The effect of feeding a commercial feedstuff on gastric squamous gastric disease (ESGD) healing and prevention of recurrence.

Feedstuffs are often recommended to mitigate potential damage from acid associated with equine squamous gastric disease (ESGD). In acidic conditions, pectin alters its structure to one like mucus and binds the stomach mucosa, whilst alfalfa has a strong intrinsic acid buffering capacity. The study aimed to determine whether feeding a commercial beet pulp/alfalfa/oat fibre mix aids ESGD healing and/or prevention of recurrence. Ten adult horses with naturally occurring ESGD were included. All animals were treated with omeprazole as per the attending veterinarian's recommendation and randomly allocated to also be fed a commercial beet pulp/alfalfa/oat fibre mix (1Kg/horse divided into 2 meals/day; n=5) or no additional feed (n=5) for one month. Gastroscopy was then repeated to assess response to therapy. If the ESGD had healed, omeprazole therapy was discontinued, and the commercial feed given to all horses for a further month. Gastroscopy was repeated to determine ESGD recurrence. The mean (±SD) age of the horses was 11.6 (±3.8) years; 4 mares and 6 geldings; various breeds were represented; and the median (range) initial ESGD grade was 2 (2-4). ESGD had healed (grade 0/4) in all animals after one month. After a further month, ESGD had recurred in significantly (p=0.04) more animals that did not receive the commercial feed initially (3/5; 60%; mean [range] ESGD grade 3 [0,4]) compared to those that did (0/5; 0%; mean [range] ESGD grade 0 [0,0]). Thus, the commercial beet pulp/alfalfa/oat fibre mix aided prevention of ESGD recurrence when fed during the healing and prevention phases.

The efficacy of N-acetylcysteine in decreasing airway inflammation and mucus accumulation in horses with 18 hours of head confinement.

BACKGROUND: During transportation many horses develop post-transportation infection, which can be life-threatening and end their sport career. Preventing mucus accumulation and inflammation during transportation is vital, emphasizing the need for effective strategies to enhance overall horse health welfare. OBJECTIVES: Assess the impact of N-acetylcysteine (NAC) on mucus accumulation and inflammation in horses subjected to 18 hours of head confinement. ANIMALS: Six healthy crossbred horses, 5.3 ± 2.1 years of age and weighing 387 ± 30 kg. METHODS: Prospective placebo-controlled cross-over design study. The horses' heads were restrained in their stalls for a period of 18 hours. They were studied under 4 conditions: Not confined (NC): before head confinement, placebo (P), and confined head (CH): 18 hours of head confinement without treatment, and N-Acetylcysteine (NAC): 18 hours of head confinement treated with NAC before confinement (15 mg/kg/day NAC PO for 3 days). Bronchoalveolar lavage (BAL) was performed in each condition. Mucus accumulation along the trachea was evaluated by endoscopy. RESULTS: Endoscopic scores were significantly different between CH and other conditions, whereas no significant differences were found among NC, P, and NAC. The BAL cell count (34 291 ± 2624 cells/µL), neutrophil and lymphocyte count (18 601 ± 3193 cells/µL and 3337.4 ± 593 cells/µL, respectively) in CH were significantly higher compared to NAC. Neutrophil percentage was significantly higher in CH (53.8 ± 8%) compared to horses that received NAC (20.08 ± 8%). Conversely, in comparison to NAC (66.33 ± 9%), the percentage of macrophages was significantly lower in CH (35.7 ± 10%). CONCLUSIONS: N-acetylcysteine was found to significantly decrease mucus accumulation and inflammatory cell counts in horses with head confinement.

Antimicrobial prophylaxis is not indicated for horses undergoing general anaesthesia for elective orthopaedic MRI.

