It is spring in the southern hemisphere and fall here in the northern hemisphere. With the advancing season, hours of daylight become less until the winter solstice on December 21, 2026, at 3:50pm EST, when the earth begins tilting back to its summer position and the hours of daylight increase

until June 21^st. If timely fall rains come, native range and improved grasses (crested wheatgrass and bromegrass) will begin growing. However, this growth is short lived as cooler freezing temperatures reduce soil temperature, which coupled with shorter day length stimulates perennial grass dormancy.

Winter grazing of dormant grass is common in the northern Great Plains and is a vital forage source for many ranchers. The protein content of dormant grass hovers between 4.5 to 5.5% crude protein. The total protein requirement for a 1,300 lb. non-lactating, dry pregnant beef cow in the middle third of pregnancy being fed an all-roughage diet is approximately 1.10 lbs. and digestible protein requirement is 0.51 lbs.

The ruminant multi-chambered stomach is uniquely formed to digest forages considered to be inedible for humans and yet with the addition of a small, but important quantity of supplemental protein, beef cattle thrive on dry mature dormant forages. Protein utilization in ruminants has different functions and is divided into two categories based on their rumen degradability, i.e., degradable intake protein (DIP) and undegradable intake protein (UIP). Rumen dynamics are complex. DIP supports rumen microorganism reproduction. Microorganisms are the heart and soul for ruminant animals because they possess enzymes necessary to break down structural fiber compounds releasing volatile fatty acids from which 70% to 80% of the animals energy is derived. As the feed mass passes through the remaining chambers of the stomach, these digesting microorganisms become a protein source referred to as microbial protein. UIP forms of protein that escape rumen degradation are classified as metabolizable protein for body maintenance and production. Escape protein and microbial protein sources combine to meet the cow’s metabolizable protein nutrient requirement.

Supplying supplemental degradable protein for cows grazing dormant pastures is met with a variety of supplement sources to include range cake, lick blocks and tubs, and alfalfa hay. Protein sources do not need to be fed daily as compared to energy supplements that are best fed daily due to rumen dynamics. Protein sources can be fed on alternate days or every third day. Some research has shown that animal performance is not negatively affected by long interval feeding. However, feeding on alternate days and every third day is most common. When providing a protein supplement for multiple days, the amount delivered per cow must be increased by the number of interval days. For example, if the nutrient requirement is to be met feeding 1.5 lb. of a 25% CP cake supplement/cow/day and supplement is delivered every third day, then 4.5 lbs./cow will need to be fed. Lick tubs are nutritionally and density formulated to regulate intake.

Bloat and acidosis are potential problems for ruminants especially when feeding grain-based supplements. This is generally not a problem when feeding protein sources. Although, when feeding 3 to 6 lbs. of alfalfa/cow/day as a protein source, aggressive cows may consume more than desired resulting in a bloat potential. This is usually not a problem when feeding first cutting alfalfa because the plant is more coarse and stemmy. However, second and third cutting alfalfa is finer textured and there is a greater potential for bloat among aggressive cows.

Cow wintering research at the DREC with cows grazing stockpiled grass or stockpiled grass combined with grazing corn residues reduced winter feeding cost 2.8 times (Senturklu and Landblom, 2016).

Senturklu, S. and D. G. Landblom. 2016. Reducing cow wintering cost grazing stockpiled grass and crop residues. In: Dickinson Research Extension Center Annual Report https://www.ndsu.edu/agriculture/sites/default/files/2022-10/Cow Wintering Study-V4_Annual Rpt_Senturklu - Landblom_8-4-17 %281%29.pdf