Forage Calculators
The University of Arkansas, Division of Agriculture offers assistance to producers in the areas of ag lime quality, grazing, and livestock hay calculators. Brief descriptions are provided along with a link to download the calculators.
University of Arkansas Division of Agriculture Ag Lime Quality Calculator
Ag lime is applied to neutralize soil acidity and raise soil pH. Lime quality is dependent on the fineness of the material and the percent calcium carbonate of the limestone source.
In Arkansas, ag lime does not have to meet a minimum quality standard, but each lime vendor is required by state law to have their ag lime product tested for sieve size and % CCE (calcium carbonate equivalent). The fineness measure used in Arkansas is the amount of material passing through 10, 60, and 100 mesh sieves. The University of Arkansas ag lime recommendations are based on a lime product with a liming value of 47%.
To use this calculator, lime test information is needed from the lime vendor for the percent of the lime product passing through 10, 60, and 100 mesh sieves and the percent CCE (calcium carbonate equivalent). Cost per ton of material, including hauling, and spreading costs, can also be included so lime products can be compared for economic value per pound of effective liming material. Up to three lime samples can be evaluated with this calculator.
Download the 2020 Ag Lime Quality Calculator
University of Arkansas Division of Agriculture 2020 Grazing Calculator
This program includes three calculators that allow the user to makes estimates for pasture rotations, setting stock density for mob grazing, and estimating field strip sizes for strip grazing stockpiled forage
Information on animal numbers and field or paddock size is needed. Drop down menu boxes are provided for certain factors to standardize estimates.
Click one of the tabs on the bottom of the spreadsheet to select one of the three calculators. Click on each cell where indicated to highlight an arrow. Click the arrow to open a menu of choices for that option. Select the option nearest to the farm conditions being evaluated.
Pasture Rotation Calculator
The Pasture Rotation Calculator helps estimate the number of days a given size paddock or pasture can be grazed by a given size herd. Calculations are for beef cattle. However, there are some rules of thumb for other types of livestock. Horses are substituted one for one with cows for stocking rate. Generally 4-5 sheep or goats consume about the same amount of forage as one mature cow. And common recommendations suggest that one sheep or goat can be added per cow when both species are grazed together.
Mob Grazing Calculator
Mob grazing is often used as a tool where high stocking rates are used to trample down overgrown vegetation to open the canopy allowing regrowth of desirable forage. Forage utilization can be as low as 20% for brushy, mature vegetation, but can be higher for quality forage. When high stock densities are used, paddocks must be rotated frequently to provide enough quality forage to sustain the grazing animals. This calculator estimates the paddock size or herd size needed to achieve certain stock densities per acre. It also estimates the rotation frequency needed to provide adequate forage availability to sustain the grazing herd.
Strip Grazing Calculator
Strip grazing is often used for short-term grazing across a large field or when stockpiled forage is grazed during winter. This calculator estimates the strip size of forage needed for a given size herd. It also estimates the number of grazing days from a pasture or paddock based on given forage availability estimates. The field size, field width (feet), and forage height with forage density are needed.
Download the 2020 Grazing Calculator
University of Arkansas Division of Agriculture Hay Quality Calculator
This program calculates the percent of crude protein (CP) and total digestible nutrients (TDN) requirements met by hay for different classes of livestock. The hay sample ID and CP and TDN levels from hay tests (dry matter basis) for up to six hay samples can be entered and compared for beef cows, stocker calves/heifers, horses, and sheep/goats. When the hay data are entered, click on the tab corresponding to the animal being fed. Values shown in green meet 100% or more of requirement for that animal. Values shown in red meet 90% or less of requirement for that animal. A nutritionist should be consulted for feeding recommendations when values do not meet CP or TDN requirements.
Download the 2020 Livestock Hay Calculator