Observations on outbreaks of respiratory disease in housed calves--(2) Pathological and microbiological findings.

Extensive pneumonic lesions were present in 42 out of 43 calves obtained for post mortem examination from 34 outbreaks of respiratory disease in Northern Ireland. Bronchiolitis and alveolitis with necrosis of bronchiolar mucosa which progressed to bronchiolitis obliterans and peribronchiolar fibrosis were prominent histopathological features in the lungs of calves obtained live. The majority of calves which died within the first two months of these outbreaks had severe exudative bronchopneumonia with marked vascular damage and necrosis of pulmonary parenchyma. Pasteurella spp, Mycoplasma spp and P13 virus were the organisms most frequently recovered from the pneumonic lungs.     

Treatment of premature calves with clinically diagnosed respiratory distress syndrome

BACKGROUND: Respiratory distress syndrome (RDS) has been reported previously in premature calves. However, there have been no published data on the effect of surfactant replacement therapy in the treatment of premature calves with RDS. HYPOTHESIS: Surfactant replacement therapy added to the standard treatment for premature calves clinically diagnosed with RDS would increase the viability of the calves. ANIMALS: Twenty-seven premature calves with clinically diagnosed RDS. METHODS: Twenty calves were instilled intratracheally with bovine lung surfactant extract and provided with standard treatment for RDS (surfactant group). Seven calves were given only standard care for RDS without surfactant therapy and placed in the control group. Standard treatment for newborn calves with RDS includes warming, administration of intranasal oxygen, fluid replacement, administration of antibiotics, and immunoglobulin solution. Arterial blood samples were collected from the calves at 3 observation points, the first just before treatment (hour 0) and at 2 hours (hour 2) and 24 hours (hour 24) after treatment was started to determine if ventilation was adequate, improving, or deteriorating. Blood gases, pH, bicarbonate, and lactate concentrations were measured. RESULTS: In the surfactant group, mean partial pressure of oxygen significantly increased at hours 2 and 24. Mean partial pressure of carbon dioxide decreased and mean arterial blood pH increased at hour 24 in the surfactant group compared with the control group (P < .05). Of the 20 calves in the surfactant group, 12 survived and 8 died. All 7 calves in the control group died. CONCLUSIONS AND CLINICAL IMPORTANCE: The results of this study suggest that surfactant replacement therapy may reduce neonatal deaths in premature calves with clinically diagnosed RDS.     

Effect of intranasal oxygen administration on blood gas variables and outcome in neonatal calves with respiratory distress syndrome: 20 cases (2004-2006)

OBJECTIVE: To determine the effect of intranasal oxygen administration on blood gas variables and outcome in neonatal calves with respiratory distress syndrome (RDS). DESIGN: Retrospective case series. ANIMALS: 20 neonatal calves with RDS. PROCEDURES: Arterial partial pressure of oxygen (PaO(2)), arterial partial pressure of carbon dioxide, and arterial oxygen saturation (SaO(2)) before and after intranasal administration of oxygen were analyzed. RESULTS: There were significant increases in PaO(2) and SaO(2) in the first 24 hours after oxygen administration was begun, with mean +/- SD PaO(2) increasing from 38.4+/-8.8 mm Hg to 58.7+/-17.8 mm Hg during the first 3 hours of treatment. Calves with PaO(2)>55 mm Hg within the first 12 hours after oxygen administration was begun had a significantly higher survival rate (9/10) than did calves that did not reach this threshold (4/10). CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that intranasal oxygen administration was a simple method of improving blood gas variables in neonatal calves with RDS and that PaO(2) could be used to predict outcome.     