BACKGROUND: Post-anaesthetic fever is a known complication of general anaesthesia, however, its incidence in horses undergoing elective magnetic resonance imaging (MRI) is unknown. OBJECTIVE: To determine the incidence of post-anaesthetic fever in horses undergoing elective orthopaedic MRI and determine whether prophylactic antimicrobial therapy would be associated with a reduction in the incidence of post-anaesthetic fever. We hypothesised that prophylactic antimicrobials would be associated with a reduction in the incidence of post-anaesthetic fever. STUDY DESIGN: Retrospective cross-sectional study. METHODS: This retrospective study included 791 elective orthopaedic MRIs in systemically healthy horses between June 2006 and March 2020 that recovered from general anaesthesia and did not undergo surgery or intensive medical therapy soon after recovery. Potential factors associated with post-anaesthetic fever were evaluated using multivariable logistic regression. Case signalment, travel time, preanaesthetic haematology and fibrinogen abnormalities, use of prophylactic antimicrobials, peri-anaesthetic nonsteroidal anti-inflammatories, anaesthesia time and recovery time were all evaluated for association with post-anaesthetic fever. RESULTS: Of 791 MRI cases, 44 (5.6%) developed a post-anaesthetic fever. Horses that received prophylactic antimicrobials were [odds ratio (OR) 3.8, 95% confidence interval (CI) 1.98-7.46; p ≤ 0.001] more likely to develop a post-anaesthetic fever than those that did not receive antimicrobials. Young horses (1-4 years of age) were (OR 2.8, 95% CI 1.26-6.17; p = 0.01) more likely to develop fever compared with adult horses (≥5 years of age). MAIN LIMITATIONS: Limitations of this study pertain to retrospective analysis including nonrandomised case selection and incomplete data records. CONCLUSIONS: While fever may indicate infection, the majority of early post-anaesthetic fevers resolved before discharge from the hospital with no identified cause. The use of prophylactic antimicrobials to reduce the risk of post-anaesthetic fever for elective MRI is not supported by this study.

CONTEXTO: Febre é uma complicação comum após anestesia geral. Contudo, a incidência de febre em cavalos submetidos à ressonância magnética (RM) é desconhecida. OBJETIVO: Determinar a incidência de febre pós­anestésica em cavalos submetidos à RM devido à lesões ortopédicas e determinar se terapia antimicrobiana é necessária para reduzir a incidência de febre pós­anestésica. Nossa hipótese é que o uso de antimicrobianos é associado com a redução da incidência de febre pós­anestésica. DELINEAMENTO DO ESTUDO: Estudo retrospectivo transversal. METODOLOGIA: Esse estudo retrospectivo incluiu 791 equinos submetidos à RM por motivos ortopédicos, entre Junho de 2006 e Março de 2020, que recuperaram de anestesia geral, e não foram submetidos à cirurgia ou terapia intensa logo após a recuperação. Fatores que potencialmente poderiam ser associados com febre pós­anestésica foram avaliados utilizando regressão logística multivariada. Informações do paciente, como sexo e idade, tempo de viagem, anormalidades nos exames de sangue (hemograma e bioquímico) pré­anestésico, uso profilático de antimicrobianos, uso de anti­inflamatório não­esteroidal no período peri­anestésico, tempo de anestesia, e tempo de recuperação foram avaliados para possível associação com febre pós­anestésica. RESULTADOS: Dos 791 casos de RM, 44 (5.6%) desenvolveram febre pós­anestésica. Cavalos que receberam terapia antimicrobiana profilática foram (OR 3.8, 95% CI 1.98­7.46; p ≤ 0.001) vezes mais prováveis de desenvolverem febre pós­anestésica do que aqueles que não receberam antimicrobianos. Cavalos jovens (1­4 anos de idade) foram OR 2.8, 95% CI 1.26­6.17; p = 0.01) vezes mais prováveis de desenvolverem febre comparado com cavalos adultos (≥5 anos de idade). PRINCIPAIS LIMITAÇÕES: As limitações deste estudo são aquelas de uma análise retrospectiva, incluindo a seleção não randomizada dos pacientes e prontuários incompletos. CONCLUSÕES: Enquanto febre pode indicar a presença de infecção, a maioria das febres no período logo após anestesia se resolveram antes da alta do hospital e não tiveram nenhuma causa identificada. O uso profilático de antimicrobianos para reduzir a possível chance de febre pós­anestésica em casos de RM eletiva não é suportada por este estudo.

Effect of a blend of magnesium oxide on Equine Squamous Gastric Disease in young trotter horses under training.

BACKGROUND: Equine squamous gastric disease (ESGD), as part of the equine gastric ulcer syndrome (EGUS), are common in racing horses. The use of buffering feed supplements to treat and/or prevent gastric ulcers is an option to control this condition. OBJECTIVE: The purpose of this study was to evaluate the effect of a 30-day supplementation with a blend of magnesium oxide (MgO) on ESGD scores in trotters under training. METHODS: Forty-two young trotters were submitted to a gastroscopic evaluation to assess their ESGD score and were randomly assigned in a group supplemented with MgO or in a control group. After 30 days, a second evaluation by gastroscopy was performed. The effect of the MgO supplementation was assessed by comparing the evolution of the ESGD score in supplemented and control groups between day 0 and day 30. RESULTS: The results confirm the high prevalence of EGUS in young Trotters. The supplementation significantly decreased the ESGD scoring in the supplemented group whereas the control group remain unchanged. CONCLUSION: The oral MgO supplementation was efficient to control ESGD in the population studied.

