The effects of incremental calcium levels throughout the laying period on egg shell quality

The purpose of this experiment was to determine the effect of constant levels of calcium in the diet and the effects of increasing the calcium level in the diet at three different constant rates throughout the laying year on shell quality; egg production, egg weight, and feed consumption. This study was conducted for 10-28 day periods, using three constant and three variable levels of calcium with three replicate lots per treatment. Five orthagonal contrasts were developed, and a multivariate analysis of variance was used where the response variables were expressed as regression coefficients to show the relationship of the parameters measured over time. The results show no statistically significant relationship among calcium treatments for average egg weight, feed consumption, body weight and exterior quality. There was no consistent or significant effect of calcium level upon average specific gravity of the eggs. The possibility of further research into incremental calcium feeding is suggested in that the dietary calcium levels of 3.11 to 4.00 percent and 3.15 to 4.25 percent had the highest average specific gravity. Egg production was not statistically significantly affected by dietary calcium level, except that hens fed the 3.00 and 4.00 percent constant calcium levels laid at a higher rate than hens fed the 3.50 percent constant calcium level diet (P<0.05). No logical explanation for this difference can be offered at this time.