Calf Pneumonia Research Articles

Immunohistopathology of calf pneumonia induced by endobronchial inoculation with bovine adenovirus 3.

Three 1-week-old and three 3-month-old Holstein calves that had received colostrum were inoculated endobronchially with bovine adenovirus 3 (BAV-3). The gross and histologic lesions in these six infected calves were localized mainly in the right caudal lobe of the lung and were closely associated with the site of the deposition of the inoculum. The pneumonic lesions were severe necrotizing bronchitis, bronchiolitis, and alveolitis, accompanied by infiltration of inflammatory cells and proliferation of type 2 pneumocytes. Intranuclear inclusion bodies, BAV-3 antigen, and virus particles were detected in the degenerated epithelial cells in the 1-week-old but not the 3-month-old calves. After infection, the total cell count in the bronchoalveolar lavage (BAL) fluid cells was increased. The results of BAV-3 isolation from BAL fluid were correlated with the detection of intranuclear inclusion bodies in the desquamated epithelial cells in the BAL fluid cells from the right caudal lobe but not in cells from the left caudal lobe. CD8+ T lymphocytes in the pneumonic lesion were found only in the 3-month-old infected calves. The difference in the immunopathologic reactions between the 1-week-old and the 3-month-old infected calves may be attributed to differences in immune system development.

An experimental vaccine for calf pneumonia caused by Mycoplasma bovis: clinical, cultural, serological and pathological findings

A single dose of vaccine for Mycoplasma bovis pneumonia, inactivated with saponin, was inoculated subcutaneously into 3–4 week-old calves. The calves were challenged 3 weeks later with a virulent strain of M. bovis on two occasions within 24 h using the aerosol route. The calves were monitored for clinical signs and serological responses then post mortemed 3 weeks after challenge. The vaccine was shown to be highly immunogenic in calves and did not cause adverse effects. Vaccinated calves showed few clinical signs while all unvaccinated calves developed signs of pneumonia. There was a significant decrease in body weight gain in unvaccinated calves compared to vaccinates and a significant increase in lung lesions and rectal temperatures in unvaccinated calves. The vaccine also reduced the spread of M. bovis to internal organs. In conclusion the M. bovis vaccine produced a significant level of protection against a large virulent challenge.

54. Enhanced severity of induced Mycoplasma bovis pneumonia in calves following immunisation with different antigenic extracts

54. Enhanced severity of induced Mycoplasma bovis pneumonia in calves following immunisation with different antigenic extracts

Clinical efficacy of florfenicol in the treatment of calf respiratory tract infections

Summary This paper reports on a study of the aetiology of calf pneumonia and the clinical efficacy of florfenicol, a new antibiotic in Turkey. Twenty‐seven weaned and unweaned calves (13 males and 14 females) between 1 and 16 months of age brought to the clinics of Selguk University, Faculty of Veterinary Science. Broncho‐alveolar lavage (BAL) fluid samples were taken from the animals diagnosed to have upper respiratory tract infection associated with bronchitis (N=2), bronchitis (N=5), bronchopneumonia (N=4), pneumonia (N=3), pleuropneumonia (N=11), bronchopneumonia plus pulmonary oedema (N=2) based on the results of the clinical and laboratory examinations. Then microbiological isolation and antibiotic culturing were performed. The animals were treated with 1 m1/15 kg (20 mg/kg) florfenicol (Nuflor®, DIF) twice within 48 hours via intramuscular injection. At the end of the treatment, 23 of the weaned and unweaned calves were completely healed, 1 calf had died and 3 calves showed no healing. The results of BAL samples and microbiological examinations of the 3 calves that did not respond to the treatment indicated that these cases were affected by mixed infections of yeasts, fungi, and bacteria. Widespread pleuropneumonia was observed. According to the results of the microbiological examination of the BAL samples, Mannheimia (Pasteurella) haemolytica had the highest isolation rate (25%) compared with the other isolated bacteria, namely, Klebsiella pneumonia (20%), Actinomyces pyogenes (15%), β‐henwlytic streptococci. (10%), Staphylococcus spp. (5%), and E. coli (5%). The study also revealed fungi [Penicillum spp. (5%) and Aspergillus spp. (5%)I and two calves (10%) had a yeast infection.. We conclude that florfenicol has a high bacteriological and clinical efficacy (100% and 96% respectively) in the treatment of calf respiratory tract diseases.