Papillomavirus-like Particles in Equine Medicine.

Papillomaviruses (PVs) are a family of small DNA tumor viruses that can induce benign lesions or cancer in vertebrates. The observation that animal PV capsid-proteins spontaneously self-assemble to empty, highly immunogenic virus-like particles (VLPs) has led to the establishment of vaccines that efficiently protect humans from specific PV infections and associated diseases. We provide an overview of PV-induced tumors in horses and other equids, discuss possible routes of PV transmission in equid species, and present recent developments aiming at introducing the PV VLP-based vaccine technology into equine medicine.

Prevention of fatal equine herpesvirus type 1 encephalitis in mice by immunization with a limited-replication cycle virus.

Equine herpesvirus type 1 (EHV-1) is a devastating pathogen of horses, their natural hosts, and causes fatal encephalitis in non-natural hosts. We previously demonstrated that acylation of the tegument protein UL11 is required for viral replication in cultured cells. We created a mutant virus (EHV-1 UL12 trunc UL11 G2AC7AC9A), in which glycyl and cysteinyl residues at positions 2, 7 and 9 of UL11 that are normally acylated were replaced with alanyl residues. This virus, designated the 2/7/9 mutant, has a limited-replication cycle (LRC), in which replication stops after just a few cycles. Here, we tested whether the 2/7/9 mutant could be used as a vaccine against fatal encephalitis in a mouse model. A virulence test showed that the 2/7/9 mutant was not pathogenic in mice and elicited an antibody response. We also attempted to use the 2/7/9 mutant to immunize mice against a zebra-borne EHV-1, 94-137. Two trials were conducted, each with five immunized mice, five non-immunized and five control mice. In both trials, clinical signs and fatalities were much lower in the immunized mice than in the non-immunized mice. In addition, none of the mice in either trial developed neutralizing antibodies, indicating that the immunity induced by the 2/7/9 mutant was not due to neutralizing activity. The results indicate that the 2/7/9 LRC mutant has promise as a vaccine against EHV-1 infection non-natural hosts.

Long-chain polyunsaturated fatty acid supplementation increases levels in red blood cells and reduces the prevalence and severity of squamous gastric ulcers in exercised Thoroughbreds.

OBJECTIVE: To assess the relationship between plasma and RBC fatty acid composition and incidence and severity of squamous gastric ulcers when altered by short-chain (SC) or long-chain (LC) polyunsaturated fatty acid (PUFA) supplementation. ANIMALS: 13 fit Thoroughbred horses in training. PROCEDURES: Horses were evaluated by gastroscopy for squamous ulcer score, gastric pH, and blood fatty acid composition prior to supplementation (UNSUPP) and after 3 months of supplementation with a corn-flax oil blend of alpha-linolenic acid and linoleic acid (SC-PUFA) or a gamma-linolenic acid (GLA)-fish oil blend of GLA, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA; LC-PUFA) in a crossover design. Prior to gastroscopy and blood collection, horses performed a 4,600-m standardized exercise test on the racetrack as a stressor. RESULTS: Three months of supplementation with LC-PUFAs increased RBC levels of GLA, dihomo-gamma-linolenic acid (DGLA), arachidonic acid (AA), EPA, and DHA, and reduced severe ulcer prevalence (38% UNSUPP vs 8% LC-PUFA with a severe ulcer score of grade 3 to 4). Short-chain PUFA supplementation did not effectively elevate RBC GLA, DGLA, AA, EPA, or DHA and severe ulcer incidence was not different (38% UNSUPP vs 23% SC-PUFA with a severe ulcer score of grade 3 to 4). Lower levels of RBC GLA, DGLA, AA, and EPA correlated with severe squamous gastric ulceration (grade 3 to 4). CLINICAL RELEVANCE: Equine gastric ulcer syndrome is prevalent in high-performance horses and is a concern to owners and trainers. Long-chain PUFA supplementation increased levels of GLA, DGLA, AA, EPA, and DHA, unlike SC-PUFA supplementation, and was associated positively with prevention or resolution of severe squamous gastric ulceration. Further studies are needed to evaluate different management styles and exercise intensities.

Castration Complications: A Review of Castration Techniques and How to Manage Complications.

