The four principal trace elements essential to successful beef cow reproduction, are copper, zinc, manganese and selenium.
All too often, they are either deficient in forage or bound by compounds also found in forage, which makes them biologically unavailable to cattle. I instruct beef producers to plan the best mineral-(and vitamin-) feeding program to their breeding cows (and bulls), so high conception rates can be achieved during this year’s breeding season.
Even the most promising beef cows, if truly trace-mineral deficient, will suffer from poor conception rates or high failure of embryonic survival. These mineral-deficient cows might look and act reproductively sound (active estrus), but their true reproductive system (ovulation) might be inactive. Similarly, bulls can suffer from general infertility.
This happened at a 150-head cow-calf operation I visited a couple of years ago. These cows had a consistent history of reproductive issues until a good mineral (and vitamin) program was implemented.
Here is their story. At the end of their 2017 calving season, things were very dismal. There were lots of pulled calves and a good percentage of cows had retained placentas. It was also common to see both weak cows and small calves.
A couple of weeks into the breeding season, things remained bad. Many cows (as well as replacement heifers) failed to cycle early, with many first-cycling when the bulls were turned out. The newborn calves were not doing well either. Many had persistent scours throughout the summer. The final assessment of the 2017 breeding season confirmed everybody’s worst nightmare — 30 out of 149 cows (20 per cent) were vet-confirmed ‘open.’
With some investigation, I revamped their entire mineral-feeding program. Rather than feed their favoured “economical” cattle mineral, which I found had unbalanced levels of salt, phosphorus, trace minerals and vitamins, I switched their entire herd to well-fortified “breeder” cattle mineral throughout the winter of 2017-18, the 2018 calving and subsequent breeding seasons.
The foundation of their “breeder” cattle mineral is a specific complement of macro minerals (calcium, phosphorus and magnesium) as well as a high level of trace minerals, especially copper, zinc, manganese and selenium fortified at the best concentrations as well as in highly bioavailable chelated/organic forms. Once these macro and trace minerals are consumed at three to four oz. per head, daily, they reach the cows’ digestive tract, where they are: (i) quickly absorbed, (ii) efficiently metabolized and (iii) highly retained to build optimum mineral status.
As a result, November 2018 vet-confirmed pregnancies showed that out of 120 cows and replacement heifers, all but four older brood cows were pregnant (three per cent open). Furthermore, the breeding season of the cow herd was tightened from 90 to 65 days. Its weaned calves benefited too — weaning weights on average were 45 lbs. heavier. The goal for the fall of 2019 is to achieve a 98 per cent conception rate and 60-lb. heavier weaned calves.
This personal testimony is a reflection of the importance of essential trace minerals (and vitamins) status upon cattle reproduction as backed by an array of scientific research. Here is a summary of comparing good versus poor mineral status upon reproductive performance in beef cattle.