Pathophysiologic study of 3-methylindole-induced pulmonary toxicosis in immature cattle

In 5 Friesian calves given 3-methylindole (3-MI) (100 mg/kg once a week for 8 weeks, except calf 4, given a 50 mg/kg dose on weeks 3 to 8), pulmonary function (PF) values and arterial blood gas tensions (PaO2 and PaCO2) were measured 24 hours after dosing was done and were correlated with clinical, biochemical, and pathologic changes. Three of the calves (No. 1, 2, and 3) showed acute respiratory distress syndrome 24 hours after the first 3-MI treatment, with a large increase in respiratory frequency, minute viscous work, and PaCO2 and a large decrease in tidal volume, dynamic lung compliance, and PaCO2. They died 36, 38, and 84 hours after dosing. Pulmonary function changes were compatible with the severe pulmonary edema and alveolar damage observed at necropsy. The 2 other calves, after they were given the 1st dose, showed only subacute respiratory distress syndrome with less severe changes in PF values recorded at 24 hours. Furthermore, they became progressively more tolerant to the 2nd, 3rd, and 4th weekly treatments, and showed base-line PF values after the 5th weekly treatment. Pathologic changes were not observed in lung biopsy material from these 2 animals at 2 and at 12 weeks after the 8th (or last) 3-MI treatment.     

A clinical and immunopathological study of Brucella abortus strain 19--induced arthritis in cattle

From a series of 11 calves presenting with a clinical unilateral gonitis (inflammation of the stifle), six were subjected to serological examination for titres against Brucella abortus and to subsequent post mortem examination. Tissues from five calves studied showed similar clinical and radiological features with post mortem examination confirming the presence of characteristic arthritic lesions in the affected stifle and other joints. The immune studies indicated the presence of B abortus strain 19 antigenic material within the cells of the stifle, synovial membrane and the drainage lymph nodes. Attention is drawn to the apparent absence of intact brucella organisms and to the incompatibility between some of the serum agglutination titres and the results of the immune studies. It is concluded that the absence of an elevated serum agglutination titre to B abortus is not an indication of the absence of B abortus antigenic material and that B abortus strain 19 under certain circumstances is pathogenic to calves causing a characteristic and serious clinical syndrome.     

Acute lung injury/acute respiratory distress syndrome in 15 foals

REASONS FOR PERFORMING STUDY: Few reports exist in the veterinary medical literature describing clinical and pathological findings resembling conditions described as (ALI) and acute respiratory distress syndrome (ARDS) in man. OBJECTIVES: To document history, clinical, laboratory and diagnostic findings, treatment and outcome of foals age 1-12 months diagnosed with ALI/ARDS at a referral hospital. METHODS: Medical records, including radiographic, cytological, microbiological, serological and post mortem findings, were reviewed in a retrospective manner to identify foals with acute onset of respiratory distress, a partial pressure of arterial oxygen (PaO2) to fraction of oxygen in inspired gases (FiO2) ratio of < or = 300 mmHg, pulmonary infiltrates on thoracic radiographs or post mortem findings consistent with ALI/ARDS. RESULTS: Fifteen foals age 1.5-8 months were included in the study. Seven foals had previously been treated for respiratory disease, and all foals developed acute respiratory distress <48 h prior to presentation. Findings on presentation included tachycardia and tachypnoea in all foals, with fever recorded in 8 cases. Eight cases met the criteria for ALI and 7 for ARDS. Radiographic findings demonstrated diffuse bronchointerstitial pattern with focal to coalescing alveolar radiopacities. An aetiological agent was identified in foals ante mortem (n = 6) and post mortem (n = 4). All foals were treated with intranasal oxygen and antimicrobial drugs; 13 received corticosteroids. Nine patients survived, 4 died due to respiratory failure and 2 were subjected to euthanasia in a moribund state. Follow-up was available for 7 foals; all performed as well as age mates or siblings, and one was racing successfully. CONCLUSIONS: A condition closely meeting the human criteria for ALI/ARDS exists in foals age 1-12 months and may be identical to previously described acute bronchointerstitial pneumonia in young horses. POTENTIAL RELEVANCE: ALI/ARDS should be suspected in foals with acute severe respiratory distress and hypoxaemia that is minimally responsive to intranasal oxygen therapy. Treatment with systemic corticosteroids, intranasal oxygen and antimicrobials may be beneficial in foals with clinical signs compatible with ALI/ARDS.     

Pulmonary inflammation associated with aspirated meconium and epithelial cells in calves.

