Can veterinary medicine improve diversity in post-graduate training programs? Current state of academic veterinary medicine and recommendations on best practices.

The American Association of Veterinary Clinicians (AAVC) convened a Diversity, Equity, and Inclusivity working group in March 2021 to address the limited diversity (including but not limited to ethnic, racial, and cultural diversity) in clinical post-DVM graduate training programs and academic faculty. Concurrent with a working group formation, the AAVC developed a strategic plan. The central mission of the AAVC is to develop, support, and connect academic leaders to fuel the future of the veterinary medical profession. House officers and their training programs are central to all goals outlined in the strategic plan. Amongst other strategic goals, the working group identified best practices for intern and resident recruitment and selection. We report herein from the current health profession literature ways to identify and recruit talented, diverse candidates especially those with non-traditional (atypical) preparation and experience. We also provide recommendations on best practices for intern and resident selection. This document highlights holistic approaches, some of which are incrementally being incorporated into the Veterinary Intern Resident Matching Program application, that emphasize diversity as a selection criteria for intern and resident selection an important step towards building a more resilient and inclusive workforce. These include expanding candidate assessment beyond grades and class rank into a more standardized method for screening candidates that includes consideration of life experiences and talents outside of veterinary medicine.

Plasma l-indospicine and 3-nitropropionic acid in ponies fed creeping indigo: Comparison with results from an episode of presumptive creeping indigo toxicosis.

BACKGROUND: Creeping indigo (Indigofera spicata) toxicosis is an emerging problem among horses in Florida and bordering states. OBJECTIVES: To quantify the putative toxins l-indospicine (IND) and 3-nitropropionic acid (NPA) in creeping indigo collected from multiple sites and to measure plasma toxin concentrations in ponies fed creeping indigo and horses with presumptive creeping indigo toxicosis. STUDY DESIGN: Experimental descriptive study with descriptive observational field investigation. METHODS: Air-dried creeping indigo was assayed for IND and NPA content. Five ponies were fed chopped creeping indigo containing 1 mg/kg/day of IND and trace amounts of NPA for 5 days, then observed for 28 days. Blood samples from these ponies and from horses involved in a presumptive creeping indigo toxicosis were assayed for IND and NPA. RESULTS: IND in creeping indigo plants was 0.4-3.5 mg/g dry matter whereas NPA was <0.01 to 0.03 mg/g. During creeping indigo feeding, clinical and laboratory signs were unchanged except for significant weight loss (median 6%, range 2%-9%; p = .04) and significant increase from baseline plasma protein concentration (median 16 g/L, range 8-25 g/L; p < .001). These changes could not definitively be ascribed to creeping indigo ingestion. Plasma IND rose to 3.9 ± 0.52 mg/L on day 6. Pharmacokinetic modelling indicated an elimination half-life of 25 days and a steady state plasma concentration of 22 mg/L. Plasma IND concentration in sick horses during an incident of creeping indigo toxicosis was approximately twice that of clinically normal pasture mates. Plasma NPA was <0.05 mg/L in all samples. MAIN LIMITATIONS: Creeping indigo used in the feeding trial may not be representative of plants involved in creeping indigo toxicosis. There was no control group without creeping indigo in the feeding trial. CONCLUSIONS: Indospicine can be detected in blood of horses consuming creeping indigo and the toxin accumulates in tissues and clears slowly. The role of NPA in the neurological signs of this syndrome is unclear.

A Pilot Study Exploring the Relationship Between Digesta Retention Time in the Equine Gastrointestinal Tract and Compartment Models.

