Inappetence in ruminants as a measure of fluoride solubility in various phosphates

Experiments with soft phosphate and fertilizer grade concentrated superphosphate and diammonium phosphate were to measure effects on voluntary intake of their fluoride in relation to that from calcium fluoride and sodium fluoride given once daily by capsule. Mature wethers were offered 1200 or 1400 g daily of mixed grain-roughage diet, and responses to fluoride were measured by inappetence, consumption of less than 10% of offered diet. When 40 ppm fluoride as sodium fluoride was given for 2 days, inappetence resulted, whereas 2,400 ppm fluoride as calcium fluoride did not decrease feed intake. Time required for recovery of appetite increased with more fluoride. When soft phosphate, concentrated superphosphate, and diammonium phosphate were tested at 100, 200, and 400 ppm fluoride, inappetence occurred always but severity of reduction of intake was related to parts per million fluoride. Solubility of fluoride in soft phosphate, concentrated superphosphate, and diammonium phosphate is more similar to sodium fluoride than to calcium fluoride, and their use should be in keeping with fluoride tolerances established for ruminants fed sodium fluoride.