EFFECT OF BOTH MYCOPLASMA GALLISEPTICUM (MG) AND INFECTIOUS BRONCHITIS (IB) CLASSICAL AND VARIANT STRAINS ON THE EGG PRODUCTION OF THE BROILER BREEDER FLOCKS

Authors

1 Veterinary Serum & Vaccine Res. Inst., Abbassia, Cairo

2 Faculty of Vet. Med. Moshtohor, Banha

3 Faculty of Vet. Med., Cairo University

Abstract

It was later observed that the IB was common in semimature and lying flocks as well and caused a marked losses in egg production. Prior to 1956 avian infectious bronchitis was considered to be caused by a single antigenic type of virus (pathogenic Massachusetts M41, and the Beaudette non pathogenic embryo lethal strain M, since that time a number of isolates have 42 been identified from outbreaks that are different antigenically from the original Massachusett type Winterfield et al., 1971 and Hopkins, 1974). Variant strains most frequently found to be involved in IB problem herds, belonged to two main groups namely (D207 and D212) which have poor immunogenic properties. A field isolate called D274, however belonging to the D207 serotype, proved to induce cross-protection with D3896 and to a lesser extent D3128. Also, in the D212 group haemagglutinating strains were found, of which D1466 was found to be more immunogenic than D212. Mycoplasma gallisepticum [MG] infected chickens have been reported to suffer from a drop in egg production [Carpenter et al., 1979; Carpenter et al., 1981; Lin and Kleven, 1982). MG infected hens have been observed to lay an average of 15.7 fever eggs/hens housed than MG free hen over a 45 week laying period [Carpenter et al., 1981). The aim of this work was to demonstrate and evaluate the role of IB variant strains either alone or combined with Mycopeasma gallisepticum on the egg production of layer breeder flocks.

Main Subjects

Veterinary Medical Journal (Giza)
Volume 39, Issue 1
January 1991
Pages 169-179

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