Cattle need energy to survive the big picture, but that survival does not mean much if their daily nutrition is not balanced. Growth requires the appropriate combination of many nutrients, including protein, minerals, vitamins and even water.
Good supplementation programs will help meet these needs. However, as the summer slowly shifts to fall, finding adequate protein is more of a challenge. In general, as cattle graze, there is an expectation that producers match the season of the year with the nutritional requirements cattle need.
At the Dickinson Research Extension Center, Songul Senturklu, visiting scholar from Canakkale Onsekiz Mart Universitesi, BMYO, Canakkale, Turkey, measured the seasonal changes of protein by taking seasonal bimonthly forage samples.
Senturklu found cool-season crested wheatgrass went from 18 percent crude protein in early May to 8.5 percent in early June.
The native grasses had 13 percent crude protein in early June but decreased to a low of 7 percent in early August. No wonder cows with calves like to graze cool- season grass in the spring and then switch to native grass in early summer.
The cool-season grass has ample protein to meet the protein requirements for cows in late pregnancy or early lactation. Native grass has excellent summer protein as well and will meet the requirements of most beef cows nursing calves into mid-July. High milk producing cows struggle to meet their daily nutrient needs before those cows that do not milk as well.
Cow-calf operations depend on the nutrients that plants produce to meet the late-calving and early lactation nutritional requirements for their cows in late spring and early summer. The same is true for other cattle types such as replacement heifers and grass calves.
Medium- to large-frame grass yearlings may have slightly less crude protein requirements than the beef cow nursing a calf, so the early grass pastures meet those requirements as well. Of course, those requirements are reflective of the gain desired.
In recent years, the center has been running grass yearlings, and 2 pounds per day seems to be a reachable goal in terms of body weight gain. If a producer was to desire greater gains, the protein requirement will go up, but so will the energy requirement.
The center's cattle consistently have had around 2 pounds per day of average daily gain. They are given all the cool-season grass they can consume in May.
This is followed by putting the cattle on native grass in early June. Likewise, the replacement heifers have done well.