Using a Herd Profile to Determine Age-Specific Prevalence of Bovine Leukemia Virus in Michigan Dairy Herds

<table>Bovine Leukemia Virus herd profile (BHP) by testing 40 milking cows (ten from each of the first, second, third and fourth or greater lactations), for Bovine Leukemia Virus (BLV) as compared to testing all milking cows in the herd and calculating either: (1) the actual BLV prevalence (solid line-□) as measured by the number of BLV positive cows divided by the total number tested, or (2) a lactation-specific BLV profile (dashed line-♦), calculated as an average of the percent of BLV infected cows in each of the four lactation groups. The correlation between the actual BLV prevalence and BHP was 0.988 (<svg height="11.375" id="M26" style="vertical-align:-0.1638pt" version="1.1" viewbox="0 0 75.025002 11.375" width="75.025002" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
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</svg>), and the total herd profile and BHP was 0.995 (<svg height="11.375" id="M27" style="vertical-align:-0.1638pt" version="1.1" viewbox="0 0 75.025002 11.375" width="75.025002" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
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</svg>).</table>

Veterinary Medicine International

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Figure 3

Figure 3: Using a Herd Profile to Determine Age-Specific Prevalence of Bovine Leukemia Virus in Michigan Dairy Herds 