title: Effect of breed (Angus vs Simmental) on immune function and response to a disease challenge in stressed steers and preweaned calves.
abstract: Two experiments were conducted with feeder steer calves and preweaned calves to determine the effects of breed on immune response. In Exp. 1, newly weaned Angus (n = 24) and Simmental (n = 24) steer calves were blocked by weight within breed and randomly assigned to 12 pens with four calves per pen. The basal diet consisted of 87% corn silage (DM basis) and 13% of a soybean meal-mineral-vitamin supplement. Steers were allowed ad libitum access to feed throughout the study. On d 2 following weaning, calves received an intranasal inoculation of infectious bovine rhinotraecheitis virus (IBRV; 2.7 x 10(8) CCID50). Rectal temperatures in response to the IBRV were higher (P < .05) in Angus calves. On d 9, calves were injected i.m. with 10 mL of a 25% pig red blood cell (PRBC) suspension. Total immunoglobulin (Ig) and IgM titers against PRBC were higher (P < .05) for the Angus calves. Breed did affect cell-mediated immune response to phytohemagglutinin (PHA). In Exp. 2, preweaned (16 Angus and 16 Simmental) calves were selected based on breed, body weight, and sex. On 0 d, all selected calves were injected i.m. with 10 mL of a 25% PRBC suspension. Total Ig and IgG titers against PRBC were higher (P < .05) for Angus calves. On d 28, lymphocytes were isolated from peripheral blood obtained from eight calves per breed. Peripheral lymphocytes from the Angus calves had a greater (P < .07) blastogenic response to 6.25 microg/mL of PHA than lymphocytes from Simmental calves. Results indicate that the immune response of Angus and Simmental calves may differ.
authors.affiliation: Department of Animal Science, North Carolina State University, Raleigh 27695-7621, USA.
authors.forename: T E
authors.initials: TE
authors.lastname: Engle
authors.forename: J W
authors.initials: JW
authors.lastname: Spears
authors.forename: T T
authors.initials: TT
authors.lastname: Brown
authors.forename: K E
authors.initials: KE
authors.lastname: Lloyd
mesh_terms: D000818:Animals; D001831:Body Temperature; D001947:Breeding; D002417:Cattle / Q000145:classification / Q000276:immunology*; D004435:Eating; D004912:Erythrocytes / Q000276:immunology; D005260:Female; D007113:Immunity, Innate; D007136:Immunoglobulins / Q000096:biosynthesis; D008297:Male; D010835:Phytohemagglutinins / Q000276:immunology; D013312:Stress, Physiological / Q000276:immunology*; D013552:Swine; D015430:Weight Gain
chemical_list: D007136:Immunoglobulins; D010835:Phytohemagglutinins