using a double-row transosseous-equivalent anchor technique either with an interposition nanofiber scaffold composed of polyglycolic acid-poly-L-lactide-co-ε-caprolactone or with no scaffold. Animals were euthanized at the 6-week (20 samples) and 12-week (20 samples) postoperative time points to assess the biomechanical and histologic properties of the repairs and to compare differences within each group. RESULTS: Within the scaffold-treated group, there was a significant increase in ultimate failure force (in newtons) from 6 to 12 weeks (P < .01), a significant increase in ultimate failure load from 6 to 12 weeks (P < .01), and a significant increase in ultimate failure stress (in megapascals) from 6 to 12 weeks (P < .01). At 6 weeks, the tendon-bone attachment was most consistent with an "indirect" type of insertion, whereas at 12 weeks, a visible difference in the progression and re-formation of the enthesis was observed. Compared with controls, animals in the scaffold-treated group displayed an insertion of the fibrous tendon with the humeral footprint that was beginning to be organized in a manner similar to the "native" direct/fibrocartilaginous insertion of the ovine infraspinatus tendon. In the majority of these animals treated with the scaffold, prominent perforating collagen fibers, similar to Sharpey fibers, were present and extending through a region of calcified fibrocartilage and attaching to the humeral footprint. No surgical complications occurred in any of the 40 sheep, including delayed wound healing or infection. CONCLUSIONS: In a sheep acute rotator cuff repair model, securing a nanofiber scaffold between the tendon and the bone using a double-row transosseous-equivalent anchor fixation technique resulted in greater failure strength. Additionally, at the enthesis, Sharpey fiber-like attachments (ie, collagen fibers extending from the tendon into the calcified fibrocartilage of the humerus) were observed, which were not seen in the control group.

Outcomes following single, caudally based bilateral versus unilateral frontonasal sinusotomy for treatment of equine paranasal sinus disease.

BACKGROUND: Bilateral sinus disease is relatively uncommon in horses, accounting for 3%-4.5% of horses with sinonasal disease, but may require bilateral paranasal surgery for complete resolution. Complications and recurrence following bilateral sinusotomy have not been reported or compared to those following unilateral procedures. OBJECTIVE: To describe clinical features and outcomes in horses undergoing standing single, caudally based bilateral frontonasal sinusotomy compared to unilateral frontonasal surgery. METHODS: Records of horses (n = 37) undergoing surgical treatment for sinus disease (five bilateral, 32 unilateral) were retrospectively reviewed (2010-2017) for signalment, presenting complaint, duration of signs preoperatively, diagnostic imaging, treatments administered, duration hospitalization, complications, and owner satisfaction with the procedure. Mann-Whitney testing was used to compare age, duration of hospitalization, and follow-up time in horses undergoing unilateral or bilateral procedures. Fisher's exact testing was used to determine if sex predilection was present for unilateral or bilateral disease. Survival time and time to recurrence were compared by Kaplan-Meier survival curves and log-rank curve comparison testing. Significance was assessed at p < 0.05. RESULTS: Length of signs prior to admission did not differ between horses with unilateral and bilateral disease (p = 0.09), but there was a tendency for horses with bilateral disease to have clinical signs for longer. Age (p = 0.19) and hospitalization duration (p = 0.53) did not differ between horses undergoing unilateral versus bilateral procedures. Recurrence or failure to resolve signs was reported in 11/32 (34%) of unilateral and 0/5 bilateral cases (p = 0.07). CONCLUSIONS: The bilateral single, caudally based sinusotomy approach may be considered to effectively treat bilateral paranasal sinus disease without concern for increased risk of life-threatening complications or longer hospitalization duration than would be typical for unilateral sinusotomy procedures.

Investigation of neonatal disorders in New World camelids and factors associated with death during and after hospitalization of affected crias.

OBJECTIVE: To assess signalment, clinical findings, and treatments for New World camelids (NWCs) hospitalized for evaluation and treatment of neonatal disorders and investigate associations between these factors and death during and after hospitalization. ANIMALS: 267 NWCs ≤ 30 days of age. PROCEDURES: Medical records of a veterinary teaching hospital were retrospectively reviewed to identify NWCs admitted for evaluation and treatment of neonatal disorders between 2000 and 2010. Signalment, physical examination data, diagnostic findings, treatments, and outcomes were recorded. Factors were examined for association with death during hospitalization and the overall hazard of death by use of multivariable logistic regression and Cox proportional hazards analysis, respectively. RESULTS: The sample comprised alpacas (n = 255) and llamas (12). Median age at admission was 3 days, and median hospitalization time was 2 days; 208 of the 267 (77.9%) neonatal NWCs survived to hospital discharge. Factors associated with increased odds of death during hospitalization included prematurity or dysmaturity, hypothermia, sepsis, toxic changes in neutrophils, and undergoing surgery. The odds of death during hospitalization also increased as anion gap increased. After discharge, 151 of 176 (85.8%) animals had follow-up information available (median follow-up time, 2,932 days); 126 (83%) were alive and 25 (17%) had died. Prematurity or dysmaturity, congenital defects, sepsis, oxygen administration, and undergoing surgery as a neonate were associated with an increased hazard of death; the hazard of death also increased as serum chloride concentration at the time of hospitalization increased. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested the prognosis for survival during and after hospitalization is good for most NWCs hospitalized because of neonatal disorders.

