Selection for Optimum Genetics

11/16/01

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Table of Contents

Selection for Optimum Genetics

Important Phenotypic or Visual Characteristics

Importance of Structure and Muscling

Basic Traits to Measure

Yearling Weight

Yearling Scrotal Circumference

Scrotal Circumference Portion of Breeding Soundness Exam

What Traits Should be Measured

Unique Identification Systems

Possible Ear Tag Numbering Systems

Letter and Corresponding Year

Adjusted Weights and Measures

Contemporary Group

Adjusted Birth Weight

Age of Dam Adjustment Factors for Birth Weight (lbs.)

Age of Dam Adjustment Factors for Weaning Weight (lbs.)

Definition: Expected Progeny Difference

Expected progeny Differences

Comparing Animals Using within Breed EPD Values

Average Non-Parent EPDs for Calves Born in 1994

Expected Progeny Differences

EPDs are Predicted for:

Heritability (h2)

Heritabilities for Beef Cattle Traits

Heritability Ranges and Selection Potential of Traits

Correlated Response

Genetic Correlations to Remember

Most Common EPDs

All Breeds Have EPD Values For...

Terms Used by Various Breeds For Maternal Ability

Direct Calving Ease

Possible Change

Possible Change Table(Each value is ?)

Possible Change(in reference to previous table)

Example of Possible Change

Example of Possible Change

EPDs can not be compared across breeds because:

Heterosis or Hybrid Vigor

Types of Heterosis

Heterosis or Hybrid Vigor

For Crossbreeding to be Most Successful

Crossbreeding Systems

What About Composite Bulls?

Examples of Composite Bulls:

Advantages/ Disadvantages to Composites

How to Combine Commercial Cow Herds and EPDs

Author: ACES

Email: sschmidt@acesag.auburn.edu

Home Page: http://www.ag.auburn.edu/~sschmidt/ads401/index.htm