J Vet Sci.  2005 Sep;6(3):227-230.

Establishment of a bovine leukemia virus-free dairy herd in Korea

• Suh GH
• Lee JC
• Lee CY
• Hur TY
• Son DS
• Ahn BS
• Kim NC
• Lee CG

Abstract

In view of the high prevalence rate of bovine leukemia virus (BLV)infections in cattle over the entire country, a large dairy farm in Chungnam province was chosen and 'test and segregate' program was instituted. On July 1999, ELISA test was performed on 491 animals on the farm and only 163 cattle (139 adult cows, 18 female and 6 male calves)were BLV-seronegative. From February 2000 through April 2004, the seronegative group was placed in barns 1,500 to 2,000 m from seropositive group and thereafter tested at 3-to 5-month intervals by ELISA. Animals seroconverted in consecutive tests were removed from the seronegative group immediately after the detection of anti-BLV antibodies. The changes in management were aimed at preventing iatrogenic transfer of blood between cattle. Replacement heifers imported from other countries and calves born at the farm were repeatedly tested by ELISA, and only seronegative animals were introduced into the group. As of April 2004, there were 311 cattle in the BLV seronegative group of the farm. Twent y four cows of the initial 139 adult cows were seroconverted in 2000, and no seropositive animals were found since February 2001. Follow up of the group, from which all seropositive cattle were moved to a separate location, revealed no recurrence of BLV infection for three years. The approach in the present study might be valuable for Korean producers who would like to move toward a BLV-negative status.

Keyword

bovine leukemia virus; dairy cattle; ELISA; test and segregate

MeSH Terms

*Animal Husbandry
Animals
Antibodies, Viral/*blood
Cattle
Enzootic Bovine Leukosis/*prevention&control
Female
Korea
Leukemia Virus, Bovine/*isolation&purification
Male
Prevalence