Digesta retention time within specific segments of the equine gastrointestinal tract (GIT) may be more relevant to scientific inquiries than total tract mean retention time (TTMRT); however, measuring retention time in individual segments requires access to the digestive tract. The objective of this study was to compare prececal, cecal, and colonic mean retention time (MRT) with model-derived compartment MRT. A cecally fistulated gelding was fed indigestible particulate and liquid markers to determine TTMRT and dosed with different pairs of particulate and liquid markers into the cecum (hindgut MRT) and into the right ventral colon through the cecocolic orifice (colon MRT). Fecal marker concentrations were fit to stochastic and mechanistic models using nonlinear least squares methods (MATLAB). Total tract MRT and MRT for each GIT segment were compared with model-derived compartment MRT using paired t-test to determine differences and two one-sided tests to determine equivalence. All models resulted in parameter estimates and an acceptable fit to fecal marker excretion curves, but some parameter estimates did not differ from zero (95% CI included 0). Model-derived TTMRT were equivalent (P < .05) to arithmetically calculated MRT. Most GIT segment MRT differed (P < .05) from model-derived compartment MRT. Differences ranged from -26.1 hours to 25.8 hours. In these exploratory data, model derived compartment retention times failed to pair with MRT in different GIT segments. Significant methodological and analytical challenges remain to describe retention time in individual segments of the equine GIT.

Accuracy of calculated arterial saturation in oxygen in neonatal foals and effects of monitor, sensor, site of sensor placement, and degree of hypoxemia on the accuracy of pulse oximetry.

OBJECTIVES: To (1) assess the agreement between calculated values for arterial hemoglobin saturation of oxygen (SaO2 ) and values obtained by co-oximetry, (2) assess the accuracy of 2 pulse oximetry monitors for measurement of SaO2 in foals, and for each monitor, and (3) determine the optimal combination of sensor type and site of sensor placement for SaO2 monitoring. DESIGN: Prospective experimental study. SETTING: University teaching hospital. ANIMALS: Six neonatal foals. INTERVENTIONS: Foals were anesthetized with isoflurane and SaO2 was manipulated by varying the inspired fraction of oxygen. SaO2 was calculated from oxygen tension or measured by pulse oximetry using 2 monitors equipped with transmission or reflectance sensors attached to the foal's tongue, lip, ear, or inserted rectally (reflectance sensor only). SaO2 values measured by co-oximetry were used as the gold standard to calculate bias. MEASUREMENTS AND MAIN RESULTS: Mean (±SD) SaO2 determined by co-oximetry was 65.2% ± 11.8%, 85.4% ± 2.5%, and 97.2% ± 0.4% at the low, intermediate, and high SaO2 level, respectively. Sensors attached to the ear failed to provide SaO2 readings for most attempts. Reflectance sensors placed on the lip or rectally gave significantly larger biases at low SaO2 (-17.0% and -23.6%, respectively) than at higher levels. Bias of all other combinations of monitors, sensors, and sites (-1.8 to -4.1%) was not significantly influenced by the level of SaO2 or different from each other. The bias of calculated saturation was similar to that of pulse oximetry. CONCLUSIONS: Transmission sensors placed on the lip or tongue or reflectance sensors placed on the tongue give the most accurate assessment of SaO2 in anesthetized neonatal foals. Calculated saturation is not more accurate than pulse oximetry to estimate SaO2 .

Removal of ureteral calculi in two geldings via a standing flank approach.

CASE DESCRIPTION: Two geldings, aged 11 and 17 years, were examined for treatment of ureteroliths located approximately 10 cm proximal to the bladder. CLINICAL FINDINGS: Ureteral obstruction was an incidental finding in 1 horse that was referred because of urinary tract obstruction and a cystic calculus. This horse did not have clinical or laboratory evidence of renal failure, although severe hydronephrosis was evident on transabdominal ultrasonography. The second patient had a serum creatinine concentration of 6.3 mg/dL (reference range, 0.8 to 2.2 mg/dL) and mild hydronephrosis of the affected left kidney. TREATMENT AND OUTCOME: In both patients, the obstructed ureter was exteriorized through a flank incision as a standing procedure, and the calculus was crushed and removed with a uterine biopsy forceps introduced through a ureterotomy approximately 25 cm proximal to the calculus. The cystic calculus was removed through a perineal urethrostomy by lithotripsy, piecemeal extraction, and lavage. The horse without azotemia developed pyelonephritis in the affected kidney and was euthanatized because of complications of a nephrectomy 13 months later. In the horse with azotemia, the serum creatinine concentration decreased after surgery, and the horse returned to its intended use. However, it was euthanatized approximately 2 years after surgery because of progressive renal failure, and a large nephrolith was found in the previously unobstructed right kidney. CLINICAL RELEVANCE: The technique used for ureterolith removal was successful in both horses in this report, did not require sophisticated equipment, and could be effective in the early stages of ureteral obstruction as a means of restoring urine flow and renal function. The outcome in the horse with advanced unilateral renal disease without azotemia would suggest that nephrectomy should be considered as a treatment in such patients.

