Faecal occult blood tests represent an unreliable way of detecting gastro-intestinal haemorrhage in cases of mild melaena. The animal must be deprived of meat, bismuth subsalicylate and ferrous sulphate for 3 days before the faecal samples are taken for analysis. | Faecal occult blood tests represent an unreliable way of detecting gastro-intestinal haemorrhage in cases of mild melaena. The animal must be deprived of meat, bismuth subsalicylate and ferrous sulphate for 3 days before the faecal samples are taken for analysis. |