The ingestion of sow's faeces by suckling piglets.

1. Six sows were housed in solid-floored farrowing pens and fed daily with approximately 200 microCi 198 Au, three of them from 3 d before farrowing until their piglets were 10 d old and three fr om 10 d after farrowing until their piglets were weaned at 21 d. 2. The sows' faeces and sawdust bedding became radioactive but their milk remained free of radioactivity. The piglets' radioactivity was measured daily in a whole-body counter after they had been washed to remove external contamination. 3. The piglets' mean whole-body radioactivity was equivalent to 20.9 +/- 2.5 g (range 5.7-85 g) of faeces and bedding. If the average passage time of the digesta through the gastrointestinal tract is assumed to be 24 h these values are equal to the average daily intake of faeces and bedding by the piglets. 4. This intake of faeces could possibly prevent the piglets becoming anaemic if the sow's diet were supplemented with iron to increase the Fe concentration of her faeces to approximately 2 mg Fe/g fresh faeces.