Browsing by Subject "Migrant breed"

Now showing 1 - 1 of 1

Pedigreeanalysen zur Beschreibung der populations- und quantitativgenetischen Situation von baden-württembergischen Lokalrinderrassen
(2014) Hartwig, Sonja; Bennewitz, Jörn
The challenge of a conservation breeding program is to solve a conflict of goals: genetic variability and genetic autonomy should be maintained, and on time a certain amount of breeding progress has to be realized to ensure the ability to compete. The aim of the present study was to analyse the situation concerning the targets mentioned above for traditional cattle breeds of Baden-Württemberg. Furthermore, methods for the consolidation and development of these breeds should be reconsidered. In chapter 1 the organisation of a breeding program for small cattle breeds is discussed. The challenge of such a program is the conservation of agrobiodiversity, culture and traditions and the progress of traditional local breeds. Number and extend of these breeds declined due to the increasing popularity of high-yielding breeds. Additionally, some of the local breeds are used in different branches of production compared to their original usage. Breeding programs have to be fitted. The establishment of individual adapted breeding methods is required for a sophisticated solution of the conflict mentioned above. Federal support is requested. Nowadays the implementation of genomic selection is not yet practicable for small breeds. But future opportunities should be analysed. The establishment of performance tests concerning breed specific product and efforts is demanded to improve these characteristics. In the following genetic variability of Vorderwald, Hinterwald and Limpurg cattle was examined. In chapter 2 for each breed two reference populations were defined that enable to observe the development over the years. Animals within the reference population comply with restrictions concerning racial origin and completeness of pedigree. Effective population size and the effective number of founders, and ancestors were estimated. The interpretation of the results was done with regard to the history of the breeds. The absolute population size of Vorderwald cattle is the biggest one. The number of Hinterwald cattle is intermediate; Limpurg cattle have the smallest population size. Whereas the management of Hinterwald cattle seemed to maintain genetic variability, the management of Vorderwald cattle was not that target-orientated. With an effective population size greater than 100 there is enough genetic variability within Vorderwald and Hinterwald. In contrast the values of Limpurg cattle are too low. Besides genetic variability, genetic autonomy and breeding progress are the targets of a conservation breeding program. Cross-breeding was carried out to mitigate the risk of inbreeding depression and to improve the performance of local breeds. However, breeding activities for local breeds were not as intensive and target oriented as for popular high yielding breeds. While the gap between the performance of high-yielding and local breeds increase, genetic autonomy of local breeds declined due to migrant influences. Chapter 3 examined the importance of migrant breed influences for the realization of breeding progress of beef traits of Vorderwald and Hinterwald cattle. The results show that there is a high amount of migrant contributions and their effects on performance are substantial for most traits. Breeding values adjusted for the effects of the migrant breeds showed little genetic trend for beef traits. The subject of chapter 4 is the development of milk yield and the associated migrant influences. Yield deviations for milk, fat, and protein content were analysed. Migrant contributions to Vorderwald cattle were high and even rose in the latest past. All the effects of foreign breeds were positive and in most cases highly significant. Most influential breed was Montbéliard. The influences of migrant breeds were substantial for the development of milk performance. However, the trend of milk yield traits for both breeds was positive even without foreign breeds’ influences. In comparison the number of analysed Hinterwald cows was small due to the reason that just a few Hinterwald husbandries take part at the official milk performance recording. Migrant breed contributions were moderate and nearly constant over the time. The most influential migrant breed was the Vorderwald cattle. The development of milk yield shows a flat trend. Influences of migrant breeds were low. The thesis ends with a general discussion.