What would the value be in your operation if you could predict drought? I know we can’t predict the weather, but we can keep track of monthly rainfall. Rainfall is going to be a darn good predictor of forage growth. In addition to rainfall, we can also keep track of monthly livestock head counts and their approximate weight to determine the total grazing demand. When we compare those two numbers, the Stock Days per Acre per Inch of Precipitation (SDA/1”) is a wonderful tool to help production and marketing decisions on the ranch.
Back to value, Bud Williams always talked about managing three inventories: grass, money, and livestock. He followed that by saying you can never go broke having too much grass or money, but you can go broke by having too many animals at the wrong time. What would the value be of destocking two months before the rest of your region? It could be several hundred dollars per head. What would the value be of having extra grass when the rest of your region is looking for grass? This depends on the going rate for custom grazing in your area.
The SDA/1” along with a written drought plan that includes critical dates can help you manage those three inventories by comparing the amount of forage growing, based on rainfall, to the amount of forage being grazed by the herd.
It starts by predicting your baseline, which is a factor of long-term carrying capacity, animal numbers and weights, and average annual precipitation. This will give you a flat baseline (shown in red below) to start comparing your actual numbers to. Next you will calculate the trendline each month by recording actual precipitation and actual stocking rates. We can then start analyzing the cumulative 12-month totals. If the 12-month total precipitation starts dropping, that isn’t good or bad news, it is just news. Depending on what the stocking rate is doing in those same twelve months, will determine if it is good or bad news. In the example below, the actual trendline (green line) is rising, meaning there is more grazing than growing forage. That means, go look at your grass! It may mean destocking should be considered; and remember destocking doesn’t mean the cows need to be sold. It just means go look at your grass, and make an informed decision for ecological and economical impacts.
Two other important factors are effective precipitation and the timing of precipitation. Effective precipitation is the moisture that falls that is actually available for plants to grow. If there is a big thunderstorm gully washer, how much rain stays put? Or huge snow events? Those are going to be big questions depending on your climate. The timing of precipitation will also depend on the ranch’s cool and warm season forage mix. Last week, we just got a wonderful rain here in Wheatland, WY, over an inch of rain in a two day period. Rain is generally always good, but let’s be honest, how much is growing in southeast Wyoming in October? And how much moisture will be available next May and June when the peak of our forage grows? Summer rains can be beneficial to cow herd conception rates because they provide a quality bump when the cows need it.
Drought should be expected; what is important to us as ranchers is our response to it. Better yet, our response before it is too late. Our Australian friends try to resist using the word “drought” because it makes us think of it as an exceptional event. Instead they say “just missed a bit of rain!” If you are a member of RFP Online (any Ranching for Profit School alumni business can join), you can head over to the platform to check out the SDA/1” spreadsheet template for your own operation. If you are interested in attending a Ranching for Profit School this winter to learn about managing drought risk, seats are filling up but we still have spots available in a few schools, click here to check out our schedule!