Risk factors for strap-related lesions in working donkeys at the World Heritage Site of Petra in Jordan

A risk analysis was undertaken in an attempt to improve improvised rump straps on donkeys carrying tourists at the World Heritage Site at Petra, Jordan. Tail-base lesions were identified in 63 of the 86 donkeys. Observations and questionnaires were used to collect data relating to the straps, donkey health and human attitudes. The worse lesions were associated with padded rather than unpadded straps, if tightly fitted. Padding could be a cause of, or a response to lesions, but results suggest that it did not effectively aid healing. Significantly worse lesions occurred with unclean than with clean straps and, contrary to many recommendations, cotton straps were associated with worse lesions than were synthetic straps. Since this was an exploratory study, findings should be considered to generate (not to test) hypotheses and any resulting interventions will require monitoring. Further possible risks are discussed, referring to medical and veterinary literature and applied expertise in working equines.     

Effects of α-tocopherol and Ascorbic Acid on Equine Semen Quality after Cryopreservation

This study investigated the effects of ascorbic acid and α-tocopherol supplementation on semen quality parameters of equine thawed-frozen semen. Semen was divided in seven different treatments in a final concentration of 100 × 10⁶ sperm/mL by using Gent extender containing no supplements (control) and the following supplements with three different concentrations: α-tocopherol (0.5, 1, and 2 mM) and ascorbic acid (0.45, 0.9, and 1.8 g/L). After thawing, all samples were maintained at 37°C, while analyses were performed at 0, 60, and 120 minutes. Evaluation of viability and acrosome status (using Pisum sativum agglutinin conjugated to fluorescein isothiocyanate and propidium iodide), mitochondrial membrane potential (5,5′,6,6′-tetrachloro-1,1′,3,3′tetraethylbenzimidazolyl carbocyanine iodine [JC-1]), membrane lipid peroxidation (LPO; C₁₁-BODIPY^581/591), and stability of the plasmatic membrane (merocyanine 540 and Yo-Pro-1) of each sample was determined by flow cytometry. Relative to the control group, supplementation with α-tocopherol improved (P ≤ .05) postthaw membrane LPO, yet the higher concentrations of ascorbic acid (0.9 and 1.8 g/L, respectively) showed a negative effect on membrane LPO. Neither antioxidant significantly increased (P > .05) the acrosome integrity and mitochondrial membrane potential of frozen-thawed spermatozoa, although supplementation with α-tocopherol and ascorbic acid (0.9 and 1.8 g/L, respectively) had a positive effect on membrane integrity and stability (P ≤ .05). For all semen parameters, the lower concentration of ascorbic acid (0.45 g/L) did not show significant differences (P > .05) compared with the control. In conclusion, α-tocopherol seems to be an efficient antioxidant for reducing the oxidative stress provoked by cryopreservation, decreasing lipid peroxidation on equine spermatozoa.     

Dexmedetomidine constant rate infusion for 24 hours during and after propofol or isoflurane anaesthesia in dogs

OBJECTIVE: To evaluate cardiovascular and respiratory effects and pharmacokinetics of a 24-hour intravenous constant rate infusion (CRI) of dexmedetomidine (DMED) during and after propofol (PRO) or isoflurane (ISO) anaesthesia in dogs. STUDY DESIGN: Prospective, randomized, cross-over study. ANIMALS: Ten healthy adult Beagles. METHODS: Instrumented dogs received a DMED-loading bolus (25 microg m(-2)) at time 0 followed by a 24-hour CRI (25 microg m(-2) hour(-1)), with PRO or ISO induction/maintenance of anaesthesia during the first 2 hours (PRO and ISO treatment groups, respectively). Cardiovascular, respiratory, blood gas, airway gas, serum chemistry variables and DMED plasma concentration data were collected at -15, 5, 15, 30, 45, 60, 90 and 120 minutes. A number of cardiorespiratory and tissue oxygenation variables were calculated from the above data. After the 2-hours of anaesthesia, heart and respiratory rates and electrocardiograms were recorded and DMED plasma concentrations were determined for up to 26 hours. RESULTS: Vasopressor effects and the decrease in heart rate (HR) and cardiac index induced by DMED were greater for PRO than ISO, but were within clinically acceptable ranges. Adequate oxygenation was maintained above the critical O(2) delivery level. The overall incidence of unfavourable arrhythmias was low and tended to vary inversely with HR. Mean DMED plasma concentration ranged from 0.23 to 0.47 ng mL(-1) for both groups during the 24-hour CRI with a mean elimination half-life of approximately 0.46 hour. CONCLUSION AND/CLINICAL RELEVANCE: DMED CRI resulted in typical alpha(2)-agonist induced haemodynamic changes with minimal respiratory effects, and appeared to be an efficacious adjunct during and after PRO or ISO anaesthesia in healthy dogs.     

