Maintaining cow herd nutritional requirements in an economically feasible way is vital to efficient cattle production, according to John Jaeger, Kansas State University associate professor of animal sciences. Jaeger has researched how producers can use dormant native range to graze beef cattle in conjunction with providing protein supplements.
One of the biggest ways to improve economic net returns is by limiting reliance on hay, he said. But before using dormant forages in place of hay, producers should consider a number of items.
"While using dormant forage as a forage base for our cow herd, we have to be aware of how much is available in the pasture before beginning to graze," Jaeger said. "This is important so we can calculate animal days on the pasture and know the nutrient content of the available forage to know how much protein supplement to provide."
Jaeger, a beef cattle scientist with K-State Research and Extension located in Hays, Kansas, noted a past method for gathering forage availability information was by measuring a square meter, clipping and drying the forage, then weighing what was left. A more modern method of collection is to use a disc meter on a stick with a hole in the disc.
Using this method, the disc is dropped down the stick; the amount of forage underneath the disc prevents it from hitting the ground. There is a ruler on the stick to measure how far the disc is being held from the ground. Similar to the previous method, the forage under the disc is clipped, dried and weighed. The resulting weight is then multiplied by 44 to get an estimate of pounds of forage per acre.
"Extension agents are knowledgeable about how to clip forage," Jaeger said. "To get a representative sample of the whole pasture, you need to clip multiple places within the pasture, and an extension agent can help you. He or she can also teach you how to use a disc meter so you get accurate measurements."
The quality of the forage and its protein content also are important, he said, and some factors can alter quality. Droughts can lead to problems, including differences in plant moisture, early plant maturing and early plant senescence. However, a drought can also lead to higher protein content in the dormant forages.
So while there is less available forage available during drought conditions, it is usually higher in nutrients, Jaeger noted. Therefore, producers will not need to provide as much protein supplementation when compared to a year with normal moisture.
"It is important to think about how the pasture has been used in the past as that can affect the quality or amount of forage in the dormant grazing season," Jaeger said. "Typically, here at the research center (Agricultural Research Center - Hays), we prefer to graze our stockpiled pastures early in the spring and allow the pasture to accumulate dry matter the rest of the year."
Jaeger suggested that if a producer needs to graze a pasture over a longer period for summer grazing, he or she should use the pasture early in the summer. This will allow dry matter in the pasture to accumulate the remainder of the growing season.
Also, while many forbs are not palatable to livestock, some are useful for grazing, he said. Wild petunias and sunflowers, for example, can be grazed and often have a higher protein concentration into the winter compared to native grasses. The nutrient content of these forbs also varies throughout the summer.
"Supplementation is typically required to maintain animal performance once the pasture drops below 7 percent crude protein," Jaeger said. "During winter months in western Kansas, we have found pastures drop to about 4 percent crude protein."
By supplementing protein to cattle, producers are feeding the rumen microbes to aide in digestion, which allows for improved performance, he said.
The supplement, Jaeger said, needs to be greater than 30 percent protein. If the supplement is lower, it provides other nutrients that may be unnecessary to the cow. If the supplement is greater than 30 percent, it will improve animal performance more so than the supplements that contain less than 30 percent crude protein. When providing adequate protein, a producer will ultimately improve forage digestion.
However, beef cattle also can be over-supplemented, he said. When over-supplemented, they will try to recycle some of the protein, but most is passed as waste. Past research has found that about three-tenths of a percent of body weight was the maximum, and feeding beyond that did not improve animal performance.
Traditionally, the cattle industry has used oilseed supplements, such as cottonseed and soybean meals, for protein supplementation, Jaeger said. Due to the recent rise of the ethanol industry, producers have begun using distiller's grains for protein. Distiller's grains are often readily available and can be more cost effective on a pound-of-protein basis.
"We also examined the frequency of supplementation, as it can reduce the labor and delivery costs associated with protein supplementation," Jaeger said. "Over the years a lot of research has been done on traditional oilseed supplements. Researchers found that protein can be fed once every six days or once weekly and still maintain adequate cow performance due to the ability of the cow to recycle excess protein."
Jaeger suggested that if a producer was going to feed two pounds of a supplement daily, the producer could instead feed 14 pounds once weekly and maintain adequate performance.
He also wanted to examine distiller's grain byproducts, as they have a different crude protein makeup. The oilseed supplements have less than 50 percent rumen non-degradable protein, while the distiller's grains have greater than 50 percent. He found there is not a difference in animal performance when feeding distiller's grains during the last trimester of gestation when that animal was fed daily, once every three days or once every six days.
Once a feeding time of either - once every three days or once every six days is scheduled, Jaeger said it should not be changed during the last trimester of gestation, as it can result in a decrease in performance.
More information about beef cattle systems research at the Western Kansas Agricultural Research Centers is available online.