Theileria orientalis MPSP types in Australian cattle herds associated with outbreaks of clinical disease and their association with clinical pathology findings     

Graeme J. Eamens  Jocelyn R. Gonsalves  Cheryl Jenkins  Damian Collins  Graham Bailey 《Veterinary parasitology》2013,191(3-4):209-217

Between September 2010 and November 2011, 350 EDTA blood samples were received from 73 Australian cattle herds, as cases suspected to be infected with Theileria orientalis. Beef cattle were predominantly affected, with Angus and Angus-crossbred cattle representing 48% of smear positive samples examined. DNA extracts were tested in conventional polymerase chain reaction (PCR) assays for genes encoding the p32, Ikeda, Chitose and Buffeli major piroplasm surface proteins (MPSP). PCR findings were compared with results of clinical pathology examinations of stained blood smears for parasitaemia and packed cell volume (PCV). PCR testing was much more sensitive than clinical pathology examinations in detecting T. orientalis infections, and concurrent testing of neat and diluted extracts gave significantly more PCR positive results than testing of neat extract alone. Significant associations and correlations were shown between PCR results of p32 and Ikeda assays with PCV levels indicative of anaemia, and with the level of parasitaemia estimated by smears. A high proportion of samples had concurrent Ikeda and Chitose infection, and significantly more clinical cases of theileriosis were associated with the Ikeda MPSP type as the sole infection, compared with sole infection with types Chitose or Buffeli. The findings indicate Ikeda type organisms were significantly associated with clinical parameters of theileriosis in cattle herds in eastern Australia, and that this type is most likely to be responsible for outbreaks of theileriosis experienced in affected Australian herds. In New South Wales, 11 of 14 regulatory districts yielded Ikeda positive samples, with five (Mid-Coast, Cumberland, Central North, Hume and Lachlan) containing 234/307 (76%) of the Ikeda positive samples.  相似文献   

Seasonal and annual influence on insulin and cortisol results from overnight dexamethasone suppression tests in normal ponies and ponies predisposed to laminitis     

K. E. Borer‐Weir  N. J. Menzies‐Gow  S. R. Bailey  P. A. Harris  J. Elliott 《Equine veterinary journal》2013,45(6):688-693

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Distribution and temporal prevalence of Theileria orientalis major piroplasm surface protein types in eastern Australian cattle herds     

GJ Eamens  G Bailey  JR Gonsalves  C Jenkins 《Australian veterinary journal》2013,91(8):332-340

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Anthelmintic use in goats and the effect of route of administration     

K.M. Bailey 《New Zealand veterinary journal》2013,61(1):37-38

The control of gastrointestinal parasites in goats by the use of anthelmintics has been and continues to be problematic. Products used successfully in sheep sometimes appear to be less effective than expected when used in goats. Parasites resistant to ivermectin have been reported in goats in New Zealand but not in sheep. I write to report a case that raises issues pertaining to the relative effectiveness of different routes of anthelmintic administration in goats.  相似文献   

The response of vaccinated rams to experimental challenge using Brucella ovis     

Karen M. Bailey  D.M. West  A.N. Bruere  B.S. Cooper 《New Zealand veterinary journal》2013,61(2):70-72

One hundred and thirty eight rams were allocated to four experimental groups. An inactivated Br. ovis vaccine was administered either once by the intraperitoneal route (1 i/p), twice by the intraperitoneal route (2 i/p), or twice by the subcutaneous route (2 s/c), and the last group was left unvaccinated. They were then challenged by the intravenous inoculation of between 123 and 1.23 × 10⁸ live Br. ovis bacteria. The number of rams that succumbed to infection within the four groups was 4/35 (11%) for the 2 s/c, 7/33 (21%) for the 2 i/p, 9/35 (26%) for the 1 i/p and 18/35 (51%) for the unvaccinated rams. Vaccination reduced the number of rams that succumbed to experimental challenge and although there were differences between the vaccinated groups, these were not statistically significant.

Following challenge, unvaccinated rams were the first to excrete Br. ovis in their semen; three weeks following inoculation. Next, those vaccinated by either one or two doses by the intraperitoneal technique began to excrete the organism (five weeks) and then finally those rams vaccinated twice by the subcutaneous route (seven weeks).  相似文献   

Phase I Dose Escalation of Single‐Agent Vinblastine in Dogs     

D.B. Bailey  K.M. Rassnick  O. Kristal  J.D. Chretin  C.E. Balkman 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2008,22(6):1397-1402