Bovine Mycoplasmosis

Mycoplasmal diseases remain among the most intractable infectious diseases of cattle. Difficulties in diagnosis, poor response to treatment, few preventive measures and increased incidence have converted these diseases into a new frontier for the bovine practitioner. On this frontier, unknown factors and scarce resources create conditions of great danger, and perhaps also opportunity. A regional context is in order. In Asia, Africa, the Middle East, and parts of southwestern Europe contagious bovine pleuropneumonia, caused by Mycoplasma mycoides subsp. mycoides continues to be a problem. Rapidly spreading into new regions, or to regions previously cleared of this disease, the disease represents a continuing world-wide threat.8 Introductions of this endemic disease into North America via infected bovidae have been prevented by prolonged quarantine observations.
 In the United States several diseases of bovines that are caused by mycoplasmas can be recognized. Feedlot pneumonia, arthritis, and mycoplasmal mastitis are diseases that can cause severe losses at this time. Pneumonia, arthritis and otitis of young diary calves can also be significant. Some mycoplasmas can play a significant role in enzootic pneumonia of dairy or beef calves. Finally, some diseases of minor importance have been recognized, such as ulcerative vulvovaginitis, ureaplasmal infertility and bovine mycoplasmal conjunctivitis. This paper will only provide an overview of the major bovine mycoplasmal diseases of North America.

Vaccination of Young Dairy Calves against Mannheimia haemolytica and Pasteurella multocida

Enzootic calf pneumonia is responsible for significant economic losses in the dairy industry because of its high morbidity and mortality. An effective vaccine could help reduce these losses. The purpose of our study was to evaluate the efficacy of a commercial Mannheimia haemolytica - Pasteurella multocida vaccine in young dairy calves.

An economic model to calculate farm-specific losses due to bovine respiratory disease in dairy heifers

This paper describes a personal-computer-based model estimating the economic losses associated with clinical bovine respiratory disease in replacement heifers raised on individual dairy farms. The model is based on the partial-budgeting technique, and calculates the losses for two types of the disease separately: calf pneumonia and a seasonal outbreak. Model input includes farm-specific data such as the incidence of bovine respiratory disease, prices, and effects of the disease on the heifers’ productivity. The input database was linked directly with the economic model. For all input parameters, default values used are available to the user and can be modified easily. Losses considered by the model include treatment expenditures and costs associated with increased mortality, increased premature culling, reduced growth, reduced fertility and reduced milk production in first lactation. Uncertainty is taken into account for parameters related to disease incidence, mortality and culling. Basic calculations for a typical Dutch dairy farm with 60% of the heifers (<3 months) affected, indicated total annual losses due to pneumonia average ▪ 31.2 per heifer present on the farm (range ▪ 18.4–57.1). The estimated losses for one seasonal outbreak with heifers up to 15-months old affected were ▪ 27.0 per heifer present (range ▪ 17.2–43.1). For both BRD types, the model’s outcome was most sensitive to the number of heifers affected. Most of the parameters that had a major impact on the total losses were related to treatment or to the effects on the heifers’ productivity. The model is user-friendly and flexible, and can be used as an interactive tool by farmers and veterinarians in the (economic) decision-making process regarding on-farm prevention and control of bovine respiratory disease.

Reduction in serum lecithin:cholesterol acyltransferase activity in natural cases of pneumonia in calves.

In experimental calf pneumonia induced by inoculations of Pasteurella haemolytica or bovine herpesvirus-1, lipoprotein lipid concentrations and lecithin:cholesterol acyltransferase (LCAT) activity decrease. The purpose of this study was to examine whether similar changes in lipoproteins occur in natural cases of calf pneumonia. When monitored in a time-course study, the activity of LCAT, and the concentrations of free cholesterol, cholesteryl esters, phospholipids and triglycerides were steadily decreased. No significant decreases in LCAT activity or lipid concentrations were detected in sera from cows with mastitis. These results, coupled with the previous findings on experimental calf pneumonia, indicate that, while decreases in LCAT activity and the LCAT-related lipid concentrations are involved in the pathogenesis of calf pneumonia, this is not the case for all inflammatory diseases.

