Investigation And Diagnosis Of The Paralysis Syndrome Of Caged Laying Hen

The paralysis syndrome of caged laying hen is one of the most important diseases that recently have impacted laying hen-breeding. The morbidity of the paralysis syndrome and the death/culling rate of laying hen is going up year by year, and the disease have been thought more and more of by many farmers and workers in science and technology.During the past three years from January 2006 to December 2008, we have invested the morbidity of the paralysis syndrome of caged laying hen in a few farms of Rugao City, Haian County, Dongtai City and other Cities that are the laying hen-farming intensive areas.8622 batches of laying hen were investigated, and the batches of the incidence are 1123, and the incidence rate is 13.02% and the death/culling rate 11.58%. It is shown that the main factors that result in the paralysis of caged laying hen are as follows:Viral diseases (28.22%), bacterial diseases (33.42%), sudden death syndrome (8.34%), osteoporosis (11.65%), nutrition and metabolic diseases (10.78%), poisoning (0.14%), stress (2.96%), other factors (4.27%). The disease may break out throughout the year, and the incidence rate is highest in hot season, especially concentrated in the May to September.We have investigated 325 batches of laying hen population from 100 farms of breeding self-produced feed in Duntou area of Hai'an county and detected the calcium and phosphorus of the blood collected from the laying hen population of post-hatching paralysis disease. Result show that the ratio serum Ca/P in the ill-falling hen is significantly lower than in the health hen (P<0.01), and the conclusion reveal the incidence of the paralysis is directly related to the abnormal proportion of serum Ca and P. The survey of 120 batches of laying population from other 40 farms of breeding compound feed produced from certain plant in the same area have greatly proved the paralysis of laying hen is related to the proportion of Ca and P.In September 2007, kept by farmer yang in Haian country, Nantong city,5000 hen over 28 weeks old called Lohmann commercial laying hen, the rate of whose egg production suddenly decreased from 95% down to 40%, and the shell color of the eggs is lighter, shell and soft-shell, part of laying hen are paralyzed. Through the pathological anatomy, laboratory tests, feed testing, Attack toxicity tests and feeding trials,It was diagnosed as caused by an imbalance of calcium and phosphorus feed. By replacing the feed, after the flocks soon returned to normal.