Mining value out of minerals: Vitamin/mineral abnormalities and effects in Montana
for Tri-State Livestock News
Copper may have historically been king in Montana, but today, it’s the most common deficiency in the state’s beef cattle.
Jeff Hall, DVM, said 72 percent of the Montana-specific tests run at the Utah Veterinary Diagnostic Lab showed copper deficiencies. The toxicologist spoke at the Montana Nutrition Conference in Bozeman April 29.
But just like in the mining days of yore, a good mineral plan can mean good money.
“I want to put this in terms of not only a health impact, but also a bottom line,” Hall said.
He shared an example of a 6:1 return on investment for a south-central Montana ranch with a corrected copper deficiency.
When they identified the deficiency, Hall said, the ranch had reported a multi-year breed-back average of 88-89 percent, culling 10-11 percent of the herd each year after preg-checking. They treated 10-15 percent of their calves each spring for health issues. Weaning weights were average, he said, but based on the genetics they were investing into the herd, they should have been better.
“You can see it in cows, but the predominant economic loss we see [with copper deficiencies] is in calves,” Hall said.
In the three years following a correction of the mineral deficiency, Hall said the ranch averaged a breed-back efficiency in excess of 95 percent, and less than 0.5 percent of calves require health treatments in the spring. Weaning weights increased 36 pounds per calf on the three-year average.
In current cattle prices, Hall said, the ranch figured they added $110 per calf on the added weaning weights, lower treatment costs and higher conception rates. They were previously supplementing the herd with a mineral that costs $16-$17 per cow-calf pair, but moved to a more complete supplement that costs $34 per cow-calf pair.
“So they increased costs by $18, but they increased their profit by $110,” Hall said. “That’s the kind of results I see with a good mineral program.”
Mineral deficiencies are often presented in other health issues. Nationwide, Hall said more than 92 percent of calves their lab tested with dust pneumonia were found to have either a copper or selenium deficiency at the time they got the pneumonia.
“They’re immunocompromised because of the mineral deficiency,” Hall said.
Selenium deficiencies are the number two offender in the state of Montana, with 56 percent of the state’s samples at the Utah lab showing inadequate levels. However, selenium availability varies greatly in the state. The majority of selenium deficiencies are found in the west third of the state. The central third of the state is hit or miss, he said, but the eastern third is more likely to deal with excess and toxicity of selenium.
“So you need to be very careful with selenium, depending on the areas that the cattle will be grazing on. It does vary significantly on a herd-by-herd basis,” Hall said. “Deficiency is often the same clinical presentation as excess.”
The sample method of choice to test for both copper and selenium levels is a liver biopsy.
Hall recommended testing a good cross-section of the herd to get a true picture of the overall health. He shared another example of a ranch that submitted 10 liver biopsies to test for mineral deficiencies, with results all over the board – some severely deficient, some just inadequate, some with very healthy levels. With more investigation into the test subjects, they found it wasn’t a supplementation problem, rather, a pecking order issue. The replacement heifers were very deficient, first-calf heifers somewhat deficient, and up the line to the “boss” cows who were in good shape.
“A dominant cow will camp out at the mineral tub and hog it all,” Hall said.
To alleviate that concern, he recommended a mineral station for every 50 head in the pasture.
In Big Sky country, big ranges present another common concern for mineral supplementation.
“A question I get a lot in Montana especially is – we supplement well in the winter when they’re down in the valley, but they don’t get anything in the summer when they’re up in the high mountain range,” Hall said.
That’s OK, but you can expect the cattle to “eat it like cotton candy” when they come back to mineral in the fall.
“I’m yet to see a case of an animal over-eating that mineral when they’re on free choice. They’re trying to stock up,” he said.
It may take 2-3 weeks to build their system back up to adequate mineral levels after a summer without, so let them eat as much as they want.
“The recommended daily amount is based on 365 days a year, so if they’re only getting it five months out of the year, you can expect their intake to go up – they’re trying to make up ground.”
He pointed to another study conducted in three different states where different test groups were supplemented year-round, held off minerals for three months, held off for six months and held off for nine months. In the end, there was a less than 10 percent difference in intake across the four treatment groups.
The cows that were held off mineral the longest actually had the highest intake, overeating to try to make up for deficiencies while passing more through the system without absorbing it.
Of course, the most critical mineral moments for a cowherd are in gestation.
“If the calves have inadequate body reserves, it’s because mama ran out of stuff to give the calf in utero,” Hall said.
Most of that transfer occurs in the third trimester, when the cow is also working to produce antibodies necessary to produce high-quality colostrum.
“So, if she’s already depleted her system to make sure the fetus has enough and put herself in a deficient state, how effective do you think that colostrum is going to be?” he asked.
Increases in production outputs and changes in the production cycle over the past 30-40 years have put more pressure on cows and increased the need for complete mineral supplementation.
“We’re forcing these cattle to calve 30-60 days before there’s even a thought of any green up, and from a physiology standpoint is the worst possible time of the year to have those babies drop,” he said. “So unless you’re supplementing them adequately to allow for what they would have normally been getting had they calved in green vegetation, we’re going to have problems.”
Timing is everything to make sure nutrition and health correspond, too.
“Most every vaccine failure I’ve tracked, nationwide, goes back to a poor response to the vaccine, which most likely means they were immune compromised,” Hall said.
If cows have been off supplements over the summer months, he said, the worst time to vaccinate is as soon as you pull them off summer range. “To optimize vaccinations, get them back on supplements, give them a couple weeks to rebuild their systems, then vaccine and you’ll get a much better response.” ❖
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