Pathological Studies on the Effect of Some Gumboro Disease Vaccines in Poultry

1- One hundred and fifty chickens in the age of one day were used in thisstudy. These chickens were classified into five equal groups. The first,2nd, 3rd and 4th groups were vaccinated with live and l..”: __ d Gumborovaccines and challenged with Gumboro disease virus, while the 5thgroup was used as a control.2- The most clinical signs of chickens which had been vaccinated withdifferent types of live vaccines showed depression, weak. less, loss ofappetite, diarrhoea and 20% mortality.The chickens which were vaccinated with both ki lied and I ive vaccineshowed normal activity during the experiment and recorded 6.6%mortality after their challenging. The chickens which had beenvaccinated with only killed vaccine showed loss of appetite, depressionand 13.3% mortality. The chickens which were not vaccinated but werechallenged with the virus of Gumboro disease showed depression, lossof appetite, whitish watery diarrhea, ruffled feathers and 68.4%mortality.3- The most pathological changes had been seen in the bursae of fabricius,where it appeared normal in size and colour in the vaccinated and thenchallenged with the virus, while in the non vaccinated ones and thenchallenged with the virus showed congestion, hemorrhagic andenlargement. The thymus gland and the livers were normal in size and