Laparoscopic Ovariectomy in a Domestic Yak.

Owners of a juvenile domestic yak elected bilateral ovariectomy to prevent future reproduction. The yak was noted to be healthy at presentation. Both ovaries were removed using a laparoscopic approach as follows: after induction and maintenance of general inhalant anesthesia, 15 degrees Trendelenburg positioning was required to view the ovaries. Ovariectomy was conducted within a surgical time of 50 minutes. Due to the small ovarian size, portal enlargement was not necessary for removal. Mild hemorrhage from the left ovarian pedicle was controlled with application of a vessel-sealing device. Postoperative complications were not encountered during hospitalization. At 12 months following surgery, the yak was healthy, and the owner was highly satisfied with the procedure. The described approach was successful for performing laparoscopic ovariectomy in a juvenile yak. Positioning for surgery was similar to other small ruminant species. Further case enrollment is needed to optimize the surgical approach and better describe clinical outcomes.

Atypical Salmonellosis in a Horse: Implications for Hospital Safety.

A 17-year-old Quarter Horse mare was evaluated for colic of 24-hour duration. Clinical signs and diagnostic evaluation were consistent with duodenitis-proximal jejunitis. The horse's clinical condition deteriorated despite medical treatment and was euthanized. Aerobic culture collected from small intestinal ingesta was positive for Salmonella enterica subsp. enterica serovar Hadar. Salmonella sp. is commonly implicated in nosocomial infections in equine veterinary hospitals usually through feces containing the organism. Considering Salmonella sp. was cultured from the jejunal luminal contents and the large volume of nasogastric reflux that was evacuated in this case, a perceived risk of Salmonella sp. transmission from infected gastric reflux to other hospitalized cases was realized. Infectious agent biosecurity precautions should be undertaken in horses with nasogastric reflux to prevent hospital-acquired transmission.

Partial Infraspinatus Tendon Transection as a Means for the Development of a Translational Ovine Chronic Rotator Cuff Disease Model.

OBJECTIVE: Rotator cuff tendon tears are the most common soft tissue injuries in the shoulder joint. Various animal models have been described for this condition, but all current translational animal models have inherent weaknesses in their ability to generate chronically degenerated rotator cuff tendons. The objective of this study was to evaluate a partial infraspinatus tendon transection model as a means of creating a chronically degenerated rotator cuff tendon in an ovine model and compare the injury characteristics of this model to those observed in human patients with severe chronic rotator cuff tendon injuries. STUDY DESIGN: The infraspinatus tendons of six sheep were partially detached followed by capping of the detached medial section of the tendon with Gore-Tex. Human tissue samples of the supraspinatus tendon were harvested from patients undergoing primary reverse shoulder arthroplasty and served as positive controls of chronic rotator cuff tendinopathy. RESULTS: Transected sheep tendons were characterized predominantly by an acute reactive and reparative pathological process as compared with the chronic degenerative changes observed in the human tendons. In contrast, the non-transected portion of the ovine tendon showed histological changes, which were more chronic and degenerative in nature when compared with the transected tendon. CONCLUSION: Overall, histological features of the non-transected portion of ovine tendon were more similar to those observed in the chronic degenerated human tendon.

Evaluation of the Element point-of-care blood gas analyzer for use in horses.

OBJECTIVE: To compare the Element point-of-care (POC) portable blood gas analyzer with a laboratory-based bench-top reference analyzer using whole blood samples obtained from horses presenting to a referral center with various disorders in order to determine agreement between these analyzers. DESIGN: Prospective clinical study. SETTING: The study was conducted at a university teaching hospital at moderate altitude. ANIMALS: One hundred paired samples from 80 horses >1 year of age were collected after obtaining informed client consent. Fifty paired samples were from patients admitted for elective procedures and considered to be healthy, and 50 paired samples were emergency admissions and considered to be critically ill. MEASUREMENTS AND MAIN RESULTS: Paired whole blood samples were evaluated on both the Element POC and Radiometer ABL 800 FLEX analyzers simultaneously, and results were compared. Pearson correlation coefficients between analyzers were calculated. To assess agreement, scatter and Bland-Altman plots were evaluated, and mean difference and 95% limits of agreement were calculated for each analyte. Correlation was either good (0.8-0.92) or excellent (>0.93) for the majority of analytes. All analytes apart from hemoglobin had acceptable agreement, with ≥80% of individual results within agreement targets. Precision targets were acceptable for most analytes, with partial pressure of carbon dioxide (pCO2 ) and calcium (Ca2+ ) exceeding precision targets. CONCLUSIONS: The portable Element POC system had acceptable agreement with the ABL 800 FLEX bench-top analyzer currently in use at the study center when evaluating the majority of analytes from equine whole blood samples.

