The Ulster Farmers' Union says the results of the December Agriculture Survey, published by DARD, highlight the problems faced by the beef and pig sectors.
The number of beef cows in Northern Ireland fell by 9% in the past year and the number of sows and gilts fell by 8% in the previous twelve months.
UFU President Kenneth Sharkey said; "This sample survey is an interesting indicator of trends in the farming industry. Since CAP Reform and the decoupling of CAP support from production, farmers have much more flexibility in their business decisions. It is clear from this survey that during 2007, many suckler cow and pig producers have downsized their herds or ceased production. This has been our warning to processors and retailers for a long time. If producers aren't paid sustainable prices they will not stay in the industry and consumers will be deprived of high quality local produce".
Mr Sharkey added; "19% fewer prime cattle were slaughtered in Northern Ireland in January 2008, compared to January 2007. Many pig producers are also seriously considering de-stocking because of unsustainable prices. The retail sector must respond to this and look seriously at how to secure sustainable supplies of local produce which their customers are demanding".