Characterization of normal tidal breathing flow-volume loops for Thoroughbred horses

The purpose of this study was to characterize the normal equine tidal breathing flow-volume loop (TBFVL). The study was performed using 18 healthy Thoroughbred horses. TBFVLs constructed from data collected from resting horses had a typical biphasic inspiratory and expiratory phase. The interindividual variability of the indices used to describe TBFVLs was in the range 16–32%, which is comparable to the variability of other measures of equine pulmonary mechanics. The large variability of these data probably limits the value of resting TBFVL indices for detecting subclinical respiratory conditions in individual horses. Factor analysis of these data revealed that in excess of 90% of the variance of the initial response variables could be explained in terms of three common factors. Varimax rotation of these three common factors provided three subsequent factors that were readily identifiable as (1) a factor describing the time-volume relationships of TBFVLs, responsible for 81% of the total variance, (2) a factor explaining the expiratory portion of the TBFVL, explaining 12% of the variance, and (3) a factor describing the inspiratory portion of the loops, responsible for the remaining 7% of the variance. The analysis also provided standardized factor scoring coefficients for use in subsequent studies using similar experimental techniques.Abbreviations EF₂₅ expiratory flow at expiratory volume plus 25%V _E - EF₅₀ midtidal expiratory flow - f respiratory rate - IF₂₅ inspiratory flow at 25% of inspiratory volume - IF₅₀ midtidal inspiratory flow - MSA measure of sampling adequacy - PEF peak expiratory flow - PIF peak inspiratory flow - TBFVL tidal breathing flow-volume loop - T _E expiratory time - T _I inspiratory time - USPTM ultrasonic pneumotachometer - V _E expiratory volume - V _I inspiratory volume     

The effects of three models of airway disease on tidal breathing flow-volume loops of thoroughbred horses

The effects of histamine and methacholine aerosols and of a fixed inspiratory resistance on tidal breathing flow-volume loops (TBFVL) were investigated using 18 unsedated, standing, healthy thoroughbred horses. The data were first analysed using traditional flow-volume loop indices and then reduced using standardized factor scoring coefficients obtained in a previous study in this laboratory using similar experimental techniques. On the basis of resting TBFVL analysis, the degree of pulmonary dysfunction caused by inhalation of histamine and methacholine aerosols with concentrations of 10 and 2 mg/ml, respectively, was similar. The fixed resistance also caused significant changes in the resting spirogram and TBFVL indices, suggesting that this model may prove valuable for further studies involving upper respiratory tract (URT) conditions.Administration of histamine and methacholine aerosols resulted in significant changes in all factor scores, although most of the observed changes were due to the effects of these aerosols on the respiratory rate. These findings re-emphasize the importance of the effects of respiratory rate on pulmonary mechanics. Application of the resistance resulted in significant changes in factor score 3, the inspiratory factor, which lends support to the validity of this model for URT conditions. The close agreement between the factor scores obtained under controlled conditions in this study and in a previous study in this laboratory confirms that the factor analysis used for both of these studies provides an adequate means of reducing TBFVL data obtained from thoroughbred horses.The large intra- and inter-individual variation observed both with the indices of TBFVL and with the factor scores limits the potential of these variables for detecting individual animals with obstructive airway disease. Re-evaluation of these indices under the stress of exercise may reduce the variability observed in these data and may increase the magnitude of differences between different animals, providing a means of detecting individual animals with subclinical obstructive airway conditions.Abbreviations CV coefficient of variation - P _pl,max maximal intrapleural pressure difference - FVL flow-volume loop - LRT lower respiratory tract - P _ao airway opening pressure - P _tp transpulmonary pressure - TBVFL tidal breathing flow-volume loop - URT upper respiratory tract - USPTM ultrasonic pneumotachometer     

Diagnosis of bovine viral respiratory diseases

Enzootic bronchopneumonia (EBP) is an infectious, multifactorial respiratory disease of cattle. Different viruses may be involved in its pathogenesis. In this study an adapted method of endoscopic bronchoalveolar lavage (BAL) of caudal parts of the right cranial lung lobe was established and evaluated. The obtained bronchoalveolar lavage fluid (BALF) served as template for the detection of BRSV, BPIV-3 and BCoV specific nucleic acids by RT-PCR. BALF samples of 44 cattle affected with respiratory disease were compared to nasal swabs in their reliability to detect the causative agent(s). In 6/7 animals tested positive for BRSV, RNA of this virus was detected in the BALF, in 4 animals it could be found in the nasal swabs. In two of the three BPIV-3 positive animals, the BALF was the only material that tested positive. The most reliable samples for detection of 15 BCoV positive animals were the nasal swabs. BAL was easy to perform, it led to severe coughing in one case and moderate worsening of dyspnoe in three cases. In conclusion this study shows that BAL of the right cranial lung lobe is in many cases the only tool to detect BRSV and BPIV-3, major viral triggers of EBP.     

