Timing of Vaccination Critical To Saving Eggs

Timing really is everything when vaccinating laying hens for mycoplasmosis, a serious respiratory disease.

Vaccinating the birds at just the right time of their development could save millions of dollars for the egg industry each year, according to a new Agricultural Research Service study. ARS is the principal research agency of the U.S. Department of Agriculture.

Mycoplasmosis, a bacterial disease of the respiratory tract in poultry, affects about 80 percent of all laying hens. Without vaccination, egg losses can be as high as 15 per year per hen. Without this loss, maximum annual production would average about 253 eggs per hen.

Earlier studies showed that vaccinating laying hens at 18 weeks of age with the F strain of Mycoplasma gallisepticum cut annual egg losses to only eight per bird—an improvement, but still nothing to cackle about.

Now, a new ARS study indicates that vaccinating before egg laying begins--at 10 weeks of age--is a better way to go. This achieves a net gain of 15 eggs per year over non-treated birds, and seven eggs over birds vaccinated at 18 weeks. The seven-egg difference would translate into an $82 million a year savings for U.S. egg producers. The industry's annual sales total nearly $3.8 billion. The study was done at the ARS Poultry Research Unit, Mississippi State, Miss.

But, the ARS researchers aren't stopping here. They're working on a new, genetically engineered form of the vaccine that could be used to inoculate eggs that would hatch to become a new generation of laying hens. The egg vaccine would be easier to administer and should lower production costs.

A story about the research appears in the March issue of Agricultural Research magazine. The story also is on the World Wide Web at:

http://www.ars.usda.gov/is/AR/archive/mar99/hens0399.htm

Scientific contact: Scott L. Branton, ARS Poultry Research Unit, Mississippi State, Miss., phone (601) 323-2230, fax (601) 323-2230, sbranton@ag.gov.