Influence of Increased Supplementation of Organic-Complexed Zinc to Beef Cows During Gestation and the Effects on Offspring

The objective of this study was to determine the effect of increasing zinc (Zn) supplementation of beef cows during gestation on calf performance. Angus crossbred cows confirmed pregnant with female sexed semen (n = 83) were allotted to 4 groups (20 to 21 cows/group), 2 groups/treatment. There were 2 treatments: 1) grain supplement with inorganic Zn to meet current National Academies of Sciences, Engineering, and Medicine requirements (CONTROL), and 2) grain supplement containing an additional 360 mg/day of Zn as an amino acid complex (Zinpro Availa Zn; HIGHZN). A subset of cows (n = 32; 16 cows/treatment) was selected for colostrum sampling. Once a cow had given birth, the cow-calf pair was left alone until the calf stood and suckled once, then colostrum samples were collected from the dam. Birth weights and morphometric measurements were recorded for every calf. At 48 hours following parturition, blood samples were collected from calves whose dam had been sampled. Calf whole blood samples were utilized for a complete blood cell analysis. The number of basophils tended to be greater (P = 0.09) for the calves from dams on the HIGHZN treatment (0.17 K/µL) when compared to calves from dams on the CONTROL (0.09 K/µL) treatment. Colostrum and serum samples were analyzed for immunoglobulin A and G concentrations. There were no differences observed (P > 0.5) in any of the measures collected. Overall, organic-complexed Zn supplementation during gestation had minimal effects on the calves at birth.