Background: Vinblastine (VBL) is commonly used in dogs at a dosage of 2.0 mg/m². The minimal toxicity observed at this dosage indicates that higher dosages might be well tolerated. Hypothesis: The maximum tolerated dosage (MTD) for a single VBL treatment is higher than the previously published dosage of 2.0 mg/m². Animals: Twenty‐three dogs with lymphoma or cutaneous mast cell tumors. Methods: Dogs received 1 single‐agent VBL treatment IV. The starting dosage was 3.0 mg/m², and dosages were increased in increments of 0.5 mg/m² in cohorts of 3 dogs. Hematologic toxicity was assessed with weekly CBCs. Gastrointestinal toxicity was assessed from medical histories from owners. Once the MTD was determined, additional dogs were treated with VBL at that dosage. Dogs whose cancers responded to VBL continued to receive treatments q2–3 weeks. Results: VBL dosages ranged from 3.0 to 4.0 mg/m². Neutropenia was the dose‐limiting toxicity, with the nadir identified 7 days after treatment and resolving by 14 days after treatment. The MTD was 3.5 mg/m². Sixteen dogs were treated at this dosage, and 3 experienced severe toxicity characterized by asymptomatic grade 4 neutropenia, febrile grade 4 neutropenia, and death. Gastrointestinal toxicity was mild and self‐limiting. Preliminary evidence of antitumor activity was identified in 2 of 12 dogs with lymphoma treated at the MTD. Conclusions and Clinical Importance: In dogs, single‐agent VBL is well tolerated at a dosage of 3.5 mg/m² IV. At this dosage, the minimum safe treatment interval is q2 weeks, and adjunct treatment with prophylactic antibiotics should be considered.  相似文献   

Evaluation of the induction of vasoactive mediators from equine digital vein endothelial cells by endotoxin     

Menzies-Gow NJ  Bailey SR  Berhane Y  Brooks AC  Elliott J 《American journal of veterinary research》2008,69(3):349-355

OBJECTIVE: To determine the effect of endotoxin (lipopolysaccharide [LPS]) on vasoactive mediator production by cultured equine digital vein endothelial cells (EDVECs). SAMPLE POPULATION: EDVECs obtained from forelimb digital veins of 7 healthy adult horses. PROCEDURES: EDVECs were incubated with or without LPS (1 microg/mL) for 0, 2, 4, 6, 22, and 24 hours. The EDVECs were incubated for 18 hours with LPS (10 pg/mL to 1 microg/mL) with or without ibuprofen, cycloheximide, or L-nitroarginine methyl ester. Medium concentrations of prostacyclin, cyclic guanosine monophosphate, endothelin-1, and thromboxane A(2) were determined. Changes in inducible nitric oxide synthase and cyclooxygenase-2 expression were determined. RESULTS: LPS stimulated mean 4.2- and 14.1-fold increases in EDVEC prostacyclin and cyclic guanosine monophosphate production, respectively, after 22 hours. These effects were LPS concentration-dependent (LPS concentrations that induced a response halfway between the maximum response and baseline of 1.50 and 1.22 ng/mL, respectively). The LPS-induced cyclic guanosine monophosphate production was significantly inhibited (to basal concentrations) by L-nitroarginine methyl ester, and prostacyclin production was inhibited by cycloheximide and ibuprofen. Production of thromboxane A(2) by EDVECs was not detected. Endothelin-1 accumulated in the medium, but LPS did not enhance its production. Inducible nitric oxide synthase expression in EDVECs was not detected with the available antibodies, whereas LPS stimulated cyclooxygenase-2 expression in a time- and concentration-dependent manner. CONCLUSIONS AND CLINICAL RELEVANCE: LPS stimulated vasoactive mediator production by equine endothelial cells, which may play a role in LPS-induced digital hypoperfusion.  相似文献   

Levetiracetam as an adjunct to phenobarbital treatment in cats with suspected idiopathic epilepsy     

Bailey KS  Dewey CW  Boothe DM  Barone G  Kortz GD 《Journal of the American Veterinary Medical Association》2008,232(6):867-872

OBJECTIVE: To assess pharmacokinetics, efficacy, and tolerability of oral levetiracetam administered as an adjunct to phenobarbital treatment in cats with poorly controlled suspected idiopathic epilepsy. DESIGN-Open-label, noncomparative clinical trial. ANIMALS: 12 cats suspected to have idiopathic epilepsy that was poorly controlled with phenobarbital or that had unacceptable adverse effects when treated with phenobarbital. PROCEDURES: Cats were treated with levetiracetam (20 mg/kg [9.1 mg/lb], PO, q 8 h). After a minimum of 1 week of treatment, serum levetiracetam concentrations were measured before and 2, 4, and 6 hours after drug administration, and maximum and minimum serum concentrations and elimination half-life were calculated. Seizure frequencies before and after initiation of levetiracetam treatment were compared, and adverse effects were recorded. RESULTS: Median maximum serum levetiracetam concentration was 25.5 microg/mL, median minimum serum levetiracetam concentration was 8.3 microg/mL, and median elimination half-life was 2.9 hours. Median seizure frequency prior to treatment with levetiracetam (2.1 seizures/mo) was significantly higher than median seizure frequency after initiation of levetiracetam treatment (0.42 seizures/mo), and 7 of 10 cats were classified as having responded to levetiracetam treatment (ie, reduction in seizure frequency of >or=50%). Two cats had transient lethargy and inappetence. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that levetiracetam is well tolerated in cats and may be useful as an adjunct to phenobarbital treatment in cats with idiopathic epilepsy.  相似文献   