Practical approach to the control of pneumonia in housed calves

CALF pneumonia continues to be a significant problem for the cattle industry, both in economic and welfare terms, and its control remains a topic of prime importance for veterinary surgeons...

Effects of the synthetic selectin inhibitor TBC1269 on tissue damage during acute Mannheimia haemolytica-induced pneumonia in neonatal calves.

To determine effects of the selectin inhibitor TBC1269 on neutrophil-mediated pulmonary damage during acute Mannheimia haemolytica-induced pneumonia in newborn calves. Eighteen 1- to 3-day-old colostrum-deprived calves. Mannheimia haemolytica or saline (0.9% NaCl) solution was inoculated in both cranial lung lobes of 12 and 6 calves, respectively. Calves were euthanatized 2 (saline, n = 3; M haemolytica, n = 4) or 6 hours (saline, n = 3; M haemolytica, n = 8) after inoculation. Four M haemolytica-inoculated calves euthanatized at 6 hours also received TBC1269 (25 mg/kg, IV) 30 minutes before and 2 hours after inoculation. Conjugated diene (CD) concentrations, inducible nitric oxide synthase (iNOS) expression, and apoptotic cell counts were determined in lung specimens collected during necropsy. Conjugated diene concentrations were significantly increased in all M haemolytica-inoculated groups, compared with saline-inoculated groups. Calves treated with TBC1269 had decreased concentrations of CD, compared with untreated calves, although the difference was not significant. Number of apoptotic neutrophils and macrophages increased significantly inTBC1269-treated calves, compared with untreated calves. Inducible nitric oxide synthase was expressed by epithelial cells and leukocytes. However, iNOS was less abundant in airway epithelial cells associated with inflammatory exudates. Degree of iNOS expression was similar between TBC1269-treated and untreated calves. Mannheimia haemolytica infection in neonatal calves resulted in pulmonary tissue damage and decreased epithelial cell iNOS expression. The selectin inhibitor TCB1269 altered, but did not completely inhibit, neutrophil-mediated pulmonary damage.

A retrospective search for bovine respiratory syncytial virus (BRSV) antigens in histological specimens by immunofluorescence and immunohistochemistry

Bovine respiratory syncytial virus (BRSV) has been only sporadically identified as a causative agent of respiratory disease in Brazil. This contrasts with frequent reports of clinical and histopathological findings suggestive of BRSV-associated disease. In order to examine a possible involvement of BRSV in cases of calf pneumonia, a retrospective search was performed for BRSV antigens in histological specimens submitted to veterinary diagnostic services from the states of Rio Grande do Sul and Minas Gerais. Ten out of 41 cases examined (24.4%) were positive for BRSV antigens by immunohistochemistry (IPX). Eight of these cases (19.5%) were also positive by indirect immunofluorescence (IFA), and 31 cases (75.6%) were negative in both assays. In the lungs, BRSV antigens were predominantly observed in epithelial cells of bronchioles and less frequently found in alveoli. In one case, antigens were detected only in the epithelium of the alveolar septae. The presence of antigen-positive cells was largely restricted to epithelial cells of these airways. In two cases, positive staining was also observed in cells and cellular debris in the exudate within the pulmonary airways. The clinical cases positive for BRSV antigens were observed mainly in young animals (2 to 12 month-old) from dairy herds. The main microscopic changes included bronchointerstitial pneumonia characterized by thickening of alveolar septae adjacent to airways by mononuclear cell infiltrates, and the presence of alveolar syncytial giant cells. In summary, the results demonstrate the suitability of the immunodetection of viral antigens in routinely fixed tissue specimens as a diagnostic tool for BRSV infection. Moreover, the findings provide further evidence of the importance of BRSV as a respiratory pathogen of young cattle in southeastern and southern Brazil.

