Shipping Suppresses Lymphocyte Blastogenic Responses in Angus and Brahman × Angus Feeder Calves

Abstract

An experiment using 40 Angus or Brahman × Angus preconditioned feeder calves was conducted to evaluate the influence of shipping on cellular immune reactivity. Steers were allotted on the basis of weight and breed to a control or shipped group. Shipped steers were trucked 700 km to a feedlot; control steers remained at the ranch of origin. Total and differential leukocyte counts, phytohemagglutinin skin-test responses, lymphocyte blastogenic responses, monocyte phagocytic function, packed cell volumes and concentrations of plasma cortisol were determined before, immediately after and 1 wk after shipment. At unloading, total leukocytes were increased (P<.05) in shipped Angus steers. Shipped steers also had higher (P<.01) numbers of neutrophils. Skin-test responses to phytohemagglutinin were higher (P<.05) in Angus than in Brahman × Angus steers, but shipping did not influence the reaction. Lymphocyte blastogenic responses were lower (P<.05) in shipped steers; however, cortisol levels in plasma were not elevated (P>.10) in shipped calves. Monocyte phagocytosis and packed cell volume were not influenced by shipping. These data suggest that shipped steers have suppressed lymphocyte blastogenic responses. Copyright © 1984. American Society of Animal Science . Copyright 1984 by American Society of Animal Science