Effects of a high dose of diethylstilbestrol on the delivery of the placenta after corticoid-induced parturition in cattle: Preliminary communication

Abstract

Parturition was induced in 61 young cows and heifers of the German Black Pied breed by injection of 20 mg dexamethasone (Dex) on Days 266 to 291 (mean Days 274). Forty animals served as untreated controls and calved spontaneously. While 21 animals received no additional treatment (Group I), 6 animals were injected simultaneously with 10 mg estradiol benzoate (E 2) i.m. (Group II), and 34 with 120 mg diethylstilbestrol (DES) (60 mg i.m., 60 mg i.v., together with 100 ml of 24% calcium borogluconate (Group III). Parturition was observed in all 61 animals after 42.3 (I), 37.3 (II), and 36.4 (III) hrs, respectively. The number of stillbirths, dystocias and perinatal losses observed were low and equally distributed between groups. Birth weights were lower with induced parturitions. After dexamethasone alone, 61.9% of all animals showed retained placenta; addition of estradiol benzoate was without effect (66.7% retained placenta), while the use of 120 mg DES reduced the extent of retained placenta markedly to 23.5% (p<.05). DES treatment was without noticeable adverse effects on puerperium, lactation and postpartum fertility. Since its first description in 1969, corticosteroid-induced parturition in cattle has become a useful therapeutic or prophylactic procedure and an accepted management tool in the cattle industry (4,6,12,15,16,25,31,33). The high incidence of retained placenta (r.p.) remains its most undesirable side effect (4,6,12,15,16,33). Unlike the situation in the ewe, where corticoids induce parturition of fetus as well as placenta (15,16), exogenous corticoids in cattle trigger mechanisms for the delivery of the fetus, but often not those for the simultaneous shedding of the placenta. The closer to term parturition is induced, the lower the incidence of r.p. (7,15,33). Retention is influenced by breed (33), sex of the fetus (32), dose of the drug (4,6,15), or age of the dam (4). Spontaneous retention of the fetal membranes may be associated with nutritional deficiencies (8), seasonal changes (21) or high milk production levels in combination with a tendency toward twinning (21, 30). Multiple gestations per se are frequently followed by retained placenta (21). Induction of parturition with corticosteroids may augment the above tendencies beyond the common 4–10% level (6,19,21). Management practices have been developed for beef cattle with r.p. after induced parturition, which consists of systemic, not local antibiotic treatment, beginning within 24 hr postpartum, and strict refraining from manual intervention. These procedures are effective in preventing possible adverse effects resulting from r.p. on lactation, uterine involution, and subsequent fertility (3,6,18,26,33). Despite these prophylactic measures, r.p. is poorly accepted by dairymen in many parts of Europe (9,10,12). Attempts to induce simultaneous delivery of fetus and placenta have included the use of corticoid preparations of different pharmaco-dynamic properties. While the most widely used “short-acting” corticosteroids induce parturition at a predictable short time interval (20–72 hrs), accompanied by a variable percentage of r.p., but a low incidence of stillbirths and perinatal losses (16,33), the so-called “longer acting” compounds (esters, or crystalline suspensions, or both) cause parturition at a much less predictable and longer interval of 10 (5–15) days, with a lower incidence of r.p. (2,22,23,34), but a high percentage of stillborn or weak calves Prostaglandins induce parturition in cattle like “short-acting” corticoids, but the occurrence of r.p. is equally high (17,35,36). Concomitant treatment with progestins (15) or estrogens (estradiol [E 2] or diethylstilbestrol [DES]) (15,16,18,20,27) was unsuccessful except for one claim that 20 mg dexamethasone +6 mg E 2 promoted simultaneous delivery of fetus and placenta (11). The purpose of this study was twofold: To examine the effect of E 2 at a single 10 mg dose; and to explore DES at a single high dose of 120 mg, postulating that estrogens at considerably higher dose levels might be effective in preventing r.p. following induction of parturition with dexamethasone. This dose was selected since it had been used routinely in this department two decades ago just before or at the onset of deliveries to alleviate parturition stress. At the time it was found to be without undesirable effects on delivery, puerperium, lactational performance or subsequent fertility (1).