Abstract
Other papers (Winter, Cummings and Stewart, 1947; fine and Winters, 1952) have reported on portions of the extensive swine breeding experiments conducted at the Minnesota Agricultural Experiment Station since the formation of the Regional Swine Breeding Laboratory in 1937. The primary purpose of the present paper was to summarize certain aspects of an experiment on inbreeding which was completed by 1958. These concern mainly the effects of inbreeding on litter productivity, including litter size, total litter weight and average pig weight at birth and weaning. The results can be related to similar studies for other stations in the Regional Laboratory (Bereskin et al., 1968a) and to other reports in the literature. Materials and Methods Sources and Description of Data. Upon entry into the Regional Laboratory in 1937, several Minnesota substations initiated programs of producing inbred lines in the Poland China breed. Also, crosses of Tamworth and Landrace were used to develop the Minnesota No. 1 breed, and Yorkshires and Polands were crossed to produce the Minnesota No. 2 breed (Winters et al., 1943). Copyright © 1970. American Society of Animal Science . Copyright 1970 by American Society of Animal Science