NDSU Extension Service, Published January 23 2012
Sufficient nutrients vital for beef cowsFARGO - A summer of excessive moisture and good grass growth followed by record high temperatures and record low precipitation this winter has provided many northern Plains cattle producers with the opportunity to extend their grazing season well beyond normal.
"Although producers currently grazing are most likely saving money by not dipping into harvested or purchased hay reserves, cow stage of gestation and coincident nutrient requirements must be considered to determine whether cows are getting the nutrients they need from midwinter grasses," says Carl Dahlen, a North Dakota State University Extension Service beef cattle specialist.
These cows' nutrient requirements are changing as the animals progress into the third trimester of pregnancy. Depending on their calving season, many of the cattle on pastures are experiencing this requirement increase.
However, the protein of forages standing at this point is very low (probably no more than 4 to 5 percent). Cows during the third trimester should be eating feed with around 8 percent protein, Dahlen says.
In addition to protein percentage, producers need to keep in mind the physical form of the standing forage.
"As we progress into winter, the pasture grasses are more susceptible to being knocked over by cattle or weighted down by snow and wind," Dahlen says. "Add this to the fact that winter grasses are less palatable compared with earlier in the year, and it becomes difficult for cattle to consume the amount of forage they need."
The mineral and vitamin content of standing forages likely is below requirements as well. Minerals at this stage largely are needed to develop a calf's immune system through nutrients circulating through the cow and from nutrients that will be available for colostrum and milk production once the calf is born. Not having proper minerals now could be a big issue for calf health in a few months.
Not meeting cattle's nutrient requirements also can affect fetal programming, although the impact is not necessarily seen immediately, according to Dahlen.
Rick Funston, Extension beef reproductive physiologist at the University of Nebraska-Lincoln, has conducted considerable research on the impact of protein supplementation during late gestation on the health and performance of the offspring. Funston found that calves born from cows that were fed supplements during late gestation had better growth rates, a greater percentage of heifers became pregnant during their first breeding season, and calves put into feedlots had greater feedlot performance.
"We're talking lifetime productivity, and it is not something that can be seen in the cows today but can have big impacts on herds into the future," Dahlen says.
He recommends producers who have cattle in late gestation provide their cattle with some type of protein and energy supplementation, such as lick tubs, range cubes or distillers grains. Free-choice alfalfa hay delivered to cows in addition to grazing also will provide additional protein.
"Also monitor cow body condition very closely and ensure the proper delivery of vitamin/mineral supplements to cows," he advises. "Pre-calving losses in body condition set cows up for issues after calving. Metabolic conditions, retained placenta and delayed rebreeding are things that I would be concerned with if cows came through the summer on great grass but then lost a lot of condition just prior to calving."