Calf Pneumonia Research Articles

Calf Diseases and Mortality in Swedish Dairy Herds

A survey of the mortality and morbidity affecting calves during the first 3 months of life was carried out. Results are reported from 131 herds with altogether 5,050 calvings. These herds kept individual calf cards for all calves born. The incidences of abortions and stillborn calves were 0.6% and 3.6%, respectively. During the period 0-90 days the mortality and morbidity were 2.6% and 11.0%, respectively. The frequencies of enteritis and pneumonia in calves were 7.2% and 0.8%. Mortality and morbidity were influenced by breed, season, age of the dam and time of first colostrum. The frequencies of abortions, stillborn calves, mortality and morbidity varied considerably between herds. Herd factors influencing mortality and morbidity during different periods of time were: herd size, yield, zero-grazing, whether the calf was allowed to feed by suckling, the design of the calf pens, and previous incidence of infectious enteritis in the herd. On average, both mortality and morbidity in calves were low, though in certain herds, temporarily high frequencies were registered.

Susceptibilities of Mycoplasma bovis, Mycoplasma dispar, and Ureaplasma diversum strains to antimicrobial agents in vitro

The purpose of this study was to determine the susceptibility of various strains of Mycoplasma bovis, Mycoplasma dispar, and Ureaplasma diversum, which are prevalent causes of pneumonia in calves, to 16 antimicrobial agents in vitro. The MICs of the antimicrobial agents were determined by a serial broth dilution method for 16 field strains and the type strain of M. bovis, for 19 field strains and the type strain of M. dispar, and for 17 field strains of U. diversum. Final MICs for M. bovis and M. dispar were read after 7 days and final MICs for U. diversum after 1 to 2 days. All strains tested were susceptible to tylosin, kitasamycin, and tiamulin but were resistant to nifuroquine and streptomycin. Most strains of U. diversum were intermediately susceptible to oxytetracycline but fully susceptible to chlortetracycline; most strains of M. bovis and M. dispar, however, were resistant to both agents. Strains of M. dispar and U. diversum were susceptible to doxycycline and minocycline, but strains of M. bovis were only intermediately susceptible. Susceptibility or resistance to chloramphenicol, spiramycin, spectinomycin, lincomycin, or enrofloxacin depended on the species but was not equal for the three species. The type strains of M. bovis and M. dispar were more susceptible to various antimicrobial agents, including tetracyclines, than the field strains. This finding might indicate that M. bovis and M. dispar strains are becoming resistant to these agents. Antimicrobial agents that are effective in vitro against all three mycoplasma species can be considered for treating mycoplasma infections in pneumonic calves. Therefore, tylosin, kitasamycin, and tiamulin may be preferred over oxytetracycline and chlortetracycline.

Recognition of Mycoplasma canis as part of the mycoplasmal flora of the bovine respiratory tract

Mycoplasma strain C3b was isolated in the Netherlands from the lung of a pneumonic calf. Forty similar strains were isolated afterwards from calves in 19 other herds in different parts of the Netherlands. Eight strains from eight different herds were investigated in this study. Results of tests to determine whether the organism catabolized glucose were inconclusive. Four strains, including strain C3b, apparently catabolized glucose under some test conditions; the remaining four strains did not. Although strain C3b and similar strains were slightly different from canine M. canis strains in growth inhibition tests and glucose metabolism tests, we concluded that strain C3b and similar strains have to be classified as M. canis. A close contact between calves and dogs was observed in several herds where strains C3b or similar strains were isolated. This is the first report of M. canis isolated from cattle.

Pasteurella haemolytica serotypes isolated in Northern Ireland during 1989–1991

Pasteurella haemolytica isolates from clinical veterinary samples were serotyped over a three year period to determine the distribution of strains in Northern Ireland, to compare the results with the recorded distribution in the remainder of Great Britain and to extend information on the geographical prevalence of the serotypes. Four hundred and nine typable and 91 untypable strains were isolated from 490 animal cases. From 127 typable cattle isolates, the commonest serotype was A1, most frequently associated with calf pneumonia. Serotypes A2, T4, T10 and T15 were the commonest sheep isolates, A2 being most frequently associated with lamb pneumonia and the T-biovars more prevalent in adult pneumonia and lamb septicaemia. The isolates from approximately half the cases were evaluated in terms of the results obtained from gross and histopathological post mortem examination. Approximately two-thirds of these isolates were associated with significant pathology, including a small number of serotypes which are not included in the sheep vaccines currently used in Great Britain.

