Abstract
In conscious sheep, the transport of calcium, phosphorus and magnesium across the rumen to the blood was observed using the method of veno-arterio differences. Two wethers, in individual pens, were each surgically prepared with a rumen fistula, a carotid loop and a rumen venous catheter and they were fed a diet of barley, soybean meal and hay. Blood and rumen fluid samples were taken 6 times a day as follows, 0, 1.0, 1.5, 2.5, 4.0 and 7.0 hours after feeding. The absorption and secretion of calcium, phosphorus and magnesium was demonstrated in normal mineral concentrations and pH values in the rumen fluid. The considerable amount of calcium and phosphorus were transported through the rumen wall. But the net adsorption of calcium and phosphorus was small in quantity. A positive correlation between the veno-arterio differences of calcium and phosphorus was found in one sheep (P<0.5). Magnesium seemed to be absorbed constantly across the rumen wall when the rumen fluid magnesium levels averaged 100mg/l. Noticeable correlation was not found between the magnesium absorption levels and the rumen magnesium concentrations, and the rumen pH values.
