[graemep]

I was wondering about that. Cattle in Britain are also predominately grass fed and Ireland has a similar climate and environment and a much lower population density and a lot more land for cattle.

Ireland also exports a lot of that grass fed beef, so could presumably export less, and consume more of it to replace whatever it could not import.

A lot of other countries are also be both importers and exporters of food. The problem might be that in some places the quality and range of diet might decline.

[roryirvine]

In Ireland (and I believe it's similar in GB), beef cattle are usually finished on some mix of silage and concentrated feed with a significant maize component to promote better fat distribution.

There's a continuum between 'extensive' and 'intensive' finishing methods - the former takes longer and uses more forage & grass, and is best suited to native breeds. The latter uses more silage & concentrate, and is used for 'continental' breeds.

Dairy cows will also have pelleted additives over the winter, making up to about a quarter of their intake (largely depending on silage quality). But those tend to be mixes of yeast, fats, and digestible fibre so shouldn't necessarily require imports.