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Abstract

AIM: To evaluate resistance to anthelmintics containing abamectin, levamisole, and oxfendazole (AB-LEV-OX), derquantal and abamectin (DEQ-AB), moxidectin, and monepantel in naturally acquired gastrointestinal nematodes present on a sheep farm.

METHODS: Faecal nematode egg count reduction tests (FECRT) were carried out on lambs that were approximately 7 months-old and infected with naturally acquired nematodes. Lambs were randomly allocated to one of five groups (n=15 per group): treatment with 2?mg/kg derquantel and 0.2?mg/kg abamectin; 0.2?mg/kg abamectin, 8?mg/kg levamisole HCl and 4.5?mg/kg oxfendazole; 2.5?mg/kg monepantel; 0.2?mg/kg moxidectin, or no treatment. Post-treatment samples were collected 12 days later. Abomasa and small intestines were collected from two slaughtered lambs from each of the DEQ-AB, AB-LEV-OX, moxidectin and control groups 15 days after treatment, for nematode counting.

RESULTS: The FECRT demonstrated that efficacy was 90.3 (95% CI=84.2–94.1)% for AB-LEV-OX, 54.5 (95% CI=28.4–71.1)% for moxidectin, 99.2 (95% CI=97.4–99.8)% for DEQ-AB and 100% for monepantel, across all genera. For Trichostrongylus spp. efficacy was 85.5% for AB-LEV-OX and 46.7% for moxidectin. Haemonchus spp. were fully susceptible to all treatments. Post-treatment nematode counts indicated that the resistant Trichostrongylus spp. were from the small intestine.

CONCLUSIONS: Anthelmintic resistance to both AB-LEV-OX and moxidectin was present in the Trichostrongylus genus on a commercial sheep farm. Monepantel and DEQ-AB were both effective against Trichostrongylus spp. based on FECRT results.

