Stocking rate impacts performance and economics of grazing beef steers on mixed grass prairies of the Southern Great Plains

Authors: BECK, PAUL - Oklahoma State University; BECK, MATT - Lincoln University - New Zealand; Gunter, Stacey; BEERMACHER, JON - Noble Research Institute; GILLEN, ROBERT - Kansas State University; MCCOLLUM, F. TED - Texas A&M University

Submitted to: Translational Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/5/2020
Publication Date: 7/18/2020
Citation: Beck, P., Beck, M., Gunter, S.A., Beermacher, J., Gillen, R., Mccollum, F. 2020. Stocking rate impacts performance and economics of grazing beef steers on mixed grass prairies of the Southern Great Plains. Translational Animal Science. 4(3). https://doi.org/10.1093/tas/txaa134.
DOI: https://doi.org/10.1093/tas/txaa134

Interpretive Summary: Stocking rate is the fundamental management factor under a producer’s control, and it has a major impact on animal performance and long-term sustainability of food production on native rangelands. This research was conducted to determine the effects of stocking rate on performance and economics of growing steers grazing mixed-grass prairie on a rolling upland red shale ecological site at the Marvin Klemme Range Research Station which is located 10 miles southwest of Clinton, OK. For many years, the USDA has recommended a stocking rate of 25 animal-unit-days/hectare to maintain a sustainable grazing system. Each year for seven years, 119 steer calves were divided among seven pastures to produce seven stocking rates ranging from 10.7 acres/steer to 4.1 acres/steer from 1990 to 1996. During the experimental period, climatic conditions were overall favorable for forage production with average precipitation during the growing season of 118% of the long-term average. Over the entire summer grazing season average daily gain decreased linearly with increasing stocking. Contrary to average daily gain, body weight gain per acre increased linearly with increasing stocking rate. With land costs included in the economic analysis, net return per acre increased linearly from $5.26 at the 10.7 acres/steer to $21.05/acre at the 4.1 acres/steer. For each additional acre available per steer, stocking rate net return was reduced by $6.40/steer. In the favorable climatic conditions during the seven-year experiment economically optimal stocking rates can be more than doubled compared with the stocking rate recommended by the USDA. Increasing stocking rates decreased individual animal performance but did not reach a point of maximum body weight gain per unit of land area, which leads to the increasing economic returns observed. Research is needed to determine the long-term implications of these stocking rates during unfavorable growing conditions and setting stocking rates based on seasonal weather patterns and extended weather outlook predictions.

Technical Abstract: Stocking rate is the fundamental management factor under producer control that has a major impact on animal performance and long-term sustainability of native range-based ecosystems. This research was conducted to determine the effects of stocking rate on performance and economics of growing steers grazing a mixed grass prairie on a rolling upland red shale ecological site at the Marvin Klemme Range Research Station is located 15 km southwest of Clinton, OK (35° 50’ N 99° 8’ W) with a recommended sustainable stocking rate of 25 animal-unit-days/hectare. Steers (n = 836, initial body weight ± standard deviation = 216 ± 11.7 kg) grazed at seven stocking rates ranging from 4.13 hectare/steer to 1.83 hectare/steer over the 7-year period from 1990 to 1996 with year considered the random replicate. During the experimental period, climatic conditions were overall favorable for forage production with average precipitation during the growing season of 118% of the long-term average, and only one year (1994) with growing season precipitation less than 93% of the long-term average. Over the entire summer grazing season average daily gain decreased linearly (P < 0.01) with increasing stocking rate such that for each additional hectare available per steer average daily gain increased by 0.05 kg/day (R2 = 0.88). Contrary to average daily gain, body weight gain per hectare increased linearly (P < 0.01) with increasing stocking rate, as stocking rate increased from 4.13 hectare/steer to 1.83 hectare/steer body weight gain per hectare doubled from 33.1 kg/hectare to 66.8 kg/hectare, respectively. With land costs included in the economic analysis, net return per hectare increased linearly (P < 0.01) from $13 (US Dollars) at the 4.13 hectare/steer stocking rate to $52/hectare at the 1.83 hectare/steer stocking rate. For each additional hectare available per steer stocking rate net return was reduced by $15.80 (US Dollars)/steer and $15.70 (US Dollars)/hectare. In the favorable climatic conditions during the 7-year experiment economically optimal stocking rates can be more than doubled compared with the stocking rate recommended by the USDA Soil Conservation Service. Increasing stocking rates decreased individual animal performance but did not reach a point of maximum body weight gain per unit of land area, which leads to the increasing economic returns observed. Research is needed to determine the long-term implications of these stocking rates during unfavorable growing conditions and setting stocking rates based on seasonal weather patterns and extended weather outlook predictions.