Interactive Tools

Some Notes On Using This Calculator:

This calculator takes the stocking rate calculator and expands it to include the mathematics behind developing paddocks. This version uses your known herd or flock size to figure out how large of a pasture or field is needed for that herd for the entire grazing season. It adds in calculations for your paddocks: how many paddocks you need, how big they should be, and how many times you should expect to rotate your animals through those paddocks throughout the grazing season. 

The important things you will need are the following:

• The estimated (or calculated from forage samples) forage yield for your pasture: this plays a huge role in how many animals you can have on the pasture. The greater the yield, the more animals you can have. The opposite is also true: the lower the yield, the fewer animals you should have.
• Utilization rate: This is the amount of forage you want animals to remove, trample, and defecate on before being moved to the next paddock. Typically, utilization rates are higher for tame pastures than native grassland, as you should be concerned with conservation of native habitat and sensitive species compared with tame pastures, which have largely very common, graze-tolerant species. Tame pastures typically range from 40 to 70% utilization rates, and native grasslands should have less than 50% utilization, ideally 25 to 30% utilization by the herd or flock. It’s crucial to keep in mind that the higher the utilization rate, the longer animals need to stay away from that paddock to allow the vegetation to fully recover. Overgrazing can occur, meaning desirable species may gradually depopulate and undesirable species that are lower in productivity or less palatable can move in. Unless you have trained your animals to eat weeds, you want to be careful about setting—and keeping—to your utilization rates.
• Herd or Flock Size: Be sure to include breeding males in the size of your herd, as well as other animals that are going to play a major role in how your pasture (and paddocks) is utilized. Most pre-weaning young stock are not going to make as much of an impact on the forage resource as their dams, however, omitting your breeding males from the count could mean the difference between inadvertently over-utilizing your forage resource and things working out optimally. (The latter is not a worry if you are grazing stocker lambs, steers, heifers, replacement heifers, or other meat-market animals.)
• The average animal body weight of your herd and percent daily intake by bodyweight: Take all the grazing animals in your herd or flock, including breeding males, and average out the body weight for the herd. Remember, the heavier the animal, the more they will eat. Percent daily intake tends to not change drastically for most animals, however it tends to change between species and between dairy versus meat animals. Dairy animals have higher nutritional demands than most meat animals (including those suckling with young), thus the percent intake by bodyweight will be higher. Consult Table 3 in the Pasture Management Workbook for more information.
• The length of the grazing season: Knowing how long your animals will be grazing in terms of from when they enter that pasture to when they leave will determine if they’re staying in there for one round of rotations or twice or more. Typically this doesn’t include stockpile grazing, but can include fall grazing if you have one or more paddocks set aside for the fall.
• The ideal recovery period: The ideal recovery period is anywhere from 45 to 60 days. This is the time that is needed for plants to recover after being grazed before they are grazed again. This time period is important with respect to plants’ ability to replenish root stocks and new leaves, as well as have enough time to put excess energy from the sun into the root zone for storage.  A 45 to 60 day recovery period is based off taking about half of the forage yield, and leaving the other half to either decompose or regrow new leaves. If your utilization rates are higher than 50%, then set your recovery period to longer than 60 days. If you are only wanting to graze your animals in the paddocks once in the grazing season, then simply change the recovery period to match the length of the grazing season.
• Number of days per paddock: This is the length of time you wish your animals to stay in each paddock. The calculator is set at days, not hours, so plug in your numbers accordingly. Ideally you should not let your animals stay in paddocks for more than 5 days to minimize risk of overgrazing. Shorter times is more labour-intensive compared with 3- to 5-day moves, but can reduce the risk of overgrazing comparatively. Please note, too, that this is an average, and each paddock may have different vegetation types that reduce time animals spend in each paddock.