The use in practice of inactivated oil emulsion vaccine against infectious bursal disease in broiler breeders and its influence on the progeny: a comparative field trial.

Field trials were conducted to establish the effect of the use of an inactivated oil emulsion vaccine against Infectious Bursal Disease (IBD OEV) in broiler breeder hens, and its effects on their progeny. The performance of 18 broiler flocks, which were the progeny of the IBD OEV vaccinated breeder hens, but which were not vaccinated with a live vaccine against IBD, was equal to that of broiler flocks which were vaccinated with a live IBD vaccine and originated from parent stock that had been vaccinated only against IBD with a live vaccine. In none of the 18 flocks, progeny of IBD OEV vaccinated parents, was IBD diagnosed. In a second stage, 15 broiler flocks were included in the trial: these were derived partly from IBD OEV vaccinated parents, and partly from parents that received only live IBD vaccine at 8-10 days of age. No cases of IBD occurred and all flocks were positive for IBD precipitins at slaughter age. Vaccination with a live vaccine against IBD at the age of 8-10 days had no influence on NCD antibody development after a NCD vaccination at 7 days. No immunosuppressive effect from this type of live live IBD vaccine could be determined under field conditions.

[Field experience with osteoporosis in broilers]. / Praktijkervaringen met osteoporose bij slachtkuikens.

Osteoporosis is a major cause of economic losses in broilers. Examination shows enteritis, retardation of growth, poor feathering, rickets and crazy chick disease (encephalomalacia) in some cases. It is almost beyond doubt that the disease is infectious and that contamination may persist on a farm over a prolonged period. To produce all clinical features, the birds should be infected during the first days of life. The incidence of osteoporosis in successive flocks may be reduced by thorough cleansing and disinfection with a 10 per cent solution of commercial formalin. Treatment of affected flocks with antibiotics for 3-4 days plus administration of additional vitamins A, D3, E and K for 10-14 days will usually result in more rapid restoration of growth. Economic losses may be considerably reduced by combining thorough cleansing and disinfection with the treatment of affected flocks.

[Stragglers and femoral lesions in broilers. A pathomorphologic study]. / 'Achterblijvers' en 'femurafwijkingen' bij slachtkuikens. Een pathomorfologisch onderzoek.

The pathomorphological features of two economically important skeletal disorders in broilers are described. So-called 'runting and leg weakness' in two-week-old broilers presents the features of rickets, whereas so-called 'lesions of the femur' in six-week-old broilers is marked by resorptive osteoporosis. Both pathomorphological features are observed during the intervening period. Hyperplastic parathyroid glands are present in all birds. The possible aetiology and pathogenesis of the two conditions are discussed. In view of the epidemiological and histopathological features, it is suggested to include the two disorders in a single syndrome in which the features of rickets, those of rickets and resorptive osteoporosis and those of resorptive osteoporosis appear in succession, and in which various clinical manifestations may be present.