Investigation of Serum Markers of Hepatic Fibrosis in Equids.

Liver disease is common in equine practice, and treatment and prognosis are dependent on histopathologic examination of biopsies. Liver biopsy is invasive and expensive which restricts its use. Serum markers are used to predict hepatic fibrosis in humans. This study aimed to investigate the enhanced liver fibrosis (ELF) test, based on serum Hyaluronic Acid (HA), procollagen III N-terminal peptide (PIIINP), and tissue inhibitor of metalloproteinase 1 (TIMP-1) to detect hepatic fibrosis in equids. Four groups were included; two with increased serum concentrations of liver-derived enzymes and a liver biopsy (group H; 10 horses and ponies and group D; 10 donkeys) and two without any evidence of liver disease (group HC; 10 horses and ponies and group DC; 10 donkeys). All samples were analyzed for concentrations of HA, PIINP, and TIMP-1. Given the failure to detect TIMP-1 in most subjects, a novel eELF (equid ELF) score was calculated, based on HA and PIIINP. HA and PIIINP concentrations and the eELF score, were compared with determined hepatic fibrosis. HA, PIIINP, and eELF were significantly greater in horses and ponies with a histopathologic fibrosis score ≥ 2 compared with those < 2. A similar observation was found with donkeys for HA and eELF. A significant correlation was found between fibrosis score and HA, PIIINP, and eELF for horses and ponies, and between fibrosis score and HA and eELF in donkeys. Serum HA and the eELF score might be useful serum markers to predict and monitor hepatic fibrosis in horses, ponies, and donkeys.

Evaluation of stress markers in horses during hippotherapy sessions in comparison to being ridden by beginners.

Hippotherapy has been used for decades and its benefits to human patients have largely been proven, whether being applied to those with physical or mental disabilities. There have been a plethora of animal welfare studies recently, pertaining especially to ridden horses. This study aimed to investigate stress markers in horses during hippotherapy sessions to address the ethical considerations raised by using horses for therapy. A ridden stress ethogram was established and validated specifically for this study via subjective observation and video recording of a ridden session involving intermediate-level riders. The experiment entailed eight healthy horses undergoing two ridden sessions on separate days, one with disabled riders and one with beginners. Several parameters associated with physiological responses to stress were evaluated at rest, such as heart rate, plasma adrenocorticotropic hormone [ACTH], serum and salivary cortisol. These parameters as well as the behavioural stress score from the ethogram scale were measured during both sessions. No significant differences were found between heart rate, plasma ACTH, and stress scores. Serum and salivary cortisol were significantly lower during the hippotherapy session than during the session with beginners. The current study found no evidence of compromised welfare when horses were used as a therapeutic aid during hippotherapy sessions compared to their usual ridden activity. Although these results indicate that hippotherapy may be ethically justified as it benefits humans without causing harm to the horses, the present study was small, and the results should be interpreted with caution.

Clinically and temporally specific diagnostic thresholds for plasma ACTH in the horse.

BACKGROUND: Pituitary pars intermedia dysfunction (PPID) is commonly investigated using plasma ACTH concentrations but problems exist with currently available diagnostic thresholds. OBJECTIVES: To derive temporally specific diagnostic thresholds for equine plasma ACTH concentration to be used alongside clinical judgement in each individual week of the year and appropriate for the degree of clinical suspicion in any given case. Furthermore, to apply these thresholds to compare the prevalence of high and low ACTH in two subgroups of animals with high and low clinical suspicion of PPID. STUDY DESIGN: A retrospective population study examining a large laboratory database of equine plasma ACTH concentrations using an indirect approach to calculate diagnostic thresholds. METHODS: Logs of plasma ACTH concentrations from 75 892 individual horses were examined using robust L2 estimation of mixtures of two normal distributions in categories of each week and month of the year. Thresholds dividing the two populations of high-ACTH and low-ACTH horses were then established at different levels of sensitivity and specificity and compared with clinical subgroups of horses divided based on reported clinical signs, as having high (n = 4036) or low (n = 3022) clinical suspicion of PPID. RESULTS: For most of the year there were small interweek differences in diagnostic thresholds. However, from mid-June to early-December diagnostic thresholds showed greater interweek variability, reaching a maximum in late September and early October. Grouping of high- and low-ACTH compared favourably with grouping based on clinical signs. MAIN LIMITATIONS: Given the multiple sources of diagnostic samples, pre-analytical data could not be fully verified. CONCLUSIONS: Diagnostic thresholds for equine plasma ACTH vary through the year. It is especially important to consider the temporally specific threshold between June and December. Different clinical thresholds can be used depending on the case circumstances and whether a false-positive or false-negative diagnosis is deemed least desirable.