Treatment of visceral pain in horses.

Identification and alleviation of visceral pain is a frequent concern for the equine owner and veterinarian. This article discusses sources, methods for identification and quantitation, and options for treatment of visceral pain in horses.

Determination of cardiac output in neonatal foals by ultrasound velocity dilution and its comparison to the lithium dilution method.

OBJECTIVE: To compare cardiac output (CO) measured by use of lithium dilution (LiDCO) and ultrasound velocity dilution (UDCO) in conditions of high, intermediate, and low CO in anesthetized foals. DESIGN: Original prospective study. SETTING: University teaching hospital. ANIMALS: Six foals 1-3 days of age (38-45 kg). INTERVENTIONS: Neonatal foals were anesthetized and instrumented to measure direct blood pressure, heart rate, arterial blood gases, and CO. The CO was measured by use of LiDCO and UDCO techniques. Measurements were obtained from each foal at baseline and during low, intermediate, and high CO states. Measurements were converted to cardiac index (cardiac index=CO/body weight) values for statistical analysis. Agreement between the 2 methods was determined using Bland and Altman analysis and concordance correlation coefficients. MEASUREMENTS AND MAIN RESULTS: LiDCO determinations of CO ranged between 4.0 and 14.0 L/min resulting in cardiac index ranging between 75.5 and 310 mL/kg/min. There was no significant effect of blood pressure variation on bias or relative bias (P=0.62 and 0.93, respectively). The mean bias and relative bias of UDCO (+/-SD) compared with LiDCO were -20.1+/-39.2 mL/kg/min and -7.7+/-23.4%, respectively. Concordance correlation coefficient between LiDCO and UDCO was 0.833. CONCLUSIONS: When compared with LiDCO, the UDCO technique has acceptable clinical utility for measuring CO in healthy anesthetized newborn foals.

Effect of detomidine on visceral and somatic nociception and duodenal motility in conscious adult horses.

OBJECTIVE: To evaluate the effects of detomidine on visceral and somatic nociception, heart and respiratory rates, sedation, and duodenal motility and to correlate these effects with serum detomidine concentrations. STUDY DESIGN: Nonrandomized, experimental trial. ANIMALS: Five adult horses, each with a permanent gastric cannula weighing 534 +/- 46 kg. METHODS: Visceral nociception was evaluated by colorectal (CRD) and duodenal distension (DD). The duodenal balloon was used to assess motility. Somatic nociception was assessed via thermal threshold (TT). Nose-to-ground (NTG) height was used as a measure of sedation. Serum was collected for pharmacokinetic analysis. Detomidine (10 or 20 microg kg(-1)) was administered intravenously. Data were analyzed by means of a three-factor anova with fixed factors of treatment and time and random factor of horse. When a significant time x treatment interaction was detected, differences were compared with a simple t-test or Bonferroni t-test. Significance was set at p < 0.05. RESULTS: Detomidine produced a significant, dose-dependent decrease in NTG height, heart rate, and skin temperature and a significant, nondose-dependent decrease in respiratory rate. Colorectal distension threshold was significantly increased with 10 microg kg(-1) for 15 minutes and for at least 165 minutes with 20 microg kg(-1). Duodenal distension threshold was significantly increased at 15 minutes for the 20 microg kg(-1) dose. A significant change in TT was not observed at either dose. A marked, immediate decrease in amplitude of duodenal contractions followed detomidine administration at both doses for 50 minutes. CONCLUSIONS AND CLINICAL RELEVANCE: Detomidine caused a longer period of visceral anti-nociception as determined by CRD but a shorter period of anti-nociception as determined by DD than has been previously reported. The lack of somatic anti-nociception as determined by TT testing may be related to the marked decrease in skin temperature, likely caused by peripheral vasoconstriction and the low temperature cut-off of the testing device.

