RUMINANT NEWS

SATELLITE IMAGERY-TOOL FOR MANAGING PASTURE AND CATTLE WEIGHT

USDA’s Agricultural Research Service (ARS) developed a unique approach to using satellite imagery to predict cattle weight gain on rangelands. By fusing multiple images over a period of time, scientists were able to monitor how forage quality changes over space and time in rangelands within the shortgrass steppe, and how this relates to the weight gain of free-ranging cattle throughout the summer grazing season. Managing the grazing season in rangelands can be challenging due to high variability in temperature and rainfall over time. From a manager’s perspective, it is essential to know when and where forage production and quality are changing to optimize free-range livestock weight gain and meet other environmental objectives.  This is not just about chasing forage quantity (total amount of vegetation biomass); it is also about looking for the highest-quality forage throughout the season. “This study is probably the first-time high-quality datasets have been used to predict cattle weight gain directly from satellite imagery,” said Sean Kearney, Post Doc Research Associate in Fort Collins, CO. The satellite-based predictions of forage quality, most notably, weight gain was affected by the timing of forage green-up and senescence (browning down). With recent climate patterns, it is critical to determine the right time to start and stop grazing cattle, in order to match up grazing timing with high quality forage. “Now we can estimate diet quality across space and time and have a better idea of what is causing changes in diet quality throughout the season.“ What is next? Scientists are linking these new diet quality and vegetation maps with GPS collar data to better understand what drives cattle foraging behavior, as well as working on a new model to predict diet quality in near-real-time to support adaptive management efforts of ranchers and other rangeland managers.