Genetic parameters were estimated for 2403 purebred Landrace pigs ever a two year period, representing 21 sires. The traits studied included average daily gain, age adjusted to 91 kg, ultrasonic measurements of backfat at the midback and loin positions, total and adjusted total ultrasonic backfat and corresponding carcass backfat measurements.
Least squares analyses were used to estimate and adjust for the effects of sex, season and sex by season interaction. Heritabilities and genetic correlations were calculated for all traits using both half and full-sib estimates. Adjusted age and adjusted total ultrasonic backfat measurements were found to be the nest appropriate predictors of carcass value.
Estimates of heritability for adjusted age and adjusted total ultrasonic backfat were 0.24±0.10 and 0.26±0.10 based on half-sib and 0.56±0.07 and 0.41±0.06 from full-sib analyses. Genetic correlations between these two traits were -0.07±0.28 and -0.01±0.10 based on the two respective methods. The total phenotypic correlation was -0.01±0.02. A selection index example was developed from half-sib estimates of the genetic parameters and economic factors were estimated from fixed and variable costs for adjusted age and the Canadian market index system. / Land and Food Systems, Faculty of / Graduate
| Identifer | oai:union.ndltd.org:UBC/oai:circle.library.ubc.ca:2429/21079 |
| Date | January 1978 |
| Creators | Jeffries, Duncan Charles |
| Source Sets | University of British Columbia |
| Language | English |
| Detected Language | English |
| Type | Text, Thesis/Dissertation |
| Rights | For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use. |
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