Submitted to: Federation of American Societies for Experimental Biology Conference
Publication Type: Abstract Only
Publication Acceptance Date: 4/21/2003
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: Current NRC recommended nutrient requirements of the young dairy calf may be inadequate to assure optimal growth and immune function. Using a BCG sensitization/PPD challenge model, we have shown that neonatal calves, relative to adult cattle, have vigorous antigen-specific cell-mediated immune responses (i.e., PPD-induced IFN-gamma, nitric oxide secretion, cutaneous reactivity) and weak antibody responses. The current study evaluated effects of plane of nutrition on lymphoproliferative responses of neonatal calves. Calves were fed a standard (ST, 0.57 kg/d of a 22% CP, 20% F milk replacer, n=4) or an intensified (IN, 1.14 kg/d of a 28% CP, 20% F milk replacer, n=4) diet for 7 wk. All calves and 4 steers (5-6 m of age) were vaccinated with BCG at the initiation of the study. Average daily gain was greater for IN than ST calves (1.55 kg and 3.28 kg, respectively). Proliferation was evaluated in antigen- and mitogen-stimulated cultures consisting of blood lymphocytes acquired immediately before and 7 wk after vaccination. Responses to PPD were absent before vaccination. PPD-induced CD4 and gamma/deltaTCR cell proliferation for vaccinated calves exceeded that of vaccinated steers. In addition, antigen-induced CD8 cell proliferation was greater in IN than ST calves, suggesting that the plane of nutrition modulates the responsiveness of a lymphocyte subset essential in cell-mediated responses.