Duration of copulation and fertility in the mink, Mustela vison.
In mink, restricting the duration of copulation (<or=6 min) results in reduced fertility, either due to too few spermatozoa being ejaculated or defective sperm transport (4). The objective of the present work was to determine the effect on fertility of prolonging mating using a sterile male. When copulation was restricted to 5 min, only 3/14 mink whelped, and in 2 of the 3 cases the litter size was well below normal. The use of a vasectomized male, either before or after the intact male, caused a significant increase both in whelp rate (21/24) and litter size. The beneficial effect of the vasectomized male was still present after 4 hr. It is concluded that in short matings, defective sperm transport is the major factor limiting fertility and that the duration of coitus affects the efficiency of sperm transport.
Adams
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A.R.C. Institute of Animal Physiology, Animal Research Station, 307 Huntingdon Road, Cambridge CB3 0JQ, England.
Rietveld
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