Pasteurization of Discard Mycoplasma Mastitic Milk Used to Feed Calves: Thermal Effects on Various Mycoplasma

Discard milk from sick or antibiotic-treated cows is often used as an economical alternative to milk replacer at dairy farms. This practice poses a health risk to calves if the discard milk is from cows with mycoplasma mastitis. Mycoplasma bovis, Mycoplasma californicum, and Mycoplasma canadense are among the agents known to cause contagious mastitis in cattle and occasionally pneumonia, otitis media, or arthritis in calves. This report describes a recent outbreak of calf polyarthritis and respiratory disease on a midwest dairy farm. The farm fed discard mycoplasma mastitic milk to its calves. On-the-farm pasteurization of the discard milk to 65°C for 1h before feeding prevented additional illness in the calves. Discard milk samples were collected before and after heating and tested for mycoplasma by culture. Only samples collected before pasteurization yielded live cultures. Common mastitic mycoplasma agents were also tested for sensitivity to heat. It was determined that 65°C killed M. bovis and M. californicum after 2min of exposure, while M. canadense remained viable for up to 10min. Exposure to 70°C inactivated M. bovis and M. californicum after 1min, but M. canadense samples were positive for up to 3min. Thus, M. canadense appears to be more heat resistant than M. bovis and M. californicum. Heat treatment that results in the destruction of M. canadense should be used for the pasteurization of discard mycoplasma mastitic milk.

Descriptive Epidemiology of Chronic Disease of Calves in a Western Canadian Feedlot

A pattern of chronic disease has been recognized in fall-placed, weaned beef calves in western Canadian feedlots. Affected calves become "non-responders" to antibiotic therapy, with weight loss, chronic pyrexia and/or lameness. These calves are moved to a chronic pen for a period of convalescence. This study is describes this pattern of chronic disease in terms of morbidity, days on feed, weight change, and mortality. Its second objective is to determine the association between bovine virus diarrhea virus (BVDV) and Mycoplasma bovis infection and chronic pneumonia and/or polyarthritis in feedlot calves.

Immunohistochemical Characterization of Calf Pneumonia Produced by the Combined Endobronchial Administration of Bovine Herpesvirus 1 and Pasteurella haemolytica

Ten calves (“group 4”) were inoculated endobronchially with Pasteurella haemolytica 4 days after inoculation with bovine herpesvirus 1 (BHV-1). Four calves (group 3) were similarly inoculated with P. haemolytica alone, and three (group 2) with BHV-1 alone. All group 4 animals showed severe respiratory signs and had bilateral lobar pneumonia; one died 6 days after inoculation with P. haemolytica. Two types of pneumonic lesion were observed. One was characterized by interlobular and interstitial lymphatic thrombosis, fibrinous pleuritis and coagulative necrosis, and the other by necrotizing bronchiolitis with intranuclear inclusion bodies. The former type of lesion was associated with the presence of P. haemolytica antigen and the latter with the presence of BHV-1 antigen. The weight of infection of BHV-1 and P. haemolytica in bronchoalveolar (BAL) fluid was clearly reflected in the immunohistochemical demonstration of the corresponding antigens in BAL fluid cells. Group 4 calves differed from the calves of groups 1–3 in showing 10–1530 times more endotoxin in BAL fluid. These findings suggested that BHV-1 infection partly destroyed the clearance mechanisms of the respiratory tract epithelium and exacerbated the subsequent P. haemolytica infection.

Aerosol challenge of calves with Haemophilus somnus and Mycoplasma dispar

The aim of the study was to examine the ability of Haemophilus somnus and Mycoplasma dispar to induce pneumonia in healthy calves under conditions closely resembling the supposed natural way of infection, viz. by inhalation of aerosol droplets containing the microorganisms. The infections were investigated by recording clinical data, cytokine expression of peripheral blood cells and pathology. Twelve calves were included in the study: Three animals were exposed to H. somnus only, and two to M. dispar only, whereas five were challenged to M. dispar followed by exposure to H. somnus 11–14 days later. Also, one calf was exposed to M. dispar followed by exposure to a sterile saline solution 11 days later, and one calf was only exposed to a sterile saline solution. Just one animal, only challenged with H. somnus, developed a focal necrotizing pneumonia, from which H. somnus was isolated. Thus, the ability of H. somnus and M. dispar to act as primary pathogens under these conditions were minimal and inconsistent. However, a transient rise in body temperature, a marked granulocytosis and increased levels of interleukin-8 in peripheral blood after inoculation with H. somnus indicated a clear systemic response, probably as a consequence of the natural non-specific local and systemic defence mechanisms acting in healthy calves.

