Abstract

Five two-tooth Coopworth ewes were used to monitor the effects of changing caecal pH on magnesium (Mg) solubility and absorption pH change was induced by infusion of volatile fatty acid (VFA) (0, 220, 440, 660, 880 mmol; ration 0.80:0.15:0.05 acetic:propionic:butyric in 2016 ml of deionised water) into the terminal ileum for 24 h. Treatments were randomly applied to each animal using a latin square design. During the infusion samples of blood and urine were taken at 4 h intervals and proximal colonic digesta at 4, 16 and 24 h. Apparent Mg absorption from the large intestine was estimated from changes in plasma Mg concentration and urinary Mg excretion. Sixteen hours after the commencement of infusion digesta pH decreased and Mg solubility increased. For example, with the 880 mmol infusion digesta pH had decreased by 2.1

TG, Watson, BC Hosking, and AP Hurford

Proceedings of the New Zealand Society of Animal Production, Volume 52, , 69-72, 1992