Investigation of the Frequency of Detection of Common Respiratory Pathogens in Nasal Secretions and Environment of Healthy Sport Horses Attending a Multi-Week Show Event during the Summer Months.

Little information is presently available regarding the frequency of the silent shedders of respiratory viruses in healthy sport horses and their impact on environmental contamination. Therefore, the aim of this study was to investigate the detection frequency of selected respiratory pathogens in nasal secretions and environmental stall samples of sport horses attending a multi-week equestrian event during the summer months. Six out of fifteen tents were randomly selected for the study with approximately 20 horse/stall pairs being sampled on a weekly basis. Following weekly collection for a total of 11 weeks, all samples were tested for the presence of common respiratory pathogens (EIV, EHV-1, EHV-4, ERAV, ERBV, and Streptococcus equi ss equi (S. equi)) using qPCR. A total of 19/682 nasal swabs (2.8%) and 28/1288 environmental stall sponges (2.2%) tested qPCR-positive for common respiratory pathogens. ERBV was the most common respiratory virus (17 nasal swabs, 28 stall sponges) detected, followed by EHV-4 (1 nasal swab) and S. equi (1 nasal swab). EIV, EHV-1, EHV-4 and ERAV were not detected in any of the study horses or stalls. Only one horse and one stall tested qPCR-positive for ERBV on two consecutive weeks. All the other qPCR-positive sample results were related to individual time points. Furthermore, only one horse/stall pair tested qPCR-positive for ERBV at a single time point. The study results showed that in a selected population of sport horses attending a multi-week equestrian event in the summer, the frequency of the shedding of respiratory viruses was low and primarily restricted to ERBV with little evidence of active transmission and environmental contamination.

Anesthesia for dystocia and anesthesia of the equine neonate.

Equine anesthesia is complicated regardless of the procedure being performed. Anesthesia for the mare experiencing dystocia is complicated by the size of the fetus, positioning of the mare for the procedure, and concern over drug effect on the fetus through the neonatal period. Anesthesia of the neonate is complicated by multiple factors, specifically, sensitivity to the drugs administered. Ventilatory support, minimizing drugs administered, and minimizing anesthesia time are essential for a positive outcome.

Lack of systemic absorption of lidocaine from 5% patches placed on horses.

OBJECTIVE: To measure concentrations of lidocaine serum after application of two 5% patches on horses. STUDY DESIGN: Prospective experimental trial ANIMALS: Six client-owned, systemically healthy horses. METHODS: The hair was clipped on the medial aspect above the carpus of both fore limbs and 2 patches of 5% lidocaine were applied within 30 minutes of jugular catheter placement and the area was then bandaged. Venous blood was drawn from a jugular vein catheter that was inserted using lidocaine as a local block. Samples were drawn immediately before and at 2, 4, 6, 8, and 12 hours after patch application. The presence of lidocaine in serum was determined using an ELISA test. RESULTS: Lidocaine was detected in the serum of three horses at 0 hours immediately following the local block for catheter placement. Lidocaine was not detected at any other time from 2 to 12 hours. There was mild erythema at the site of patch placement at 12 hours in one horse but this resolved within 1 hour of patch removal. There were no other apparent adverse effects from the patches on any other horse. CONCLUSION: Five percent lidocaine patches applied proximally to the carpus did not result in detectable systemic concentrations of lidocaine. CLINICAL RELEVANCE: Any analgesic effects that might be produced by application of 5% lidocaine patches on horses will not be due to systemic absorption of the drug.

Equine perioperative fatalities associated with general anaesthesia at a private practice--a retrospective case series.