Castration is one of the most common surgical procedures performed in equine practice. Open, closed, and semiclosed techniques are described for castration of horses, and the procedure may be performed in a standing, sedated animal or in a recumbent animal under general anesthesia. Although a relatively routine procedure, complications can occur, with reported complication rates ranging from 10.2% to 60%. Most complications are mild and resolve rapidly with appropriate treatment, but more serious or life-threatening complications can also occur. A thorough knowledge of male reproductive anatomy combined with good surgical technique is imperative to help reduce the rate of complications.

Dust exposure and pulmonary inflammation in Standardbred racehorses fed dry hay or haylage: A pilot study.

Respirable dust exposure is linked to airway inflammation in racehorses. Feeding haylage may reduce dust exposure by 60-70%. The objective of this study was to compare dust exposure, airway cytology, and inflammatory cytokine concentrations between horses fed haylage or hay over 6 weeks while in training. Seven healthy Standardbred horses were randomly assigned to be fed alfalfa hay (n = 3) or grass-alfalfa mix haylage (n = 4) for six weeks while training on a treadmill. Dust exposure was measured gravimetrically at the breathing zone. Endotoxin and ß-glucan concentrations in respirable dust were measured. Bronchoalveolar lavage fluid (BALF) cytology was determined at baseline and after 2, 4, and 6 weeks. Cytokine concentrations (interferon-γ, tumor necrosis factor-α, and interleukin-4) were measured in BALF at baseline and week 6. The effect of forage on exposure, airway cytology and cytokines were evaluated using generalized linear mixed models. Respirable dust and ß-glucan exposures were lower in horses fed haylage than hay (0.02 ± 0.001 mg/m3 vs. 0.06 ± 0.01 mg/m3; P = 0.03, and 69 ± 18 pg/m3 vs. 160 ± 21 pg/m3; P = 0.02, respectively). In horses eating haylage, BALF neutrophil proportion decreased between baseline (2.2 ± 0.5%), week 2 (0.8 ± 0.3%; P = 0.01) and week 6 (0.7 ± 0.2%; P = 0.03). By week 6, horses fed haylage had lower BALF neutrophilia than horses fed hay (4.0 ± 0.7 %; P = 0.0004). Interleukin-4 concentration in BALF was higher at week 6 (14.4 ± 4.6 pg/mL) in horses fed hay compared to baseline (2.9 ± 4.6 pg/mL; P = 0.007). In conclusion, feeding haylage instead of hay to horses in training can reduce exposure to respirable irritants and mitigate airway neutrophilia.

In vitro efficacy of a 0.2% polyhexamethylene biguanide-impregnated gauze dressing against pathogenic bacterial isolates found in horses.

OBJECTIVE: To determine the ability of 0.2% polyhexamethylene biguanide (PHMB)-impregnated gauze to inhibit the growth of bacteria isolated from equine infected sites. STUDY DESIGN: In vitro study. METHODS: Nine bacterial isolates were obtained from cultures submitted from equine patients presenting with penetrating injuries of the hoof (n = 4), septic osteitis (n = 1), synovial sepsis (n = 1), wounds (n = 2), and incisional infection following laparotomy (n = 1). Two standardized strains were also included. A standard inoculum of each isolate was placed on 12 Muller-Hinton agar plates. Squares (2.5 cm × 2.5 cm) of 0.2% PHMB-impregnated (n = 6) and nonimpregnated control gauze (n = 6) were placed on inoculated agar plates. Bacterial growth under each gauze square was assessed after a 24-h incubation period and areas of inhibition were measured to a standardized scale, using image-processing software. Mean ± SD growth inhibition (%) using 0.2% PHMB-impregnated gauze was compared to the nonimpregnated gauze for each isolate using Student's t test (p < .05). RESULTS: The 0.2% PMHB-impregnated gauze inhibited the growth of Staphylococcus spp. (n = 4) by 33%-83.1% and that of Escherichia coli spp. (n = 4) by 6.5%-37%. There was no inhibition of growth of Pseudomonas aeruginosa or either Enterococcus spp. CONCLUSION: The 0.2% PHMB-impregnated dressing tested here inhibited the growth of staphylococcal and E. coli isolates, but the magnitude of inhibition varied between strains. CLINICAL RELEVANCE: These results justify in vivo studies to evaluate the ability of the dressing to reduce the bacterial growth of common equine bacterial pathogens in clinical practice.

Intraincisional medical grade honey decreases the prevalence of incisional infection in horses undergoing colic surgery: A prospective randomised controlled study.

