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 frequently uses cattle grazing as an udder-ly integral conservation and management strategy.

Cattle grazing is the strategic distribution of cattle throughout a region to manage the land in a natural way, and one of the Authority’s tools for conservation. When done properly, it’s a minimally invasive and an effective conservation technique. For years, the Open Space Authority has used this practice on eight thousand acres of the land the agency manages.


There are a variety of benefits and goals that this practice 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 Galli Basson, Resource Management Program Manager at the Authority. Managing the quantity of the growth of invasive species makes more space available for native plants to grow and grazing of excess dry plant matter means less fuel for fires to use.

And these benefits are measurable. The Authority is working with a GIS consultant to support the agency’s fire fuel management program, and preliminary GIS modeling shows that its use of cattle grazing substantially lowered the fire risk on grasslands when compared to nearby non-grazed grasslands.

Cattle grazing also provides the benefit of promoting healthy soils and promoting habitat. “It helps protect and provide habitat for rare species like burrowing owl and bay checkerspot butterflies, which depend on short grasslands.”

CRID - Bay checkerspot butterfly - D.Neumann-1

When determining which properties need to be grazed, there are short-term and long-term considerations. For the long-term determination, every property has a grazing plan that discusses our management goals which includes how much residual dry matter, or old plant material left on the ground, is on the landscape. If there is a significant amount of dry matter, which is also fuel for fires, then it's time to bring in a herd.

Short-term considerations are much more site- and weather-specific, and these change each year, based on the composition of invasive species throughout a landscape, the amount of rainfall an area experienced, and the presence, maintenance, and/or construction of trails.

Like most management strategies, cattle grazing has no shortage of challenges. For one, weather patterns are always a consideration. During years of drought, there is less for cattle to eat, and often ranchers must reduce their grazing herd and adjust their profit margins.

Cattle grazing poses logistical challenges, as well. The number of cows distributed into a region is determined by a formula – it measures the specific landcover type and the landcover’s productivity estimate, which then determines the number of animals needed to achieve respective residual dry matter targets. Once that is determined, ranchers – often on horseback -- will distribute the cows to the landscape. Water must always be readily available for cattle on any given property, and infrastructure like fencing around a landscape must be consistently upgraded or maintained for the cattle’s safety.

Regardless of the challenges, cattle grazing remains an effective and low impact landscape level conservation and land management tool. To learn more about the Authority’s conservation work, click here.

Quick tips for sharing the trail with cows:

  • Always be aware of your surroundings and keep a respectful distance from cattle. If cattle are blocking the trail, approach them slowly, speak normally, and allow them to move off the trail. If they don’t move away on their own, give them a lot of space when walking around them.
  • Avoid any behavior that may provoke livestock, including trying to touch them, or taking up-close selfies. If you see a stray calf, stay away from it. The mother will return, and you do not want to get between a mother cow and her calf. 
  • Properly latch any gates you pass through on the trail.  

RCAN - Cow-1

Photo credits
Cows on trail at Sierra Vista Open Space Preserve - Chelsea Cross
Cows on hill at Sierra Vista Open Space Preserve - Open Space Authority Archives
Bay checkerspot butterfly - Derek Neumann
Calf at Rancho Cañada del Oro Open Space Preserve -Open Space Authority Archives

May 26, 2022
For media inquiries contact:

Charlotte Graham

Public Information Officer