OBJECTIVE: To determine the fatality rate of horses undergoing general anaesthesia at a private equine referral practice using a limited number of anaesthetic protocols. METHODS: A retrospective analysis of records (n = 17 961) from all horses undergoing general anaesthesia for surgical procedures from 1997 to 2001 at Rood and Riddle Equine Hospital, Lexington, Kentucky, USA. Results were reported as percentage of the population, and as crude mortality rates for each procedure (deaths per 1000). RESULTS: The prevalence of equine fatalities directly related to anaesthesia was 0.12% (n = 21) and this rose to 0.24% (n = 42) with the inclusion of horses killed or dying within 7 days post general anaesthesia. Causes of death directly related to anaesthesia were cardiac arrest (n = 10), fracture in recovery stall (n = 8), neuropathy and myopathy necessitating euthanasia (n = 3). Crude mortality rates per procedure were < or =7 deaths per 1000 cases, except arthrodesis/osteotomy cases were 66.7 deaths per 1000 cases. CONCLUSIONS: The anaesthetic fatality rate at this practice is lower than has been reported previously. CLINICAL RELEVANCE: Familiarity with an anaesthetic protocol in combination with reduced anaesthetic time, emergencies of shorter duration between diagnosis and surgery, and adequate preoperative examination appear to minimize the risks associated with general anaesthesia in horses.

Evaluation of changes in architecture of the stratum internum of the hoof wall from fetal, newborn, and yearling horses.

OBJECTIVE: To evaluate morphologic changes of the stratum internum of hooves from near-term fetal, newborn, and yearling horses. ANIMALS: Feet from 27 near-term equine fetuses, 19 newborn foals, and 8 yearlings. PROCEDURES: Primary epidermal laminae (PEL) of the stratum internum were examined for evidence of architectural changes. RESULTS: In near-term fetuses, the PEL had a homogeneous appearance and symmetric distribution around the hoof wall with no significant differences in PEL density between the toe and quarters. However after birth, branched laminae at the toe formed within the first few weeks, which significantly increased PEL density at the toe, compared with the quarters. In yearlings, morphology of the PEL differed from that in younger foals and the PEL density was significantly greater at the toe than the quarters. The PEL density at the toe and medial and lateral quarters was significantly different from each other, as these PEL densities appeared to have been associated with conformation. No significant differences in PEL densities between forefeet and hind feet were detected in any group. CONCLUSIONS AND CLINICAL RELEVANCE: Findings indicate that the stratum internum of the inner hoof wall undergoes several morphologic changes shortly after birth. The PEL become branched with a greater PEL density at the toe than the quarters. In an asymmetric foot, more PEL were associated with the sloping side than the steep side of the foot. Findings suggested that PEL growth may also occur by bifurcation as well as by mitosis from the coronet and that wall stress may be associated with increased PEL density.

Evaluation of signs of postoperative pain and complications after forelimb onychectomy in cats receiving buprenorphine alone or with bupivacaine administered as a four-point regional nerve block.

OBJECTIVE: To evaluate signs of postoperative pain and complications after forelimb onychectomy in cats receiving buprenorphine alone or with bupivacaine administered as a 4-point regional nerve block. DESIGN: Prospective, randomized, double-blind clinical trial. ANIMALS: 20 cats. PROCEDURE: All cats received buprenorphine (0.01 mg/kg [0.004 mg/lb], IM) preoperatively. One forelimb of each cat also received bupivacaine (1 mg/kg [0.45 mg/lb] of a 0.75% solution) administered as a 4-point regional nerve block. After onychectomy, discomfort (lameness, foot reaction, and pain) scores were evaluated by 2 experienced observers 2, 4, 6, 8, 24, and 168 hours postoperatively. Complication (hemorrhage, swelling, and infection) scores were evaluated 24 and 168 hours postoperatively. Surgeries were performed by 1 experienced veterinary surgeon. Rescue analgesia was provided if needed. RESULTS: 6 cats required rescue analgesia postoperatively. There was no difference in discomfort or complication scores between control limbs and limbs in which a nerve block was administered. Additionally, there was no difference in discomfort and complication scores between cats that did or did not require rescue analgesia. CONCLUSIONS AND CLINICAL RELEVANCE: Bupivacaine administered as a 4-point regional nerve block in addition to a systemic analgesic did not decrease discomfort or complication scores in cats undergoing forelimb onychectomy.