The Effect of Slimming on Embryo Survival Rate and the Number of Corpora Lutea at 25 Days of Pregnancy of Minks (mustela vison)

Abstract

Contents: 70 yearling Scanblack breeding females (8 month old, weighing 1061 g) were randomly assigned to one of three treatment groups which were slimmed to a live weight of 787 (L), 878 (M) or 1071 g (H) during 54 days. Subsequently they were bred and at day 25 of pregnancy they were slaughtered and the number of corpora lutea, embryos and fetuses were counted. From this experiment it can be concluded that rearing conditions resulting in Scanblack breeding females of 787 g of live weight at the start of the breeding period will have a lower ovulation rate (16%) but comparable prenatal mortality rates as compared to females weighing 878 or 1071 g. Therefore reduction of littersizes caused by slimming results from a depressed ovulation rate.

Flushing of mink (Mustela vison): effects on energy metabolism and some blood metabolites

“…The number of CL increased significantly as an effect of flushing, which is in agreement with earlier experiments (Tauson, 1988 andKemp et al, 1993) and the results confirm that CL are formed and active in females that have not been pregnant, which is in agreement with Hansson's (1947) observation that the size and structure of the luteal cells change at the normal time of implantation after a sterile ovulation. Kemp et al (1993) found that the covariable live weight at the start of the experiment had no significant influence on CL counts, which makes it likely that effects can be largely ascribed to short-term nutritionally induced differences in body condition.…”