Cows depend on highly available trace minerals to deliver the essential nutrients needed to achieve and maintain pregnancy. While major trace mineral deficiencies may not be seen, the effect of marginal mineral deficiencies may still be serious in nature.

According to Mike Socha, dairy research team leader at Zinpro Corp., insufficient stores of zinc, manganese, copper and cobalt impact reproductive performance in the following ways:


Deficiency linked to decreased conception rates, increased retained placentas, increased dystocia and lead to abnormal estrus.


  • Essential for fatty acid and cholesterol synthesis, both of which are critical steps in the formation of estrogen, progesterone and testosterone.
  • Marginal deficiency linked to silent heats, reduced conception rates, abortions and cystic ovaries.


  • Research shows dairy cows with higher serum copper levels had significantly less days to first service, fewer services per conception and fewer days open.
  • In addition, factors affecting availability of copper may negatively impact follicular development, resulting in reduced or absent estrus and decreased conception rates.


  • Recent research shows that multiparous dairy cows may be deficient in vitamin B-12 stores when supplemented at or above National Research Council recommended levels for cobalt. Milk production creates a significant drain on cobalt stores, while poor availability of cobalt makes replenishment difficult.
  • Deficiency linked to reduced fertility and suboptimal conditioning of the offspring.

Improving overall trace mineral status by providing highly available (complexed) trace mineral sources in the diet is one way of minimizing the risk of less than favorable reproductive performance. Research has shown that even in diets fortified well in excess of NRC (2001) requirements for zinc, manganese, copper and cobalt, replacing inorganic minerals with complexed sources resulted in more cows becoming pregnant and cows becoming pregnant sooner after calving.

The decline in animal performance when trace mineral status is compromised is shown here: