Microsatellite diversity of the Nordic type of goats in relation to breed conservation: how relevant is pure ancestry?

In the last decades, several endangered breeds of livestock species have been re-established effectively. However, the successful revival of the Dutch and Danish Landrace goats involved crossing with exotic breeds and the ancestry of the current populations is therefore not clear. We have generated genotypes for 27 FAO-recommended microsatellites of these landraces and three phenotypically similar Nordic-type landraces and compared these breeds with central European, Mediterranean and south-west Asian goats. We found decreasing levels of genetic diversity with increasing distance from the south-west Asian domestication site with a south-east-to-north-west cline that is clearly steeper than the Mediterranean east-to-west cline. In terms of genetic diversity, the Dutch Landrace comes next to the isolated Icelandic breed, which has an extremely low diversity. The Norwegian coastal goat and the Finnish and Icelandic landraces are clearly related. It appears that by a combination of mixed origin and a population bottleneck, the Dutch and Danish Land-races are separated from the other breeds. However, the current Dutch and Danish populations with the multicoloured and long-horned appearance effectively substitute for the original breed, illustrating that for conservation of cultural heritage, the phenotype of a breed is more relevant than pure ancestry and the genetic diversity of the original breed. More in general, we propose that for conservation, the retention of genetic diversity of an original breed and of the visual phenotype by which the breed is recognized and defined needs to be considered separately.

Genetic management of Dutch golden retriever dogs with a simulation tool.

Excessive inbreeding rates and small effective population sizes are an important problem in many populations of dogs. Proper genetic management of these populations can decrease the problem, and several measures are available. However, the effectiveness of these measures is not clear beforehand. Therefore, a simulation model was developed to test measures that aim to decrease the rate of inbreeding. The simulation program was used to evaluate inbreeding restriction measures in the Dutch golden retriever dog population. This population consisted of approximately 600 dams and 150 sires that produce 300 litters each year. The five most popular sires sire approximately 25% of the litters in a year. Simulations show that the small number of popular sires and their high contribution to the next generation are the main determinants of the inbreeding rates. Restricting breeding to animals with a low average relatedness to all other animals in the population was the most effective measure and decreased the rate of inbreeding per generation from 0.41 to 0.12%. Minimizing co-ancestry of parents was not effective in the long run, but decreased variation in inbreeding rates. Restricting the number of litters per sire generally decreased the generation interval because sires were replaced more quickly, once they met their restriction. In some instances, this lead to an increase in inbreeding rates because the next generations were more related. The simulation tool proved to be a powerful and educational tool for deciding which breeding restrictions to apply, and can be effective in different breeds and species as well.

Transgenesis may affect farm animal welfare: a case for systematic risk assessment.

This paper considers (potentially) harmful consequences of transgenesis for farm animal welfare and examines the strategy of studying health and welfare of transgenic farm animals. Evidence is discussed showing that treatments imposed in the context of farm animal transgenesis are by no means biologically neutral and may compromise animal health and welfare. Factors posing a risk for the welfare of transgenic farm animals include integration of a transgene within an endogenous gene with possible loss of host gene function (insertional mutations), inappropriate transgene expression and exposure of the host to biologically active transgene-derived proteins, and in vitro reproductive technologies employed in the process of generating transgenic farm animals that may result in an increased incidence of difficult parturition and fetal and neonatal losses and the development of unusually large or otherwise abnormal offspring (large offspring syndrome). Critical components of a scheme for evaluating welfare of transgenic farm animals are identified, related to specific characteristics of transgenic animals and to factors that may interact with the effects of transgenesis. The feasibility of an evaluation of welfare of transgenic farm animals in practice is addressed against the background of the objectives and conditions of three successive stages in a long-term transgenic program. Concrete steps with regard to breeding and testing of transgenic farm animals are presented, considering three technologies to generate transgenic founders: microinjection, electroporation and nuclear transfer, and gene targeting including gene knockout. The proposed steps allow for unbiased estimations of the essential treatment effects, including hemi- and homozygous transgene effects as well as effects of in vitro reproductive technologies. It is suggested that the implementation of appropriate breeding and testing procedures should be accompanied by the use of a comprehensive welfare protocol, specifying which parameters to monitor, at which stages of the life of a farm animal, and in how many animals. Some prerequisites and ideas for such a protocol are given. It is anticipated that systematic research into the welfare of farm animals involved in transgenesis will facilitate the use of the safest experimental protocols as well as the selection and propagation of the healthiest animals and, thereby, enable technological progress that could be ethically justified.