Increasing evidence suggests that climate change is increasing the likelihood of co-occurring periods of
precipitation deficit and warm temperatures over the next century. Maintaining ecosystem function and
agricultural productivity on rangelands during increasingly intense and frequent periods of drought
presents scientific, economic, and social challenges. Rangeland livestock producers are often the first to
feel the impacts of drought; these impacts can be especially pronounced on California’s annual
rangelands (where the majority of precipitation and forage growth occurs in fall, winter and spring).
Structured interviews of ranchers conducted prior to and following the conclusion of California’s 2012-
2015 drought have highlighted the proactive and reactive strategies employed by ranchers to mitigate
drought effects. While early weaning is a strategy used by significant numbers of ranchers, very little
research has been conducted in annual rangeland systems to determine whether such a strategy is
beneficial economically or ecologically. The broad goal of this project is to quantify the costs and
benefits of early weaning as a drought management strategy for fall-calving cow-calf operations in
California. We will quantify the influence of early weaning on forage resources, evaluate influence on
cow and calf performance, and analyze the economic tradeoffs associated with early weaning compared
to traditional weaning strategies.
The overarching goal of this project is to work with fall-calving cow/calf ranchers to understand
the potential net economic and environmental benefits of early weaning as a drought
management strategy. Specific objectives include:
1. Quantify the influence of early weaning on cow and calf performance, pasture utilization, soil
protection, and plant biodiversity and examine how year-to-year variation in precipitation
influences early weaning effects.
2. Develop decision tools to help producers evaluate the economic and ecological tradeoffs
associated with early weaning compared with traditional weaning strategies using data
collected in objective #1.
3. Create and deliver a basic decision support guide that synthesizes the economic and ecological
tradeoffs with producer expert input to allow producers to determine how and when early
weaning may work as a drought adaptation practice for a particular enterprise.
We are in the initial stages of this project. To date, we have held a producer steering committee meeting, developed a detailed project schedule, and collected initial body condition scores on the cows. This winter, we will read forage transects and plots, and wean the first calves (in early March). Normal weaning will occur in late May or early June.
Educational & Outreach Activities
Our initial outreach efforts have included a producer steering committee meeting in October 2018 and a data collection session (body condition scores) in December 2018. The steering committee meeting resulted in a detailed project schedule that represents real-world management conditions for foothill cattle producers.