Measurement of tidal breathing flow-volume loop indices in horses used for different sporting purposes with and without recurrent airway obstruction

Tidal breathing flow-volume loop (TBFVL) indices in healthy horses and in horses suffering from mild and moderate to severe recurrent airway obstruction (RAO) were measured. In addition, the ability of these indices to differentiate healthy controls from horses with mild RAO by separating the horses according to their usage was investigated. The horses were assigned to three sporting categories: 1 Leisure horses; 2 Horses competing at events with a duration of more than five minutes (eventing, coaching and endurance); and 3 Horses competing at events with a duration of less than five minutes (dressage and show jumping). Flow-volume curves were recorded with an ultrasonic spirometer and TBFVL indices were calculated with specially dedicated software. The sporting usage of the horses had a significant effect on the differentiating ability of TBFVL indices in diagnosing different degrees of RAO. The index TIF50 differentiated control horses from horses with minor RAO in all sporting categories.     

几种常见禽呼吸道疾病的诊断

新城疫、禽流感、传染性支气管炎、传染性喉气管炎、传染性鼻炎、慢性呼吸道病和曲霉菌病是几种常见的禽类传染病,这几种疾病均有不同程度的呼吸道症状而引起呼吸功能障碍。不仅为临床诊断带来一定困难,而且造成了很多养禽专业户的巨大经济损失。笔者参考大量相关资料,归纳出这几种疾病的临床症状和病理解剖变化以及特征性差异。 1 新城疫 新城疫又称亚洲鸡瘟,是由病毒引起的一种高度接触性传染病,鸡和火鸡最易感染,雏鸡易感性和死亡率比老龄鸡高,且多呈急性型。主要特征是呼吸困难,下痢,神经机能紊乱,粘膜和浆膜出血。本病一年四季均可发生,但以冬春较易流行,典型性新城疫发病率和死亡率可高达90%以上。 1.1 主要临诊症状 典型性新城疫:发病突然,常无特征性症状而迅速死亡。常见症状是张口呼吸,甩头,伸颈,精神沉郁,食欲减退或消失,渴欲增加。病鸡不愿走动,垂头,翅膀下垂,好睡,体温上升可达43～44℃。嗉囊积液,倒提病鸡时从口中流出酸臭味流体。排出黄白色或黄绿色稀粪,有时混有血液。有的病鸡可出现两腿麻痹、站立不稳、歪颈、肌肉震颤等神经症状。非典型新城疫:主要表现呼吸道症状和神经系统障碍。发病率和死亡率低。成鸡轻者表现食欲减少,产蛋率下降10%～30%,2～3个月可恢复正常。重者精神沉郁、嗜睡、呼吸困难、下黄色或黄褐色稀粪。中雏、幼雏表现为呼吸困难、伸颈张口,病程稍长者出现头颈扭曲、转圈等神经症状。 1.2 病理解剖 剖检可见腺胃粘膜水肿出血,粘膜乳头或粘膜上皮有分散的出血点,腺胃和肌胃交界处更为明显。小肠前段出血,盲肠扁桃体肿大、出血和坏死。气管出血或坏死,周围组织水肿,肺有时可见淤血和水肿。 2 禽流感     

The effect of some common inactivation procedures on the antigens of bovine herpesvirus 1

Bovine embryonic kidney cells were infected with bovine herpesvirus 1 (BHV1) or were sham-inoculated. When cytopathic effect was apparent, the cells were treated with beta-propiolactone, formalin, heat (56 degrees C), or ultraviolet irradiation until the virus was inactivated. Infected-treated, infected-untreated (IU) and sham-inoculated cultures were solubilized using Triton X-100 detergent. Resulting preparations were tested by 2-dimensional- and fused rocket-immunoelectrophoresis and were evaluated for their ability to inhibit virus neutralization by BHV1 antiserum. Eleven viral antigens were detected consistently in IU preparations, which strongly inhibited virus neutralization. Eight or more IU antigens were detected in beta-propiolactone-treated, formalin-treated and heat-treated preparations; these inhibited virus neutralization less strongly than the IU preparations. No IU antigens were detected in ultraviolet-treated preparations, nor did this material inhibit virus neutralization. One of the IU antigens was reduced preferentially by all treatments. The selective destruction of antigens by the various treatments might allow antigen-specific serological testing to distinguish vaccinated from naturally-exposed cattle.     

New technology for prevention and control of infectious bovine respiratory diseases

Recent advances in molecular biology, genetics, and immunochemistry have provided the basis for a new generation of vaccines, diagnostic tools, and prophylactic substances for the prevention of infectious diseases in cattle. This article describes how these new technologies are being applied to veterinary medicine and their potential in bovine respiratory diseases caused by infectious agents.     

