Interaction of Dietary Salt, Calcium, and Phosphorus Levels for Laying Hens

Abstract

Two experiments, each of 280 days duration, were conducted with White Leghorn pullets housed in individual laying cages to study the interactive effect of feeding various levels of salt and calcium or phosphorus. A 3 X 3 factorial treatment arrangement was employed between supplemental salt levels of .18, .35, or .70% and total calcium levels of 2.25, 3.5, or 6%. When salt and phosphorus were dietary variables, total salt levels of .18, .35, or 70% were again used in all combinations with .45 or .70% total phosphorus. Six percent calcium was fed with the latter treatment combinations.The interaction of calcium and salt level was found to be significant for egg production. Increasing the salt level through .70% provided consistently significant improvements of egg production, while a calcium level of 3.5% supported statistically improved egg production over either 2.25 or 6.0% calcium. Feed efficiency improved significantly between the .18 and .70% salt level and between 2.25 and 3.50% calcium. Increasing calcium was significantly related to decreasing feed intake at each level of supplementation.In the salt X phosphorus phase of experimentation, .35% salt was associated with a significant improvement of egg production. The interaction of salt and phosphorus was also significant for egg production.