The effect of feeding pre-laying levels of dietary calcium on mineral metabolism in pullets from 15 to 21 weeks and subsequent laying performance

Abstract

A study was conducted to determine the effects of increasing dietary pre-lay calcium levels from 1.00 to 2.00 or 3.00% between 15, 17 or 19 weeks of age. A total of 840 Single Comb White Leghorn pullets were randomly assigned to seven dietary treatments. Birds were fed diets containing 2970 kcal ME/kg and either 1.00, 2.00 or 3.00% calcium. Increasing the calcium levels from 1.00% concomitantly increased serum calcium, percentage bone ash and bone mineral composition from 17 to 21 weeks of age. There were no detectable (P [less than or equal to] 0.05) differences in these parameters after 21 weeks of age in pullets fed 1.00% calcium in comparison to those fed 2.00 or 3.00% calcium. Feed consumption and feed efficiency were significantly improved by feeding 2.00 or 3.00% calcium, during the pre-lay stage. There were significant differences between treatments for egg production and egg shell characteristics. Pullets receiving 2.00 or 3.00% calcium consistently had heavier egg and shell weights, thicker shells and higher egg specific gravity than those receiving 1.00% calcium. There were no detectable differences (P [less than or equal to] 0.05) in mortality, body weights, body weight gain, liver weight, liver and kidney mineral composition, from 17 to 65 weeks of age. These data indicate that serum calcium, bone mineral mass, egg shell quality and egg production can be improved by increasing the pre-laying levels of calcium above 1.00% to 2.00 or 3.00% a t 17 or 19 weeks of age, in early maturing pullets.