"Meconium aspiration syndrome" is a condition resulting in respiratory distress and the occasional death of newborn human beings. A retrospective study was conducted on 52 calves that were submitted for postmortem examination to the Atlantic Veterinary College, Charlottetown, Prince Edward Island, Canada. These calves died of infectious and noninfectious diseases within the first 2 weeks of life due to a variety of causes. The most common cause of death was infectious enteric disease. Histologic examination of lungs revealed that 42.5% of calves had evidence of meconium, squamous cells, or keratin in the lung. There was considerable variation in the magnitude of histologic changes in lungs containing aspirated material. Typically, affected lungs had only a few inconspicuous pieces of meconium, keratin, and squamous cells within bronchoalveolar spaces. Sporadically, the entire lumen of airways was obliterated by aspirated material. Lungs with aspirated material had a mild but diffuse alveolitis characterized by exudation of a few neutrophils, macrophages, and occasional multinucleated giant cells. Obstruction of small airways and focal atelectasis were also observed. Similar lesions have been reported in human meconium aspiration syndrome. It is concluded that histologic changes similar to those of human meconium aspiration syndrome occur commonly in calves that die within 2 weeks of birth. Further studies involving healthy age-matched calves are required to evaluate the clinicopathologic significance of meconium aspiration in this species.     

Acute respiratory distress in cattle.

The term "fog fever" was originally used identify a disease of adult cattle grazing lush pastures in the autumn. Unfortunately, the name has subsequently been applied to other respiratory disorders which occurred under different epidemiological circumstances, so that the name "fog fever" has lost much of its original specificity and become almost synonymous with "acute respiratory distress". The pulmonary lesions in 151 cattle, of all ages, with acute respiratory distress are described in this report. While most of the animals were referred as examples of "fog fever", in only 43 of the 151 cases were the clinical signs, epidemiology and post mortem findings consistent with that disease. Twelve other pulmonary disturbances were encountered in the other animals and the pathology of these conditions has bee described.     

Hepatic lipidosis in pregnant cows on a dairy farm.

A syndrome very similar to hepatic lipidosis is described in dairy cows during the dry period. After being sent to pasture the animals did not eat well for undetermined reasons. The disease phenomena were mainly observed in animals carrying twins. At post mortem examination severe falty infiltration was found in the 3 animals made available for post mortem examination. Increase of the energy supply to the dry cows by addition of maize silage to the ration prevented new cases.     

Lead poisoning in calves due to old white lead paint

A case of poisoning by chronic ingestion of lead in calves with a peracute clinical course is described. The source of lead was a prime coat of white lead on old white painted doors. These doors originated from an institution for aged people and had been used as pen walls for fattening calves. About 12 weeks later five animals died within hours after onset of CNS-symptoms. The post mortem examination of three animals revealed one with multifocal laminar edema and mild vasculitis in the cerebrocortex, one with acid fast intranuclear inclusion bodies in the renal tubular epithelial cells and one without lesions. Liver, kidney and abomasal contents of two animals were analysed for lead content. The concentration was diagnostic for lead poisoning in one case only.     

Acid-base status in newborn calves during the first days of life considering different states of vitality]

The aim of this study is to describe the differentiations of the acid-base status in bovine neonates during the first 96 hours of life. Due to the short intervals in the taking of blood samples, noticeable fluctuations in the acid-base status during the first minutes and hours of life of newborn calves were documented. Altogether, 25 matures and eutrophe calves of the DSB, DRB and DFV breeds were provided by the clinic for this study. Apart from an immediate post natum clinical interpretation of the vital signs in the neonates-using the APGAR-score-the pH value, current Base Excess and the CO2 pressure were simultaneously ascertained. Further continuous evaluation of the acid-base status was subsequently followed in the first phase of adaptation. For that alone, twelve blood samples were taken from the vena jugularis within the first 60 minutes after parturition. Until the end of the examination period on the fourth day of life, the tests amounted to 26 measurements altogether per experimentee. Due to the concrete results ascertained from the initial clinical and laboratory observations, the experimentees could be divided into distinct classes of vitality. The acid-base status of all the calves deteriorated during the first minutes of life, indicating that the pH value and Base Excess fall clearly under the initial level in all aspects of vitality directly post natum. On average the minimum pH values are reached between the third and 15th minute of life and remain between 0.019 and 0.096 below the initial values during this period. A varying rapid increase of the pH value follows, together with a balancing out of the Base difference. Despite isolated individual variations as the acid-base status develops, the lowering of the pH values in the first minutes of life is assessed as being a normal biological phenomenon. Deviations from this occur rarely (8%) and do not conform to the norm. The pH value stabilization in connection with this crucial early postnatal phase occurs to such a high degree that, without stagnation, on average all experimentees show pH values between 7,270 and 7,300 after 180 minutes of life-regardless of which vitality group they belong to. After reaching this common value at the end of the third hour of life, the further development of the ph values and the consequential resulting parameters in all three vitality groups are similar. A stagnation of the rising pH value between the 4th and 12th hour of life was established during the examination. Moderate stabilization then set in after this phase. Between the 24th and 36th hour of life all experimentees reached an average highest pH value of 7,400. Until the end of the examination period, however, this then dropped slightly to values between 7,380 and 7,395.     

