Late-Breaking: Immune responsiveness of neonatal beef calves is altered by late gestational Cu, Zn, and Mn supplementation

Abstract Multiparous, fall-calving, Sim-Angus cows (n = 48) were individually-fed tall fescue-based hay and supplemented to meet/exceed nutrient recommendations except Cu, Zn, and Mn. From 91.2 ± 6.2 d pre-calving, cows received: no additional Cu, Zn, or Mn (CON); Cu, Zn, and Mn sulfates supplying 133% NASEM recommendations (ITM); Cu, Zn, and Mn metal methionine hydroxy analogue chelates (MMHAC, MINTREX®, Novus International) supplying 133% recommendations (CTM); or Cu, Zn, and Mn sulfates and MMHAC supplying 100% recommendations (reduce and replace, RR). Calf whole blood was collected at 48 h of age for ex vivo stimulation with toll-like receptor agonists lipopolysaccharide (LPS), lipoteichoic acid (LTA), and peptidoglycan (PGN) at low (-L) and high (-H) concentrations for 4 h at 37°C. Expression of inflammation-related mRNA was determined using RT-PCR (reference gene: S9). Data were analyzed with treatment and breeding group as fixed effects. When treatment P < 0.15, LS means were separated. Pro-inflammatory cytokines interleukin (IL) 1β and IL-8 were greater (P ≤ 0.10) in calves born to RR cows than all other treatments when exposed to PGN-L. Expression of IL-1β was greater (P ≤ 0.09) in CTM and CON than ITM when exposed to LPS-L and in RR than ITM when exposed to LTA-L. Expression of inducible nitric oxide synthase (iNOS) in CTM calves was greater (P ≤ 0.09) than ITM and CON when exposed to LTA-L and PGN-H and than all other treatments when exposed to LPS-L. When exposed to PGN-L, iNOS was greater (P ≤ 0.06) in CTM and RR calves than CON. Treatment did not affect (P ≥ 0.22) IL-6 and tumor necrosis factor α expression. Data demonstrate that late gestational chelated trace mineral supplementation may alter neonatal calf pro-inflammatory pathways. These changes may increase innate immune response to bacterial pathogens during the challenging neonatal period, potentially increasing survival.