Okay I feel like being a little pedantic. Goats don’t eat metal. Goats are actually very selective eaters. They can eat a wide diet but only eat the best first. The can thing mostly comes from back when labels were put on with gelatine based glues. Goats would chew on the can to get the glue off.
Interestingly enough cows will eat metal. Not intently but cows are not good at being selective eaters so if it ends up in their mouth it is usually eaten regardless if the cow wants to or not. This leads to a condition called hardware disease, where metal collects in the cows stomach specifically the reticulum. This can lead to the stomach being punctured and the cow dying from sepsis.