Evaluation of Danofloxacin in the Therapy of Pneumonia Associated With Pasteurella Species in Young Calves

Acute pneumonia is an economically important disease afflicting young cattle world-wide. The disease develops as a complex interaction and the aetiology of any outbreak is often multifactorial (1). Pasteurella spp. are the most important bacteria involved causing fibrinous bronchopneumonia (2, 3), but more frequently they increase the severity of lung lesions inflicted by viruses and/or mycoplasmas. Transport, housing and mixing of animals are management factors contributing to outbreaks of acute pneumonia. This paper summarizes the results of seven studies conducted in Europe in which the efficacy of the fluoroquinolone antimicrobial danofloxacin* against naturally occurring outbreaks of acute pneumonia in calves was evaluated in comparison with trimethoprim/sulpha.

Epidemiology of Enzootic Pneumonia in Minnesota Dairy Calves

Enzootic calf pneumonia (ECP) is one clinical manifestation of the bovine respiratory disease complex. Enzootic calf pneumonia results from a complex interaction between environmental factors, host factors, and infectious agents. The financial losses that result from ECP occur due to death loss, treatment cost, and decreased lifetime milk production. Calves that have experienced ECP have been shown to be at increased risk of culling once in the milking herd when compared to herdmates of the same age(1). Experimental studies involving the infectious agents themselves have been performed(2-9), as well as retrospective(10-16) and cohort studies(17-22). None of the current epidemiologic research has specifically targeted ECP, either through assessment of ventilation or laboratory sampling to validate morbidity or mortality.

Effects of 4-ipomeanol on bovine parainfluenza type 3 virus-induced pneumonia in calves.

Previous research has demonstrated that 4-ipomeanol toxicosis can enhance the severity of para-influenza virus-induced pneumonia in mice. The objectives of this study were to determine whether calves are susceptible to 4-ipomeanol-induced enhancement of parainfluenza type 3 viral pneumonia and to determine whether 4-ipomeanol alters pulmonary replication of parainfluenza virus. Male Holstein calves were injected with either 4-ipomeanol (3 mg/kg) or vehicle (polyethylene glycol) 3 days prior to intratracheal inoculation with either parainfluenza virus or sham inoculum of culture medium. Calves in the four treatment groups (ipomeanol-parainfluenza, ipomeanol-medium, vehicle-parainfluenza, and vehicle-medium) were necropsied at 5 days after inoculation with parainfluenza virus or medium. The lungs were studied by correlated methods of light and electron microscopy, digitizing morphometry and pulmonary lavage to quantitate the severity of pneumonia. Pulmonary viral titers were determined, and viral antigen was identified in the lung by immunoperoxidase technique. The calves in the ipomeanol-virus treatment group had over a 9-fold higher (P less than 0.05) volume density of virus-induced interstitial pneumonia than did the calves in the other three treatment groups. This 4-ipomeanol-enhanced viral pneumonia was associated with significantly greater (P less than 0.05) numbers of pulmonary macrophages and neutrophils in the lavage fluid and higher (P less than 0.05) pulmonary titers of pulmonary infectious parainfluenza virus. Four-ipomeanol-enhanced viral pneumonia was characterized in part by extensive hyperplasia of type II alveolar epithelial cells and by dense aggregates of macrophages and neutrophils in alveolar spaces and interalveolar septa. The results indicate that 4-ipomeanol exacerbates interstitial pneumonia in calves induced by bovine parainfluenza type 3 virus.

Long-acting antibiotic formulations in the treatment of calf pneumonia: a comparative study of tilmicosin and oxytetracycline

The treatment of an outbreak of acute pneumonia in 50 four- to eight-month-old Friesian and Friesian cross calves is described. At the first visit (day 0) 16 calves received 20 mg/kg bodyweight of oxytetracycline dihydrate intramuscularly and 15 received 10 mg/kg of the macrolide tilmicosin subcutaneously. The remaining 19 in-contact animals were not considered ill enough to be included in the trial and received 20 mg/kg of oxytetracycline dihydrate. The rectal temperature, demeanour, respiratory rate and respiratory effort of each calf was assessed on days 1, 2, 3, 9, 14, 21 and 28, and calves which had not responded were given repeat injections of the same antibiotic. All the calves recovered from the outbreak and of the 19 calves treated strategically, three required a second injection. Among the calves with clinical pneumonia, fewer treatments (P less than 0.01) were required by those treated with tilmicosin. The rectal temperatures of both groups decreased (P less than 0.05) after the first injection, but on day 3 the decrease was greater (P less than 0.05) in the group treated with tilmicosin. Respiratory rates varied widely but respiratory effort was less (P less than 0.05) on day 2 in the calves treated with tilmicosin. When long-acting antibiotic injections are used to treat enzootic pneumonia it is suggested that a second visit should be made on day 3 to assess the animals' response to treatment.

