Effects of late gestational copper, zinc, and manganese source and inclusion in beef cattle

Abstract

A study was conducted to determine the effects of source and inclusion of Cu, Zn, and Mn during late gestation on cow and calf mineral status, fetal growth, and offspring immune function and pre-weaning performance. Cows received 1 of 4 treatment during late gestation: no additional Cu, Zn, and Mn (CON), inorganic trace minerals to supply 133% of recommendations (ITM), chelated trace minerals to supply 133% of recommendations (CTM), or both inorganic and chelated trace minerals to supply 100% of recommendations (RR). Cows fed CTM had greater post-calving liver Cu and colostrum yield and lactose. Gestational trace mineral treatment did not affect fetal growth; however, the inclusion of chelated Cu, Zn, and Mn in the maternal diet resulted in greater neonatal calf liver Cu. Calves born to cows fed RR tended to have less liver Mn than all other treatments. Calf plasma Zn was maintained from 0 to 48 h of age in ITM and CTM calves but decreased during that period in CON and RR. Calf serum immunoglobulins at 48 h of age were not affected by treatment. Also at 48 h of age, an ex vivo whole blood stimulation assay using Toll-like receptor (TLR) agonists to determine immune responsiveness was utilized for a subset of calves. The inclusion of chelated trace mineral in the diet during late gestation resulted in greater mRNA expression of pro-inflammatory cytokines interleukin 1[beta] and 8, as well as inducible nitric oxide synthase, in calf whole blood when exposed to TLR agonists. In conclusion, gestational trace mineral supply did not alter fetal growth or passive transfer, but these data indicate that late gestational supply of chelated trace minerals improves cow and calf Cu status, neonatal calf Zn metabolism, and calf innate immune responsiveness to bacterial pathogens.