Stockpiling Forage to Extend the Grazing Season
What is Stockpiling?
Stockpiling is a forage production method where the grass is allowed to grow without being grazed and become ‘stockpiled’ in a pasture as a standing hay crop. As the summer comes to an end, hay fields are cut or pastures are grazed through August, all the bales or animals are removed, and the grass is allowed to accumulate for 8-10 weeks. Although growth will be slowed, the cooler temperatures and shorter days deter forage fiber content, resulting in a higher quality forage to be grazed in the fall and early winter. When managed correctly, stockpiling forage can extend the grazing season by 45-60 days and fill in the forage gap between warm season perennial grasses and winter rye.
Several grasses can be used for stockpiling, and selection will be dependent on ranch location. Bahiagrass, dallisgrass, limpograss, and tall fescue are great options, but the most popular is bermudagrass. Each grass has an optimal growth temperature, and around 8 weeks of regrowth is needed to provide enough stockpiled forage. For example, bermudagrass grows best between 85ºF and 95ºF, and declines sharply as night temperatures drop around 60ºF. Therefor, stockpiling needs to start early enough to provide enough time for growth before the cooler temperatures slow the grasses down. Crabgrass is another option, however, it deteriorates quickly after a hard frost. Bahia, dallis, and bermuda grasses deteriorate less than crabgrass but more than tall fescue, which is the most cold tolerant stockpiling option. Native grasses can also be used, however the crude protein (CP) and total digestible nutrients (TDN) will be much lower.
What are the benefits of Stockpiling?
Wintering costs make up a huge part of the annual cow cost. Purchasing, growing, and storing hay are expensive and labor intensive methods of providing forage to livestock. According to a study from Auburn University, stockpiling bermudagrass saved $332.35 per cow on an annual bases. Additionally, some areas experience a ‘forage gap’ in the late fall to early winter, when the cool season forages haven’t been planted yet and perennial warm seasonal forages slow down. Stockpiling provides a low costs, high quality alternative to extend the grazing season, and therefor decreasing feeding costs and labor.
The CP and TDN decline throughout the season, but generally are high enough to support dry cows that will calve in the spring and in some situations, wet cows during breeding. Well managed Bermudagrass can meet the CP and TDN requirements for lactating cattle through December, and C3 grasses, such as tall fescue, can meet the requirements for a much longer period.
How is Stockpiling managed?
The pasture or field is grazed to a short stubble height dependent on forage type (bermudagrass 2-3 in., tall fescue is 3-4 in.) in late July or August. Nitrogen will be needed (40-60 lbs. or based on recommendations) but Phosphorus and Potassium should only be added based on soil analysis. If ammonium nitrate is used as the source of N, losses due to volatilization will be minimal. If urea is used, volatilization losses are generally less than 20% and lower if rainfall occurs within a week of application.
Grazing stockpiled forage needs to be managed to maximize grazing days. If not controlled, cattle will spend the first 4-5 weeks consuming the higher quality leaves and have nothing else to eat except the stems for the remainder of the winter (or requiring hay supplementation). Strip grazing or rotational grazing allowing herds 1-2 days of forage availability works best to maximize forage utilization and grazing days.
Rain, frost, snow, and ice will cause quality loss. Location will determine when producers should be finished grazing their stockpiled forages. For example, in Arkansas, producers should be done grazing stockpiled bermudagrass around December as the DP and TDN are no longer high enough to meet the nutrient requirements for dry cows without additional supplementation. However, this will likely not be the case in areas that don’t experience frost and snow (Florida for instance), or areas that can utilize tall fescue. Tall fescue has a heavy waxy cuticle that makes it more resistant to freezing temperatures. Because of this, it maintains it’s palatability and quality and can be grazed into March.
Calculating Stockpiling acreage requirements
Producers should set a goal of 2,500 lbs. of bermduagrass grass per acre on a dry matter (DM) basis. To learn how to calculate forage production, refer to Estimating Herbage Mass on Pastures to Adjust Stocking Rates. However, some of that will be lost to defecation and trampling, so only about 65% of the forage available will be utilized by the cattle. Producers also need to know an average cow size to estimate required forage DM on a daily basis.
Example: 150 dry spring calving cows averaging 1000 lbs. are being grazed on stockpiled forage. The rancher needs to estimate how many acres of pasture need to be deferred for stockpiling. He would like to have enough grazing for 65 days.
- Assume adequate rainfall, weed control, and fertilizer management
- A dry cow in the last 1/3 of gestation needs 22 lbs. of forage DM/day. 1000 lb. cows x 0.22 lbs. DM/day = 22 lbs. Forage DM/day. Refer to Nutrient Requirements of Beef Cattle.
- 150 cows x 22 lbs. forage DM/day x 65 days = 214,500 lbs. DM required by the cows
- 214,500 lbs. DM requirement / 2,500 lbs. DM/acre = 85.8 acres required for stockpiling.