Browsing by Subject "genetic parameters"

Linear scoring of livestock and farm animals has been in use since the 1980’s. In Europe, the first linear evaluations in horse breeding were conducted in 1989. In Finland, the linear evaluation was introduced into breeding evaluation of warmblood horses in 2015. So far, there is only a limited amount of research available about the heritabilities calculated from linear evaluation. Some of the studies have shown that the judge has a statistically significant effect on the linear conformation evaluation of the horse. The heritabilites from these studies have varied within different researches. The highest siginificant heritabilities have been found for conformation traits. For now, only warmblood horses are being evaluated linearly in Finland. The aim of this study was to estimate the heritabilities of the leg and movement traits from show data between 2015 – 2019 and to estimate the genetic correlations between different traits. All in all 26 traits were analyzed in the study. There were 915 horses in the data. Observations were gathered from 29 different shows in Finland. Both geldings, mares and stallions were represented in the data, mares being the largest group of gender. From one singular age group, the two – year- old mares had the greatest amount of observations. Based on the year of birth, horses born in 2015 had the most observations. The year of birth did not, however, have any significance on the results. Both the age and the gender of the horse did have a statistic significance on the results. Also the location of the show and the year of observation had some significance. Heritibilities of leg traits based on this data were extremely low, ranging between 0,00 – 0,11. The heritabilities of type and movement traits ranged between 0,00 and 0,28. Standard errors of heritabilities ranged between 0,09 – 0,14. Genetic correlations between the traits ranged between weak to strong. Standard errors of genetic correlations ranged between 0,04 – 0,13. To get reliable heritability parameters, more data and research is needed about the linear scoring of horses.

The main objective of this study was to estimate genetic parameters to aggression- and fear-related traits in Rottweiler-breed. We also determined which kind of variables could be useful in genetic studies. We used a questionnaire which was sent to Rottweiler owners. Genetic parameters were estimated from a data including responses from owners of 510 dogs. Analysis were carried out with Restricted Maximum Likelihood method for three different variables: owner impression, behaviour components and single behaviour guestions. Heritability estimates for different types of aggression and fear were low or moderate. Most common aggression was dog-directed aggression while owner-directer aggression was most rare. Aggressive behaviour was divided into three genetic complex: social unsureness, aggression in encounter situations and sharpness. The widest complex, social unsureness, had highest heritability estimate. Dog’s aggression in social situations was related to fear and unsureness. Owner impression –guestions and behaviour components could be useful when studying personality traits because they measure a wider complex than just a single behaviour. In this study social dogs had less aggressive and fearful behaviour. It could be possible to reduce aggression- and fear-related behaviour problems by raising dog’s sociality by breeding. This study showed that owner impressions could be used to measure dog’s sociality.