Flushing of mink. Effects of level of preceding feed restriction and length of flushing period on reproductive performance

Abstract

In an experiment with 200 standard mink females (five groups of 40 females) the effect of flushing (a period of restriction followed by refeeding preceding the mating season) on reproductive performance was evaluated. The results of a non-flushed control group were compared with flushing from 20 February or 4 March until mating. For each date for start of flushing, the flushing period was preceded by a 2-week period of either moderate or severe restriction. Reproductive results confirm earlier data in that flushing from March 4, preceded by a 2-week period of moderate restriction, resulted in improved litter sizes (with 1.2 kits on average). Flushing from February 20 was less efficient. When comparing level of restriction, severely restricted females responded less to flushing than did moderately restricted females. The experimental treatment did not affect readiness to mate and the frequency of barren females was not conclusively affected. The rate of stillborn kits was not significantly affected but the highest rate was recorded in the group with superior litter size. In this investigation, both yearlings and adult females responded similarly to flushing.