24 Maternal supplementation with different sources of trace minerals to beef cattle and its effects on postweaning responses of the offspring

Abstract The goal of this trial was to evaluate the effects of different sources of trace minerals on fetal programing and their impact on cow reproductive and postweaning offspring performance until slaughter. Seventy-two non-lactating, pregnant Angus cows [initial body weight (BW) = 637 ± 13 kg; body condition score (BCS) = 5.5 ± 0.07; and age = 6.1 ± 0.57; exposed to artificial insemination (AI) = 54 and bull = 18] were ranked by BW and BCS and assigned to receive a supplement containing: 1) Cu, Mn, and Zn from sulfate source (INR; n = 24), 2) Cu, Mn, and Zn from organic source (ORG; n = 24), or 3) Cu, Mn, and Zn from hydroxychloride source (HXD; n = 24). From d 0 to calving, cows remained on the same pasture and were fed individually three times a week. After calving, pairs were assigned to the general herd management, including inorganic mineral supplementation. Calves were weaned at 6 mo of age and were managed as a single group on a backgrounding period for 85 d. Calf blood samples were collected on d -15, 0, 4, 8, 15, 20, and 28 relative to weaning to evaluate stress-related markers. After this period, calves were fed to finish in a commercial feedyard. Cattle were then harvested, and carcass data were recorded. Though not the focus of this trial, there was a numerical improvement (P = 0.22) in overall subsequent pregnancy rate for the HDX (92.1%) compared with the ING (74.3%) and ORG (75.2%) cows. Also, the HDX had a tendency (P = 0.07) for improvement in liver Cu status compared with the other treatments. At weaning, no treatment differences were detected (P ≥ 0.88) in calf weaning BW and average daily gain from weaning to feedyard receiving. There were no differences (P ≥ 0.22) in the blood stress-related enzymes and metabolites. However, there was a tendency for a decrease in plasma haptoglobin at day 15 post-weaning (P = 0.07) for the calves from HDX supplemented cows relative to other treatments (Figure 1). Which might indicate potential amelioration of inflammation for the calves from cows supplemented with HDX trace minerals during pregnancy. Feedyard growth performance were similar (P ≥ 0.35) across treatments for the offspring (Table 1). No treatment effects were detected (P ≥ 0.17) for carcass traits between treatments (Table 2). Overall, different sources of trace minerals supplemented to late gestating beef cows yield similar effects on offspring performance from weaning and background period until slaughter, whereas a potential amelioration of inflammation was observed in calves born to HDX cows.