Comparison of the intravenous and intravaginal route of oxytocin administration for cervical dilation protocol and non‐surgical embryo recovery in oestrous‐induced Santa Inês ewes

This study compared the effects of intravaginal and intravenous routes of oxytocin (OT) administration in 46 oestrous‐induced Santa Inês ewes (6‐day treatment with progestin‐releasing intravaginal sponges and a single injection of 200 IU of eCG at the time of sponge removal) that underwent transcervical embryo recovery 6–7 days after oestrous onset and mating. All ewes received 37.5 μg of d‐cloprostenol via latero‐vulvar route, and 1 mg of oestradiol benzoate i.m. 16 hr before and 50 IU of OT 20 min before non‐surgical embryo recovery (NSER), with OT being administered intravenously (n = 21) or intravaginally (n = 21). An overall oestrous response was 95.6% (44/46), and adequate cervical retraction could be accomplished in 78.6% (33/42) of ewes. The percentage of successful NSER procedures was 57% (24/42) or 72.7% (24/33) of animals with sufficient cervical retraction. The duration of NSER procedure averaged 28 min (range: 17–40 min) and ~96% of flushing fluid could be recovered (range: 85%–100%). Out of 18 ewes that could not undergo NSER, 12 (66.6%) presented various anatomical barriers, whilst the other 33.4% did not present these barriers and still could not be traversed. Excluding the ewes with those anatomical features, the overall success rate of NSER was 80% (24/30). The route of OT administration had no effect on NSER efficiency or the ease with which transcervical embryo flushing was performed. Both routes of OT administration can be used for cervical dilation protocol. Discarding ewes with anatomical features precluding cervical penetration is highly recommended to increase the efficacy of NSER in sheep.     

Factors that affect equine wound repair.

The rate and outcome of wound healing are determined by many factors,some of which are already in effect when the horse is first presented to the veterinarian. A thorough understanding of wound healing principles,coupled with clear client communication, should enable the practitioner to minimize the number of additional factors that may exacerbate the initial situation.     

Electroretinogram responses of the normal thoroughbred horse sedated with detomidine hydrochloride

Purpose The main objective was to record electroretinogram (ERG) parameters of normal thoroughbred mares using the HMsERG, a mini-Ganzfeld electroretinographic unit, and a contact lens electrode. The second objective was to determine whether IV detomidine hydrochloride at 0.015?mg/kg is consistently an effective choice for sedation of horses undergoing this ERG protocol. Methods The study population consisted of 30 normal thoroughbred mares. ERG data were harvested using a protocol that included three different light intensities (10, 3000, and 10?000?mcd?s/m(2) ) and a 30-Hz flicker at 3000?mcd?s/m(2) . Results Mean, median, standard deviation, and estimated normal ranges using the 5-95% of the data for a- and b-wave implicit times (IT), amplitudes (AMP), and b/a ratios were reported. Scotopic results at low intensity (10?mcd?s/m(2) ) had estimated ranges for b-wave IT of 41.8-72.9?ms and AMP of 19.8-173.3?μV. Middle intensity (3000?mcd?s/m(2) ) a-wave IT was 13.2-14.7?ms with a-wave AMP of 68.4-144?μV; the b-wave IT was 28.7-41.5?ms with b-wave AMP of 105.7-271.5?μV; and the b/a ratio was 0.95-2.71. The high-intensity (10?000?mcd?s/m(2) ) average recordings showed an a-wave IT of 13-14.9?ms, a-wave AMP of 85.7-186.8?μV; b-wave IT of 26.6-45.4?ms, b-wave AMP of 104.7-250.6?μV; and a b/a wave ratio of 0.7-2.0. The 30-Hz cone flicker showed an IT of 22.8-28.9?ms and AMP of 44.1-117.1?μV. Conclusions Results of normal thoroughbred ERG responses are reported. The protocol proved to be simple and safe and provided consistent results.     

