Gardai and Department of Agriculture investigators believe they made a significant breakthrough in their fight against cattle smuggling when they seized 15 cattle and a truck near Lifford, Co Donegal, yesterday.
The mature animals were being transported from Northern Ireland but, according to the Department of Agriculture, they were tagged with Republic of Ireland ear-tags.
The driver, who said he was bringing the animals for slaughter in the Republic, had papers which purported to show that the animals were born and reared in the Republic.
The driver said he had taken a short-cut through the North and the cattle had originated in Monaghan. However, this does not appear to be the case and the cattle have been taken for slaughter while investigations continue.
Since the early 1990s it has been illegal to import cattle from Northern Ireland because of BSE. The incidence in the North has been much higher than in the Republic.
However, there was a significant illegal trade in young male animals until the sealing of the Border in February because of the foot-and-mouth crisis.
Investigations into livestock smuggling uncovered over 200 calves, abandoned by farmers who had bought them illegally.
This led to a State-wide inquiry into the number of twins being recorded in herds in the Republic as some farmers had been integrating illegally imported calves into their herds and recording them as twins.
Yesterday's seizure is the first time since the ending of the foot-and-mouth crisis here that smuggled animals have been found crossing the Border illegally.
The seizure came as the Irish Farmers Association and the Ulster Farmers Union were meeting in Dublin to iron out difficulties over the importation of sheep from the North to processing plants in the Republic.
The UFU claimed that "organised pressure" by farmers in the Republic on lamb processing plants had prevented the resumption of the trade which was stopped in February because of foot-and-mouth.
The trade in sheep was due to resume on August 1st under a strict protocol which was agreed between the authorities North and South, but the factories would not accept the sheep.
Yesterday, following a four hour meeting in Dublin, an agreed statement said nothing about the difficulties, but the UFU president, Mr Douglas Rowe, said afterwards that he expected the trade could resume, subject to the protocol being observed.