Stocking rate is determined by several factors. Soil condition(fertility), types and quality of available forage, rainfall and management practices. To determine your stocking rate, I would do a survey of the types of grasses available in your pastures. I would do a soil analysis to determine fertility in each of your pastures to see if anything is needed. At 50” ave rainfall a year, sounds like you have plenty of moisture. If you rotational graze and don’t overstock, you should be able to make it through dry spells without feeding hay. I’m curious to know with 50” of rain, how long do your dry spells last?
Our farm is in what is called the short grass prairie region of the Texas panhandle. It’s not unusual to have periods of no rain that last 3-6 months. In 2011, we received 2 inches of rain in 10 months. Before we bought our first dexters, I took soil samples in the areas we were going to fence for pasture. Our soil is a sandy loam. I was surprised when the soil test results came back saying nothing was needed. Our pastures have predominantly native grasses such as side oats grama, blue grama and buffalo grass. We also have some varieties of blue stem. It’s imortant to know what types of grasses your cattle will be grazing because not all grasses offer the same nutrients. For example, blue grama is a shorter native prairie grass than even when dry can have as much as 12-14% protein. Compare that with say Johnson grass which produces a lot of volume but may only contain 5% protein. I’ll give you another example. I bought some Dexters in eastern Oklahoma. When I arrived at the ranch, the cows were standing belly deep in grass but were pretty thin. The soil was very sandy. I suspected the soil was lacking in nutrients, therefore the grass was putting out volume but was also poor in nutrients. Got those cows home and within a couple of months, they were visibly putting on weight grazing our short native grasses rich in nutrients. if you know the condition of your soil and the types of grasses/forage you have it will be easier to determine your stocking rate using a rotational grazing system. Keep in mind, stocking rate is a fluid thing that depends on many factors and can change from year to year. Hope this gives you some guidance and feel free to ask any other questions.