Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: July 11, 2008
Publication Date: July 23, 2008
Citation: Carroll, J.A., Arthington, J., Chase, C.C. 2008. Early weaning alters the acute phase immune response to an endotoxin challenge in beef cattle [abstract]. Journal of Amimal Science. 86(E. Suppl. 2):526. (Abstract #575) Technical Abstract: Previous research indicates that early weaning prior to shipment can reduce transportation-induced increases in acute phase proteins (APP), and can increase subsequent performance in the feedlot. These data suggest that the combination of weaning and transport stress may compromise the immune system of calves, thus hindering subsequent performance and health. Therefore, our objective was to determine if the innate immune response of early weaned calves (EW; 80 d of age) differed from normal weaned calves (NW; 250 d of age) in response to an endotoxin challenge. Eighteen Brahman x Angus calves (8 and 10 EW and NW, respectively; 233 ± 5 kg BW) were used. Prior to the study, calves were maintained on pasture with supplement. All calves were acclimated to their study pens for 1 wk prior to a lipopolysaccharide (LPS) challenge. One d prior to LPS challenge, calves were fitted with an indwelling jugular catheter. Blood samples were collected at 30-minute intervals from -2 to 8 hours. At 0 hour, all calves received an i.v. infusion of LPS (1.0 micrograms/kg body weight). Serum samples were stored at -80 degrees Celsius until analyzed for cortisol (CS), tumor necrosis factor-alpha (TNF), interleukin-1 beta (IL-1), IL-6, interferon-gamma (IFN), ceruloplasmin (Cp) and haptoglobin (Hp). While LPS increased serum CS (P less than or equal to 0.001) no weaning age effect (P greater than or equal to 0.15) was observed. A weaning age x time interaction (P less than or equal to 0.04) was observed for TNF, IL-1, IL-6, and Cp such that concentrations of these indices were greater in the NW compared to EW calves. For Hp, a weaning age effect (P less than or equal to 0.03) was observed with NW calves having greater average Hp concentrations compared to EW calves. Interestingly, the weaning age x time interaction (P less than or equal to 0.001) for IFN revealed greater IFN in EW opposed to NW calves. Based upon these data, the innate immune system of EW calves appears to be less naïve than that of NW calves. Additionally, the differential IFN response indicates that the immune system of EW calves may be more effective at recognizing and eliminating endotoxin. These data suggest that an altered innate immune system may be one of the factors responsible for the improved feedlot performance previously reported in EW calves.