Date of Award
2016
Publisher
North Dakota State University
Document Type
Thesis
Degree Awarded
Master of Science (MS)
Program
Animal Sciences
Department
Animal Sciences
College
Agriculture, Food Systems and Natural Resources
Faculty Advisor
Hanna, Lauren
Description
An experiment was conducted to quantify evaluator bias and determine the impacts bias may have on genetic evaluations. Three subjective evaluation methods were recorded (n = 806) at weaning, including docility score (DS; 1 to 6), temperament score (TS; 1 to 5), and qualitative behavior assessment (QBA; 12 attributes). Using Principal Component Analysis, a temperament index was calculated using QBA scores for each animal based on the first principal component as an additional temperament score. The final model utilized fixed effects of date of evaluation, sex, and evaluator (across only) in a traditional animal model to calculate estimated breeding value (EBV) and heritability for each temperament evaluation. Comparisons of EBV were based on correlation coefficients and quartile placements of animals within and across evaluators. Less than 30% of individuals had EBV that were 3 quartiles apart for all evaluation methods, indicating that evaluator interpretation has some impact on genetic evaluations.
Recommended Citation
Hieber, Jordan, "Temperament Evaluation in Beef Cattle: Understanding Evaluator Bias Within Subjective Measurements of Docility Score, Temperament Score, and Qualitative Behavior Assessment" (2016). Animal Sciences. 90.
https://digitalcommons.ndsu.edu/animal-sci/90
Rights
NDSU policy 190.6.2
Rights Link
https://www.ndsu.edu/fileadmin/policy/190.pdf
Handle Identifier
https://hdl.handle.net/10365/28137