Pharmacokinetics of pentoxifylline and its 5-hydroxyhexyl metabolite after oral and intravenous administration of pentoxifylline to healthy adult horses

OBJECTIVE: To determine serum pharmacokinetics of pentoxifylline and its 5-hydroxyhexyl metabolite in horses after administration of a single IV dose and after single and multiple oral doses. ANIMALS: 8 healthy adult horses. PROCEDURES: A crossover study design was used with a washout period of 6 days between treatments. Treatments were IV administration of a single dose of pentoxifylline (8.5 mg/kg) and oral administration of generic sustained-release pentoxifylline (10 mg/kg, q 12 h, for 8 days). Blood samples were collected 0, 1, 3, 6, 12, 20, 30, and 45 minutes and 1, 2, 4, 6, 8, and 12 hours after IV administration. For oral administration, blood samples were collected 0, 0.25, 0.5, 0.75, 1, 2, 4, 8, and 12 hours after the first dose and 0, 0.25, 0.5, 0.75, 1, 2, 4, 8, 12, and 24 hours after the last dose. RESULTS: Elimination of pentoxifylline was rapid after IV administration. After oral administration, pentoxifylline was rapidly absorbed and variably eliminated. Higher serum concentrations of pentoxifylline and apparent bioavailability were observed after oral administration of the first dose, compared with values after administration of the last dose on day 8 of treatment. CONCLUSIONS AND CLINICAL RELEVANCE: In horses, oral administration of 10 mg of pentoxifylline/kg results in serum concentrations equivalent to those observed for therapeutic doses of pentoxifylline in humans. Twice daily administration appears to be appropriate. However, serum concentrations of pentoxifylline appear to decrease with repeated dosing; thus, practitioners may consider increasing the dosage if clinical response diminishes with repeated administration.     

Investigation of changes in the middle latency auditory evoked potential during anesthesia with sevoflurane in dogs

OBJECTIVE: To investigate the middle latency auditory evoked potential (MLAEP) in awake dogs and dogs anesthetized with 2 concentrations of sevoflurane. ANIMALS: 10 adult Beagles. PROCEDURE: The MLAEP was recorded while dogs were awake and anesthetized with sevoflurane (end-tidal concentration, 2.7% or 3.5%).Three needle electrodes were inserted SC, and click stimuli were delivered biaurally. Signal acquisition, averaging, and analysis were performed by use of computer software developed in-house. Signals were recorded for 128 milliseconds, and the responses to 1,024 stimuli were averaged. Waveforms from 10 recordings in each dog were averaged, and latencies of peaks were measured. Data acquired for awake dogs and dogs anesthetized with high and low sevoflurane concentrations were compared statistically. RESULTS: Sevoflurane anesthesia attenuated the MLAEP so that only peaks P0, Na, and Pa could be identified. The MLAEP changes were maximal at the lower concentration of sevoflurane evaluated. The latencies of these peaks were significantly shorter in awake dogs, compared with values in anesthetized dogs. No difference in the peak latency was detected between the sevoflurane concentrations. CONCLUSIONS AND CLINICAL RELEVANCE: In terms of CNS responsiveness, the effects of anesthesia with sevoflurane are similar to those of anesthesia with isoflurane. Data suggest that sevoflurane is not the inhalant agent of choice in a research setting where electroencephalographic measurements are to be recorded during anesthesia. The depression of the MLAEP waveform by sevoflurane also suggests that the MLAEP is not a suitable tool with which to monitor anesthetic depth during sevoflurane anesthesia in dogs.