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Full-Text Articles in Life Sciences
Changes In Ovulation Rate, Uterine Capacity, Uterine Dimensions, And Parity Effects With Selection For Litter Size In Swine, Luis L. T. Gama, R. K. Johnson
Changes In Ovulation Rate, Uterine Capacity, Uterine Dimensions, And Parity Effects With Selection For Litter Size In Swine, Luis L. T. Gama, R. K. Johnson
Department of Animal Science: Faculty Publications
This study was conducted with random samples of pigs of a line (LS) selected for eight generations for litter size and a randomly selected control line (RS) in the Nebraska Gene Pool population and of crosses of these lines with a Large White- Landrace composite line (I) that was selected for an index of ovulation rate and embryonic survival to 50 d of gestation. Two experiments were done to obtain information on ovulation rate, uterine dimensions, and uterine capacity. In Exp. 1, 103 gilts were slaughtered 9 to 16 d after their second estrus to obtain reproductive tracts for evaluation …
Alternative Methods Of Selection For Litter Size In Mice: Iii. Response To 21 Generations Of Selection, Yvonne Kochera Kirby, Merlyn K. Nielsen
Alternative Methods Of Selection For Litter Size In Mice: Iii. Response To 21 Generations Of Selection, Yvonne Kochera Kirby, Merlyn K. Nielsen
Department of Animal Science: Faculty Publications
Alternative methods of selection to increase litter size in mice have been practiced for 21 generations followed by six generations of relaxed selection. Three replicates were used with four selection criteria: index of components (IX: I = 1.21 x total ovulation rate + 9.05 x ova success), uterine capacity (UT), litter size (LS), and an unselected control (LC). In IX, ovulation rate and ova success were measured by number of corpora lutea and number of pups born/number of corpora lutea, respectively. In UT, uterine capacity was measured and defined as number of pups born to unilaterally ovariectomized (right ovary excised) …
Effect Of Genetic Groups On Estimates Of Additive Genetic Variance, C. Pieramati, L. Dale Van Vleck
Effect Of Genetic Groups On Estimates Of Additive Genetic Variance, C. Pieramati, L. Dale Van Vleck
Department of Animal Science: Faculty Publications
This study examined the effect of genetic grouping on REML estimates of additive genetic variance with an animal model with selected base populations. A simulated population of 40 animals (20 males and 20 females) was followed under selection or random mating conditions for 10 generations. Each population was replicated 20 or 50 times. Genetic grouping reduced estimates of additive genetic variance in populations with selected base animals, whereas grouping had little effect on the estimate in unselected populations. The effect of genetic grouping varied according to the quantity and kind of information that was missing (percentage of deleted data and …