CLINICAL RELEVANCE: This finding of resistance to an AB-LEV-OX triple-combination anthelmintic in the Trichostrongylus genus in sheep in New Zealand further limits anthelmintic treatment options available, and calls into question whether this combination is suitable for use as a quarantine treatment.  相似文献   
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A case of granulomatous enteritis in a three-year-old thoroughbred horse is described. Onset of clinical signs succeeded pyrexia of unknown aetiology. The horse was emaciated, depressed and inappetent but diarrhoea was not a feature of the condition. There was hypoproteinaemia, anaemia, leucopaenia and abnormal small-intestinal carbohydrate absorption. Rectal biopsy revealed granulomatous changes in the rectal mucosa. As a result of these findings, euthanasia was performed and an autopsy was carried out. Histopathology showed marked villous atrophy in the small intestine with a diffuse mononuclear cellular infiltration htvolvbrg mainly the submucosa and lamina propria. There were occasional granulomatous foci. The mononuclear cells consisted mainly of lymphocytes and histiocytes. No aetiological agent was isolated.  相似文献   
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Bacterial infections are common in equine practice, therefore it is important that diseases caused by these organisms are diagnosed accurately. Collection of appropriate samples in a correct and timely manner is fundamental to determining the causative agent. Furthermore, transportation of samples to the laboratory must ensure that the agents survive and can be identified. This paper outlines a recommended diagnostic approach when bacteria are suspected, the samples that may be obtained in order to confirm their presence, and the transportation requirements to facilitate their isolation in diagnostic laboratories.  相似文献   
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Spring calving is recommended for beef herds in the Salado region of Argentina, but autumn calving is an alternative being used by some farmers. This study explored the biological and economic feasibility of autumn calving in cow–calf systems and their long-term performance compared with spring calving. Reproduction and calf performance data were collected from an autumn calving herd (1999–2005) and from a spring calving herd (1966–1995) at the INTA-Balcarce Research Station (37°45′ S; 58°18′ W). Similar data were obtained from a commercial farm which practiced both autumn and spring calving (1998–2003). These data showed that autumn calving is feasible in the region, provided that cows calve with a high condition score. This is a major difference with spring calving, where cows can normally gain weight during breeding. A climatically driven computer model was used to compare, at farm level, the effect of calving season across a range of combinations of weaning dates and stocking rates. Spring calving systems had greater production potential (15–20%) and profitability (17–28%) at high stocking rates. However, at low to moderate stocking rates, calving season had little effect on expected production and risk efficiency. This suggests that autumn calving could be a suitable alternative for the Salado region of Argentina. To exploit its potential, however, calf weaning age should be greater than with spring calving.  相似文献   
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OBJECTIVE: To quantify factors influencing anesthetic concentration when an innovative anesthetic delivery device (vapor wand) was used with enclosed chambers. STUDY DESIGN: Randomized study. METHODS: Two experimental chambers (57.4 and 171 L) were constructed. Anesthetic volumes necessary to reach a target concentration of 3% or 5% isoflurane with complete vaporization were calculated for each chamber. After centering the distal end of the vapor wand and multi-orifice sampler, each chamber was sealed. Air (450 mL) was cycled through the vapor wand in a to-and-fro fashion with an electric, modified air pump at either 20 or 40 cycles minute(-1). Samples taken at 30-second intervals were analyzed for isoflurane concentration. Times to reach 2.8% isoflurane concentration were compared for eight treatment combinations replicated three times. Curves were constructed to display the rate of rise to endpoint concentration. Analysis of variance was applied to the data. RESULTS: Chamber size, pump stroke rate, and target isoflurane concentration all affected time to reach 2.8%, and their three-way interaction was statistically significant (p < 0.05). Generally time to 2.8% was less with small chambers, more rapid pumping and a target concentration of 5%. CONCLUSIONS AND CLINICAL RELEVANCE: When a wild or aggressive animal is presented for clinical veterinary care, introduction of a vapor wand into its cage offers a safer, more convenient, and less stressful alternative for anesthesia than transfer to an induction chamber. By quantifying factors affecting the rate of rise of anesthetic concentration with its use in experimental chambers, this study should promote greater safety and predictability when used clinically. This information will be useful when anesthetic induction needs to be hastened or delayed depending on the responses of the patient and the clinical judgment of the anesthetist.  相似文献   
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Assessments of stock enhancement programmes for European lobsters (Homarus gammarus) require mark‐recapture analysis of stocked individuals. However, established tag technology is deemed unsuitable for extensive use by many current lobster hatcheries, particularly upon the early juvenile stages. We tested the suitability of fluorescent Visible Implant Elastomer (VIE) tags for use in 5‐month‐old juvenile lobsters. Three treatment groups comprising 348 cultured lobsters in total were used to examine survival, growth and tag retention, and to assess mobility, shelter use and moulting behaviours. Tagging had no significant effect on lobster survival, growth, mobility, shelter use or moult frequency. Survival over 7 weeks was 75% among lobsters tagged with two elastomers, 76% in those with one elastomer and 74% among untagged controls. Mortality during moulting did not increase in tagged (6%) compared to untagged lobsters (9%). We found no evidence that VIE tags cause any negative effects that would be expected to inhibit survival upon wild release, but tag loss had reached 12% in both tagged treatments after 7 weeks and showed no sign of abating. Our study suggests that VIEs effectiveness in discerning cultured lobsters long after wild release may be limited when used in smaller juveniles.  相似文献   
50.
ObjectiveTo assess the effect of morphine on the bispectral index (BIS) in dogs during isoflurane anesthesia maintained at a constant end–tidal concentration.Study designProspective, randomized, experimental trial.AnimalsEight adult Beagle dogs, weighing between 7.1 and 9.8 kg.MethodsAnesthesia was induced with isoflurane via a face mask. Dog's tracheas were intubated and anesthesia maintained with isoflurane at a constant end–tidal concentration (e′Iso) of 1.81% for a 30–minute equilibration period. Pulmonary ventilation was controlled to normocapnia. After equilibration, baseline values were recorded prior to intravenous administration of morphine sulfate (0.5 mg kg?1) (MT) or an equal volume of saline (CT). Measurements for heart rate, systolic, diastolic and mean arterial pressure (SAP, DAP and MAP) were recorded at 10, 20, 30, 45, 60, 75, 90, 105 and 120 minutes after treatment. Bispectral index was recorded every 10 seconds for 3 minutes for each time measurement. Venous blood samples were collected at baseline, 10, 20, 30, 45, 60 and 120 minutes for determination of morphine serum concentrations. Anesthesia was discontinued after the last measurement and dogs were allowed to recover.ResultsBaseline BIS for MT and CT at 1.81%e′Iso were 63 ± 10 and 58 ± 9, respectively. Bispectral index in MT was 4–8% lower at 20, 75, 90 and 105 minutes compared with CT. There were no differences in BIS between baseline and any subsequent measurement within either MT or CT. Heart rate, SAP, MAP, and DAP decreased after morphine administration.Conclusion and clinical relevanceIntravenous administration of 0.5 mg kg?1 morphine sulfate did not cause clinically significant changes in the BIS of unstimulated dogs during isoflurane anesthesia at an e′Iso of 1.81%.  相似文献   
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