Before they started gathering and killing them last year, you could ride down the Gila River in that area and see 30-50 head any day. The reason for the lawsuit from the Center for Biological Diversity is because the cattle were over grazing the bottom of the river and bothering the hikers on the Continental Trail.
They were considered property of the NM Livestock Board until the FS deemed them an Invasive Species with their Decision Letter. Just like game laws 99% of people follow the law and they were not shot.
Anybody who was half a hunter could have shot a 100 easy in 5 days. If you could shoot a 1000 to 1500 yards you could have done a bunch of bullet testing at those yardages.
So to answer the question about how many hunters could have killed.
Everyone of them.