Prospective randomized investigation of topical anesthesia during unilateral laparoscopic ovariectomy in horses.

OBJECTIVE: To compare pain-related responses in mares receiving topical or injected anesthesia of the ovarian pedicle prior to standing unilateral laparoscopic ovariectomy. STUDY DESIGN: Prospective randomized, blinded, placebo-controlled study. ANIMALS: Fifteen healthy research mares. METHODS: Mares were restrained in stocks and administered sedation. A right or left paralumbar ovariectomy was performed by using a laparoscopic portal and two instrument portals. Mares were divided into two treatment groups, and equal volumes of mepivacaine anesthesia were administered either topically (n = 8) or by injection into the ovarian pedicle (n = 7). Saline controls were simultaneously administered topically (n = 7) or by injection (n = 8), and surgeons were blinded to the treatment group. Ovarian removal was performed with traumatic forceps and a blunt tip vessel sealer and divider. Pain responses were measured by operative visual analog scale (VAS) scoring and perioperative serum cortisol response. Visual analog scale and serum cortisol were compared between groups by using Mann-Whitney testing. Serum cortisol concentrations were evaluated using repeated-measures one-way analysis of variance. RESULTS: Ovaries were removed in all mares by using the described technique without operative complications. Quantity of sedation required to complete the procedure, operative VAS scores, and perioperative cortisol concentrations did not differ between treatment groups. CONCLUSION: Application of topical mepivacaine to the ovary provided intraoperative analgesia similar to injection of the ovarian pedicle when performing unilateral standing laparoscopic ovariectomy in mares. CLINICAL SIGNIFICANCE: Topical anesthesia application to the ovary could provide an alternative to laparoscopic needle use, reducing the risk of inadvertent trauma to the pedicle or other visceral organs during laparoscopic ovariectomy.

A prospective study comparing tendon-to-bone interface healing using an interposition bioresorbable scaffold with a vented anchor for primary rotator cuff repair in sheep.

BACKGROUND: The purpose of this study was to evaluate the biomechanical and histologic properties of rotator cuff repairs using a vented anchor attached to a bioresorbable interpositional scaffold composed of aligned PLGA (poly(l-lactide-co-glycoside)) microfibers in an animal model compared to standard anchors in an ovine model. METHODS: Fifty-six (n = 56) skeletally mature sheep were randomly assigned to a repair of an acute infraspinatus tendon detachment using a innovative anchor-PLGA scaffold device (Treatment) or a similar anchor without the scaffold (Control). Animals were humanely euthanized at 7 and 12 weeks post repair. Histologic and biomechanical properties of the repairs were evaluated and compared. RESULTS: The Treatment group had a significantly higher fibroblast count at 7 weeks compared to the Control group. The tendon bone repair distance, percentage perpendicular fibers, new bone formation at the tendon-bone interface, and collagen type III deposition was significantly greater for the Treatment group compared with the Control group at 12 weeks (P ≤ .05). A positive correlation was identified in the Treatment group between increased failure loads at 12 weeks and the following parameters: tendon-bone integration, new bone formation, and collagen type III. No statistically significant differences in biomechanical properties were identified between Treatment and Control Groups (P > .05). CONCLUSIONS: Use of a vented anchor attached to a bioresorbable interpositional scaffold composed of aligned PLGA microfibers improves the histologic properties of rotator cuff repairs in a sheep model. Improved histology was correlated with improved final construct strength at the 12-week time point.

Combined tube cystostomy and urethrotomy for the treatment of urethral obstruction due to urolithiasis in goats.

