Dwarfing his owner in the paddock, you can see why Guernsey steer Big Moo has become an object of wonder around Glencoe, in South Australia's south-east.

Measuring 190cm at his enormous withers, the steer's back is about level with the forehead of your average NBL basketballer.

But it is his sheer bulk that surprises most people.

Owner Joanne Vine, who has to stand on tiptoe to reach his back, has become well used to awestruck faces and hearing the words 'big', 'enormous' and 'huge' when it comes to introducing the affable steer to interested people.

Is the Vines' steer the biggest in Australia? Ms Vine would love to hear from anyone who thinks they can top him, and is prepared to wager a steak dinner on the outcome.

"I'm sure he must be up there with the biggest in Australia," she said.

"He must be in contention, especially for a Guernsey, which aren't a particularly big breed."

Hand-reared as a pet on the Vine property, the calf was originally destined for the family freezer, but his sweet nature won him a reprieve.

"He's such a gentle nice guy and he just loves people. He follows me around everywhere and the grandkids can play around him. He's just part of the family," Ms Vine said.

"I'm sure he's half human."

"He's such a gentle nice guy," Ms Vine says of Big Moo. ( ABC South East SA: Kate Hill )

The family watched in amazement as their little calf grew and grew, and now at the age of seven, suspect he is still adding the odd centimetre to his bulky frame.

"We are sure he is still growing," Ms Vine said.

She believes the steer's continuing growth may actually stem from an undiagnosed pituitary gland disorder, the area responsible for producing growth hormones.

But Ms Vine said if there was something wrong with Big Moo, there was no sign he was in any pain.

Indeed, watching Big Moo's enormous frame power down the paddock at a full gallop can be a little intimidating for the casual observer.

"You can feel the earth tremble. He scares people. If he sideswiped you with his hip, he'd have you over the fence," Ms Vine said.

Home, sweet home

Big Moo lives on a large block at Glencoe, with a team of horses and another pet steer companion, aptly dubbed Little Moo.

Transporting him there last year proved a comedy of errors.

"It took us ages to find something. He would never fit in a normal cattle trailer," Ms Vine said.

"Eventually we packed him in the horse float and he nearly didn't fit. He took up the whole float."

After a few scary moments thinking the car engine might break down under the weight of the trailer, Ms Vine said she laughed watching Big Moo wedge his large head out the trailer door, checking out his future home.

"He'll live out his days with us." Joanne Vine and her beloved Big Moo at Glencoe. ( ABC South East SA: Kate Hill )

Potential record holder?

Big cows are big business for the Guinness Book of World Records, which has dished out records for the tallest bovine and the largest horn spread for a steer — a whopping 307cm by Lazy J's Bluegrass.

In August 2014, American Holstein cow Blosom was awarded the record for the world's tallest cow at 190cm, but passed away just a year later.

Many people believed images of a towering Blosom were digitally altered, but her owner defended the shots, saying it was all cow and no trickery.

Should the good folks of Guinness ever come to Glencoe with their measuring sticks, Ms Vine said she was ready for them.

"It is like having a kid genius. You just want to show him off," she said.

Until then, he is just a big steer with a big heart — and a big appetite.

"See that haystack?" Ms Vine said, pointing at a sizable stack in the distance. "That is for Moo.

"He lives out here and that is where he will stay. He comes up for a pat every day," she said, scratching the steer gently behind his big ears.

"We'll look after him until he's no longer with us."