BACKGROUND: Medical grade honey has previously been described as a prophylactic treatment for wounds. Local prophylactic treatment may be valuable in preventing post-operative incisional infections in horses undergoing colic surgery but has not been evaluated. OBJECTIVES: To establish whether medical grade honey gel, applied on the linea alba intraoperatively, decreases the prevalence of incisional infections in horses undergoing colic surgery with no associated adverse effects. STUDY DESIGN: Prospective blinded randomised controlled clinical study. METHODS: Horses older than 4 months that underwent colic surgery between May 2017 and December 2018 and survived for >2 weeks were included in the study. Horses were allocated 1:1 to treatment or control by block randomisation. In the treatment group, following closure of the linea alba, medical grade honey gel (L-Mesitran Soft® ) was placed in the incision followed by apposition of subcutaneous tissue and skin. Information regarding the incision and post-operative complications was obtained at five time points (24 hours, 48 hours, 5 days, 14 days and 3 months). RESULTS: Eighty-nine horses were included in the study. No adverse effects associated with treatment were observed. Horses in the treatment group had a lower rate of incisional infection compared with the control group (8.2% vs. 32.5%, P = .02). The protective effect of MGH had a calculated adjusted odds ratio (OR) of 0.2 (95% CI:0.07-0.8, P = .03). The number of patients required to receive treatment to prevent one case of incisional infection (NNEB) was 4.7. Risk factors associated with infection included: younger age (OR = 27, 95% CI: 2.3 to 306, P = .008) and diarrhoea 48 hours post-operatively (OR = 20, 95% CI: 1.5 to 277, P = .02). MAIN LIMITATIONS: Follow-up was performed by different veterinary surgeons, hence not completely uniform. CONCLUSION: Local prophylactic treatment with medical grade honey gel in the abdominal incision during surgery is safe and may significantly decrease the prevalence of incisional infections in horses undergoing colic surgery.

Nephrosplenic space closure significantly decreases recurrent colic in horses: a retrospective analysis.

BACKGROUND: Nephrosplenic space closure is commonly used to reduce relapse of nephrosplenic space entrapment in cases of left dorsal displacement of the left colon (LDDLC). Nevertheless, studies documenting the effectiveness of this surgery are sparse in the literature. The aim of this study was to analyse clinical data of horses presented for LDDLC and evaluate the effect of nephrosplenic space closure on the incidence of colic recurrence. METHODS: Medical records of 156 horses diagnosed with LDDLC at the Equine Clinic of the University of Liège between 2004 and 2016 were retrieved for analysis. Extracted data included horse breed, sex, age and weight, initial treatment, and if a subsequent preventive surgical closure of the nephrosplenic space was carried out or not. Follow-up information was obtained by telephone interview. Statistical analyses were performed using a chi-squared test with significance set at P<0.05. RESULTS: Follow-up data were available for 65 per cent of horses. The mean follow-up was 35 months. There was a significant decrease in the total incidence of colic after closure surgery compared with non-operated horses. No horse was diagnosed with LDDLC after closure of the nephrosplenic space. CONCLUSION: Closure of the nephrosplenic space significantly decreases recurrent colic in horses compared with non-operated horses.

Effects of pentoxifylline supplementation to semen extender on post-breeding inflammation response assessed by endometrial cytology and vascular perfusion in mares.

The aim was to evaluate effects of addition of pentoxifylline to skimmed milk semen extender on uterine inflammatory response. Thirty-six estrous cycles of 15 mares were randomly divided into five groups for artificial insemination (AI): Control: mimicking the AI procedure (n = 7); Extender: deposition of skimmed milk based extender (n = 7); Extender + PTX: skimmed milk based extender plus pentoxifylline (7.18 mM; n = 8); Semen: semen diluted with extender without pentoxifylline (n = 7), and Semen + PTX: semen diluted with extender containing pentoxifylline (n = 7). Mares in estrus were examined by trans-rectal palpation and using ultrasonography, and ovulation was induced. Uterine hemodynamics were assessed immediately before ovulation induction (T-30), immediately before AI (T0), 2 (T2), 6 (T6), 12 (T12), 24 (T24) and 48 (T48) h after AI. Endometrial samples were collected 6 h after AI, and slides were stained and examined to determine percentage of PMN. Pentoxifylline had no additional effect on vascular perfusion. There was a major inflammatory response with pentoxifylline treatment that was greater than that of the control group. In the group treated with Extender + PTX, there were more PMN (57.98 ±â€¯9.42%) than in the group treated with Extender (20.20 ±â€¯6.63%) and in the Semen + PTX group more PMN (82.84 ±â€¯5.71%) than in the Semen-treated group (47.83 ±â€¯10.61%). These findings indicate the addition of pentoxifylline does not stimulate blood flow; however, it induces a greater immune defense response because more neutrophils migrate to the uterine lumen.

