The Influence of Calcium Intake During the Period of Sexual Maturation of Pullets on its Retention and Eggshell Quality of Laying Hens

The aim of the study was to determine the calcium requirements in preparation period of the sexual mature and egg-laying and evaluate development of calcium retention in the first laying period of the hybrid combination Bovans Brown hens. The experimental trial lasted from 14 to 30 weeks of hens age. The animals were fed ad libitum with a pelleted complete feed mixture with 42 g/kg of calcium content. The amount of calcium retained by pullets gradually increased along with feed intake depending on age and preparation for sexual maturity and was around 0.39 ± 0.19 g Ca in the first period. Ca retention increased up to an average of 0.85 g Ca from 8 day before laying the first egg. Retention dropped sharply on the day of laying the 1st egg and a negative Ca balance occurred. Shell output was 1.75 ± 0.21 g/day for the beginning of laying and subsequently increased to 2.23 ± 0.08 g/ day during evaluate peak laying. The range weight of the first laid eggs was 45 ± 5 g. Percentage of eggshell move around an average of 10 ± 0.37% throughout the observed period. The daily calcium intake of pullets was 3.56 ± 0.26 g/day. With the beginning of laying, the daily intake increased to an average of 4.51 ± 0.43 g/day Ca. Before reaching sexual maturity, the calcium apparent digestibility of laying hens was relatively low, averaging around 22%, but the moment the hens began to lay, the apparent calcium digestibility began to increase to an average of 50%. Feeding a non-standard feed mixture with a higher calcium content than usual in mixtures for pullets did not have a negative effect on the finishing of animal development, the onset of sexual maturity, or deterioration of the observed parameters of eggs quality.