Should I let them graze my brown winter pastures???

[AClark]

I'm not entirely sure, but I don't think cattle folks deworm on a schedule like you do for horses, like every 8 weeks. I know ivermectin says not to use it in animals intended for food or you have to wait X amount of days before slaughter. Since we don't eat horses in the US, it's less of an issue than it would be for beef cattle.
I kick around manure piles after I've dewormed to see how bad of a worm issue we have and if I need to switch it up on types of wormers though.