Influences on calf productivity during five decades of cow-calf grazing of northern prairie

Authors: IRISARRI, J. GONZALO - University Of Wyoming; CIPRIOTTI, PABLO - Universidad De Buenos Aires; CASTRO SARDIÑA, LETICIA - Universidad De Buenos Aires; Mortenson, Matthew; Derner, Justin

Submitted to: Animal-The International Journal of Animal Biosciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/20/2025
Publication Date: 5/27/2025
Citation: Irisarri, J.N., Cipriotti, P.A., Castro Sardiña, L., Mortenson, M.C., Derner, J.D. 2025. Influences on calf productivity during five decades of cow-calf grazing of northern prairie. Animal-The International Journal of Animal Biosciences. 19(7). Article e101557. https://doi.org/10.1016/j.animal.2025.101557.
DOI: https://doi.org/10.1016/j.animal.2025.101557

Interpretive Summary: Calf gains from grazing native northern mixed-grass prairie can be influenced by individual cow, management, and climatic factors. Here, we used 5 decades of data from the growing season (June-September) near Cheyenne, Wyoming to evaluate influences of forage production, temperature, precipitation, cow age, cow body weight, calf gender, and management (stocking rate on individual calf weight gain. During the 47-years of study, temperature increased, and precipitation decreased with forage production positively associated with precipitation and negatively with temperature. Breed (Hereford vs. crossbred) was the most important factor for calf weight gain, followed by stocking rate, temperature, cow weight, precipitation, cow age, forage production and calf gender. Calves from crossbred cows gained 26% more than claves from Hereford cows. Factors influencing individual calf performance have shifted from variables associated with the cow and stocking rate to primarily climatic factors over the 5 decades of this experiment.

Technical Abstract: Understanding calf weight gains from grazing rangeland ecosystems require long-term data to disentangle influences of biophysical and individual animal factors, and management. However, long-term experiments with consistent management treatments with livestock weight gain data are scarce. To address this gap, we analyzed a legacy dataset covering 5 decades of grazing during the growing season (June-September) in native northern mixed-grass prairie of the North American Great Plains the that included individual on- and off-pasture weights of Hereford (1975-2001) and crossbreed (2003-2021) cows and calves grazing from June to September, spanning 47 years near Cheyenne, Wyoming. We used regression tree analyses to evaluate influences of biophysical (forage production estimated via NDVI LANDSAT time series, temperature, and precipitation) and individual animal factors [breed (Hereford from 1975-2001 and crossbred from 2003-2021), cow age, cow body weight, and calf gender), and management(stocking rate, AU/ha·day), on individual calf weight gain. We observed a positive temperature trend and a negative precipitation trend over the 5 decades. Forage production was positively associated with precipitation and negatively with temperature. Breed (Hereford vs. crossbred) was the most important factor for calf weight gain, followed by stocking rate, temperature, cow weight, precipitation, cow age, forage production and calf gender, with the fitted model explaining 64% of the variation in calf weight gain. Calves from crossbred cows gained 26% more than claves from Hereford cows (1.2 vs. 0.88 kg/head·day). Our findings from nearly 5 decades of grazing research offer key insights for beef production responses from native, northern mixed-grass prairie rangeland ecosystems. First, crossbreeding offers advantages to calf weight gain. Second, the importance of stocking rate and cow body weight on calf weight gain, along with observed trends of precipitation and temperature influencing forage production, underscores the need for application of adaptive grazing management for sustainable beef production. Third, over the 5 decades of this experiment, factors influencing individual performance have shifted from variables associated with the selection of the animal biotype and stocking rate to primarily climatic factors.