Mohanambal, KSelvaraju, GPalanivel, KMJohnson Rajeswar, JTANUVAS2020-02-032020-02-032015-02http://krishikosh.egranth.ac.in/handle/1/5810142375TNV_IJCR_2015_7(2)12549-12552The present study was undertaken to evaluate the immunopotentiating effect of medicinal plant products such as Withania somnifera, Tinospora cordifolia, Allium sativum and Azadirachta indica in commercial layer flock vaccinated against Newcastle disease. The HI titre values in all the groups were above the protective level throughout the study period. Withania somnifera treated group showed highest mean HI titre of 234.66 and high HI titre from 26th week to 40th week of age when compared with other groups. For normal egg production, HI titre value should be greater than 256, which is obtained in W. somnifera, T. cordifolia and A. sativum treated groups only at 32 weeks of ageenVeterinary ScienceArticle