Unsung Heifers of the Open Space Authority

Ever visit an Open Space Authority preserve to get moo-ving and spot a few cows? While they may make it feel like you're traversing through the set of an old Western film, those cows are not paid actors! The Authority uses cattle grazing as an udder-ly integral conservation and management strategy. 

What is cattle grazing?

Cattle grazing is one of the Authority’s tools for conservation. For years, the Open Space Authority has partnered with local ranchers to use cattle to help maintain 8,000 acres of owned and managed land. Cattle are strategically placed on the land to eat and reduce the amount of non-native dry vegetation that exists throughout the Santa Clara Valley landscape. 

Why does the Open Space Authority use cattle grazing?

There are a variety of benefits and goals that cattle grazing aims to achieve. “We use it to manage our vegetation--specifically grasslands, reduce invasive species in composition and in numbers, reduce fire fuel load and increase native plant diversity,” says Aaron Hébert, Natural Resources Manager. When we reduce the growth of invasive species through grazing, we’re making room for native plants to grow and reducing the amount of available dry vegetation that can act as fuel for wildfires. 
 
In places like Máyyan 'Ooyákma - Coyote Ridge Open Space Preserve, cattle grazing keeps non-native grass short, helping native species thrive. The Bay checkerspot butterfly population, for example, depends on cattle grazing for its survival. Each year, these unique butterflies lay their eggs at the base of the California dwarf plantain, a native plant that only grows in serpentine soil. Without grazing, the California dwarf plantain may become overcrowded by other vegetation and we would likely see a decrease in the Bay checkerspot butterfly populations. 

Cattle grazing also plays an important role in reducing the spread of wildfires. In June 2026, a vegetation fire broke out at Sierra Vista Open Space Preserve. Just days prior, the preserve was grazed by cattle to reduce the amount of dry vegetation available. Thanks to the grass’s short stature, fire personnel were easily able to manage and contain the fire without any harm to people or nearby structures.

When is cattle grazing used?

The Open Space Authority has a grazing plan for each of the properties we own or manage. In those grazing plans, we lay out our habitat management goals and outline how much dry vegetation should remain on the landscape. If there is a significant amount of dry matter for a particular property, the Authority connects with our ranchers to coordinate a day and time for cattle to graze the land to a safe and habitat-friendly level. 

When Open Space Authority land managers coordinate cattle grazing efforts, they consider the current weather, the amount of rainfall an area has experienced, current construction or maintenance projects that may interfere with grazing and the type and number of invasive plants that currently exist in the area. If all conditions are met, calculations are made to determine the appropriate number of cattle for the area that needs grazing. Ranchers will then dispatch their cattle to the predetermined location and monitor their progress. Once the cattle graze the grass down to the intended level, the rancher rounds up the herd and preps them for their next grazing effort.

What are some of the challenges of cattle grazing?

Cattle grazing is very weather dependent – during years of drought, there is less vegetation for cattle to eat so ranchers must reduce their grazing herds and adjust their profit margins. There are also logistical challenges for ranchers. Water must always be readily available for cattle on any property where grazing takes place, and infrastructure like fencing needs regular maintenance to keep cattle safe. 

How does the presence of cattle support other native species?

When ranchers first brought cattle to the Santa Clara Valley, they built stock ponds to provide water for their herds. Over time, those ponds became prime habitat for rare, native species like the California red-legged frog and California tiger salamander. Without that history of ranchers managing the land, many of these species would not be here today.

What should I do if I see cattle while out in nature? 

If you happen upon a single cow or a herd of cattle, use these tips to help you navigate the situation: 

• Keep a respectful distance from cattle. If they’re blocking the trail, approach them slowly, speak at a normal volume and allow them to move off the trail. If the cattle don’t move on their own and it’s safe for you to do so, walk around them while giving them plenty of space. 
• Avoid any behavior that may provoke livestock. Including “moo-ing,” touching them or attempting to take close-up selfies. 
• If you see a stray calf, stay away from it. The mother will return and you will find yourself in a dangerous position if you get between a mother cow and her calf. 
• If a cow is giving birth, keep a respectful distance from it to avoid startling or disturbing it. 
• Close any gates you pass through on the trail. 

Click here to learn about additional ways in which the Open Space Authority cares for and protects Santa Clara Valley lands for the benefit of people, water and wildlife.