Calves delay estrus cycles in postpartum cows by mechanisms other than suckling

Abstract

It is generally accepted that the suckling stimulus and the interactions between lactation and level of nutrition regulate the interval from calving to cycling in beef cows. However, rnastectomized cows (udder removed) kept with their calves had longer postpartum intervals to ovulation and estrus than mastectomized cows without calves. We conclude that ovulation and estrus can be suppressed by some cow-calf interaction that is independent of lactation and suckling.