Changes in serum calcium and phosphorus levels and their relationship to egg production in laying hens infected with velogenic Newcastle disease virus

This study evaluated the changes that occurred in the serum levels of calcium and phosphorus in laying hens infected with velogenic Newcastle disease (ND) virus (vNDV), and their relationship to the decrease in egg production usually associated with ND. Two hundred and forty laying hens (32 weeks old) were randomly assigned into four groups of 60 each viz: VAI – vaccinated with ND vaccines and intramuscularly inoculated with vNDV, VAU –...