Serologic evaluation of five unvaccinated heifers to detect herds that have cattle persistently infected with bovine viral diarrhea virus

OBJECTIVE: To determine whether serologic evaluation of 5 unvaccinated 6- to 12-month-old heifers is a valid method for identifying herds that contain cattle persistently infected (PI) with bovine viral diarrhea virus (BVDV). ANIMALS: 14 dairy herds with a history of BVDV infection, with health problems consistent with BVDV infection, or at risk for contracting BVDV infection. PROCEDURE: 5 unvaccinated 6- to 12-month-old heifers were randomly selected from each herd. Neutralizing antibody titers for type-I and -II BVDV were determined. A herd was classified as likely to contain PI cattle when at least 3/5 heifers had antibody titers > or = 128. Virus isolation was performed on all cattle to identify PI cattle. Genotype of isolated viruses was determined by nested multiplex polymerase chain reaction. RESULTS: 6 of 14 herds contained PI cattle. Sensitivity and specificity of serologic evaluation of 5 heifers for identifying these herds were 66 and 100%, respectively. In herds that contained PI cattle, the predominant BVDV titer in the tested heifers corresponded to the genotype of the isolated virus. CONCLUSIONS AND CLINICAL RELEVANCE: Serologic evaluation of unvaccinated 6- to 12- month-old heifers is an accurate method for identifying herds containing PI cattle. Both type-I and -II BVDV antibody titers should be determined to prevent herd misclassification. The genotype of BVDV found in PI cattle can be predicted by the predominant neutralizing antibody titers found in tested heifers. Serologic evaluation of 5 unvaccinated heifers can be used to determine whether a herd is likely to contain PI cattle.     

A severity score for spontaneous canine acute pancreatitis

Objective To derive a severity score for spontaneous canine acute pancreatitis applicable to general practice.
Design Cohort study of canine pancreatitis cases.
Procedure Cases (n = 68) of spontaneous canine acute pancreatitis presented to general practitioners were identified among accessions to Veterinary Pathology Services Brisbane. The primary veterinarian was surveyed by telephone to ascertain the outcome of each case. Scores were assigned for extent of hyperamylasaemia, hyperlipasaemia and number of organ systems other than the pancreas compromised. The probability of mortality with each score of each analyte was calculated. The strength of interaction between scores for each analyte and mortality rate was assessed by chi-square analysis where appropriate. Relationships between the organ system score, other physiological variables and likelihood of euthanasia were analysed.
Results Scores derived mathematically from analysis of enzyme activities had poor abilities to predict mortality. The score based upon the number of organ systems compromised showed good ability to predict mortality and the interaction between the organ system score and mortality rate was significant by chi-square analysis (P < 0.01). Distribution of data within the amylase and lipase scores was not compatible with chi-square analysis.
Conclusion Assessment of severity of spontaneous canine acute pancreatitis using pancreatic enzyme activities is potentially inaccurate. The use of a severity score based upon organ system compromise was more accurate in determining the likelihood of mortality in spontaneous canine acute pancreatitis. This is compatible with the hypothesis that severe canine acute pancreatitis is a multiple organ failure syndrome.     

Coprological methods for the diagnosis of Anoplocephala perfoliata infection of the horse

Objective To compare the sensitivities of three coprological techniques for the diagnosis of Anoplocephala perfoliata infection in horses and to assess the value of the methods for diagnosis of horses at risk of clinical cestodiasis.
Design Faecal samples were collected from necropsied horses with or without A perfoliata infection and examined using one sedimentation and two different flotation methods. The coprological results were compared with worm counts performed at necropsy of the horses and the degree of mucosal damage. In addition, the efficiency of recovery of A perfoliata eggs from faeces was tested.
Results The overall sensitivities of the methods ranged from 22.5 to 37.5%, and the capacity of the methods to diagnose infection increased with the intensity of infection. A simple flotation method achieved a better sensitivity (37.5%) at all intensities of infection compared with the other two methods (22.5 to 25%). That method was also more sensitive in detecting eggs in 'negative' faecal samples spiked with known numbers of A perfoliata eggs.
Conclusion The results indicated that, despite the low sensitivities of present methods, faecal flotation is likely to be of value in detecting horses at risk of clinical disease.     

Comparison of two methods of seminal plasma removal on buffalo (Bubalus bubalis) sperm cryopreservation

Cryopreservation causes damage to spermatozoa, and methods minimizing this damage are therefore needed. Although much discussed, seminal plasma removal has become an alternative to improve sperm quality and viability after freezing and has been applied to different species in attempt to obtain good results. The objective of this study was to evaluate semen quality in buffaloes submitted to two methods for seminal plasma removal (filtration and centrifugation). Semen samples were collected from seven Murrah buffalo bulls (Bubalus bubalis) once a week for 8 weeks. Each ejaculate was divided into three groups: control (presence of seminal plasma), centrifugation and filtration. Sperm kinetics was evaluated with the computer‐assisted sperm analysis (CASA) system. Plasmalemma and acrosomal membrane integrity, mitochondrial membrane potential and reactive oxygen species (ROS) were measured by flow cytometry, and lipid peroxidation was evaluated by the thiobarbituric acid reactive substances (TBARS) assay. Seminal plasma removal did not improve sperm kinetics compared to the control group. Centrifugation increased the number of cells with damaged acrosomal membranes (0.77 ± 0.05) and filtration caused greater plasmalemma and acrosomal membrane damage (22.18 ± 1.07). No difference in the mitochondrial membrane potential was observed between groups. In contrast, ROS production was higher in the centrifugation group compared to the control and filtration groups, although no differences in TBARS formation were detected. In conclusion, seminal plasma removal did not improve the quality of thawed buffalo semen compared to control in terms of sperm kinetics, membrane integrity, mitochondrial membrane potential or lipid peroxidation.     

Turbulent transport reduction by zonal flows: massively parallel simulations

Three-dimensional gyrokinetic simulations of microturbulence in magnetically confined toroidal plasmas with massively parallel computers showed that, with linear flow damping, an asymptotic residual flow develops in agreement with analytic calculations. Nonlinear global simulations of instabilities driven by temperature gradients in the ion component of the plasma support the view that turbulence-driven fluctuating zonal flows can substantially reduce turbulent transport. Finally, the outstanding differences in the flow dynamics observed in global and local simulations are found to be due to profile variations.     

Principles for the use of macrocyclic lactones to minimise selection for resistance

OBJECTIVE: To provide principles for the appropriate use of avermectin/milbemycin or macrocyclic lactone (ML) anthelmintics in sheep, to ensure effective worm control and to minimise selection for ML resistance. STRATEGY: The principles were based on an assessment of the information currently available. The MLs were categorised into three groups (ivermectin [IVM], abamectin [ABA] and moxidectin [MOX]) based on structural differences, persistence and efficacy against ML resistant strains. The reported order of activity or efficacy against ML resistant worm strains was IVM相似文献