Graduate Thesis Or Dissertation
 

Evaluation of responses to selection and association among specific traits in three populations of swine

Public Deposited

Downloadable Content

Download PDF
https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/gm80hz547

Descriptions

Attribute NameValues
Creator
Abstract
  • Oregon State University swine herd records of 456 litters farrowed between 1962-73 in three populations were analyzed on a generation basis to compare changes in performance of a Composite population to parental Berkshire and Yorkshire breeds. Analysis was performed in six discrete and overlapping generations on backfat thickness, loin eye area and litter size (number born alive and dead); litter size was the primary trait of emphasis in the selection scheme. Phenotypic correlations adjusted for different environmental effects were estimated along with heritability for the traits considered. Phenotypic correlation between backfat thickness and loin eye area was moderate and showed a negative trend in both parental and Composite populations. Correlations between litter size and loin eye area or backfat thickness were not consistent; litter size had, where significant, a moderate negative association with loin eye area. The phenotypic correlation between litter size and backfat thickness was non-significant. The increased number of pigs born to Composite dams over parental Yorkshire and Berkshire dams, was significant only in earlier generations. The differences among the breeds for backfat thickness and loin eye area in the generations were small and mostly non-significant. Heritability estimates for each of the three traits in each of the three populations were within the usual values found in other studies and they indicate positive response in relation to selection differentials. Among other possible explanations for similarity of responses within each of the three populations is the long history of coadapted direction of selection in the populations used.
Resource Type
Date Available
Date Issued
Degree Level
Degree Name
Degree Field
Degree Grantor
Commencement Year
Advisor
Committee Member
Academic Affiliation
Non-Academic Affiliation
Subject
Rights Statement
Publisher
Peer Reviewed
Language
Digitization Specifications
  • File scanned at 300 ppi (Monochrome) using ScandAll PRO 1.8.1 on a Fi-6770A in PDF format. CVista PdfCompressor 5.0 was used for pdf compression and textual OCR.
Replaces

Relationships

Parents:

This work has no parents.

In Collection:

Items

Thumbnail Title Date Uploaded Visibility Actions
file details SmithEdwardJ1990.pdf 2017-08-16 Public Download