Trace minerals, particularly zinc, manganese and copper, are known to influence embryonic and fetal survival, growth and overall beef cattle reproduction. As we look at beef cattle research over the years, we can see consistent results across multiple studies showing improvements in pregnancy and conception rates in cattle fed trace minerals from sources using a unique absorption pathway, such as performance trace minerals.
In one study conducted at the University of Tennessee, researchers found that feeding performance trace minerals helped produce more culturable oocytes and transferrable embryos when compared to inorganic trace minerals. In a different study, performance trace minerals fed to Braford cows improved pregnancy rates and reduced calving intervals compared to inorganic trace minerals.
What ultimately matters, however, is calves being born. Most pregnancy losses occur in the first 30 to 60 days post-conception, with more than 70 percent of total pregnancy loss happening within the first 45 days of gestation. This makes early embryonic survival a crucial factor in overall beef cattle pregnancy retention. Anything producers can do to decrease embryonic loss during that time will have major impacts on overall beef cattle reproduction success.
Research overview
In a recent study feeding 129 heifers at South Dakota State University, researchers found that performance trace minerals play a key role in early pregnancy retention in heifers.
The heifers included in the study were housed in the facilities for a few weeks before the study began, allowing heifers to acclimate to their pens and develop in low-stress conditions. Around 30 days post-weaning, the heifers were randomly assigned to a diet with one of two trace mineral supplements:
• Inorganic—manganese hydroxychloride, zinc hydroxychloride, basic copper chloride and cobalt carbonate; and
• Performance trace minerals—manganese amino acid complex, zinc amino acid complex, copper amino acid complex and cobalt glucoheptonate.
At approximately 15 months of age, heifers were synchronized and then artificially inseminated. Pregnancy checks were started between days 17 and 21 post-insemination using lymphocyte gene expression. Blood samples were collected to look for markers that indicated maternal recognition.
Blood samples were taken between days 22 and 28 and checked for pregnancy-associated glycoproteins that indicate attachment of the embryo to the uterine lining. Pregnancy was further confirmed by ultrasound on day 30 and day 60.
Improve pregnancy retention
Although pregnancy rates within each time point did not differ between diet groups at the first pregnancy check (days 17 to 21), by day 60 the heifers supplemented with performance trace mineral had decreased embryonic loss that translated to a 73 percent pregnancy retention rate, 11 percent higher than the group supplemented with inorganic sources of trace minerals.
A review of existing literature suggests heifers that maintain pregnancy through day 60 post-conception have a high likelihood of remaining pregnant all the way through to calving. In other words, heifers fed performance trace minerals during development retained early pregnancies at a higher rate and would most likely have a greater calving rate.
The results of this study indicate that even in low-stress, well-managed conditions, there is still opportunity to improve pregnancy retention by supplementing performance trace minerals. Moreover, evidence suggests that higher-stress environments further magnify the need for improving trace mineral nutrition, making performance trace minerals the right choice for improving beef cattle reproduction in any operation.
This can result in a positive economic benefit for your beef cattle operation as well. Based on a price of $125/cwt for weaned calves and a 60-day breeding season, performance trace minerals can generate a return on investment of 4:1. — Jason Russell, beef nutritionist at Zinpro Corporation
