The Effect of Dietary Trace Minerals During Late Gestation on Health and Performance of the Dam and Progeny

The objective of this study was to investigate the effects of supplemental dietary trace mineral source and zinc concentration during the non-lactating period of approximately 60 d prepartum on: (1) dairy cow performance through 150 days in milk and; (2) composition of colostrum and calf performance. Fifty-two Holstein and cross-bred cows were utilized at the University of Minnesota (U of MN) St. Paul dairy (STP) and 62 Holstein cows at the U of MN Northwest Research and Outreach Center (NWROC, Crookston, MN) dairy. Treatments were: (1) 100% inorganic trace mineral supplementation (CON); (2) organic trace mineral supplemented at the following rate: 40% of supplemented zinc (Zn), 24% of supplemented manganese (Mn), 69% of supplemented copper (Cu) and 100% of supplemented cobalt (Co) supplied by 4-Plex (Zinpro Corp., Eden Prairie, MN; OTM) and (3) OTM with additional Zn from Zn-methionine (OTMZ). Dietary trace mineral supplements were formulated to provide similar amounts of Co, Cu and Mn. Dietary Zn supplemental amounts were similar for CON and OTM (75 mg/d), but approximately two times higher for OTMZ. Heifer calves born from the cows at STP and all calves born at NWROC were evaluated for feed intake and growth performance through 56 d of age. Bull calves born at STP were used in a study to evaluate the affect of additional Zn on intestinal development. Under conditions of the current study, treatment during the dry period did not have an effect on milk yield. Number of pregnant multiparous cows at NWROC fed OTMZ tended (P = 0.09) to be greater at 150 days in milk compared to CON and OTM. There were no effects of treatment on colostrum protein or immunoglobulin concentration at either location. For STP and primiparous cows at NWROC, treatments did not significantly affect the fat content of colostrum. Treatment did affect colostrum fat concentration from multiparous cows at NWROC with cows fed OTMZ having a higher concentration of fat in colostrum than cows fed CON. No effect of treatment was observed on liver TM concentration, hematology profile, and intestinal villus height or crypt depth under the conditions of this study.