I don't like the WORDING…
Depleated makes it sound like Nutrients being removed in up to 5 years.
But I think what they MEANT is POISON your soil in five years, because if the cows are eating roundup and not dying, they then poop roundup ready manure.
So the soil is like Sprayed with Round up at the roots.
I see no reason it wouldn't come in on HAY and POOP both, the hay maybe has more roundup since it was Sprayed directly as opposed to diluted by cattle eating it.