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Selection for maternal behavior in mice
In trying to find a solution for the high economic cost problem in swine of pre-weaning mortality in piglets, two experiments were carried out to study the genetics of maternal behavior in mice and its relationship with growth and survival of pups. The first experiment used 16 lactating mice with their pups from each of three replicates of two different litter size selection lines to characterize maternal behavior. A selection experiment followed to estimate the magnitude of genetic variation of maternal behavior of dam and correlation between maternal behavior and pre-weaning performance of pups. The ultimate objective was to use mice as a model to evaluate the feasibility to improve pre-weaning survival and growth in piglets through selection for maternal behavior in sows. Activity budgets during 30-min observation periods throughout 5 lactation stages (d 2 to 4, 5 to 8, 9 to 12, 13 to 17, and 18 to 22) were recorded. Maternal behavioral categories included nursing pups, licking pups, retrieving pups, nest building, and resting with pups, other behavioral categories included resting alone, eating/drinking, grooming, and other activities. Selection was based on the maternal care index (MCI). ^ Selection for larger litters altered maternal behavior. The correlated change in maternal behavior was independent of size of litter being nursed. The realized heritability of MCI was .28 ± .03. Heritabilities estimated from MTDFREML of MCI, number born alive (NBA), pre-weaning survival rate (PWS), litter weight gain during lactation (LWG), and mating weight (MW) were .17, .30, .02, .46, and .45, respectively. Selection for maternal behavior changed pre-weaning survival rate during lactation without altering the number born alive, suggesting that maternal behavior might be considered when selecting for better reproductive performance. ^
Chiang, Chung-Feng, "Selection for maternal behavior in mice" (2000). ETD collection for University of Nebraska - Lincoln. AAI9976981.