Operating profits at Aurivo Co-Op fell by 23% last year to €3 million, while the full-year financial results show a 4% increase in turnover to €443.8 million.
In a year marked by ongoing volatility in global dairy markets, Aurivo says the financial performance for the year was in line with expectations.
2018 also saw the largest investment in the Co-op's history, with new capital investment of €22 million - which was the start of a €48 million five-year investment programme.
Turnover remained steady last year in sales of milk, butter and sports nutrition, while dairy ingredients had a strong year with turnover up €10 million on the previous year.
Aurivo's Agri-business showed an 18% increase in turnover last year, but turnover at livestock marts was down €10 million on 2017 figures.
The Co-op employs about 650 people in the Northwest region.