Tidal breathing flow-volume loop analysis for clinical assessment of airway obstruction in conscious dogs

Using a mask, pneumotachograph, and X-Y recorder, tidal breathing flow-volume loops (TBFVL) were evaluated in 33 healthy dogs and in 18 dogs with acquired obstructive respiratory tract disease. The loops were evaluated for qualitative shape, tidal volume (VT), respiratory rate, peak and midtidal inspiratory flow (PIF and IF50, respectively), peak and midtidal expiratory flow (PEF and EF50, respectively), inspiratory and expiratory flow at end expiratory volume plus 25% VT (IF25 and EF25, respectively), inspiratory time, and expiratory time. Indices of loop shape were developed by division of flow measurements (eg, PEF/PIF and IF50/IF25). Twenty healthy dogs had the same TBFVL (type 1). Typically, PEF occurred at the beginning of expiration, and PIF occurred toward the end of inspiration. Three other TBFVL types were identified in the remaining dogs. Mean coefficients of variation for TBFVL indices ranged from 7% to 18%. Dogs with a fixed-type upper airway obstruction (pharyngeal or laryngeal mass, n = 7) had TBFVL abnormalities, indicating inspiratory and expiratory phase flattening. Concavity or late expiratory phase flattening was detected in TBFVL from dogs with chronic bronchitis/tracheal collapse (n = 11). The TBFVL were easily evaluated in conscious dogs and were useful in the functional assessment of airway obstruction.     

中药制剂微粉对鸡呼吸道疾病治疗效果研究

探索中药制剂微粉对禽呼吸道疾病的治疗效果,并与常规散剂进行对比。结果显示,中药制剂微粉对鸡慢性呼吸道疾病治疗效果优于常规散剂,治愈率达91．6％,比中药制剂散剂组高8．1％,应用中药制剂微粉相对增重为126。说明中药制剂微粉达到细胞破壁水平,比散剂药物有效成分释出量大,吸收迅速,疗效更加显著．     

The influence of feedlot management on an outbreak of bovine respiratory disease

Epidemic curves, odds ratios and chisquare were used to investigate an epidemic of respiratory disease in a pen of feedlot cattle. The cattle were divided into four groups by an eartag number received at processing. Data for each group were collected from feedlot records describing purchase, transportation and processing histories, daily feeding methods, daily pen movements, daily diagnoses, treatment and mortality rates. These data were used to describe the effects of market origin and feeding management on the levels and distribution of respiratory disease.

The three groups of cattle purchased from auction markets and started on high levels of grain in their rations were determined to be 6.3 times (P<0.0005) more likely to be treated for any disease, 4.9 times (P<0.0005) more likely to be treated for respiratory disease, 12.7 times (P<0.0025) more likely to die, and 6.7 times (P<0.0471) more likely to die with respiratory disease than the group made up primarily of farm-assembled heifers and started on a 10% grain ration with time for adjustment to grain.

     

The importance of Mycoplasma bovis in bovine respiratory disease

The annual damage caused by bovine respiratory disease is estimated at 45 up to 55 euro per calf of milking cattle and 117.50 euro per veal calf In Europe, M. bovis is responsible for at least 1/4 to 1/3 of all pneumonia cases in calves. Serology may help to identify the spreading of these bacteria in a herd.     

The immunology of the bovine respiratory disease complex.

The bovine respiratory disease complex continues to be an economically important syndrome in an era when immunologic control is likely to become increasingly important. Recent studies have yielded a better understanding of the interaction, at the molecular level, of various pathogens with the bovine immune system. Improved challenge models for important viral pathogens such as bovine viral diarrhea virus and bovine respiratory syncytial virus have provided evidence of the efficacy of immune responses stimulated by vaccination. This article highlights recent advances in understanding of the role of the immune response in the pathogenesis and prophylaxis of bovine respiratory disease complex.     

The effect of dose, route and virulence of bovine herpesvirus 1 vaccine on experimental respiratory disease in cattle.

Three experiments were conducted with calves in which, following intramuscular or intranasal vaccination with virulent or attenuated bovine herpesvirus 1, calves were protected against bovine herpesvirus 1 -- Pasteurella haemolytica challenge. Calves receiving low doses of vaccine had lower levels of antibody and greater evidence of virus replication upon challenge than those receiving higher doses. In contrast 11/13 unvaccinated controls had fibrino-purulent pneumonia following challenge. The immune response developed later in younger calves and those given low doses of vaccine. Neutralizing antibodies to bovine herpes-virus 1 were not found in nasal secretions, but were present in serum seven days after vaccination. Bovine herpesvirus 1 was isolated before challenge from nasal secretions of calves vaccinated intranasally or intramuscularly with virulent virus but not those vaccinated intramuscularly with vaccine virus. It was concluded that both routes of vaccination with either virulent or attenuated bovine herpesvirus 1 provided protection from challenge with homologous or heterologous bovine herpesvirus 1 and that live vaccines should contain at least 10(3) plaque forming units/dose for effective immunization.