Evaluation of radiology as a tool to diagnose pulmonic lesions in calves, for example prior to experimental infection studies

The aim of the study was to evaluate radiology as a technique to visualize pulmonary lesions in young calves, e.g. as a selection criterion for research animals in order to eliminate animals with lung lesions prior to experimental studies of pneumonia. Five calves with acute clinical signs of pneumonia were included in a direct comparative study of radiological and post mortem findings. Also, a number of animals with no signs of pneumonia were included as controls. The study revealed good agreement between the radiological and post mortem findings. Thus, in conclusion, radiology should be considered as a useful objective tool to predict the presence of pulmonary lesions in young calves.     

Hepatic lipidosis in pregnant cows on a dairy farm

Summary

A syndrome very similar to hepatic lipidosis is described in dairy cows during the dry period.

After being sent to pasture the animals did not eat well for undetermined reasons. The disease phenomena were mainly observed in animals carrying twins. At post mortem examination severe falty infiltration was found in the 3 animals made available for post mortem examination. Increase of the energy supply to the dry cows by addition of maize silage to the ration prevented new cases.     

Developments in management of the newborn foal in respiratory distress 1: Evaluation

Developments in evaluation of newborn foals with respiratory distress are discussed. Major causes of respiratory distress are outlined and discussed in terms of the similar respiratory signs exhibited by foals with this clinical syndrome. History, physical examination, clinical pathology, chest radiography and blood gas analyses are discussed as important elements of the evaluation of the condition of these foals. Foals with respiratory disease are grouped into three major categories on the basis of clinical signs and arterial blood gas profiles. The evaluation of foals with respiratory distress is designed not only to reach an accurate diagnosis of the aetiology but also to define the foal's need for respiratory support.     

Netobimin in drinking water for treatment of bovine parasitic bronchitis: a field experiment

Lungworm-infected seeder calves were used on four 1.41 ha paddocks to ensure that groups of 11 calves would be exposed to a heavy challenge with Dictyocaulus viviparus. By the 39th day after turnout there was a serious episode of respiratory disease and a diagnosis of parasitic bronchitis was confirmed by post mortem and faecal examination. One group of trial calves was treated with netobimin administered in the drinking water at 2.8 mg/kg/day for seven consecutive days; another group received the same treatment supplemented with flunixin meglumine at 2.2 mg/kg/day for three days; a third group was given a single oral dose of 7.5 mg netobimin/kg; only emergency treatments were given to calves in the control group. The clinical response to the drinking water treatments was highly satisfactory and better than the response to the single oral treatment.     

Role of Lung Surfactant in Respiratory Disease: Current Knowledge in Large Animal Medicine

Lung surfactant is produced by type II alveolar cells as a mixture of phospholipids, surfactant proteins, and neutral lipids. Surfactant lowers alveolar surface tension and is crucial for the prevention of alveolar collapse. In addition, surfactant contributes to smaller airway patency and improves mucociliary clearance. Surfactant-specific proteins are part of the innate immune defense mechanisms of the lung. Lung surfactant alterations have been described in a number of respiratory diseases. Surfactant deficiency (quantitative deficit of surfactant) in premature animals causes neonatal respiratory distress syndrome. Surfactant dysfunction (qualitative changes in surfactant) has been implicated in the pathophysiology of acute respiratory distress syndrome and asthma. Analysis of surfactant from amniotic fluid allows assessment of fetal lung maturity (FLM) in the human fetus and exogenous surfactant replacement therapy is part of the standard care in premature human infants. In contrast to human medicine, use and success of FLM testing or surfactant replacement therapy remain limited in veterinary medicine. Lung surfactant has been studied in large animal models of human disease. However, only a few reports exist on lung surfactant alterations in naturally occurring respiratory disease in large animals. This article gives a general review on the role of lung surfactant in respiratory disease followed by an overview of our current knowledge on surfactant in large animal veterinary medicine.     

