Ein vergleich der «cumulative difference» methode mit der «sire comparison» methode

International audienc

On the theory of dairy cow evaluation

International audienc

Comparison of several sire evaluation methods in dairy cattle breeding

International audienc

Sustainable management of globally significant endemic ruminant livestock in West Africa: Guidelines for the replication and improvement of the N’Dama cattle breeding program of The Gambia

This document is designed to assist countries partnered to the project ‘Sustainable Management of Globally Significant Endemic Ruminant Livestock in West Africa’ (PROGEBE www.progebe.net) in the development of plans for N’Dama cattle within breed improvement programs, following the 3-tier (nucleus/multiplier/ commercial) model of The Gambia. The document proceeds as follows. First some background information is given including the broad steps to developing an animal breeding program (based on FAO 2010), as well as a basic overview of a 3-tier breeding program. Second, The Gambia breeding program is described from both a historical perspective and in terms of its current activities. Third, detailed guidelines are given in relation to the replication/improvement of the breeding program, with a number of specific recommendations made. Finally issues which will be critical to the success of the program—including human capacity, breeding program sustainability, and scale of operation—are discussed in some detail. It should be noted that underlying assumptions to this document are that a) within-breed genetic improvement of N’Dama cattle is an appropriate livestock development intervention within the PROGEBE countries, and that b) the 3-tier model of The Gambia is the most appropriate genetic improvement and dissemination model to implement. This document does not discuss these issues further, as it is understood that the PROGEBE country partners are already committed to establishing such breeding programs. It should also be stressed that this document does not replace the need for country-level capacity in terms of trained people for genetic improvement programs to design and oversee their N’Dama breeding activities. Instead this document should be considered reference material, from which the country-level animal breeders/ quantitative geneticists and other stake-holders can draw on in designing their specific breeding plans

Genetic and environmental factors affecting some reproductive traits of Holstein cows in Cuba

International audienc

What can be gained by the BLUP procedure under various circumstances?

International audienc

On the estimation of genetic parameters via variance components

International audienc

Prediction of response to selection within families

Summary- The distinction is clarified between two different uses of the term ’withinfamily selection’, either to imply that one individual of each sex is selected from each family or to imply that individuals are selected on their deviation from family mean, in which case families may not be equally represented. In the short term, selection on withinfamily deviation is expected to give higher responses, but in the long term, selection within families is expected to give higher responses as the effective population size is larger. The two schemes are the same, however, if only two individuals of each sex are recorded in each family. artificial selection / selection index / accuracy of selection / response / effective population size Résumé- Prédiction de la réponse à la sélection intrafamille. Une distinction est faite entre deux emplois du terme « sélection intrafamille », qui implique tantôt une sélection d’un nombre égal d’individus de chaque sexe dans chaque famille, tantôt une sélection des individus sur leur écart à la moyenne de famille, auquel cas toutes les familles ne sont pas nécessairement également représentées. A court terme, l’espérance de la réponse à une sélection sur l’écart intrafamille est plus grandé; mais à long terme, l’espérance de la réponse à une sélection intrafamillé stricte est supérieure, car une telle sélection accroît l’ef,!’ectif génétique. Les deux schémas de sélection sont cependant identiques si seulement deux individus de chaque sexe sont contrôlés dans chaque famille