Diskin M G, Box P G, Sreenan J M
Vet Rec. 1982 Mar 20;110(12):268-71. doi: 10.1136/vr.110.12.268.
To avoid dystocia and calf mortality two groups of cows were induced to calve six or seven days prematurely. Group I consisted of none Hereford cross Friesian two-and-a-half-year-old recipient cows carrying Continental beef breed fetuses. Group 2 consisted of 10 four-year-old Continental beef breed cows carrying pure or crossbred fetuses of the same breeds. On day 280 of gestation a long-acting betamethasone formulation was injected into all 19 animals, followed five or six days later with an injection of short-acting betamethasone (15 animals) or prostaglandin F2alpha (one animal). Three cows calved before their second injection. Fourteen of the 15 animals given the short-acting betamethasone calved 26 to 70 hours later; the remaining animal was given prostaglandin at 72 hours and calved 36 hours later. The cow that received prostaglandin F2alpha instead of short-acting betamethasone calved after 11 hours. None of the calves in group I was born dead but three died within 36 hours. One calf was born dead in group 2. Cervical dilatation and slackening of pelvic ligaments were satisfactory in all animals. Although calf birthweights were between 39 and 60.5 kg, only two instances of dystocia were encountered. Thirteen of the 19 cows voided their fetal membranes within 12 hours of calving. Only two retained them for more than four days. All cows except two in group I showed good udder development and had a plentiful supply of colostrum at calving.
为避免难产和犊牛死亡，两组母牛被诱导提前六或七天产犊。第一组由无 Hereford 杂交 Friesian 两岁半的受体母牛组成，怀有大陆肉牛品种胎儿。第二组由 10 头四岁的大陆肉牛品种母牛组成，怀有相同品种的纯种或杂交胎儿。在妊娠第 280 天，向所有 19 只动物注射长效倍他米松制剂，五或六天后再注射短效倍他米松（15 只动物）或前列腺素 F2α（1 只动物）。三头母牛在第二次注射前产犊。接受短效倍他米松的 15 只动物中有 14 只在 26 至 70 小时后产犊；其余动物在 72 小时时注射前列腺素，36 小时后产犊。接受前列腺素 F2α而非短效倍他米松的母牛在 11 小时后产犊。第一组中没有犊牛出生时死亡，但有三头在 36 小时内死亡。第二组中有一头犊牛出生时死亡。所有动物的宫颈扩张和骨盆韧带松弛情况均令人满意。尽管犊牛出生体重在 39 至 60.5 千克之间，但仅遇到两例难产情况。19 头母牛中有 13 头在产犊后 12 小时内排出胎膜。只有两头保留胎膜超过四天。除第一组中的两头母牛外，所有母牛乳房发育良好，产犊时有充足的初乳供应。