Detection of annexins I and IV in bronchoalveolar lavage fluids from calves inoculated with bovine herpes virus-1.

Annexins are phospholipid-binding proteins and are abundant in the lung. Annexins I and IV, but not II and VI, have been detected in bronchoalveolar lavage (BAL) fluids from calves inoculated with Pasteurella haemolytica, the pathogen for calf pneumonia. In this study, BAL fluids from calves with experimental pneumonia induced by inoculation to right lung lobes of bovine herpes virus-1 (BHV-1), the major viral pathogen for pneumonia, were examined for detection of annexins I and IV. Of 6 calves inoculated with BHV-1, annexins I and IV were coincidentally detected in BAL fluids from right lung lobes of 4 calves, but not in BAL fluids from left lung lobes of 6 inoculated calves or those from left and right lung lobes of 3 control calves. Annexin II and VI were not found in any BAL fluids examined. These results, together with previous findings on calves inoculated with Pasteurella haemolytica, suggest that the release of annexins I and IV onto the alveolar surface is an essential event occurring in response to pulmonary infections of BHIV-1 and Pasteurella haemolytica.

Decreased Apolipoprotein C-III Concentration in the High-Density Lipoprotein Fraction from Calves Inoculated with Pasteurella haemolytica and Bovine Herpes Virus-1

Lipoprotein lipid and apoprotein concentrations are known to be altered during the acute-phase response. We have previously shown that the serum activity of lecithin:cholesterol acyltransferase (LCAT) and concentration of cholesteryl esters, both constituents of the high-density lipoprotein (HDL) fraction, are reduced in calves inoculated with Pasteurella haemolytica and bovine herpes virus-1, the two major pathogens for calf pneumonia. The concentration of apolipoprotein C-III (apoC-III), a low molecular mass protein component distributed mainly in the HDL fraction, was therefore examined in bacteria- and virus-inoculated calves. An enzyme-linked immunosorbent assay demonstrated that it was decreased by inoculations of Pasteurella haemolytica and bovine herpes virus-1. The decrease was detected as early as 1 day after inoculation in both groups. A decreased serum apoC-III concentration was also observed by immunoblot analysis. It was detected in the HDL fractions from the bacteria- and virus-inoculated calves, and HDL apoC-III concentrations in the inoculated calves were decreased compared with controls. These results, coupled with the previous findings on LCAT activity and the cholesteryl ester concentration, indicate that a decreased HDL concentration is one of the early events occurring during the acute-phase response evoked by infections with Pasteurella haemolytica and bovine herpes virus-1.

Development of a Model for Use in Pharmaceutical Trials

The most common method for inducing pneumonicpasteurellosis in cattle for the study of therapeutic andimmunologic interventions is to instill fresh live culturesof Pasteurella haemolytica into the trachea, into mainstem bronchi, or into the thoracic cavity percutaneously(transthoracic). Evaluating therapeutic outcome may includecomparisons of clinical recovery, mortality, weightgain, or other response variables.&#x0D; Our initial efforts to induce pneumonia in beef calves utilizing a model previously validated in neonatal dairy calves produced inconsistent results. In order to use the model in pharmacotherapeutic trials, disease must be reliably produced. We were interested in developing a model for induction of pneumonia in weaned beef calves (approximately 400 lbs.) so that differences in body temperature, lung consolidation and neutrophil function could be used to compare antimicrobial therapies.

Studies on the efficacy of intranasal vaccination for the prevention of experimentally induced parainfluenza type 3 virus pneumonia in calves

The efficacy of intranasal vaccination in preventing or limiting disease of the lower respiratory tract induced by parainfluenza 3 (P13) virus was evaluated under experimental conditions, using a commercially available...

Bovine Pneumonia: Its Radiographic Appearance

Pneumonia is a common lung disease of cattle, but because so little time is devoted to the subject in introductory radiology courses, few veterinarians feel inclined to make thoracic images of calves suspected of having pneumonia, much less render a radiographic judgment in such cases. In actuality, however, the radiographic diagnosis of pneumonia is not that difficult, provided one knows what to look for and where to look for it; and is aware of how anatomic, physiologic, and technical variations may mimic lung disease. This article provides the reader with a simple and effective integrated approach to the radiographic diagnosis of pneumonia in calves.