Control of Bovine Leukemia Virus in Three US Dairy Herds by Culling ELISA-Positive Cows

Table 1

Bovine leukemia virus (BLV) antibody testing schedule and results for Herd M.

Test Date	Test Type	Description	Results^1
August 2015	Herd (milk)	All cows in the milking herd	3/138 (2.2%)
November 2015	Additional (milk)	Cows dry at August test and fresh heifers^2	1/42
February 2016	Herd (milk)	All cows in the milking herd^3	1/153 (0.6%)
March 2016	Additional (milk)	Cows dry at February test and fresh heifers	0/13
August 2016	Additional (milk)	Cows projected to be dry at late August test	0/16
August 2016	Herd (milk)	All cows in the milking herd^4	1/143 (0.7%)
October 2016	Additional (milk)	Cows dry at August test and fresh heifers	0/18
February 2017	Herd (milk)	All cows in the milking herd^4	1/150 (0.7%)
March 2017	Additional (milk)	Cows dry at February test and fresh heifers	0/16

BLV-antibody positive (“positive”) over total tested, with point prevalence (%) for herd tests.
Excludes five cows tested in August 2015 that were inadvertently retested in November.
The one (1) positive cow was the same cow identified at the November 2015 test, subsequently culled.
The one (1) positive was a first lactation heifer, subsequently culled.