GASTROINTESTINAL PASSAGE OF CA, P, NA AND K IN COWS CONSUMING FEEDS WITH SACCHARINA AND GREEN FORAGE

The passage of Ca, P, Na and K through the gastrointestinal tract of 4 cows cannulated in the rumen and duodenum was studied in an incomplet e Latin square design (1 treatment and 3 periods). These animals consu med green forage and three feeds with 50, 70 and 90% Saccharina and a commercial feed as the control. Significant differences (P<0.05) were found between treatments for sodium and potassium consumption favourab le to the control treatment.The flow of Ca from the rumen contents was 44/day with the treatment with 90% Saccharina and significantly diffe red (P < 0.05) from 50, 70% and the control which showed values of 32, 30 and 26 g/day, respectively.An apparent absorption of Ca up to 31 g /day followed by a duodenal secretion of 44 g/day was observed. There was a greater flow of P and K towards the rumen of animals with Saccha rina which significantly differed (P < 0.05) from the control. The con tent of Na in this organ was poorer (P < 0.05) with 90% Saccharina and coincided with the highest duodenal secretion of the mineral. The res ults indicate flow variations of Ca and P in the gastrointestinal trac t of animals favourable to the treatments with Saccharina. The perform ance of Na and K seems to be related to the maintenance of an ion bala nce through the gastrointestinal tract.