Availability of Phosphorus Supplements for Chicks

The scientific literature dealing with the availability of the phosphorus in various phosphate supplements for chicks was reviewed by Motzok et al. (1956). These workers reported that four colloidal phosphates (soft phosphate with colloidal clay) gave a growth response and percent bone ash, in chicks at 5 weeks of age, below those achieved with tricalcium phosphate. One sample of a fifth colloidal phosphate did not result in inferior growth or bone ash, but another sample resulted in a lower growth response than that with tricalcium phosphate, although the percent bone ash was not significantly different. Samples from ten carload lots from the same producer gave varying growth and bone ash responses, but all were inferior to those resulting from bone meal. However, when half of the supplemental phosphorus supplied by colloidal phosphate was replaced by bone meal there was marked improvement in growth, although the average weight of the chicks . . .