An outbreak of acute pneumonia in young, single-suckled calves.

An outbreak of acute severe pneumonia which affected six to 14-week-old single-suckled calves, resulted in 45/77 requiring treatment. The examination of paired sera from all affected calves revealed that neither an adenovirus, non infectious bovine rhinotracheitis virus nor parainfluenza 3 virus was involved. The acute exudative interstitial pneumonia found at post mortem was typical of pneumonic pasteurellosis.     

Experimental production of fatal mucosal disease in cattle

Three outbreaks of mucosal disease were investigated. Careful examination of 47 cattle that were persistently viraemic with bovine virus diarrhoea virus (BVDV) revealed no clinical disease, no or low levels of BVDV antibody and only non-cytopathic virus in their blood. The four animals with mucosal disease all showed clinical disease and both cytopathic and non-cytopathic virus in their blood. Following post mortem examination, there were particularly high levels of cytopathic virus in gut tissue. A hypothesis for the induction of mucosal disease is suggested. It states that animals become persistently infected with non-cytopathic virus following in utero infection and when, in post natal life, they become superinfected with a cytopathic virus, then mucosal disease ensues. The experimental reproduction of mucosal disease in support of this hypothesis is described.     

Improved pulmonary adaptation in newborn calves with postnatal acidosis.

The adaptation of newborn calves to extra-uterine life was evaluated by measuring arterial blood gases, acid-base values, blood ions and lung mechanical function parameters in normal and acidotic calves during the first 24 h. Twenty-seven Holstein Friesian newborn calves were divided into two groups according to their immediate post partum arterial blood pH values (Group A blood pH > or = 7.2: normal group; Group B blood pH between 7.2 and 7.0: acidotic group). Pulmonary function parameters were measured and arterial blood samples were analysed for blood gases, acid-base variables and ion content immediately post partum (within 2 min) and then 6 and 24 h after calving.Lung resistance and maximal difference between pressure maximum and pressure minimum (max delta Ppl) decreased, while dynamic lung compliance increased significantly in both groups. Immediately post partum the lung resistance and max delta Ppl were significantly higher in the acidotic group than in the normal group. The arterial blood pH progressively compensated with time in both groups during the first 24 h and there was no difference in arterial blood pH values between the two groups 6 h after birth. These results showed that the compensation of acidosis was associated with the improvement in lung mechanics and these changes occurred mainly during the first 6 h of life. Moderate to pronounced acidosis did not affect the pulmonary adaptation negatively, although some respiratory mechanics parameters (max delta Ppl), blood pH and Ca(2+)ion concentrations remained significantly different between the normal and acidotic groups at 24 h. This might be the result of overcompensation of acidosis and the interdependence between blood pH and Ca(2+)concentrations.     

Mechanics of the respiratory system in healthy newborn calves using impulse oscillometry

Arterial blood gases, acid-base balance and respiratory function tests using impulse oscillometry (IOS) were performed on 40 clinically healthy newborn calves during the first 24 hours of life to evaluate their respiratory adaptation to extrauterine life. Gas exchange efficiency of the lung was significantly improved with time and was accompanied by the correction of the mixed acidosis observed at birth and by significant changes in respiratory mechanics. Major changes were detected within the first 6 hours. The significant decrease in resistance (R) and the increase in reactance (X) with time, demonstrate the improvement in respiratory mechanics of both upper and lower airways, and reflect the increase in lung volume, the improved lung tissue elasticity and/or distribution of the ventilation. Respiratory mechanical, arterial blood gases and acid-base balance data provided in this study describe a successful respiratory adaptation to extrauterine life in healthy newborn calves.