Raising livestock on free-range pastures has been a longstanding practice for ranchers, but the debate continues over whether rotational or continuous grazing is more sustainable and profitable. While many ranchers may opt for a season-long grazing approach, there has been growing interest in a more intensive rotational system, where the pasture is divided into smaller paddocks and the herd is shifted throughout the growing season.
A team of researchers at the USDA's Agricultural Research Service conducted a 10-year study comparing the grazing practices of these two systems and their effects on cattle foraging behavior, diet quality, and yearly weight gain in semi-arid, extensive rangelands. The study used global positioning system tracking collars with activity sensors to monitor the grazing activities of free-ranging cattle in both rotational and continuous grazing systems.
The technology was able to collect precise data on the animals' feeding habits, including the amount of time spent grazing each day, the grazing speed, the shape of the foraging pathways, and the length of meals. The results showed that the technology can inform livestock managers about animal distribution and foraging behaviors, allowing them to make more timely decisions on how, when, and where to move cattle within their operation, or to sell cattle at optimal times.
However, the study found that the rotationally managed cattle gained, on average, 14% less weight than cattle in the season-long management system. This was because the cattle in the rotational system did not have as much freedom to roam and be more selective on what to eat, resulting in them eating lower quality forages with less protein. The study showed that large herds grazing in small, homogenous paddocks have little opportunity to move around in ways that let them feed on high-quality diet.
Overall, the study suggests that while rotational grazing can have some benefits for sustainable grazing management, it may not always be the most profitable or effective approach for weight gain in free-range livestock production. It is important for ranchers to carefully consider the specific conditions of their operation and the needs of their herd when deciding which grazing system to use.
The study was conducted at the Central Plains Experimental Range, an ARS Long-term agroecosystem research network site in Colorado. Results were published in Agriculture, Ecosystems, and Environment.