Effects of Flushing on Reproductive Performance, Ovulation Rate, Implantation Rate and Plasma Progesterone Levels in Mink

Abstract

Abstract In three experiments with a total of 585 standard mink females, four main flushing models were investigated in relation to unflushed control groups. Flushing by ad libitum feeding followed a period of restricted feeding and started either 18 or 4–5 days before the start of the mating season, 3 days after the matings had started, or was carried out individually when the females mated. Flushing of non-restricted versus restricted animals was also compared in one experiment. To evaluate the effects on ovulation and implantation rate and plasma progesterone levels a limited number of animals per treatment was sacrificed. Flushing, following a period of restricted feeding, improved reproductive performance in yearling females when commenced 4–5 days before the start of the mating season. Litter size increased, but the frequency of barren females was not clearly affected. In yearling females mated at least twice, a quadratic regression of litter size on weight change in the flushing period was found. I...