Flushing of Mink

Abstract

Abstract Flushing by ad libitum feeding following a period of restriction has resulted in improved litter size in mink. In this investigation effects of 4 different flushing models on plasma estradiol-17β, plasma progesterone, number of corpora lutea, implantation sites and litter size were studied. Flushing from March 4, preceded by moderate restriction, resulted in superior estimated numbers of corpora lutea and a tendency for increased number of implantation sites and litter size. Plasma estradiol-17β tended to increase from February 25 to March 8 but was not affected by the experimental treatment. Plasma progesterone levels started to increase 4.0–7.7 days before the estimated day of implantation (34.0–37.7 days before parturition). The interval between day of increase in plasma progesterone and recorded day of peak plasma progesterone was shorter in three of the flushed groups compared with the control group. The level of plasma progesterone was not affected by the experimental treatment, estimated number of corpora lutea, number of implantation sites or litter size.