The students cast uncertain glances at the cow.

The steer, who seems entirely bored with the whole ordeal, looked mostly like a normal animal.

Except for the plastic portal on its side.

“We like to call this demonstration the Holey Cow,” Leticia Henderson said, a grin spreading across her face as she passed out worksheets.

The specimen standing quietly in the stall is named Jet. He is a fistulated cow, Henderson told the middle school students gathered around her. That means he underwent surgery for the installation of a fistula — basically a 6-inch-wide hole that creates a passage into the stomach.

“We have a window into the stomach,” Henderson said. “We can learn a lot about digestion. They will live a long, healthy life. We have them for research and demonstration.”

Henderson works for the OSU Extension Service. On Aug. 14 she welcomed the Jump Start program, which is designed to ease seventh-graders into middle school life.

As part of their two-week program in August, the students took various field trips in addition to brushing up on math and reading.

Their visit to the Extension Office focused on natural resources.

The first presenter was Terrah Owens, an OSU graduate research assistant who studies sage grouse in Eastern Oregon.

She explained the lives of sage grouse and detailed how she and her colleagues study the birds by counting males and fitting females with radio collars.

“Then we track them to see how they’re doing on their nests,” she said.

By the end of her talk, students knew what sage grouse eat (sagebrush), what kill the birds (predators and West Nile virus), and how to encourage the population to grow (remove invasive weeds and protect their habitat).

The middle schoolers could also rattle off definitions of “dimorphic” (male and female sage grouse look different), “lek” (the place where sage grouse gather), and “indicator species” (the presence of sage grouse indicates the health of sagebrush).

Christo Morris of the Powder Basin Watershed Council spoke next. He explained the importance of water quality and quantity, and how the environment can affect those attributes.

When a wildfire burns a forest, for example, there aren’t enough trees to trap winter runoff so it can soak into the ground. Instead, it runs down the hillside and into streams.

He also described how management of water on one property has a direct effect on an adjacent property.

“Not only does it move from one property to the next, it does it quickly,” Morris said. “What one person does on their property can affect the water downstream.”

The next station for the students sent them on a scavenger hunt outside to find noxious weeds (the specimens were made of plastic).

Sam Bernards of Tri-County Weed explained her job in helping control weeds in the county, and asked if anyone knew the meaning of “noxious weeds.”

“They can be toxic,” Blake Long said.

Bernards said yes, and pointed the students to the noxious weed booklet they could take home.

“The first step is to identify them,” she said.

She focused on three weeds: leafy spurge, with its 30-foot tap root and ability to shoot seeds up to 20 feet; yellow star thistle that is toxic to horses; and dalmatian toadflax, which is controlled by bringing in an insect that only munches this plant.

To finish her section, the students went outside to find the faux examples of these weeds and jot down some descriptions.

The final station was learning about ruminants, which are animals that chew cud regurgitated from one of their stomachs.

Henderson had two fistulated cows — Jet and Gizmo — borrowed from OSU’s Eastern Oregon Agricultural Research Center Union Station near Union.

First she had students trace a cow’s digestive system on a paper handout.

When a cow eats grass, the roughage first goes to the rumen, which can hold 25 gallons or more of food and water.

“The rumen is where all the magic happens,” Henderson said.

In the rumen, microbes break down the food, which then moves forward to the reticulum. This is where it is regurgitated and rechewed as cud.

Next it travels to the omasum, then the abomasum before moving through the intestine and out as manure.

The hole in these cows gives access to the rumen. Henderson offered a plastic glove to teacher Jonathan Baer, who pulled it clear up to his shoulder.

Then he slowly approached the cow and, after Henderson pulled out the plastic plug, gently put his hand inside the steer’s stomach.

“It’s really warm,” he said, pulling out a handful of partially digested grass.

The students stayed back at first, then edged forward in fascination.

After Baer had gathered a few samples from the stomach, he stepped back and let the students get a closer look.

Danny Davis immediately pulled out his phone and took a photo.

Back at the tables, the students slipped on gloves to touch the grass samples and examine it under the microscope.

“It smells like grass that has been barfed up,” Sheylin Karolski said as she pulled some grass apart.

With her focus on the grass, she didn’t notice the reaction of her classmates — Brandon Unrein, Blake Long and Cooper Colton all had hands cupped over their noses.

Then came a question from Baer:

“Who’s ready for lunch?”