OBJECTIVE: To describe the treatment of goats with urethral obstruction secondary to urolithiasis by combining tube cystostomy and urethrotomy. ANIMALS: Eight male goats. STUDY DESIGN: Short case series. METHODS: Medical records (September 2012-September 2017) of male goats treated for obstruction secondary to urolithiasis with tube cystostomy and urethrotomy were reviewed. Data collected included signalment, history, physical examination findings, diagnostic results, perioperative treatments, operative details, hospitalization duration, intraoperative and postoperative complications, urolith analysis, and time to restoration of urethral patency. Long-term follow-up (>12 months) was obtained by email or telephone interviews of owners or by clinical examination. RESULTS: Seven of eight goats were castrated males of various of breeds. All goats were tachycardic with urethral pulsation at admission. Uroliths were composed of calcium carbonate in four goats and silica in one goat. All goats regained urethral patency during hospitalization, and all were discharged alive from the hospital. Seven goats were alive at long-term follow-up. Postoperative complications included persistent urethral obstruction requiring a second urethrotomy 2 days postoperatively, premature dislodgement of the bladder catheter and jejunal obstruction secondary to adhesions, and recurrence of obstructive urolithiasis within the proximal perineal urethra requiring a second surgery 8 months later (1 each). Long-term outcome was good, with urethral patency beyond 12 months in six of eight goats. CONCLUSION: Combining tube cystostomy and urethrotomy restored urethral patency in goats with urethral obstruction from uroliths. Although none of the complications seemed directly related to the urethrotomy, formation of abdominal adhesions and recurrence of urolithiasis affected long-term outcomes. CLINICAL SIGNIFICANCE: Uroliths that do not dissolve in acidic urine may be more frequent in some practices. The combined approach of tube cystostomy and urethrotomy appears to successfully restore urethral patency with promising long-term outcomes.

Cortisol and adrenocorticotropic hormone concentrations in horses with systemic inflammatory response syndrome.

BACKGROUND: Plasma adrenocorticotropic hormone (ACTH) and serum cortisol concentrations increase with illness-associated stress. Dynamics of plasma ACTH and serum cortisol concentrations in adult horses with systemic illness are undocumented. HYPOTHESIS/OBJECTIVE: To determine whether ACTH and cortisol concentrations and the ACTH/cortisol ratio vary with survival, the presence of systemic inflammatory response syndrome (SIRS), or ischemic gastrointestinal lesions at admission, or throughout hospitalization. ANIMALS: One hundred fifty-one adult horses. METHODS: Prospective study measuring serum cortisol and plasma ACTH at admission and on days 2, 4, and 6 of hospitalization. Horses were grouped by outcome (survival, SIRS status, number of SIRS criteria [SIRS score], SIRS severity group, and the presence of an ischemic lesion). Differences between groups and over time for ACTH, cortisol, and ACTH/cortisol ratio were investigated with a mixed effect model. Receiving operator characteristic curves and odds ratios were calculated for survival and ischemia. RESULTS: In all groups, ACTH, cortisol, and ACTH/cortisol ratio significantly decreased over time (P < .0001). ACTH, cortisol, and ACTH/cortisol ratio were higher at admission in nonsurvivors, and ACTH and cortisol were higher in horses with ischemic lesions (P < .01). Horses with ACTH above reference interval at admission were 6.10 (2.73-13.68 [95% confidence interval]) times less likely to survive (P < .0001). No significant difference in ACTH, cortisol, and ACTH/cortisol ratio between horses with different SIRS status, scores, or groups were detected, although nonsurvivors had a higher SIRS score (P < .0001). CONCLUSIONS AND CLINICAL IMPORTANCE: Pituitary and adrenal responses are altered in nonsurviving horses and those with an ischemic gastrointestinal lesion.

A retrospective cohort study of racing performance in Quarter Horses undergoing prosthetic laryngoplasty for treatment of recurrent laryngeal neuropathy.

OBJECTIVE To determine effects of prosthetic laryngoplasty on return to racing, performance index, and career longevity in racing Quarter Horses with recurrent laryngeal neuropathy (RLN) and to evaluate performance variables for horses with RLN undergoing prosthetic laryngoplasty, compared with a control horse population. DESIGN Multicenter, retrospective cohort study. ANIMALS 162 racing Quarter Horses with RLN treated with prosthetic laryngoplasty (case horses) and 324 racing Quarter Horse without RLN (control horses). PROCEDURES Medical and race records of case and control horses examined at 5 referral centers between January 2000 and December 2015 were reviewed retrospectively. Two control horses were matched with each case horse. Return to racing, earnings, number of racing starts, performance index, and career longevity were evaluated. RESULTS The odds of returning to racing did not differ significantly between case and control horses but decreased with increasing age. Neither racing starts nor career longevity were affected by prosthetic laryngoplasty or by RLN grade. In fact, horses undergoing laryngoplasty for treatment of RLN and horses with the lowest RLN grade before surgery had higher performance indices after the surgery, compared with indices for control horses. CONCLUSIONS AND CLINICAL RELEVANCE The faster speeds and shorter distances raced with Quarter Horses could alter how RLN impacts respiratory variables and performance in Quarter Horses, compared with other racehorse breeds. Further study is needed to understand the impacts of RLN and surgical treatments for RLN in racing Quarter Horses.