Performance comparison of 159 Thoroughbred racehorses and matched cohorts before and after desmotomy of the interspinous ligament.

Racehorses may perform poorly because of impinging dorsal spinous processes (DSPs) of the thoracolumbar vertebrae. No study has looked objectively at the long-term outcome of racehorses undergoing desmotomy of the interspinous ligament as a treatment for horses with poor performance caused by impinging DSPs. The aim of this study was to examine objectively, by using pre-operative and post-operative racing records, the effectiveness of desmotomy of the interspinous ligament (DISL) in improving the performance of racehorses with impinging DSPs. Medical records of all horses undergoing desmotomy of one or more interspinous ligaments at a referral equine hospital, between February 2015 and September 2016, were reviewed. The study was confined to Thoroughbred racehorses with sufficient historical information and racetrack data to allow their racing performances be compared to that of matched controls. Matched controls were of the same age, sex, and racing type and were trained at the same time by the same trainer as those undergoing desmotomy. The time to follow-up was at least 12 months. Of the 6545 horses presented for poor performance or lameness during the study period, 236 horses (3.6%) underwent desmotomy of one or more interspinous ligaments, and of these, 159 met the inclusion criteria. Horses undergoing desmotomy had significantly better improvement in racing performance than did matched controls. Eight horses developed unilateral neurogenic atrophy of epaxial musculature. DISL between impinging DSPs can improve the performance of racehorses experiencing from poor performance caused by pain resulting from the impinging processes.

Validation of modified radio-frequency identification tag firmware, using an equine population case study.

BACKGROUND: Contact networks can be used to assess disease spread potential within a population. However, the data required to generate the networks can be challenging to collect. One method of collecting this type of data is by using radio-frequency identification (RFID) tags. The OpenBeacon RFID system generally consists of tags and readers. Communicating tags should be within 10m of the readers, which are powered by an external power source. The readers are challenging to implement in agricultural settings due to the lack of a power source and the large area needed to be covered. METHODS: OpenBeacon firmware was modified to use the tag's onboard flash memory for data storage. The tags were deployed within an equine facility for a 7-day period. Tags were attached to the horses' halters, worn by facility staff, and placed in strategic locations around the facility to monitor which participants had contact with the specified locations during the study period. When the tags came within 2m of each other, they recorded the contact event participant IDs, and start and end times. At the end of the study period, the data were downloaded to a computer and analyzed using network analysis methods. RESULTS: The resulting networks were plausible given the facility schedule as described in a survey completed by the facility manager. Furthermore, changes in the daily facility operations as described in the survey were reflected in the tag-collected data. In terms of the battery life, 88% of batteries maintained a charge for at least 6 days. Lastly, no consistent trends were evident in the horses' centrality metrics. DISCUSSION: This study demonstrates the utility of RFID tags for the collection of equine contact data. Future work should include the collection of contact data from multiple equine facilities to better characterize equine disease spread potential in Ontario.

Phenylbutazone blood and urine concentrations, pharmacokinetics, and effects on biomarkers of inflammation in horses following intravenous and oral administration of clinical doses.

Phenylbutazone (PBZ) is a potent mon-steroidal anti-inflammatory drug used commonly in performance horses. The objectives of the current study were to describe blood and urine concentrations and the pharmacokinetics of PBZ and its metabolites following intravenous (IV) and oral administration and to describe the duration of pharmacodynamic effect. To that end, 17 horses received an IV administration and 18 horses an oral administration of 2 g of PBZ. Blood and urine samples were collected prior to and for up to 96 hours post drug administration. Whole blood samples were collected at various time points and challenged with lipopolysaccharide or calcium ionophore to induce ex vivo synthesis of eicosanoids. Concentrations of PBZ and eicosanoids were measured using liquid chromatography-tandem mass spectrometry (LC-MS/MS) and non-compartmental pharmacokinetic analysis performed on concentration data from IV and oral administration. Serum concentrations of PBZ and its metabolites were below the limit of quantitation at 96 hours post administration. The volume of distribution at steady state, systemic clearance, and terminal half-life was 0.194 ± 0.019 L/kg, 23.9 ± 4.48 mL/h/kg, and 10.9 ± 5.32 hours, respectively. The terminal half-life following oral administration was 13.4 ± 3.01 (paste) and 15.1 ± 3.96 hours (tablets). Stimulation of PBZ treated whole blood with lipopolysaccharide and calcium ionophore resulted in an inhibition of TXB2 , PGE2 , LTB4 and 15-HETE production for a prolonged period of time post drug administration. The results of this study suggest that PBZ has a prolonged anti-inflammatory following IV or oral administration of 2 g to horses.

