I had a look at the reference and the Wikipedia creates a misleading picture. The source states

> Ireland has very limited horticultural and grain production on account of its topography and climate, and it imports around 80 percent of its animal feed, food, and beverage needs.

Cattle are predominantly grass-fed in Ireland which is largely self-sufficient in grass/silage. Not to minimize the fragility of its economy wrt to food production - but the 80% I imagine is due to the reliance on other EU for fruits, vegetables and grain but these imports are almost exclusively for human consumption.