Characterization of the Acute-Phase Protein Response Following Vaccination and Weaning in Beef Steers

The objectives of this study were to assess the acute-phase protein response of beef steers following vaccination with two different vaccines, and to determine if this response is additive to weaning. Forty-eight Brahman x Angus steers (average age = 7 mo) were randomly assigned to one of six treatments in a 2 x 3 factorial arrangement, including: weaning vs. non-weaning, and vaccination with One Shot ® (2 mL), UltraBac ® 7 (5 mL), or saline control (5 mL). Blood samples were collected on d 0, 1, 3, 5, 7, 10, 14, and 21, relative to weaning and vaccination, for determination of plasma concentrations of inflammatory acutephase proteins. During the course of the study, free-choice hay and a grain-based supplement (up to 10 lbs/steer daily) were offered to weaned steers, while non-weaned steers remained with their dams. Weaned steers had greater (P<0.05) ceruloplasmin concentrations on d 3, and greater haptoglobin concentrations on d 3 (P<0.01) and 5 (P<0.05) compared to nonweaned steers. Across weaning treatment, steers administered One Shot ® had greater (P<0.01) fibrinogen concentrations on d 1, 3, and 5, greater (P<0.01) acid soluble protein concentrations on d 3, and greater (P<0.01) haptoglobin concentrations on d 1 and 3 compared to steers receiving UltraBac ® 7 or saline control. Within weaned steers, those receiving One Shot ® had greater (P<0.05) mean ceruloplasmin concentrations compared to steers receiving UltraBac ® 7 or saline control. Data from this study imply that steers vaccinated with One Shot ® experience a greater inflammatory response compared to steers vaccinated with UltraBac ® 7 and saline control, and this response mainly occurs during the 5 d following vaccination. Further, additive effects of vaccination on weaning were only detected for plasma ceruloplasmin concentrations.