Mycoplasma, Use of Antibiotics and Alternatives

PHONGTHEP MORAWAN mycoplasma freedom is only possible when you have goood underlying biosecurity - this includes farm siteing and isolation - very difficult in the short term (but some gains can be made in the medium term with rearing away from multiage sites. Live mycoplasma vaccination is the other way of controlling mycoplasma infections. Simply you need the same strategy for MG and MS. No use only vaccinating for MG (especially if you use antibiotics to limit the impact of MS infections). The efficacy of live vaccination is greatly enhanced if you can get replacement stock wthout infections (mycoplasma free).

Chris Morrow, Is this vaccine applicable in broiler meat production especially looking at 5 weeks production cycle. Can we get the MG vaccine in Nigeria

Eric Gingerich thank you. I should emphasis that phasing out mycoplasma antibiotic prophylaxis is at different stages around the world and also varies in countries between table egg production and broiler meat production. So Australia is probably the most advanced from having the mycoplasma vaccines (including MS) over 25 years, The US, Argentina and UK especially poultry meat production are very advanced generally. Countries like Spain are rapidly changing. In Brazil the meat industry is very far ahead of the egg industry. Exporting poultry meat industries have had to make sure that residues donot get into product - but really the focus is to stop antimicrobial resistance determinants from developing and heading towards human pathogens in the food chain. The easiest way to speed this along would to be to give a minimum withdrawal time for eggs of two days. This would leave antibiotics to treat sick flocks but stop them from being used for prophylaxis. The success of mycoplasma vaccination in decreasing antibiotic dependence in chicken industries should be a model for other industries especially the pig industry which in most parts of the world is still very antibiotic dependant.

Eric Gingerich your comments about MS are certainly the current view in the USA (in states without turkeys) but I think MS is causing more subtle losses in the US egg industry. F strain and MS in the US avain respiratory background are not causing clinical problems unlike many other places in thre world (TRT, respiratory virus control etc). But sublinically? Certainly F strain in the US was estimated by Carpenter a long time ago to be costing 7 eggs per hen housed when comparing vaccinated flocks to MG flocks that are not challenged with field strain. The average MS strain has the same impact on egg numbers according a review in the OIE in 1996 (Stipkovits and Kempf). But the studies that gave all off us this information were done in commercial layers before 1990 and none of them looked at the FCR of food into eggs. Many farms nowdays can still not measure this FCR but it is the most importantj finacial parameter. People decide what breed to purchase on genetic company claims on FCR. I have not seen an estimate for the losses from MG in egg FCR but continous feeding of birds with tylosin (Ose 1979) showed a 12% improvement in FCR - so another benefit for controlling MG. MSH vaccinated flocks in Europe, Japan, Argentina, and even Ohio (1996 Merial trial) consistently show at least 4% improvement in FCR (more than the claimed differences between breeds). I think future researchers will show that there is a cost of using any live mycoplasma vaccines but it will be less than field strains. (So maybe freedom is the best except for having large populations with no resistance to getting infected and MS has significant potential for airborne transmission). Everywhere in the world feed is about 70% of the cost of production and therefore 4% better FCR goes straight to the bottom line as 3% less cost of production. Sometimes people say to me that investing in MS vaccination is expensive and the future egg price is unpredictable so they worried about the ROI. Well feed is something you have to purchase every week and it the bill is 4% less you rapidly pay for the cost of the vaccine. Anyhow live MS vaccines are in the pipeline for North America and although people may not take notice of me just wait until a big vaccine company starts pushing one and the opinion will change - It happened in Europe and Asia when MSD had a live MS vaccine even though they are not supplying the market any more. Watch this space

Eric Gingerich : I started to see tracheitis with secondary bacterial airsaccultis in broiler breeders infected with MS. Some MS strains in USA are more pathogenic than others. We need to keep our eyes on these strains.