Browsing by Subject "maatiainen"

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  • Riihimäki, Anna (Helsingin yliopisto, 2019)
    The target of pork production is to produce lean meat efficiently in a sustainable way taking into account environment and ethical aspects. The most important production traits in pigs are average daily gain, feed efficiency and leanness. A lot of research is conducted related to production traits in comparison to feeding behavior traits. The objective of this study was to estimate heritability of feeding behavior traits and their genetic correlations with production traits in Finnish Landrace population. The data included feeding records of 4059 Landrace pigs measured automatically in Figen’s test station. The pigs had started their test period during 2010 - 2016. The measured traits were the number of visits per day (NVD), time spent in feeding per day (TPD), daily feed intake (DFI), time spent feeding per visit (TPV), feed intake per visit (FPV), feeding rate (FR), average daily gain (ADG), back fat thickness (BF) and feed conversion ratio (FCR). Feeding behavior traits were divided into 5 periods. Heritability estimates of feeding behavior traits were moderate. The heritability estimates were 0,22-0,29 for NVD, 0,33-0,47 for TPD, 0,16-0,25 for DFI, 0,22-0,31 for TPV, 0,28-0,36 for FPV, 0,35-0,38 for FR, 0,27 for ADG, 0,22 for BF, and 0,24 for FCR. Compared to other published results heritabilities of TPD and FR were similar. However, heritabilities of other feeding behavior traits were quite low compared to published results. In addition, heritability of BF was unexpectedly low. The genetic correlations of feeding behavior traits were similar at different test periods. The highest positive genetic correlations were between traits TPV – FPV, FPV – FR, and NVD – TPD. The highest negative genetic correlations were between traits NVD – FPV, TPD – FR, and NVD – TPV. Genetic correlations between feeding behavior traits and production traits were low. Only between DFI – ADG, DFI – FCR, and FPV – FCR the genetic correlations were significant (and positive). In conclusion, heritabilities of feeding behavior traits were moderate. Because the only strong genetic correlation between feeding behavior and production traits was obtained between DFI and ADG, including feeding behavior traits in breeding programs is not necessary. However, feeding behavior data are easy to collect from the electronic feeders and the observations are reliable, thus daily feeding records can be used for monitoring animal’s health and welfare.
  • Partanen, Reeta-Maria (Helsingin yliopisto, 2018)
    Effective population size is one of the most important concepts in population genetics. Large enough effective population size is important in maintaining genetic variation in populations. The aim of the study was to estimate effective population size in Landrace and Yorkshire populations and to find out if there is variation in the effective population size between chromosomes and chromosome segments. Effective population sizes were estimated using changes in allele frequencies across generations. Estimation was done from a SNP-genotype data consisting of 1020 Landrace and 1824 Yorkshire boars born in 1996-2013. Average effective population size in Landrace was approximately 40 individuals when estimated at chromosome level and approximately 47 individuals when estimated from chromosome segments. In Yorkshire, the respective estimates were around 37 and 46 individuals. It was noticed that there is variation in the estimated effective population size in both Landrace and Yorkshire populations. In Landrace, the largest chromosome-wise estimates of the effective population size were four times larger than the smallest estimates. The largest chromosome segment based estimates were 21 times larger than the smallest estimates. In Yorkshire, the largest estimates of chromosome-wise effective population size were three times larger and the largest estimates of chromosome segment based effective population size as much as 35 times larger than the smallest ones. The estimates of average effective population size in this study were clearly smaller in both breeds than the estimates of effective population sizes in previous studies that were based on pedigrees or linkage disequilibrium between SNPs. Chromosome-wise or chromosome segment based estimates of effective population size can be utilized in maintaining genetic variation in populations and in optimizing breeding programs.