Drought-impacted forages may be low in trace minerals which can also lead to a reduced ability to cycle causing a failure to breed back and have a live healthy calf. Average mineral concentration of grasses from a MT study showed that Cu and Zn in grasses were deficient (< 6 ppm Cu) and < 21 ppm for Zn. The requirement for Cu is 10 ppm and 30 ppm for Zn. Similar results were also reported for native grasses in TX. Reproductively, a deficiency in Cu can lead to decreased conception rates, infertility, silent heats and fetal resorption. Other symptoms include: poor growth, rough hair coat, fragile bones, diarrhea, and cardiac failure. Zinc (Zn) deficient cows appear to display abnormal estrus as well as reduced fertility. Manganese (Mn) deficiency will result in impaired ovulation while a deficiency of selenium (Se) can lead to cystic ovaries and erratic, weak or silent heat periods. All four of these trace minerals can be provided by a Multimin®90 injection at critical production periods (calving, branding/prebreeding, weaning).
In one research study, cows were provided Zn, Cu and Mn supplementation and were compared to cows not given any additional Cu, Zn or Mn. The average length of time from the beginning of the breeding season to conception was 22 days for trace mineral supplemented cows compared to 42 days for non-supplemented cows.