Table 2 Approximate numbers of annual surveillane samples analysed for serum antibodies to the causative agents of Aujeszky's disease (AD), transmissble gastroenteritis (TGE), classical swine fever (CSF), and swine vesicular disease (SVD) in Nordic countries. In 1998, these countries were considered free of all these disease.
a A systematic sample comprising 10% of boars and 5% of sows slaughtered or exported for slaughter; in border areas all boars and 10 % of sows intended for slaughter are sampled.
b A systematic sample from slaughtered sows and fatteners.
c The sample comprises all boars slaughtered annually, all sows slaughtered during April and May (corresponding to 10% of total sows slaughtered), and a systematic sample (n = 3000) from fatteners.
d All elite breeding and multiplying herds (n = 200), and a stratified random selection (n = 290; fattening herds Under-represented) of the rest of the pig herds are tested; samples are collected first and foremost from sows.