Genetic Aspects of the Repeatability of Some Reproductive Traits of Polish Large White Sows

摘要

The progress in reproductive traits of sows by improving the animal genotype through selection is very difficult. The final effect which is the number of born alive and weaned piglets in the litter is due to physiological (Svedsen, 1992), anatomical (Bennet and Leymaster, 1989) and genetic (e.g. Jensen et al., 1968; Kristjansson, 1964; Rothschild et al., 1994) factors of both parents influencing offspring in prenatal and postnatal periods. At the same time the effect of environment considerably modifies fertility of sows and the number of piglets obtained within a year.