Campus Units

Animal Science

Document Type

Article

Publication Version

Published Version

Publication Date

1981

Journal or Book Title

Journal of Dairy Science

Volume

64

Issue

3

First Page

497

Last Page

507

DOI

10.3168/jds.S0022-0302(81)82599-4

Abstract

Sires selected for milk in first lactation (Yield) and those selected for udder conformation, percentage of daughters culled in first lactation, and fat-corrected milk (Merit) were mated randomly to cows in the Beltsville herd. Subsequent offspring were mated to bulls from the same selection group as their sires. Reproductive traits were numbers of heats and services, age at first heat, gestation length, and age at first calving for heifers and numbers of heats and services, gestation length, days to first heat postpartum, and calving interval for cows. Selection groups differed only for gestation length with Merit females having a 2 day longer gestation than Yield females. Yield females calved earlier (12 days) and had shorter calving intervals (14 days) than Merit females.

Mating bull was significant for gestation length and for percent pregnant on a given service but not on first or first four services. Selection groups differed in gestation length only. Variance components for mating bulls for all traits and for sire of cow for gestation length were all less than 10% with most less than 3%.

Reproductive performance of offspring from selection of bulls solely for milk in first lactation was not inferior to that of offspring of bulls selected less intensely for milk.

Comments

This is an article from Journal of Dairy Science 64 (1981): 497, doi:10.3168/jds.S0022-0302(81)82599-4. Posted with permission.

Rights

Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.

Language

en

File Format

application/pdf

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