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Correlated Responses Of Carcass And Reproductive Traits To Selection For Rate Of Lean Growth In Swine, E. R. Cleveland, R. K. Johnson, P. J. Cunningham

Department of Animal Science: Faculty Publications

Mass selection for an index of increased post-weaning average daily gain and decreased backfat thickness was practiced for five generations. Litter size and weight for 221 gilt litters, birth weight and nipple number for 2,242 piglets and weaning weight at 42 d of age for 2,111 pigs were recorded. Carcass measurements were taken on 331 pigs. Differences between means of the lines (select control) were regressed on cumulative selection differential of the index. These regression coefficients were negative (P > .10) for total number born, number born alive, number weaned per litter, nipple number and carcass backfat thickness. Coefficients were …