Antimicrobial susceptibility of bacterial isolates from ambulatory practice and from a referral hospital.

BACKGROUND: Responsible use of antimicrobials in equine practice relies on knowledge of common bacterial isolates and their antimicrobial sensitivities. OBJECTIVES: To assess the frequency of bacterial resistance to a combination of parenteral penicillin and gentamicin and to trimethoprim and sulfamethoxazole for PO use in a selection of clinical isolates, and subsequently to determine the prevalence of resistance to antimicrobials that might then be used as alternatives to first-line antimicrobials for the same isolates. METHODS: Retrospective analysis of minimal inhibitory concentrations (MICs) of antimicrobials for 6354 bacterial isolates from 365 ambulatory practices and 519 isolates from a referral hospital. The MICs were used to indicate sensitivity or resistance to commonly used antimicrobials and the prevalences of resistance were compared between origin of the isolates, and among antimicrobial drugs. RESULTS: Isolates from the referral hospital were significantly (P < .05) more likely to be resistant to the antimicrobials tested than those derived from ambulatory practice. Overall, 91% of the ambulatory isolates and 64% of the hospital isolates were sensitive to penicillin-gentamicin. For trimethoprim-sulfamethoxazole combination, 82% of the ambulatory practice isolates and 56% of the referral hospital isolates were sensitive. CONCLUSIONS AND CLINICAL IMPORTANCE: Most isolates were sensitive to penicillin and gentamicin as well as trimethoprim-sulfamethoxazole. No predictable efficacious second choice antimicrobial was identified for those isolates resistant to the first-line antimicrobials. The likelihood of isolates being sensitive to second choice antimicrobials was variable but generally higher for ambulatory isolates compared to referral isolates. Bacterial identification and measurement of MIC are essential to make the appropriate antimicrobial choice.

The Modification and Performance of a Large Animal Anesthesia Machine (Tafonius®) in Order to Deliver Xenon to a Horse.

INTRODUCTION: Xenon, due to its interesting anesthetic properties, could improve the quality of anesthesia protocols in horses despite its high price. This study aimed to modify and test an anesthesia machine capable of delivering xenon to a horse. MATERIALS AND METHODS: An equine anesthesia machine (Tafonius, Vetronic Services Ltd., UK) was modified by including a T-connector in the valve block to introduce xenon, so that the xenon was pushed into the machine cylinder by the expired gases. A xenon analyzer was connected to the expiratory limb of the patient circuit. The operation of the machine was modeled and experimentally tested for denitrogenation, wash-in, and maintenance phases. The system was considered to consist of two compartments, one being the horse's lungs, the other being the machine cylinder and circuit. A 15-year-old, 514-kg, healthy gelding horse was anesthetized for 70 min using acepromazine, romifidine, morphine, diazepam, and ketamine. Anesthesia was maintained with xenon and oxygen, co-administered with lidocaine. Ventilation was controlled. Cardiorespiratory variables, expired fraction of xenon (FeXe), blood gases were measured and xenon was detected in plasma. Recovery was unassisted and recorded. RESULTS: FeXe remained around 65%, using a xenon total volume of 250 L. Five additional boli of ketamine were required to maintain anesthesia. PaO2 was 45 ± 1 mmHg. The recovery was calm. Xenon was detected in blood during the entire administration time. CONCLUSION: This pilot study describes how to deliver xenon to a horse. Although many technical problems were encountered, their correction could guide future endeavors to study the use of xenon in horses.