Influence of Exposure to Bulls on Resumption of Estrous Cycles Following Parturition in Beef Cows1

Publisher Website
Google Scholar
Abstract
The effect of bull exposure on the resumption of estrous activity following parturition was studied in an experiment using mature Hereford and Hereford × Angus beef cows. In the spring of 1981 and 1982, cows were assigned by breed and calving date to one of two treatment groups. Cows were exposed to bulls either from 3 to 85 d postpartum (BE; n=45, 1981; n=35, 1982) or from 53 to 85 d postpartum (NE; n=39, 1981, n=36, 1982). Blood samples were collected from all cows once weekly from calving until 85 d postpartum to determine progesterone concentrations. The first increase in progesterone, which indicated onset of estrous cycles occurred at 43 ± 2 vs 63 ± 2 d (P<.01) in 1981 and at 39 ± 2 vs 61 ± 3 d (P<.01) postpartum in 1982 in BE cows and NE cows, respectively. Early postpartum exposure of cows to bulls reduced the postpartum anestrous interval. Copyright © 1984. American Society of Animal Science . Copyright 1984 by American Society of Animal Science

This publication has 0 references indexed in Scilit: