Masters Theses

Date of Award

8-1975

Degree Type

Thesis

Degree Name

Master of Science

Major

Animal Science

Major Professor

F. B. Masincupp

Committee Members

J. B. McLaren, K. M. Barth

Abstract

Seventy-two pigs were used to study the correlation estimates of weaning traits, performance and carcass traits, and prediction of some carcass traits from some weaning traits. The weaning traits studied were weaning weight, cannon length, chest depth, body width, backfat thickness, body length, shoulder height, body depth, muscle score, and cannon circumference. Most traits were correlated with each other. Weaning weight was significantly correlated with almost all weaning traits studied, except body depth in barrows. Body depth had no significant correlation estimate with other traits in barrows, but it had a positive correlation estimate with shoulder height and body length (P < .01), and with backfat thickness and weaning weight (P < .05) in gilts. Average daily gain had a positive correlation estimate with final backfat (P < .05) and marbling (P < .01), but had a negative correlation estimate with loin eye area (P < .05) and percent ham-loin (P < .01) in gilts. Final backfat thickness had a negative correlation estimate (P < .01) with percent primal, loin eye area, percent ham-loin, and ham-loin index in barrows, but it had a significant correlation estimate only with average daily gain (P < .05) and ham-loin index (P < .01) in gilts. Percent primal had a positive correlation estimate (P < .01) with loin eye area, percent ham-loin, and ham-loin index, but had a negative correlation estimate with backfat thickness and carcass length in barrows. Loin eye area had a positive correlation estimate (P < .01) with percent primal, percent ham-loin, and ham-loin index in barrows, but it was not consistent in gilts. Ham score had a positive correlation estimate (P < .01) with marbling in both sexes. Carcass length had a positive correlation estimate with ham score and marbling (P < .01) in barrows, and (P < .05) in gilts. Four weaning traits, weaning weight, weaning backfat thickness, body depth, and muscle score were used in estimating of percent primal cut, loin (ham) score and average daily gain. The coefficient of determination for percent primal cut were 21.76 percent in barrows and 20.39 percent in gilts; for loin score, it was 9. 18 percent in barrows and 26.90 percent in gilts; and for daily gain, it was 18.93 percent in barrows and 11.45 percent in gilts. In barrows, none of the weaning traits studied had a significant affect on percent primals, loin score or average daily gain. In gilts, backfat thickness had a significant affect (P < .05) on percent primal cut, and body depth had a significant affect on average daily gain. The traits used in the regression model were not good predictors of final carcass outcome.

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