Passive immunization of lambs through colostrum of ewes vaccinated E. Coli K99 vaccines

ABSTRACT

A total of 80 Barki lambs were fed on colostrum of 3 groups vaccinated dams by E. coli K99 vaccines and one group was Ieft non vaccinated as control. A total of 80 colostrum samples were collected at parturition time and blood samples were collected at different intervals, from the newborn lambs [born to vaccinated and non - vaccinated ewes]. The indirect method of ELISA technique and agglutination test were preformed for the detection of K99 antibodies in sera and colostrum samples. Vaccination of pregnant ewes during the late period of pregnancy, resulted in an increase of the K99 antibody levels in the colostrum samples when compared with that of non - vaccinated dams. The mean antibody reading of lamb serum samples showed a gradual increase during the first week of life. It reached the maximum level in samples of the 3[rd] to the 7[th] day of age. There was a decrease in the antibody titers later on, but a detectable level of antibody was still recorded up to 12[th] week after parturition. Lambs nursing ewes vaccinated with aluminum hydroxide formalin killed vaccine showed a significant abrupt rise in their K99 antibody levels, followed by those vaccinated with scourguard vaccine and then lambs nursing ewes vaccinated with irradiated vaccine