In fact grain is mostly given at the end for a few weeks to give a fat cover. There are feedlots in the USA, but these are a minor part of the world beef trade. There are non in England, it is too cold. So there are the next facts. Making beef illegal would save no lives, it would just mean that the animals are killed sooner.
Every milk cow causes one death each year.
All over the world, the most profitable farming enterprise is arable crops. It is only the poor land, which can only grow grass, which is used for animal husbandry as its only enterprise. Therefore, it is the peasant farmers who would be displaced, and this glorious wild habitat would be destroyed. Nothing else will keep it as it is, because it is not natural and has been created by this type of farming in the last two millennia. It is this inability to face up to facts which stops me being an active animal rights campaigner.