AABP Executive Director Dr. Fred Gingrich is joined by Dr. Jeffrey Hall, a cattle technical services veterinarian with Huvepharma, Inc. Hall discusses the critical role that copper, selenium, manganese and zinc play for optimal immune system function, reproductive performance and growth. He reminds us that it is critical to provide an adequate amount of mineral to the cow during the last trimester of pregnancy. Over 95% of the transfer of minerals to the fetus occurs during the last trimester to ensure the calf is born with adequate body stores of these trace minerals since 95% of the calf’s diet is milk and stores will be depleted during this time. Hall states that trace mineral deficiencies are common and veterinarians can play a key role in assisting producers with assessing the trace mineral program. We discuss various testing and monitoring strategies for trace minerals. Hall suggests to start with testing the animals to evaluate if there are deficiencies or excesses within the herd and then do nutrient and ration analysis to determine the cause. Hall describes testing strategies to determine if liver biopsies or blood samples are appropriate, which animals to test and when to test them. In addition, he offers tips for performing a liver biopsy. Cows should be supplemented with trace minerals year round and veterinarians should establish monitoring programs to ensure the program is working. Hall suggests that veterinarians can discuss the economic implications to producers to demonstrate the importance of a testing program. Loss of young open cows, health of calves and weaning weight implications are all financial reasons to work with producers on a testing program. Hall estimates that minor deficiencies can results in a loss of $75 per cow per year and major deficiencies can cost up to $200 per year. One way for veterinarians to establish the amount of mineral consumed per cow is to look at the purchase history for the past year of minerals. To calculate, use the following formula: 
Tons of mineral purchases * 2000 * 16 = number of ounces used per year.
 (# of ounces used/number of cows)/365 = ounces per head per day.

 Evaluation of a trace mineral program is a valuable service veterinarians can provide to their cow calf producers.

 Links:

Common Vitamin and Mineral Abnormalities in Beef Cattle – Jeffery Hall DVM, PhD, DABVT 

List of liver biopsy supplies needed 

AABP Nutrition Committee page