ECONOMIC EFFICIENCY OF LEAN TISSUE PRODUCTION THROUGH CROSSBREEDING: SYSTEMS MODELING WITH MICE
Abstract
Twenty-seven crosses derived from three random mating, unselected strains of mice with 16 matings per cross were cohabited continuously for 365 days to evaluate long-term reproductive performance of the parents and lean tissue production from the progeny. A bioeconomic objective was developed to include parent and progeny feed costs, labor and facilities costs and income from lean tissue from progeny with slaughter at 42 or 49 days of age. Economic values for the bioeconomic objective were calculated relative to a two-litter system in swine production. The bioeconomic objective was utilized to determine economic conversion (the ratio of inputs to outputs) for each cross and each of 64 reproduction-termination rules based upon number of litters, average age of parents at weaning of a litter and weaning to birth interval. The optimum longevity system with the smallest economic conversion value of .8624 was for cross P x PS, ending at 8 litters, 10 months of age or 40 days between litters, whichever occurs first, with growth to 42 days. Constituent traits associated with reproduction of the parents and growth and carcass composition in the progeny (reproductive rate, maternal ability, age of parents, parental feed consumption, progeny postweaning average daily gain, feed conversion, postweaning survival, protein yield) and their primary traits, along with costs and incomes, were subjected to a genetic analysis to determine maternal and progeny average and specific heterosis. This analysis determined that the P x PS cross was superior in terms of smallest economic conversion by virtue of its high reproductive rate (.41 pups/day) and high lean (protein) yield (7.1%) from genetic and paternal effects of P with superior maternal heterosis for reproductive rate (.06 pups/day), maternal ability (.93 gms/pup) and progeny postweaning average daily gain (.005 gms/day). Path analysis of the constituent traits with their primary traits revealed that characters associated with high cost of measurement might be dropped from the phenotypic prediction function without great loss of accuracy of describing economic conversion. However, for genetic selection, the remaining traits are rather lowly heritable and/or measured later in life and therefore response to selection for the overall bioeconomic objective might be slow.
Degree
Ph.D.
Subject Area
Genetics
Off-Campus Purdue Users:
To access this dissertation, please log in to our
proxy server.