Ultrastructural Features of Lesions in Bronchiolar Epithelium in Induced Respiratory Syncytial Virus Pneumonia of Calves

Ultrastructural changes were observed in bronchioles in acute and repair stages of respiratory syncytial virus pneumonia induced in eight young calves (calf Nos. 1-8) using a bovine strain of respiratory syncytial virus. Five of the calves were Friesians and three were Hereford x Friesians and all were male. Tissues from three mock-infected control calves (two Friesian, one Hereford x Friesian) were also examined. Calves were from 3 to 6 days old at the time of first inoculation, with the exception of calf No. 8, which was 2 weeks old. In the acute stage of the induced pneumonia, evidence of respiratory syncytial virus replication and release was demonstrable in both ciliated and non-ciliated bronchiolar epithelial cells, with the virus-releasing process most obvious at 4 and 5 days after infection. Respiratory syncytial virus infection of bronchiolar epithelium was associated with various changes, including hypertrophy, hyperplasia, and formation of syncytia. Necrosis of epithelial cell structures usually appeared to be preceded by their desquamation from bronchiolar walls. Respiratory syncytial virus infection resulted in considerable damage to the bronchiolar ciliary apparatus. Such damage was seen as early as 1 day post-infection and was still obvious at 10 days post-infection. Neutrophils were closely associated with respiratory syncytial virus infected epithelial cells and evidence of neutrophil fusion with infected epithelial cells was seen. These observations suggest that neutrophils may be involved in killing respiratory syncytial virus infected cells and that neutrophils might play an important role in early antiviral defense against respiratory syncytial virus at a time when antibody levels are low and other cellular defenses are not fully in play. Bronchiolar repair was evident from 6 days after infection and was well advanced at 10 and 13 days after infection.

Ultrastructural Features of Alveolar Lesions in Induced Respiratory Syncytial Virus Pneumonia of Calves

Ultrastructural changes occurred in alveolar epithelium in the acute and repair stages of induced respiratory syncytial virus pneumonia induced in eight calves (calf Nos. 1-7, 3 to 6 days old and calf No. 8, 2 weeks old), using a bovine strain of respiratory syncytial virus. Five of the calves were Friesians, three were Hereford x Friesians, and all were male. Tissues from three mock-infected control calves (two Friesian, one Hereford x Friesian) were also examined. Evidence of respiratory syncytial virus infection was observed in both type I and type II pneumocytes from day 4 to day 8 after infection. Infection of type I pneumocytes frequently resulted in necrosis. The response of type II pneumocytes to respiratory syncytial virus infection varied and included hypertrophy, hyperplasia, and syncytial formation. In some infected type II pneumocytes, there were numerous irregular projections of the cell surface, associated with viral budding. Hypertrophy and hyperplasia of type II pneumocytes, epithelial syncytium formation, and irregular cytoplasmic projections from epithelial cells caused considerable thickening of respiratory membrane and occlusion of alveolar lumina. Neutrophils were frequently observed in close association with virus-infected epithelial cells, but evidence of respiratory syncytial virus infection and replication was not observed in alveolar macrophages or neutrophils. Proliferation of type II pneumocytes appeared to play a major role in maintaining the integrity of the alveolar epithelium during the acute stage of the experimental pneumonia. Increased numbers of type II pneumocytes were present on alveolar walls, particularly from 4 to 8 days after infection, and some alveoli were lined entirely by this cell type. In some areas, however, squamous epithelial cells were also involved in covering exposed alveolar basement membrane.

