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By Susan Himes—
Ranchers need to keep in mind that the wrong quantities of minerals can be dangerous or even deadly to cattle, said experts from the Texas A&M AgriLife Extension Service.
When it comes to cattle and minerals, what works for a rancher 700 miles away may actually work better for you than what works for a neighbor seven miles down the road; it all depends on what is in your soil, supplements, feed, forage and water supply.
There is no one-size-fits-all approach to minerals,” stressed Joe Paschal, Ph.D., AgriLife Extension livestock specialist, Corpus Christi. “What works for your neighbor’s cattle won’t necessarily work for you. There are a lot of factors producers must take into consideration.”
“Proper livestock nutrition is a key factor in your cattle’s health and productivity,” added Thomas Hairgrove, DVM, Ph.D., AgriLife Extension cattle veterinary specialist in the Texas A&M University Department of Animal Science. “Knowledge of your herd’s mineral status is fundamental to developing an optimal herd health program.”
The key to understanding individual needs centers on the total nutrition of the herd. For example, diets high in protein and/or potassium or low-carbohydrate diets can impair magnesium absorption, said Hairgrove.
He said zinc and copper need to be absorbed in a specific ratio. Excess zinc reduces the amount of copper absorbed and excess iron or sulfur can interfere with absorption of other minerals.
“In other words, an excess or deficiency of one mineral affects how other minerals function in the animal,” said Hairgrove.
Sometimes, he said, extreme cases can lead to death in a herd. So, what happens when you find a dead cow, or multiple dead cows over a period of a few months or a year? Hairgrove and Paschal hope Texas producers and veterinarians realize AgriLife Extension offers an invaluable resource.
“In Burleson County we had a producer who had almost 20 head of cattle die over a period of a year,” said John Grange, AgriLife Extension agent for Burleson County. “This was an older producer in his 90s and when his son became aware of the situation, they consulted their local veterinarian.”
The veterinarian was having trouble diagnosing the issue, so she contacted Texas A&M AgriLife. Grange said once he, Paschal and Hairgrove put their heads together, they decided to conduct several tests to rule out possible causes.
“Working as a team, we conducted tests on hay, forage, soil and water samples,” he said. “Dr. Hairgrove also pulled blood and urine samples on the cattle. This case showed the importance of how strong the Texas A&M AgriLife Extension Service is and how, together, we were able to help our producer.”
Grange said they were able to rule out many common issues and get to the core problem for the producer and that by utilizing the entire team not only were they able to help this producer, but ultimately aid in another local case as well.
The Burleson County producer found most of the animals observed experienced a sudden death in the pasture. The few animals observed appeared to exhibit grass tetany signs, which are usually associated with magnesium deficiency.
Urine and blood samples were taken from 10 cows and submitted to the Texas Veterinary Medical Diagnostic Laboratory to determine mineral status. These indicated only a low serum copper status, which would not cause sudden death. Magnesium deficiency cannot always be evaluated from urine or blood.
The most sensitive and practical test to determine the animal’s magnesium status and predict supplementation value requires measuring urinary creatinine and magnesium. Further testing indicated these cattle were deficient in magnesium in their diet. These cows were determined to be also deficient in selenium, as shown in alternate testing strategies.
Analysis of soil, forage and water confirmed the deficient dietary status of this herd. Protein, energy and mineral supplementation based on forage, water and soil analysis began, and follow up with the owner indicates no more death loss.
“It is never as simple as putting out a mineral block and assuming that it will meet your cattle’s needs,” stressed Hairgrove. “This producer’s mineral supplementation consisted of white salt, yellow salt and trace mineral block, yet the deaths of 20 animals appear related to their mineral status.”
Hairgrove said the take-home message is to work with your local veterinarian and AgriLife Extension county agents to interpret laboratory results relative to your cattle’s body condition, forage and water quality, and potential for disease ortoxic plant
“The reality is there is a lot of cropland that has been turned into pasture that is very low in soil mineral, not just nitrogen, phosphorus or potassium, but many of other soil minerals too,” said Paschal. “Before putting animals out to graze on a new location, a little soil and water testing and forage analysis can go a long way. If you know what you are working with in advance, it will really be to your animals’ benefit.”
“We want producers to be aware that no matter where in Texas they live, there’s an AgriLife Extension county agent they can call for help,” said Grange. “We encourage ranchers to call us first when they have a problem, not last. Even if we do not know the answer, the access and resources available to us are extensive and we will know how to find the AgriLife expert who can provide the answer.”
Paschal added that “Dr. Google” doesn’t have the answers and should not be considered a reliable source and that a little testing, common sense, and best management practices can go a long way in stopping preventable deaths.