Effects of cortisol on in vitro interferon-gamma production, acute-phase proteins, growth, and feed intake in a calf castration model.

The objective of this study was to determine the effects of castration, with its presumed pain and inflammatory effects, including increased cortisol, and elevated cortisol per se on in vitro interferon-gamma (IFN-gamma) production, ADG, ADFI, and plasma haptoglobin and fibrinogen. Thirty Friesian bull calves (174 +/- 3.8 kg) were assigned to three treatments (given on d 0): 1) control (CON); 2) i.v. cortisol administration to mimic castration-induced increases in cortisol (CORT); and 3) surgical castration (SURG). Blood samples were collected for 12 h on d 0 and at 24 and 72 h after treatment for cortisol determination. Keyhole limpet hemocyanin (KLH)- and concanavalin A (Con A)-induced in vitro IFN-gamma production in blood, and plasma haptoglobin and fibrinogen were measured in blood samples taken before treatment on d 0 and on d 1 and 3. On d 0, CORT and SURG animals had higher peak cortisol (P < .001) and area under the cortisol curve (P < .001) than CON animals. There were no differences (P > .05) between CON, CORT, and SURG animals in cortisol at 24 and 72 h. There were no differences (P > .05) between CON and CORT animals in IFN-gamma production, haptoglobin, fibrinogen, ADG, and ADFI. Compared with CON animals, SURG animals had lower (P < .05) KLH-induced IFN-gamma on d 1 and CON A-induced IFN-gamma on d 1 and 3. Haptoglobin concentrations were greater (P < .05) for SURG than for CON animals on d 1 and 3. Fibrinogen concentrations were greater (P < .001) for SURG than for CON animals on d 3. The SURG animals had lower (P < .01) ADG and ADFI during d 0 to 7 than CON animals. In conclusion, castration decreased IFN-gamma production, ADG, and ADFI and increased haptoglobin and fibrinogen, and these effects seemed to be independent of plasma cortisol concentrations.