Announced in May, the combined UK businesses will now trade as Dunbia.
Former Dunbia CEO Jim Dobson will act as CEO. Dawn Meats CEO Niall Browne is executive chairman.
A new brand and logo for the joint venture was unveiled to staff and customers at the business' headquarters in Dungannon, Northern Ireland.
In the Republic of Ireland, Dawn Meats has acquired Dunbia's operations, and now has nine facilities, including five abattoirs, following the addition of two complementary Dunbia facilities - one abattoir in Slane, and one boning hall in Kilbeggan.
Combined business
The combined businesses in the UK and Ireland will process approximately 900,000 cattle and 2.6 million sheep annually.
In the UK, the Competition and Markets Authority (CMA) conducted a phase one investigation into the merger, which found it "does not give rise to competition concerns".
This applies to both the purchase of livestock (cattle and sheep) from farmers and the supply of unprocessed and processed meats to customers across the UK. This is because the companies do not currently compete strongly for the purchase of livestock.
The CMA added that they also would continue to face strong competition from alternative suppliers in the supply of unprocessed and processed meats and that the merger will therefore not be referred for an in-depth investigation.
Dawn Meats
The merger included the acquisition by Dawn Meats of the Irish beef business of Dunbia, which was assessed separately by the Irish Competition and Consumer Protection Commission (CCPC).
A statement from the CCPC said: "With respect to the other four potential markets examined by the CCPC (i.e., the sale of fresh beef meat to grocery retailers in the State; the sale of fresh beef meat to industrial processors in the State; the purchase of live lambs and live sheep for slaughter in the island of Ireland; and the sale of fresh lamb meat to grocery retailers in the State) the CCPC has concluded that the proposed transaction will not substantially lessen competition in any of these four potential markets. In each of these four potential markets, there is a negligible horizontal overlap between Dawn Meats and Dunbia and, post-transaction, Dawn Meats will continue to face competition from a number of competitors currently active in the State."
Commenting on the decision, Niall Browne, CEO of Dawn Meats, said: "We are very pleased to have successfully concluded this process and can now look to deliver the benefits that we believe this transaction will bring for our customers, staff and suppliers. Our focus will continue to be on quality and sustainability across three leading national businesses: Dawn Meats in Ireland, Dunbia in the UK and Elivia in France.
"The combined businesses in the UK are highly complementary, and will offer customers regionally sourced solutions for both beef and lamb from 15 facilities across Scotland, England, Wales and Northern Ireland."
Jim Dobson, CEO of Dunbia, added: "I am excited today to be introducing a fresh look for the new Dunbia business in the UK. The partnership will ensure that we can grow as a leading supplier in the UK market and deliver long-term solutions for our customers and a strong relationship with our farmer suppliers."