Fetal Erythropoiesis and Other Factors which Influence Uterine Capacity in Swine

Vallet, J.L. 2000. Fetal erythropoiesis and other factors which influence uterine capacity in swine. J. Appl. Anim. Res., 17; 1–26. Large litter size of healthy piglets at weaning is an important aspect of swine production efficiency, this is influenced by several factors like ovulation rate, fertilization rate, early embryonic mortality and utrine capacity. Several studies showed that none of the single trait is effective to influence the production efficiency. Genetic selection in association with hormonal manipulations to reduce placental size and increase its efficiency has been found effective. The uterine capacity is also improved through the improvement of fetal erythropoiesis during early as well as late gestation due to use of genetic selection, marker assisted selection or other treatments. Increased uterine capacity may be useful for increasing litter size when treatments are applied for increasing the number of available embryos either by increasing ovulation rate and decreasing embryonic mortality or transfer of viable embryos.