Factors associated with survival of neonatal foals with bacteremia and racing performance of surviving Thoroughbreds: 423 cases (1982-2007).

OBJECTIVE: To identify factors associated with short-term survival in bacteremic neonatal foals, evaluate the racing performance of Thoroughbred survivors, and evaluate changes in causative organisms and their antimicrobial susceptibility. DESIGN: Retrospective case series. ANIMALS: 423 bacteremic foals. PROCEDURES: Medical records of foals that were hospitalized in 1982 through 2007 were reviewed, and those with bacteremia were included in the study. Data retrieved included signalment, physical examination and clinicopathologic findings at admission, localized infections, concurrent illnesses, duration of hospitalization, and outcome (survival to discharge from the hospital vs nonsurvival). The number, identity, and antimicrobial susceptibility of organisms isolated from blood samples were also obtained. Racing records for surviving Thoroughbred foals and maternal siblings were examined. RESULTS: Of 423 bacteremic foals, 254 survived. Odds of survival were negatively associated with age at admission, septic arthritis, band neutrophil count, and serum creatinine concentration and positively associated with year of admission, diarrhea, rectal temperature, neutrophil count, and arterial blood pH. Overall, microbial culture of blood samples yielded 554 isolates; Escherichia coli was consistently isolated most frequently. Percentage of isolates susceptible to enrofloxacin, but no other antimicrobial, decreased over time. Surviving Thoroughbred foals did not differ from siblings with regard to percentage of starters, percentage of winners, or number of starts; however, surviving foals had significantly fewer wins and total earnings. CONCLUSIONS AND CLINICAL RELEVANCE: During the study period, microbial resistance to antimicrobials commonly used to treat bacteremic foals did not develop. Surviving bacteremic Thoroughbred foals were as likely to start races as their siblings but earned less money.

Effect of acepromazine, butorphanol, or N-butylscopolammonium bromide on visceral and somatic nociception and duodenal motility in conscious horses.

OBJECTIVE: To evaluate effects of butorphanol, acepromazine, and N-butylscopolammonium bromide (NBB) on visceral and somatic nociception and duodenal motility in conscious, healthy horses. ANIMALS: 6 adult horses. PROCEDURES: Visceral nociception was evaluated by use of colorectal distention (CRD) and duodenal distention (DD) threshold. Somatic nociception was evaluated via thermal threshold (TT). Nose-to-ground height, heart rate, and respiratory rate were also measured. Each horse received each treatment in randomized order; investigators were not aware of treatments. Butorphanol was administered IV as a bolus (18 microg/kg) followed by constant rate infusion at 13 microg/kg/h for 2 hours, whereas acepromazine (0.04 mg/kg), NBB (0.3 mg/kg), and saline (0.9% NaCl) solution (2 mL) were administered IV as a bolus followed by constant rate infusion with saline solution (10 mL/h) for 2 hours. Variables were measured before and for 3 hours after treatment. Data were analyzed by use of a 3-factor ANOVA followed by a Bonferroni t test for multiple comparisons. RESULTS: Nose-to-ground height decreased after acepromazine. Respiratory rate decreased after acepromazine and increased after butorphanol. Heart rate increased briefly after NBB. Some horses had an increase in TT after butorphanol and acepromazine, but there was not a significant treatment effect over time. Drug effect on DD or motility was not evident. The CRD threshold increased significantly at 5, 65, 155, and 185 minutes after acepromazine and from 5 to 65 minutes after NBB. CONCLUSIONS AND CLINICAL RELEVANCE: Each drug caused predictable changes in sedation and vital signs, but consistent anti-nociceptive effects were not evident.

Comparison of the effects of caffeine and doxapram on respiratory and cardiovascular function in foals with induced respiratory acidosis.

