Effects of pseudopregnancy and ergocornine treatment on synchronization of mating, duration of gestation and production of young in rats.

Cyclic and pseudopregnant rats were treated with ergocornine hydrogenmaleate (1 mg), to evaluate the use of induced luteolysis as a method for synchronizing mating. Pseudopregnancy in non-treated rats was found to decrease the degree of mating synchronization, prolong gestation and decrease the number of young born per pregnant female. Ergocornine treatment of both cyclic and pseudopregnant rats decreased pregnancy rate. Ergocornine treatment of pseudopregnant rats also increased the degree of synchronization in mating, decreased the length of gestation and increased the number of young and placental scars per pregnant female. It had little effect on these end-points when given to cyclic rats. Length of gestation was negatively correlated (P<.001) with number of young, live young and placental scars ( r=.53 , . 5 8 and . 4 7 , respectively; n=96). (