Long-term effect of organic trace minerals on growth, reproductive performance, and first lactation in dairy heifers

The effect of trace mineral nutrition in utero and during growth and first lactation was evaluated using 64 multiparous dry cows supplemented with organic (OTM) or inorganic trace minerals (ITM) for 60 d before calving. At calving each calf was alternately assigned to OTM or ITM, to obtain 32 calves in each treatment. Calves received OTM or ITM treatments in colostrum (from treatment mothers), milk replacer, and starter, and then as heifers they received treatment in a TMR until 100 DIM. Growth, reproductive, and lactation performances until 100 DIM were evaluated. Age at calving was compared by treatment. Body weight, hip height, withers height, and heart girth were not affected by the trace mineral form received before calving (P > 0.05) except near calving, when these traits were affected by some heifers leaving the study as they calved. Heifers fed OTM tended to calve earlier than those supplemented with ITM (P = 0.07). Overall milk yield until 100 DIM was greater in OTM supplemented heifers (P = 0.09); however, trace mineral form did not affect milk quality. Overall, in the long term, OTM appeared to improve age at calving and early-lactation milk production of dairy heifers, which may affect their future productive life.