Investigation On Prophylactic And Controlling Methods Of Postweaning Multisystemic Wasting Syndrome

Postweaning multisystemic wasting syndrome (PMWS) is a new disease affecting pigs primarily at the age of 5-12-weeks of age. The disease is characterized by weight loss, dyspnoea and jaundice combined with the pathological findings of interstitial pneumonia, enlarged lymph nodes, hepatitis and nephritis. PMWS was first identified within high-health herds in Western Canada in 1991 but has since been reported in pigs throughout the world.Porcine circovirus type 2 (PCV2) has been identified as a necessary component of PMWS. While infection with PCV2 does not consistently induce PMWS, co-infection with other viral pathogens like porcine parvovirus or porcine reproductive and respiratory syndrome virus, or immune stimulation by vaccination has been used to induce disease in experiment and is very likely a phenomenon in the field. Typically, morbidity rates can reach 5% to 30% in affected herds, and the mortality among the piglets varies between 20% and 100%.The prophylactic effect of farm self-developed tissue inactive vaccine against PMWS was evaluated in the present trial for there is no commercial vaccine available. Eighteen sows in the trial group were inoculated with the tissue inactive vaccine 20 days before parturition. The piglets of the immunized group and control group were under the same produce practices and medication besides two times vaccine inoculation in 21 and 42 days age respectively. The information of morbidity and mortality because of expression of PMWS and production parameters of piglets in both groups were collected and analyzed. As a result, the level of maternal PCV-2 specific antibodies of the piglets is higher than that of the control group. The morbidity rate and mortality rate of the 175 piglets in the control group during growth period was 18.9% and 8.6%, while it was respectively 10.5% and 4.9% lower of the inactive vaccine immunized group. The average daily body weight gain during growth period of piglets of control group and immunized group were 444g and 498g respectively. The result the present trial indicates that farm self-developed tissue inactive...