Behavioral and physiologic changes in Holstein steers experimentally infected with Mannheimia haemolytica

OBJECTIVE To evaluate changes in behavior and surfactant protein (SP) A and D concentrations in serum and bronchoalveolar lavage fluid (BALF) samples of calves experimentally infected with Mannheimia haemolytica. ANIMALS Twelve 4- to 5-month-old Holstein steers. PROCEDURES Calves were divided into 2...

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Bibliographic Details
Published in:	American journal of veterinary research Vol. 78; no. 9; pp. 1056 - 1064
Main Authors:	Eberhart, Nicole L, Storer, Jennifer M, Caldwell, Marc, Saxton, Arnold M, Krawczel, Peter D
Format:	Journal Article
Language:	English
Published:	United States 01-09-2017
Subjects:	Animals Behavior, Animal Body Temperature Bronchoalveolar Lavage Fluid Cattle Cattle Diseases - drug therapy Cattle Diseases - physiopathology Mannheimia haemolytica Pneumonia of Calves, Enzootic - physiopathology
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Summary:	OBJECTIVE To evaluate changes in behavior and surfactant protein (SP) A and D concentrations in serum and bronchoalveolar lavage fluid (BALF) samples of calves experimentally infected with Mannheimia haemolytica. ANIMALS Twelve 4- to 5-month-old Holstein steers. PROCEDURES Calves were divided into 2 treatment groups and instrumented with a data logger to collect behavioral data. After 10 days of acclimation, calves were experimentally inoculated with 3 × 10 CFUs to 5 × 10 CFUs of M haemolytica suspended in approximately 5 mL of PBS solution (infected calves; n = 6) or 5 mL of PBS solution without M haemolytica (control calves; 6) through a catheter into the right accessory lung lobe. Calves were clinically evaluated twice daily for 7 days after inoculation. Blood and BALF samples were collected from all calves at predetermined times for determination of serum and BALF SP-A and SP-D concentrations. Serum and BALF concentrations of SP-A and SP-D and behavioral data were evaluated over time and between treatment groups. RESULTS Compared with control calves, infected calves spent more time lying in general and more time lying on the right side during the 24 hours and 6 days after inoculation, respectively. Mean rectal temperature for infected calves (41.3°C) was significantly greater than that for control calves (39.2°C) 12 hours after inoculation. Mean respiratory rate for infected calves (52.5 breaths/min) was significantly greater than that for control calves (45.4 breaths/min) throughout the observation period. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated continuous behavioral monitoring may improve detection of calves with respiratory tract disease.
Bibliography:	ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	0002-9645 1943-5681
DOI:	10.2460/ajvr.78.9.1056