Tilmicosin and calf pneumonia

Tilmicosin and calf pneumonia

Reclassification of German, British and Dutch isolates of so-called Pasteurella multocida obtained from pneumonic calf lungs

The taxonomic relationship of 131 strains previously identified as Pasteurella multocida obtained from calf pneumonia in West Germany, United Kingdom and Netherlands was investigated by extended phenotypic and limited genotypic characterization. Twenty-four strains were classified as P. multocida ssp. multocida, 15 strains as P. avium biovar 2 and 13 strains as P. canis biovar 2. Sixty-five and five strains were tentatively classified as ornithine negative P. multocida ssp. multocida and P. multocida ssp. septica, respectively. Genetic investigations showed that ornithine negative strains of P. multocida were related on species level. Less genomic binding was found between an ornithine negative strain of P. multocida ssp. septica and the type strains of the three subspecies of P. multocida. The taxonomic position of ornithine negative strains of P. multocida is still under investigation. The taxonomic position of the remaining nine strains is uncertain underlining the need for genotypic characterization within the genus Pasteurella to aid in defining single species by phenotypic tests.

Clinical and pathologic studies of experimentally induced Pasteurella haemolytica pneumonia in calves

SUMMARY Pasteurella haemolytica pneumonia of the right caudal lung lobe was experimentally induced in 2-week-old Holstein calves (n = 11) by endobronchial inoculation of 7.9 × 1010 colony-forming units of 6-hour log-phase bacteria. Calves were studied for 72 hours after inoculation. The challenge procedure consistently induced a lesion in the right caudal lung lobe, which was consistent radiographically with results of pathologic examination and a similar volume of bronchography contrast medium. Clinically, the calves developed a significant increase in rectal temperature within 24 hours after inoculation. Seventy-two hours after inoculation, the total wbc counts, absolute band neutrophil counts, monocyte counts, and blood fibrinogen concentrations were significantly higher than normal and albumin concentration was significantly decreased. Necropsy revealed a circular to oblong lesion that was congested, edematous, and firm and occupied 20 to 40% of the right caudal lung lobe. Histologic examination revealed a severe acute inflammatory reaction characterized by cellular exudate and proteinaceous fluid in the alveoli, interlobular septa, and pleura.

Pathological, immunocytochemical and microbiological findings in calf pneumonias associated with Haemophilus somnus infection

SummaryPathological, immunocytochemical and microbiological findings in 32 cases of calf pneumonia associated with Haemophilus somnus infection are described. The majority of cases were "found dead" or died after a sudden onset pneumonia of less than 24 h duration. Lesions of exudative bronchopneumonia were present and the cases could be divided into two main groups on the basis of histopathological and immunocytochemical features. In group A, cases were dominated by necrotizing bronchiolitis, degeneration and necrosis of airway and alveolar exudates, severe alveolitis with accumulations of degenerate basophilic cells, interstitial inflammatory changes and the widespread distribution of H. somnus antigen in airways and alveoli. In Group B, necrotizing and degenerative changes were much less extensive and less severe and the overall appearance was of suppurative bronchopneumonia with H. somnus antigen much less widespread within the lungs. Alveolar oedema, hyaline membrane formation and alveolar epithelial hyperplasia were present in caudodorsal lung areas of several calves. No major differences were seen between the histopathology of lungs where H. somnus was the sole isolate and that of lungs where H. somnus was isolated along with other bacterial pathogens.

Influence of recombinant bovine interferon gamma and dexamethasone on pneumonia attributable to Haemophilus somnus in calves

Summary The influence of recombinant bovine interferon gamma (rBoIFN-gamma) treatment on resistance of clinically normal and dexamethasone-treated calves to Haemophilus somnus infection was evaluated. Four groups of 6 calves each were treated with saline solution (controls), dexamethasone (0.04 mg/kg of body weight/for 3 days), rBoIFN-gamma (2 μg/kg for 2 days), or dexamethasone and rBoIFN-gamma (aforementioned dosages). All treatments were started 24 hours before intrabronchial challenge exposure with 5 × 109 colony-forming units of H somnus. Rectal temperature and WBC count were monitored daily. Two of the dexamethasone-treated calves died of pneumonia 4 days after challenge exposure and were necropsied. All other calves were euthanatized and necropsied 7 days after challenge exposure. All calves had pneumonia of variable intensity. Dexamethasone-treated calves had increased volume of pneumonic lung (P < 0.05) and increased severity of pneumonia, compared with control calves. Recombinant bovine interferon gamma treatment resulted in reduction in pneumonic lung volume and severity of pneumonia in dexamethasone-treated calves (P < 0.05), although it did not influence severity of pneumonia in nondexamethasone-treated calves.

