AIPL EVALUATION REPORT

February 2006 Elite Cow Statistics Animal Improvement Programs Laboratory, ARS-USDA, Beltsville, MD 20705-2350 301-504-8334 (voice) ~ 301-504-8092 (fax) ~ rlaipl@aipl.arsusda.gov ~ http://aipl.arsusda.gov

Determination of elite or high-ranking grade status was based on a two-stage screening procedure. The first-stage screening criteria for eligibility were:

• Management groups included lactations of at least three other cows when averaged across a cow's lactations.
• Last calving within 2 years, 3 months of current run date.
• Last record was either in progress (code R) or had a termination code of 0 (blank), 1, 2, or 8.
• First lactation was not predominantly owner-sampler type of test.
• Reliability of milk evaluation at least 30%

Summary information for eligible (those passing first-stage screening) registered cows are in Table 1.

TABLE 1. Mean PTA's for milk, fat, protein, productive life (PL), somatic cell score (SCS), and NM$ for registered¹ cows passing first-stage screening.

TABLE 2. Standard deviations of PTA's for milk, fat, protein, productive life (PL), somatic cell score (SCS), and NM$ for registered¹ cows passing first-stage screening.

¹ Includes cows in identity enrollment for some breeds

For registered eligible cows a percentile table for each breed was constructed based on NM$. Those percentile tables are provided with USDA-DHIA evaluations for active AI bulls. A percentile was assigned for each cow with data distributed in format 105. Although the data for Red and White cows are combined with those for Holstein cows for genetic evaluations, a separate percentile is used for screening Red and White cows for elite or high-ranking grade status. Second-stage screening criteria are the NM$ corresponding to a specified minimum percentile (Table 2).

TABLE 3. Percentiles and corresponding NM$ for a cow to be designated as elite or a high-ranking grade and numbers by breed.