Studies on enzootic bovine leukosis II. Survey for antibodies to bovne leukemia virus in the Holstein calves in a dairy farm

축우의 유행형 (지방병성) 백혈병에 관한 연구 II. 한 유우군에서 출생한 송아지에 대한 우백혈병 바이러스 항체 검사

Total 51 calves born from both 28 seropositive and 23 seronegative dams were subjected to study both prenatal and postnatal infections of bovine leukemia virus (BLV), and the duration of passive colostral antibody by means of immunodiffusion (ID) test. All calves were tested for precolostral and postcolostral periods by 16 months of age. The results were as follows: 1. Of 28 precolostral sera of the calves born from infected dams, one appeared positive, indicating in utero BLV infection from the dam. 2. BLV-antibody test for the postcolostral sera of the calves born from seropositive or seronegative dams showed that the colostral antibody of the calves disappeared from 2 to 6 months of age, and the increase of the number of seropositive calves initiated from 3 to 4 months of age indicated postnatal infection.