Avian Mycoplasma Control – Central For Antibioitic Independent Production

C.J. Morrow


The effects of avian mycoplasma infections are overt disease (often chronic), subclinical losses and antibiotic dependence. Routine administration of antibiotics in broilers at 18-22 d was developed to prevent chronic respiratory disease in vertically mycoplasma infected broilers. The timing of this administration is after all the birds are infected but before overt disease occurs. The routine administration of antibiotics to layers (and in some parts of the world breeders) every four to eight wk during lay is to similarly knock back mycoplasma on a regular basis. Mycoplasma infection freedom (MIF) was developed as a strategy to prevent these problems. It has one big problem which is that the birds in uninfected flocks are totally unprotected against infection. Live vaccines that are safe (low transmission) and efficacious (protecting against wild strain disease) can provide the additional benefit of increasing the resistance of flocks to mycoplasma wild strain infection. This is particularly important where neighbouring operations may not have the same priority on controlling both M. gallisepticum (MG) and M. synoviae (MS) and challenge is continuous. Having vaccines to protect against both MG and MS infection means that no antibiotics are needed. Other infections that routine antibiotics have controlled include Brachyspira, Avibacterium, and Pasteurella but these can be attacked with biosecurity, other interventions and vaccines as well and are not the universal problems that mycoplasma infections are. MIF is at the core of being able to farm poultry and egg layers in modern production systems without dependence on routine therapeutic antibiotic administration and perhaps with vaccination should be considered state of the art in high risk areas.