Heuß, Esther Maren: Genetic analyses of piglet survival and postnatal growth. - Bonn, 2020. - Dissertation, Rheinische Friedrich-Wilhelms-Universität Bonn.
Online-Ausgabe in bonndoc: https://nbn-resolving.org/urn:nbn:de:hbz:5-58092
@phdthesis{handle:20.500.11811/8179,
urn: https://nbn-resolving.org/urn:nbn:de:hbz:5-58092,
author = {{Esther Maren Heuß}},
title = {Genetic analyses of piglet survival and postnatal growth},
school = {Rheinische Friedrich-Wilhelms-Universität Bonn},
year = 2020,
month = mar,

volume = 194,
note = {Piglet survival determines the success of piglet production. Decreased piglet survivability raises animal welfare concerns and increasing litter sizes intensified this situation. In the recent work, the prospects to select for improved piglet survival were analysed. Therefore, the complex determinants of survivability were evaluated with respect to the immune system. In addition, traits representing piglet survival were analysed genetically in Landrace and Large White.
The complex relationships between piglet survival and the immune system were reviewed in the chapter 3. The aim was to discuss potential selection strategies and especially the missing conditions that have to be created in order to include survival traits and immune parameters into reasonable breeding programs for improved survivability and immunocompetence.
In chapter 4, the piglet traits stillbirth (SB), pre-weaning loss (PWL) and birth weight (BW) as well as litter traits were investigated using univariate and bivariate generalized linear mixed models. For this purpose, comprehensive data sets including 168,823 piglets and 4,642 sows of a German breeding organization were available. The analysis focused especially on the binary character of SB and PWL applying threshold models and a logit link function. Due to the large data sets available and accurate records of cross-fostering (CF) the maternal genetic effect of the CF dam was investigated.
In conclusion, the consideration of piglet survival and the immune system in selection indexes is complex and should be designed population specific. Immune traits revealed profound genetic variability. However, it remains unclear how they should be included into a breeding program. Piglet survival and BW traits show low heritabilities, except for the mean BW within litter, and unfavourable genetic correlations (rg) to LS. In addition, the rg estimated for SB, PWL and BW revealed distinct relationships between the traits indicating that uniform individual BW are required to reduce the odds for a piglet to be stillborn and to ensure the vitality needed to survive until weaning. Breeding for piglet survival is possible and can be even more efficient if genotypic information is included in the analyses via genome-wide association studies (GWAS) and genomic selection (GS).},

url = {http://hdl.handle.net/20.500.11811/8179}
}

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