Alfalfa with selenium boosts calf immunity

Alfalfa with selenium boosts calf immunity

A NEW study by Oregon State University researchers has found that adding selenium to fields planted with alfalfa will allow the perennial forage crop to "take up" the mineral in its tissues, providing better feed for calves and other livestock.

Results of the study were published, in part, in the journal PLOS One.

Selenium is a naturally occurring mineral that is found in heavy concentrations in some parts of the country and at low levels in others. Ranchers often provide selenium in supplements to livestock, but applications must be done carefully because there is a narrow range between the required level of selenium and toxic levels.

Providing the mineral in organic form greatly lessens the threat of toxicity, according to Jean Hall, a professor in Oregon State's College of Veterinary Medicine and lead author on the research.

"When selenium gets picked up by the plant, it goes right into the amino acid selenomethionine, and when the animals consume it, the selenium gets stored in the muscle in a benign way," Hall said. "The ranchers we've spoken with are extremely interested in these results because not only does it appear that this is safer for the animals, (but) it may be cost-effective as well."

During field trials, selenium was applied at varying levels to alfalfa hay fields after the first of three scheduled cuttings. Regardless of the level of selenium applied, the plants had taken up 83% of the selenium by the time of the second cutting. The remaining 17% of the applied selenium was taken up in the alfalfa by the third cutting.

The percentage of selenium uptake by the alfalfa was consistent, regardless of the amount applied, according to Hall.

"If we doubled the amount of selenium, the plants took up twice as much," she said.

The researchers then fed selenium-fortified alfalfa to calves and compared their growth to control animals. Several weeks later, the calves with supplemented diets had higher blood selenium levels at a rate commensurate with the amount of selenium applied to the fields. The calves fed selenium-fortified alfalfa also weighed up to 10% more than calves fed alfalfa without selenium.

Calves' weight growth increased with additional selenium, although there was more variability than the linear response by the plants, Hall said.

"We also tested weaned calves to see if selenium-fortified alfalfa might boost the efficacy of vaccinations, giving a boost to the animals' immune system," Hall said. "It appears that is the case. Calves fed the selenium-fortified alfalfa had increased antibody production — at a rate that mirrors the amount of selenium applied.

"The study demonstrates that selenium-fortified hay boosts the growth and vaccination response of weaned beef calves, which results in decreased mortality and improved slaughter weights," she added.

Selenium studies at Oregon State date back 50 years.

"Oregon is the only state where you can artificially fertilize fields with selenium, and because most areas of the state are deficient in the mineral, this may be a strategy to consider for ranchers," Hall said. "Some countries, including Denmark and Finland, require fertilization in fields to increase the amount of selenium in the food chain, so the precedent is there."

Other authors on the paper, all from Oregon State, include Gerd Bobe, Janice Hunter, William Vorachek, Whitney Stewart, Jorge Vanegas, Charles Estill, Wayne Mosher and Gene Pirelli.


Feed 'candy' patent

A U.S. patent has been granted to a Kansas State University-developed feed "candy" that stimulates the growth, health and reproductive functions of cattle, bulls and other livestock.

Jim Drouillard, Kansas State professor of animal sciences and industry, discovered a specific combination of molasses, oilseeds and oilseed extracts that, when heated and evaporated, forms a substance that improves the absorption of specific omega-3 fatty acids.

"It's a free-choice type of supplement in a block form — sort of like a big, 250 lb. piece of candy for livestock," Drouillard said. "It's put in the pasture, and the animals consume it whenever they want. The product's physical characteristics restrict the animals to consuming less than 1 lb. each day, making it a convenient and cost-effective way to deliver essential nutrients."

According to the announcement, the substance contains desirable fats that elevate levels of specific omega-3 fatty acids in the bloodstream, which can stimulate growth, improve immunity and enhance reproductive function and overall fertility in livestock that consume the supplement.

New Generation Feeds, a South Dakota-based company, has retained exclusive rights to the patented technology for use in its SmartLic brand of livestock supplements.

The patent, "Product & Process for Elevating Lipid Blood Levels in Livestock," was issued to the Kansas State University Research Foundation, a nonprofit corporation responsible for managing technology transfer activities at the university.

Drouillard is continuing research on the combination by working to improve the fats' resistance to bacteria in the digestive system.


Summer annuals

With hay stock levels at record lows in several midwestern states, beef producers looking to supplement their forage options could turn to summer annuals, which are known to thrive in summer heat, are drought tolerant and can be grazed or stored as feed, according to a forage expert from The Ohio State University College of Food, Agricultural & Environmental Sciences.

Viable examples include sorghum, sudangrass, sorghum-sudangrass hybrids, millet, teff grass and corn, according to Rory Lewandowski, an agriculture and natural resources educator for Ohio State University Extension.

These plants have the capacity to produce up to five tons of dry matter over the summer months, and a majority of them can be grazed or cut two or three times starting as soon as 30-45 days after planting, which makes them a good option for producers seeking other options amidst reports of declining hay supplies, he said.

Hay stored on U.S. farms as of May 1 totaled 14.2 million tons, a 34% decline compared to the same time last year, according to the U.S. Department of Agriculture's May 10 "Crop Production" report.

"While most producers are optimistic about the growing season, with the first hay crops looking good at this point, I want to alert producers that there are other opportunities out there," Lewandowski said. "This way, producers are aware of what their options are and have time to do some planning and planting now so they won't be in a position over the summer wishing they'd known about these options sooner."

An advantage of summer annuals is that they can be used as a double crop when a previous crop is harvested by the end of June, he said. For example, producers can plant a summer annual after the first or second cutting of alfalfa or after harvesting barley.

Other advantages are that summer annuals grow fast, mature quickly and can be harvested for stored feed, Lewandowski said.

However, he cautioned, forage quality for summer annuals is good at the vegetative growth stage but declines quickly once the plant reaches its reproductive stage. Extremely dry conditions or drought can also be a concern, Lewandowski said.

"Summer annuals can accumulate nitrates in the lower portions of the stems under drought conditions," he said. "To reduce the risk of nitrate toxicity in livestock, producers should reduce nitrogen fertilization and make sure livestock don't graze lower than 8 in.

"Producers also need to be aware that sorghum, sorghum-sudangrass hybrids and sudangrass all have varying levels of potential for prussic acid poisoning if plants are consumed when they are under stress conditions," he added.

Lewandowski provided the following tips for planting summer annuals:

* Plant summer annuals when the soil temperature is 60-65 degrees F.

* Plant forage sorghum at 12-15 lb. per acre; millet, sudangrass and sorghum-sudangrass hybrids at 25-35 lb. per acre; teff grass at 4-5 lb. per acre, and corn used as forage at about 80,000 kernels per acre and seeded with a grain drill.

* Soil pH should be 6.0-6.5, soil phosphorus should be at least 15 parts per million and soil potassium should be 100-125 ppm.

* All summer annuals respond to nitrogen, and the best yields will be obtained when nitrogen is applied at 50 lb. per acre before or at planting and then again following each cutting or grazing pass.

Volume:85 Issue:24

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