HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Tomaszewski, M. A. Articles by Dickinson, F. N. Search for Related Content PubMed Articles by Tomaszewski, M. A. Articles by Dickinson, F. N.

Correlations Between Sire Summaries of Progeny in Different Herds^1,2,

Department of Animal Science, North Carolina State University, Raleigh 27607
Animal Physiology and Genetics Institute, U. S. Department of Agriculture, Beltsville, Maryland 20705

ABSTRACT

Summaries were computed for each of two separate sets of progeny of individual Holstein sires. The two sets were based independently on different herds. Each summary contained one or more progeny in each of 20 or more herds. Summaries contained deviations of average milk production for daughters of sires from contemporaries sired by bulls in artificial insemination, contemporaries by all types of bulls, and all herdmates. Holstein sires, 222, with progeny in first lactation and 147 with progeny in the second lactation were in the analyses. As the number of herdmates in the comparisons increased, correlations between summaries containing the same progeny increased from .60 to .69 for first and from .56 to .70 for second lactations. These were slightly above correlations of .64 for first lactations and .63 for second lactations expected from sire summaries where progeny are compared "to all herdmates. Adjusting progeny tests for transmitting abilities of herdmates' sires increased correlations between independent sets of progeny only .01 to .02. Second lactation yield variables were as repeatable as first. Correlations between Predicted Differences of herd-mates' sires in independent sets of herds were .80 indicating progeny groups are not compared with representative samples of sires even for large numbers of progeny. Increase in accuracy of genetic evaluation by adjustment for variation in genetic merit of herdmates' sires is almost certainly greater than is indicated by correlations between repeated, independent sets of progeny.

¹ Paper number 4263 of the Journal Series of the North Carolina Agricultural Experiment Station, Raleigh, North Carolina.

² Supported in part by U. S. Department of Agriculture, Animal Physiology and Genetics Institute Contract USDA-ARS 12-14-100-11,345(44).