AUSTRALIAN POULTRY CRC - Poultry Hub

inactivated vaccination should be less than 40%. For live vaccine applications, the % CV should beless then 60%. With live priming, complete sero-conversion is more important than % CV and oneshould check if all birds test positive.All farms had positive initial EDS titres (average 3397) with farms 1and 3 also having 100% ofsamples with a positive initial IBV titres (4721 and 3734, respectively). Farms 2 and 5 had an overallpositive initial IBV titre however farm 2 had 20% of samples with suspect results, and farm 5 had 30%of samples with suspect results and 15% of samples with negative titres. Farm 4 had an overallnegative IBV titre (985) with only four samples out of 15 showing a positive result. Farm 1 was theonly farm with all samples showing positive initial NDV titres (average 4407). All other farms had anoverall positive initial NDV titre however each farm had a percentage of samples that were suspect ornegative (Farm 2 – 13% suspect, 7% negative; Farm 3 – 18% suspect, 18% negative; Farm 4 – 13%suspect, 33% negative and Farm 5 – 10% suspect).All farms except farm 2 showed a decrease in EDS titre from the start to the end of the survey howeverthe titres of the four farms sampled remained positive (average 3141). Farm 1 had all positivesamples, farm 2 had two negative results, farm 4, two negative and one suspect result and farm 5 onesuspect result. IBV titres were positive for all farms at the end of the survey (average 3053) withfarms 1, 2, and 5 having all positive samples. Farm 4‟s titre had increased over the period of thesurvey from negative (985) to positive (1737), with the number of positive samples increasing from 4to 7 out of 15. As with the initial NDV titre, all farms had an overall positive titre (average 3318) withfarms 1 and 2 having all positive samples. Farm 4 had three suspect and one negative sample and farm5 had two suspect and one negative sample.One should take in consideration that, factors like age, vaccination method and disease history of theflock could have influenced the vaccination titre. However, except for Farm 4, all farms have had agood protection against IB, NDV, and EDS.Table 8: Percentage of positive (+), suspect (s) and negative (-) EDS, IBV and NDV titres from bloodsamples taken at the start and end of the survey period (ns – no sample).EDS(%)IBV(%)NDV(%)Initial Final Initial Final Initial FinalFarm + s - + s - + s - + s - + s - + s -1 100 100 100 100 100 1002 100 87 13 80 20 100 80 13 7 1003 100 ns 100 ns 64 18 18 ns4 100 80 13 7 27 73 46 27 27 54 13 33 73 20 75 100 95 5 50 30 20 100 90 10 85 10 517