Sheep Don’t Read the Books and Other Observations on Targeted Grazing

According to the Targeted Grazing Handbook (Launchbaugh and Walker 2006), targeted grazing is defined as:

“the application of a specific kind of livestock at a determined season, duration, and intensity to accomplish defined vegetation or landscape goals.”

As a sheep producer who practices targeted, and as a county extension agent who helps other practitioners, I would amend this definition slightly. In my experience, targeted grazing grazing requires “a specific kind of the right livestock.” All sheep (or goats, or cows, for that matter) are not created equal when it comes to consuming targeted vegetation!

At the risk of oversimplifying most livestock production textbooks, cows prefer to graze grass, goats prefer to browse brush, and sheep prefer to consume a combination of broadleaf plants and grass. My sheep, however, have not read these books! I’ve watched my ewes walk past lush grass to eat the leaves off coyote brush. I’ve watched them pass up dry annual ryegrass to eat the seed-heads off yellow starthistle.

While livestock do have some innate preferences when it comes to grazing or browsing behavior, they can also develop localized nutritional wisdom over time. Dr. Fred Provenza, who made a career out of studying grazing behavior at Utah State University, demonstrated that grazing animals learn what plants to graze (and what plants they shouldn’t graze) by watching their mothers. He has even suggested that some dietary preferences may begin to form in utero – that fetuses are influenced by their mother’s diet during gestation.

Based on this understanding, and on my own observations of our sheep over the last 15 years, we intentionally try to focus on breeding sheep that will allow us to target a wide variety of vegetation in our Sierra foothill environment – including invasive plants like Himalayan blackberry, yellow starthistle, and medusahead. We try to use high-intensity, short-duration grazing whenever possible, finding that the competition between sheep helps us impact desirable and undesirable plants (from a sheep’s perspective) in a particular paddock. We lamb on pasture, as well, which means the lambs can observe their mother’s grazing behavior from day 1! And we strategically use supplemental feeding (mostly minerals and protein when needed) to help our sheep digest plants that might not meet their nutritional requirements.

All of these strategies compliment the other elements of targeted grazing described by Launchbaugh and Walker. We wouldn’t necessarily use sheep to impact chaparral that’s 8 feet tall – large goats might be more effective in that situation. We try to focus on the timing of our grazing, too – grazing yellow starthistle rosettes in the early spring doesn’t seem to impact seed production; grazing these plants as they begin to bolt and flower does reduce seed production! Similarly, some of our winter foothill rangeland contains native perennial grasses (like purple needlegrass and California melic). Grazing these plants in the early spring – and then resting them through the rest of the growing season – allows them to reproduce.

Using livestock to manage invasive weeds, or to support the restoration of native plants, can sometimes be more complicated than more conventional approaches. Livestock-plant interactions, livestock behavior, and (perhaps especially) human behavior – and the interactions between all of these elements – are incredibly complex! We aren’t always successful at having the right sheep in the right place at the right time to impact the targeted vegetation. But we always learn something – and we generally get a chance to try again. And our sheep go right on ignoring the textbooks!