Ultrastructural Morphogenesis of 4-ipomeanol-induced Bronchiolitis and Interstitial Pneumonia in Calves

The two objectives of this research were 1) to describe the ultrastructural morphogenesis of pulmonary damage and repair induced in calves after treatment with 4-ipomeanol and 2) to characterize infiltrating pulmonary inflammatory cells by bronchoalveolar lavage. Interstitial edema was observed as early as 4 hours after intravenous injection of 4-ipomeanol (5 mg/kg body weight) and progressed to severe alveolar edema by 72 hours. Damage to type I alveolar epithelial cells and terminal bronchiolar nonciliated cells included dilation of endoplasmic reticulum and perinuclear envelopes and was present at 4 hours after treatment. Necrosis and sloughing of these cells from basement membranes occurred at times from 12 to 96 hours after treatment. Alveolar capillary endothelial cells had mild dilation of endoplasmic reticulum at times from 12 to 72 hours after treatment. Necrosis of endothelial cells was not observed. Inflammatory cell infiltrates in bronchioles and alveoli were dominated by macrophages and neutrophils. Significant elevations (P less than 0.05) in numbers of neutrophils and macrophages were recovered by bronchoalveolar lavage at times from 24 to 96 hours after 4-ipomeanol-treatment. Hyperplasia of nonciliated bronchiolar epithelial cells and of type II alveolar epithelial cells were observed at 72 and 96 hours after treatment. The results indicate that type I alveolar epithelial cells and nonciliated bronchiolar epithelial cells are most susceptible to 4-ipomeanol-induced damage and necrosis in calves. 4-ipomeanol-induced pulmonary edema in calves occurs prior to ultrastructurally-demonstrable, mild, alveolar capillary endothelial cell damage.

Untersuchungen zur Oberfläuchenstruktur von Pasteurella multocida

AbstractDetailed studies of the surface structures are an important requirement for the development of efficient vaccines against enzootic pneumonia in calves and piglets caused by Pasteurella multocida.Electron microscopical examination after Alcian Blue staining shows capsular material extending far into the surrounding medium.The extent of the capsules depicted by light microscopy did not correlate with virulence and immunogenicity. However, the extent of the capsules was effected by different culture conditions.The immunization with extract material resulted in a good protection against homologous infection.It has been shown that different cultivation conditions can result in heterogeneity of LPS and in altered OMP‐profiles.

Increased severity of calf pneumonia associated with the appearance of Mycoplasma bovis in a rearing herd.

An increase in deaths in calves from respiratory disease from an average of 9.7 per year to 36.5 per year corresponded with the isolation of Mycoplasma bovis from the lungs. It is suggested that this mycoplasma enhanced the severity of the disease which was normally present on the farm. The characteristic microscopic lesion and demonstration of M bovis by immunoperoxidase labelling could be useful aids to diagnosis.

Bacteriological findings in nasal and lower respiratory tract samples of calves with acute respiratory disease

Infectious calf pneumonia passes off with high morbidity and is frequent in housed dairy animals in the winter. In Sweden the greatest disease problems occur in the “specialized calfrearing units” for meat production. To these farms about 100,000 calves (> 2 weeks old) are now mediated every year from dairy farms. Viral mycoplasmal and bacterial agents are involved in the complex etiology. From emergency slaughtered animals in Sweden Pasteurella multocida, Pasteurella multocida, Pasteurella hemolytica and Actinomyces pyogenes were the most commonly isolated bacteria. Mycoplasma dispar was the most commonly mycoplasmal species isolated. No investigation has been performed in Sweden over bacteria present in the lower respiratory tract at the acute phase of calf pneumonia.
 The aim of the present study was to compare the bacteriological flora in the nasal cavity with that of the lower respiratory tract in diseased animals and in healthy animals.

Pathological and immunological responses of calves to Mycoplasma bovis

Mycoplasma bovis was identified in the UK for the first time in association with a severe outbreak of bovine respiratory disease. Subsequently it was shown to cause moderate lesions of arthritis and pneumonia in gnotobiotic calves.
 The following paper describes a hitherto unrecognized necrotic lesions caused by M. bovis in the lung parenchyma of gnotobiotic calves; it describes certain features of the immune response to the infection and contrasts the mechanisms of pathogenesis for M. bovis with that of other respiratory mycoplasmas. The paper summarizes some of the work described more fully elsewhere.