Prospective, randomised clinical trial of four different presurgical hand antiseptic techniques in equine surgery.

BACKGROUND: Currently, the World Health Organization recommends the use of alcohol-based hand rubs (ABR) for surgical hand preparation in human surgery. When disinfecting soaps are used, a rubbing technique causes less skin irritation than brush scrubbing. Based on a recent survey, most equine surgeons still use disinfecting soap. The efficacy of scrubbing vs. rubbing and the use of sole ABR compared with chlorhexidine (CHx)- based products has not been evaluated in the equine surgical setting. OBJECTIVES: To compare four surgical hand antisepsis techniques in equine surgery for reduction of aerobic bacterial counts from pre- to post-preparation (immediate efficacy) and at the end of surgery (sustained efficacy). STUDY DESIGN: Randomised, prospective clinical trial. METHODS: A 4% CHx-based product applied with either a scrub or rub technique, one sole ABR (ET; 80% ethanol) and one CHx/alcohol-combination (CHx/ET; 1% CHx and 61% ethanol) product both applied with a rub technique were evaluated. Samples were collected by glove juice technique and cultured on 3M™ Petrifilm plates and counted using a 3M™ Petrifilm plate reader. RESULTS: Immediate mean bacterial log10 colony forming unit (CFU) reduction was 2.4 for CHx-scrub, 2.8 for CHx-rub, 3.1 for CHx/ET and 2.1 for ET. CHx/ET resulted in significantly lower bacterial counts than CHx-scrub (P<0.005) and ET (P<0.001) while CHx-rub resulted in significantly lower counts than ET (P<0.001). At the end of surgery bacterial counts were the lowest for CHx-rub, significantly lower than CHx/ET (P<0.001) and ET (P<0.001). There was no difference between CHx-rub and -scrub techniques (P = 0.7). MAIN LIMITATIONS: Bacterial counts were used as the outcome measure rather than prevalence of surgical site infection, and the effect of hand preparation on skin health was not assessed. CONCLUSIONS: ABR did not decrease bacterial log10 CFU counts more effectively than CHx products. When using CHx soaps in the equine setting, hand-rub is as effective as a hand-scrub-technique.

Postoperative complications in equine elective, clean orthopaedic surgery with/without antibiotic prophylaxis.

OBJECTIVE: Retrospective analysis of postoperative complications in equines after clean, orthopaedic surgical procedures in order to detect differences between animals treated with antibiotics and horses without receiving these drugs. MATERIAL AND METHODS: Details on 652 patients, surgical procedures and surgery-associated complications were compiled from horses being operated between June 2011 and January 2015. Antibiotic-receiving patients (n = 259) were tested for differences in complication rates and characteristics to controls (n = 393). RESULTS: The total complication rate was 39.1 %. Increased swelling was observed most often (25.6 %), followed by exudation (7.5 %), fever without incisional alterations (2.3 %), suture dehiscence (1.8 %), and seroma (0.8 %). Seven patients (five treated, two controls) developed septic arthritis within a total of 463 arthroscopies (1.5 %). There were no significant differences in the development of postoperative complications, which were seen in 97/259 (37.5 %) antibiotic receiving patients and in 158/393 (40.2 %) controls. The application of perioperative antibiotics was significantly influenced by surgeon (p < 0.0001) and type of surgery (p = 0.0007) and increased with the number of surgical lesions (p = 0.03). In patients undergoing tendovaginoscopy/ bursoscopy, fasciotomy and neurectomy (n = 98), antibiotic prophylaxis was initiated less frequently than in other surgeries, e. g. combinations of surgeries, splint bone extraction, tenotomy, and arthroscopy (n = 554). CONCLUSION: Severe complications in equine clean orthopaedic surgery are rare and complication rates in patients either receiving perioperative antibiotics or not were not significantly different. CLINICAL RELEVANCE: Based on the results the use of antibiotics appears to be non-essential in uncomplicated elective orthopaedic interventions in the horse.

Salpingopharyngeal fistula as a treatment for guttural pouch mycosis in seven horses.

