Summary and Implications
It appears from this summary of previous Iowa State University research results that protein and energy levels in forages stockpiled starting in August will for the most part have sufficient protein and energy to maintain a beef cow during the middle and last part of their pregnancy. Tall fescue-alfalfa stockpiled forage had two months that would not meet protein and energy requirements, but it is important to realize that selective grazing in that forage type would likely overcome those deficiencies. However, it is important to realize that sufficient forage accumulation is imperative to meeting the total nutrient demand of the beef cow.
Iowa State University
Strohbehn, Daryl R.; Loy, Daniel D.; Morrical, Daniel G.; Russell, James R.; and Driskill, Ronda
"A Summary of Monthly Nutrient Values for Stockpiled Forages in Iowa State University Research Studies,"
Animal Industry Report:
AS 650, ASL R1886.
Available at: https://lib.dr.iastate.edu/ans_air/vol650/iss1/45