OBJECTIVE: To determine and compare the effects of caffeine and doxapram on cardiorespiratory variables in foals during isoflurane-induced respiratory acidosis. ANIMALS: 6 clinically normal foals (1 to 3 days old). PROCEDURES: At intervals of > or = 24 hours, foals received each of 3 IV treatments while in a steady state of hypercapnia induced by isoflurane anesthesia (mean +/- SD, 1.4 +/- 0.3% endtidal isoflurane concentration). After assessment of baseline cardiorespiratory variables, a low dose of the treatment was administered and variables were reassessed; a high dose was then administered, and variables were again assessed. Sequential low- and high-dose treatments included doxapram (loading dose of 0.5 mg/kg, followed by a 20-minute infusion at 0.03 mg/kg/min and then 0.08 mg/kg/min), caffeine (5 mg/kg and 10 mg/kg), and saline (0.9% NaCl) solution (equivalent volumes). RESULTS: Administration of doxapram at both infusion rates resulted in a significant increase in respiratory rate, minute ventilation, arterial blood pH, PaO(2), and arterial blood pressure. These variables were also significantly higher during doxapram administration than during caffeine or saline solution administration. There was a significant dose-dependent decrease in PaCO(2) and arterial bicarbonate concentration during doxapram treatment. In contrast, PaCO(2) increased from baseline values after administration of saline solution or caffeine. The PaCO(2) value was significantly lower during doxapram treatment than it was during caffeine or saline solution treatment. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that doxapram restored ventilation in a dose-dependent manner in neonatal foals with isoflurane-induced hypercapnia. The effects of caffeine on respiratory function were indistinguishable from those of saline solution.

Effect of fentanyl on visceral and somatic nociception in conscious horses.

BACKGROUND: Transdermal fentanyl is used clinically in horses based on pharmacokinetic data and antinociceptive effects documented in other species. HYPOTHESIS: Fentanyl IV administration increases both visceral and somatic nociceptive threshold in conscious horses. ANIMALS: Six clinically normal horses, each fitted with a permanent gastric cannula. METHODS: Visceral nociception was evaluated with 2 methods of threshold detection--olorectal distention and duodenal distention. Somatic nociception was assessed by measurement of thermal threshold. Fentanyl was administered as an increasing stepwise infusion followed by a continuous-rate infusion for a total of 2 hours. There were 4 doses of fentanyl and 1 dose each of saline and xylazine administered to each horse. Serum fentanyl concentrations were measured and the resulting data were used to determine pharmacokinetic parameters for each horse. All data were analyzed by means of a 3-factor analysis of variance followed by either a simple t test or a Bonferroni t test for multiple comparisons. RESULTS: Fentanyl administration did not result in significant changes in duodenal or colorectal distention threshold. Thermal threshold showed an increased trend at the 15-minute time point for the highest fentanyl group only, with a corresponding mean serum fentanyl concentration of 7.82 +/- 2.10 ng/mL. Two horses in this group became agitated and tachycardic during the first 15 minutes of the infusion. CONCLUSIONS AND CLINICAL IMPORTANCE: Fentanyl did not produce a significant antinociceptive effect at the doses used, 2 of which resulted in serum concentrations above the nociceptive threshold in other species.

Comparison of noninvasive cardiac output measured by use of partial carbon dioxide rebreathing or the lithium dilution method in anesthetized foals.

OBJECTIVE: To compare cardiac output (CO) measured by use of the partial carbon dioxide rebreathing method (NICO) or lithium dilution method (LiDCO) in anesthetized foals. SAMPLE POPULATION: Data reported in 2 other studies for 18 neonatal foals that weighed 32 to 61 kg. PROCEDURES: Foals were anesthetized and instrumented to measure direct blood pressure, heart rate, arterial blood gases, end-tidal isoflurane and carbon dioxide concentrations, and CO. Various COs were achieved by administration of dobutamine, norepinephrine, vasopressin, phenylephrine, and isoflurane to allow comparisons between LiDCO and NICO methods. Measurements were obtained in duplicate or triplicate. We allowed 2 minutes between measurements for LiDCO and 3 minutes for NICO after achieving a stable hemodynamic plane for at least 10 to 15 minutes at each CO. RESULTS: 217 comparisons were made. Correlation (r = 0.77) was good between the 2 methods for all determinations. Mean +/- SD measurements of cardiac index for all comparisons with the LiDCO and NICO methods were 138 +/- 62 mL/kg/min (range, 40 to 381 mL/kg/min) and 154 +/- 55 mL/kg/min (range, 54 to 358 mL/kg/min), respectively. Mean difference (bias) between LiDCO and NICO measurements was -17.3 mL/kg/min with a precision (1.96 x SD) of 114 mL/kg/min (range, -131.3 to 96.7). Mean of the differences of LiDCO and NICO measurements was 4.37 + (0.87 x NICO value). CONCLUSIONS AND CLINICAL RELEVANCE: The NICO method is a viable, noninvasive method for determination of CO in neonatal foals with normal respiratory function. It compares well with the more invasive LiDCO method.