BACKGROUND: Guttural pouch mycosis (GPM) is a cause of nasal discharge, dysphagia and fatal haemorrhage in the horse. OBJECTIVES: To report the complications and success of salpingopharyngeal fistulation in horses with GPM. We hypothesised that creating a direct static opening into the guttural pouch from the pharynx would cause a regression of fungal plaques due to a change in the guttural pouch environment and that this treatment would result in resolution of infection prior to secondary complications. STUDY DESIGN: Retrospective case series. METHODS: The medical records of all horses diagnosed with GPM that were presented to New Bolton Center between the years 2006 and 2017 were examined retrospectively. Seven cases of guttural pouch mycosis treated with salpingopharyngostomy without other surgical intervention were included. Information collected included signalment, presenting complaint, which pouch was affected, size and location of the plaques, laryngeal and pharyngeal function, concurrent medical therapy, location of the fistula, surgical time, time to resolution of clinical signs, time to full resolution of the mycotic plaque, and patency of the salpingopharyngostomy site. RESULTS: Nasal discharge resolved in 10-30 days post-operatively in all cases where nasal discharge was present. The mycotic plaques showed complete resolution at time points ranging from 1 to 6 months post-operatively. No case developed epistaxis or neurological deficits post-operatively that were not present at presentation. MAIN LIMITATIONS: There were differing adjunctive treatments between cases. This technique is not appropriate for horses that have had epistaxis or are currently bleeding. CONCLUSIONS: Salpingopharyngostomy can minimise cost of treatment, be performed on an outpatient basis and provide better exposure of the infected area with few complications. This case series documents seven cases treated with this method that resolved the infection without any further complications of the mycosis.

The anti-inflammatory effect of exogenous lactoferrin on breeding-induced endometritis when administered post-breeding in susceptible mares.

The deposition of semen into the uterus of the horse induces a transient innate immune response that lasts 24-36 h in the normal mare. There exists a subset of mares that are unable to resolve this inflammation in a timely manner, and are classified as susceptible to the disease of persistent breeding-induced endometritis (PBIE). Lactoferrin is a protein of interest as a potential therapeutic for this persistent inflammation due to its anti-inflammatory and bactericidal properties. The addition of human recombinant lactoferrin (hrLF) to the insemination dose was previously shown to suppress mRNA expression of the pro-inflammatory cytokine tumor necrosis factor (TNF)-α at 6 h after insemination, but no studies have shown the effect of lactoferrin when infused post-breeding. Therefore, the objectives of this study were to (1) assess the safety of intra-uterine infusion of hrLF, (2) evaluate the effect of intrauterine infusion of hrLF post-breeding as a modulator of the immune response to breeding in the susceptible mare, and (3) determine the most effective concentration of hrLF. For the first experiment four normal mares received an intrauterine infusion of 500 µg/mL hrLF resuspended in 10 mL lactated Ringer's solution (LRS) and heart rate, rectal temperature, respiration, and endometrial quality were evaluated. For the second experiment, six mares classified as susceptible to PBIE were bred during estrus with 500 × 106 progressively motile sperm comprised of the ejaculates from two stallions, which were centrifuged over Androcoll-E to remove seminal plasma. Each insemination dose was resuspended in 30 mL LRS. Six hours after breeding, a 1L LRS uterine lavage was performed prior to treatments. Four treatments were administered over four consecutive estrous cycles in randomized order of: 10 mL LRS (vehicle control), 50 µg/mL hrLF resuspended in 10 mL LRS, 250 µg/mL hrLF resuspended in 10 mL LRS, and 500 µg/mL hrLF resuspended in 10 mL LRS. Twenty-four hours after breeding the mares were evaluated via transrectal ultrasonography for fluid retention. A low volume uterine lavage (250 mL LRS) was performed and the effluent was evaluated for polymorphonuclear neutrophils (PMNs). Finally, an endometrial biopsy was obtained for qPCR analysis of selected inflammatory cytokines. Lactoferrin had no significant overall effect on vital signs or endometrial quality. The addition of hrLF (50 µg/mL, 250 µg/mL, 500 µg/mL) did not significantly affect the amount of fluid detected post-breeding, but suppressed the ratio of PMNs to epithelial cells at all three concentrations compared to controls. In addition, all three concentrations of hrLF increased the mRNA expression of the anti-inflammatory cytokine interleukin-1 receptor antagonist (IL-1RN), while the 50 µg/mL dose significantly suppressed mRNA expression of the pro-inflammatory cytokine interferon gamma (IFNγ). In conclusion, the infusion of hrLF post-breeding was found to modulate the inflammatory response to breeding in the mare, and appears to be most effective at the 50 µg/mL concentration.