Påverkar kullstorleken smågrisens utveckling fram till födseln?

Abstract: The aim of this literature review was to analyze if the number of fetuses in the uterus will have an effect on the development of the fetuses until birth. Breeding for larger litter size creates a possibility to increase the number of weaned piglets. The uterus physical and physiological characteristics affect the chance of survival for the embryo where the available amount of space for the embryos, and later fetuses, in the uterus is an important factor. Embryos developing from eggs released from both ovaries will spread over both uterine horns. In the uterus the placenta is responsible for all nutrient transfer from the mother to the fetus. An insufficient placenta may lead to an increased proportion of stillborn and intrauterine growth restricted piglets. The nutrient transfer is important for a normal development of the piglets and for the fetus to be able to store glycogen. Fetuses that are intrauterine growth restricted will weigh less at birth compared to those that have been able to develop normally. At birth the piglets have to adapt quickly to the new environment and until they have an intake of colostrum the piglets depend on the stored glycogen and a fully developed thermoregulation. Piglets that are intrauterine growth restricted show less viability at birth and have difficulties competing for colostrum with their littermates. Larger litter size can have a negative effect on the development of the fetuses.