Characterization of agonist-induced endothelium-dependent vasodilatory responses in the vascular bed of the equine digit     

Berhane Y  Bailey SR  Putignano C  Elliott J 《Journal of veterinary pharmacology and therapeutics》2008,31(1):1-8

The role of endothelium-derived relaxing factors was studied in the regulation of vascular responses in the Krebs perfused equine isolated digit. Perfusion pressure was recorded in response to bolus doses of 5-hydroxytryptamine (6 nmol) alone or co-administered with carbachol (CCh; 0.2 micromol), bradykinin (BK; 0.2 nmol), substance P (SP; 0.2 nmol) or sodium nitroprusside (SNP; 0.2 micromol). N(omega)-Nitro-L-Arginine methyl ester hydrochloride (L-NAME; 300 microm) caused partial but significant inhibition of CCh-induced vasodilatory response, whereas BK and SP-induced responses were resistant to L-NAME. High potassium (K(+), 30 mm) and the cytochrome P-450 (CYP) epoxygenase inhibitor, clotrimazole (10 microm) plus L-NAME (100 microm), completely abolished the CCh, BK and SP-induced vasodilatory responses, whereas the response to SNP was unaffected. In contrast, the L-NAME-resistant proportion of CCh, BK and SP-induced vasodilatory response was not inhibited by the highly selective CYP2C9 inhibitor, sulphaphenazole (10 microm). The cyclo-oxygenase inhibitor, ibuprofen (10 microm) did not affect the CCh, BK and SP-induced responses. These data demonstrate that CCh, BK and SP-induced relaxation in the equine digit involve a combination of the NO and endothelium-derived hyperpolarizing factor (EDHF) pathways. These results do not support the evidence for the involvement of CYP-derived epoxyeicosatrienoic acids and the exact nature of EDHF in the equine digit remains to be established.  相似文献   

Evaluation of age,weaning weight,body condition score,and reproductive tract score in pre-selected beef heifers relative to reproductive potential     

Sarah E.Dickinson  Michelle F.Elmore  Lisa Kriese-ANDerson  Joshua B.Elmore  Bailey N.Walker  Paul W.Dyce  Soren P.Rodning  Fernando H.Biase 《畜牧与生物技术杂志(英文版)》2019,(2)

Background: Artificial insemination is a preferred breeding method for beef heifers as it advances the genetic background, produces a predictive and profitable calving season, and extends the heifer's reproductive life span.As reproductive efficiency in heifers is key for the success of beef cattle production systems, following artificial insemination, heifers are exposed to a bull for the remainder of the breeding season. Altogether, up to 95% of heifers might become pregnant in their first breeding season. Heifers that do not become pregnant at the end of the breeding season represent an irreparable economical loss. Additionally, heifers conceiving late in the breeding season to natural service, although acceptable, poses serious losses to producers. To minimize losses due to reproductive failure, different phenotypic parameters can be assessed and utilized as selection tools. Here, we tested the hypothesis that in a group of pre-selected heifers, records of weaning weight, age at weaning, age at artificial insemination, and age of dam differ among heifers of varied reproductive outcomes during the first breeding season.Results: None of the parameters tested presented predictive ability to discriminate the heifers based on the response variable(‘pregnant to artificial insemination', ‘pregnant to natural service', ‘not pregnant'). Heifers categorized with body condition score = 6 and reproductive tract score ≥ 4 had the greatest proportion of pregnancy to artificial insemination(49% and 44%, respectively). Furthermore, it was notable that heifers presenting body condition score = 6 and reproductive tract score = 5 presented the greatest pregnancy rate at end of the breeding season(89%). Heifers younger than 368 d at the start of the breeding season did not become pregnant to artificial insemination. Those young heifers had 12.5% chance to become pregnant in their first breeding season,compared to 87.5% if the heifers were older than 368 days.Conclusion: Our results suggest that beef heifers with body condition score = 6 and reproductive tract score ≥ 4 are more likely to become pregnant to artificial insemination. Careful assessment should be undertaken when developing replacement heifers that will not reach 12 months of age by the beginning of the breeding season.  相似文献