A field trial was conducted to compare 60/90 day nonreturn rate for routine inseminations with the rate obtained when an outer sheath was used to protect the insemination catheter from vaginal contamination. Eleven technicians using frozen semen from ten Holstein bulls inseminated all cows with or without the protective sheath on alternate weeks for a three month period in late winter-early spring and for a similar period in late summer-early fall. The use of protective sheaths had no effect on the nonreturn rate.
展开▼
