Induction of Parturition in Cattle with Cloprostenol

Relaxin on induction of parturition in cattle: effects on hormonal, pelvic and cervical changes, and postpartum fertility

“…In vitro relaxin induces the release of cathepsln B and dipeptidyl peptidase I in the mouse pubic symphysis (McDonald and Schwabe, 1982). These are lysosomal cystine protease and exopeptidase, respectively, which break down cartilage.The results are consistent with earlier reports that cloprostenol or dexamethasone induced parturition causes high incidence of dystocia and retained placenta (Adams, 1969;Wagner et al, 1974;Johnson and Jackson, 1982). The incidence and severity of dystocia and 144 the duration of retained placenta seem to depend upon the stage of gestation when the induction occurs (Johnson and Jackson, 1982).…”

“…The combined induction resulted in reduced intervals between drug treatment and calving, shortened the calving period, reduced the incidence and severity of dystocia, reduced the proportion of heifers with retained placenta as well as the duration of retained placenta. These events were preceded by an accelerated decrease of plasma progesterone, and pelvic and cervical relaxation in much the same manner as reported earlier (Musah et al, 1986a,b).In this study, the profile of plasma peripheral progesterone levels during the periparturient period was similar to those observed during the periparturient period associated with normal calving, relaxin facilitated calving, prostaglandin or glucocorticoid induced calving (Johnson and Jackson, 1982;Musah et al, 1986a). Relaxin alone or combined with cloprostenol and dexamethasone is associated with luteal demise, consistent with earlier reports (Musah et al, 1986a).…”

“…This variability is greater in small heifers given glucocorticoids and prostaglandins to induce calving up to 10 days before the normal duration of gestation (Johnson and Jackson, 1982). This study indicates that relaxin administered to heifers during the last week before parturition increased the rate of pelvic growth as well as pelvic canal opening.…”

“…A related paradox is the peak release of relaxin which always precedes total or partial luteal demise in pregnant and hysterectomized gilts (Sherwood et al, 1975; Felder et al, 1986). The source of the signal for the timely peak release of relaxin in the presence or absence of the fetus and uterus is as intriguing and elusive as the 143 mechanism responsible for the partial luteal demise after the peak release of relaxin in hysterectomized gilts.Cloprostenol and dexamethasone induce cervical and pelvic softening, decrease progesterone concentrations in peripheral plasma and elevates plasma levels of estrogens (Mostle et al, 1985;Johnson and Jackson, 1982). This study shows that these effects are potentiated by relaxin.…”

“…Similarly, the high incidence of stillbirths associated with the artificial separation of the prepartum surge of relaxin from parturition and the observation that relaxin administered to ovariectomized progesterone-treated gilts resulted in increased live birth rates from 44% to 94% also indicate that relaxin might be essential for other aspects of parturition in addition to cervical and pelvic relaxation (Taverne et al, 1982; Nara et al, 1982). In cattle, daily administration of 1000 U relaxin, IM, causes earlier calving compared with that in saline-treated controls (Ferszgrovas and Anderson, 1982).The patterns of steroid hormone secretion in heifers induced to calve with relaxin were similar to blood levels found during normal parturition or parturition induced by im injection of prostaglandin (PGF2^) Johnson and Jackson, 1982). For example, a rapid decrease in progesterone plasma concentrations occurred in heifers given relaxin.…”