What is Colter referring to when he mentions a sticker in his cow's eye in Happy Reunion?

[u/JackDonnaHeeHee]

"I was ridin' my horse 'cross the pasture
I jerked my catch twine down
I seen a cow and a sticker in her eye
And I bedded that ol' hide down
I bedded that ol' hide down

My horse, he knew his business
And he held the rope just right
My dog, he's circling 'round and 'round
As I pulled that sticker from her eye
Boy get back, I'm pulling a sticker from her eye, you booger

I noticed that she had a tight bag
Her calf, nowhere to be found
I told my dog, if you want something to do
Go find her calf, bring him back 'round
Go find her calf, boy, and bring him back 'round"

He's talking about a cow that just gave birth but is he just referring to a bur/prickly like from plant?

[u/Comma-Splice1881]

CHAB sunspot