Pollard, B.Bigalke, R.D.Cameron, Colin McKenzieGilchrist, Frances M.C.Jordaan, E.Morren, A.J.Verster, Anna J.M.Verwoerd, Daniel WynandWalker, Jane B.Steyn, P.J.J.2015-12-072015-12-0720151982Pollard, B 1982, 'Immune response to the simultaneous vaccination of day-old chickens with live and inactivated oil-based Newcastle disease vaccines’, Onderstepoort Journal of Veterinary Research, vol. 49, no. 2, pp. 123-125.0330-2465http://hdl.handle.net/2263/51096The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.The immune response, as measured by the haemagglutination-inhibition test, to the simultaneous administration of live Hitchner B1 and 2 commercially available, inactivated, oil-based, emulsified, Newcastle disease vaccines at day-old is described. The response was monitored from day-old to 18 weeks, when the birds were challenged with a standardized virulent virus. It was found that the haemagglutination-inhibition titre fell below log₂ 5 when the chicks were 10 weeks of age. Challenge at 18 weeks yielded a mortality rate of 25% in the groups receiving both live Hitchner B1 and an oil-based vaccine in comparison with 94% in the group receiving Hitchner B1 alone. Simultaneous application of live and oil-based vaccines at day-old is conclusively insufficient to maintain adequate protection until18 weeks and it is recommended that a booster vaccine be administered at 10 weeks.en©ARC - Onderstepoort and Faculty of Veterinary Science, University of Pretoria (original). ©University of Pretoria. Dept. of Library Services (digital).Veterinary medicineVeterinary medicine -- South AfricaArticle