Date of Award

6-2-2025

Degree Type

Thesis

Degree Name

Master of Food and Animal Sciences (M.S.)

Department

Agricultural and Environmental Sciences

First Advisor

Richard Browning

Abstract

Sire Evaluations: Boer, Kiko, And Spanish Kid Weaning Weights in the Southeast Research was completed with weaning weight ratio (WWR) and expected progeny difference (EPD) efficiency values compared from pedigree data across six seasons (2003-2009). Four models: WWR, 90- day unadjusted, adjusted, and new adjusted WW models compared sire breed, dam breed, month of birth, dam age, sex, litter size at birth, litter size at 90 day weaning age, and birth year effects. Correction factors were re-adjusted when non-genetic effects (sex, dam age, and litter size at birth and weaning) remained significant (p<0.05) in the original 90-day adjusted WW models. The new correction factors eliminated non-genetic effects (p>0.05). Sire breed effects were not significant (p<0.05) in any models. Spearman ranking correlations showed new and original correction factors did not noticeably affect ranking similarity. Reference sire influence increased ranking similarity between new sire adjusted weaning weight ratio (NSWWR) and original sire adjusted weaning weight ratios (SWWR), and sire ratio deviation (SRD) values compared to EPDs. New SWWRs represented less non-genetically biased sire rankings than originally adjusted SWWRs due to new adjusted correction factors. New correction factors had unexpectedly lower correlation strengths and attributed to adjustment differences between EPD and SWWR methods and SRD calculation methodology. Many producers lack access to EPDs, which are considered a reliable tool. The SWWR would aid producers using visual selection for breeding. Accessible selection methods will enhance genetic improvement and encourage producers to be active in genetic evaluation programs. Future studies should focus more on herd specific adjustment factors and base sire selection for generating sire deviations.

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