Prevalence of egg shell apex abnormalities in commercial layer chicken of namakkal region of Tamil Nadu

Egg shell plays a major role in determining the quality of commercial layer chicken table eggs. Many factors are involved in causing abnormalities of egg shells, particularly in the apex part of eggs. The present investigation was aimed to study the prevalence of Mycoplasma associated eggshell apex abnormalities (EAA) in commercial layer chicken of Namakkal poultry zone of Tamil Nadu. Flock history and clinical samples from live and dead birds were collected from 24 flocks belongs to 14 different farms with the history of showing egg shell abnormalities. Collected clinical samples were subjected for detection of Mycoplasma gallisepticum (Mg) and Mycoplasma synoviae (Ms) by culture and polymerase chain reaction. Among the 24 flocks Ms and Ms + Mg infection were observed in 16.6 and 12.5 per cent of flocks respectively. In EAA affected flocks 0.65 to 1.35 per cent of eggs showed shell defects at the apex (pointed end). The incidence of the condition was increased in large flocks (ie., above 10, 000) under peak production of laying from 25 to 40 wk of age and winter seasons. Egg production drop and mortality were ranged from 2.0 to 7.7 and 0.05 to 0.35 per cent respectively. Four out of 14 farms experienced EAA like defects in their previous flocks. Antimycoplasmal drugs were given periodically however periodic mycoplasmalmonitoring was not carried out. The study indicates the prevalence of mycoplasma associated EAA in commercial layer flocks is increasing and should be controlled by proper monitoring and enhancing biosecurity measures.

HIGHLIGHTS

EAA is most commonly noticed in 25 to 45 weeks of age with 0.66 to 1.35% of produced eggs revealed these defects.

EAA affected flocks showed 2.0 to 7.7% drop in production and 0.05 to 0.35% mortality without any clinical signs.

Among the Mycoplasma Spp., M. synoviae associated egg shell quality problem is increasing in commercial layer chicken.