The purpose of this study was to compile when and why piglets die during the suckling peri-od. Piglet mortality is an important factor influencing the profitability of piglet production. There are many factors that play a role and interact whit each other. This study summarizes when the piglets die during the suckling period and reasons why the piglets die. The infor-mation given is crushed, illness, management/environmental, genetic influence and piglet birth weight/Farrowingprocess.

Piglet survival is of importance because it affects the farmer?s economy and the welfare of the pigs. There are several factors affecting piglet survival and they are often linked to each other. This paper will focus on how the behaviour of the sow can affect the growth and survival of the piglets and also possible causations of differences in maternal behaviour. Sows in intensive production systems have different possibilities to express their maternal behaviour than free ranging sows.

Barren rearing environment and early weaning of piglets can lead to a high level of distress, behavioural disturbances and reduction in weight gain. The main aim of this thesis was to study the effects of potential enrichment objects on piglet?s behaviour and weight gain during the pre- and post-weaning period. The second aim was to examine what type of object stimulated the highest frequency of interaction. The study was carried out at the Swedish Livestock Research Centre in Lövsta where a batch of litters from 10 first-parity Yorkshire sows were used.

This study concerns congenital defects in pigs; umbilical and scrotal hernia, cryptorchidism, kyphosis, splay legs, anal atresia, intersexuality and congenital tremor. The aim was to describe and estimate the prevalence of these defects and estimate the heritability for the most frequent defects, scrotal hernia and cryptorchidism in purebred Swedish Hampshire, Landrace and Yorkshire populations. Furthermore, information and opinions from herdsmen in commercial herds was collected and analysed. A low proportion of congenital defect pigs is of importance both from animal welfare and economic point of view. The accuracy of registration of the presence of defects in the litters has a decisive role for the ability to select against these defects.