Effects of dobutamine, norepinephrine, and vasopressin on cardiovascular function in anesthetized neonatal foals with induced hypotension.

OBJECTIVE: To determine the effects of dobutamine, norepinephrine, and vasopressin on cardiovascular function and gastric mucosal perfusion in anesthetized foals during isoflurane-induced hypotension. ANIMALS: 6 foals that were 1 to 5 days of age. PROCEDURES: 6 foals received 3 vasoactive drugs with at least 24 hours between treatments. Treatments consisted of dobutamine (4 and 8 Sang/kg/min), norepinephrine (0.3 and 1.0 Sang/kg/min), and vasopressin (0.3 and 1.0 mU/kg/min) administered IV. Foals were maintained at a steady hypotensive state induced by a deep level of isoflurane anesthesia for 30 minutes, and baseline cardiorespiratory variables were recorded. Vasoactive drugs were administered at the low infusion rate for 15 minutes, and cardiorespiratory variables were recorded. Drugs were then administered at the high infusion rate for 15 minutes, and cardiorespiratory variables were recorded a third time. Gastric mucosal perfusion was measured by tonometry at the same time points. RESULTS: Dobutamine and norepinephrine administration improved cardiac index. Vascular resistance was increased by norepinephrine and vasopressin administration but decreased by dobutamine at the high infusion rate. Blood pressure was increased by all treatments but was significantly higher during the high infusion rate of norepinephrine. Oxygen delivery was significantly increased by norepinephrine and dobutamine administration; O2 consumption decreased with dobutamine. The O2 extraction ratio was decreased following norepinephrine and dobutamine treatments. The gastric to arterial CO2 gap was significantly increased during administration of vasopressin at the high infusion rate. CONCLUSION AND CLINICAL RELEVANCE: Norepinephrine and dobutamine are better alternatives than vasopressin for restoring cardiovascular function and maintaining splanchnic circulation during isoflurane-induced hypotension in neonatal foals.

Equine neonatal sepsis.

Neonatal infection remains a leading cause of morbidity and mortality in the equine industry, despite advances in prevention and treatment. Many factors can influence a foal's risk for the development of sepsis in the peripartum period. This article discusses those factors, causative organisms, and therapeutic options. Factors that influence prognosis and potential preventative strategies also are addressed.

Nondiarrheal disorders of the gastrointestinal tract in neonatal foals.

Neonates can have a variety of gastrointestinal disorders, primary and secondary in nature. Important primary disorders include con-genital abnormalities and meconium retention. One of the most important secondary lesions is generalized ileus. Gastric ulceration can occur as a primary or secondary event. This article addresses the pathophysiology, diagnosis, and treatment of gastrointestinal problems commonly observed in neonatal foals.

Evaluation of risk factors associated with development of postoperative ileus in horses.

OBJECTIVE: To determine factors associated with development of postoperative ileus (POI) in horses undergoing surgery for colic. DESIGN: Prospective case-control study. ANIMALS: 251 horses undergoing colic surgery, of which 47 developed POI. PROCEDURE: Signalment, history, clinicopathologic data, pre- and postoperative treatments, lesions, complications, costs, and outcome were recorded for all horses during hospitalization. RESULTS: Variables associated with increased odds of POI included small intestinal lesion, high PCV, and increased duration of anesthesia. There was modest evidence that pelvic flexure enterotomy and intraoperative administration of lidocaine may have reduced the odds of developing POI. CONCLUSIONS AND CLINICAL RELEVANCE: Findings during the preoperative and intraoperative periods can be used to identify horses at increased risk of POI. Reducing surgical and anesthetic duration should decrease the incidence of POI.