EFFECT OF OVARIECTOMY ON PREGNANCY MAINTENANCE AND PARTURITION IN DAIRY COWS
EFFECT OF OVARIECTOMY ON PREGNANCY MAINTENANCE AND PARTURITION IN DAIRY COWS
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DOI：
10.3168/jds.s0022-0302(67)87615-x
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发表时间：
1967-01-01
影响因子：
3.5
通讯作者：
BULLARD, JF
中科院分区：
文献类型：
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作者：
ESTERGREEN, VL;FROST, OL;BULLARD, JF
本试验选用3个奶牛品种的41头母牛，于妊娠48-268天，采用剖腹法切除卵巢，以研究其对妊娠期和分娩的影响。双侧卵巢切除术和仅切除含有黄体的卵巢（单侧）之间不存在差异，也不存在品种差异。12头在妊娠48-117天切除卵巢的母牛在切除黄体组织后平均4天流产。8头母牛在139-174天时切除卵巢，平均23天后流产。21头妊娠200-268天的母牛切除卵巢后，妊娠2-74天（X = 33）终止，平均妊娠262天。根据这些奶牛的既往病史，预期妊娠期为278天。在41头奶牛中，36头保留了胎膜，26头胎仔或小牛死亡。产犊困难，由于部分宫颈扩张和子宫惯性，产后子宫炎是常见的。在165-180天之前，妊娠黄体对维持牛妊娠至关重要;此后，有时在没有腺体的情况下维持活胎。然而，黄体在妊娠晚期是必不可少的，以防止缩短妊娠和异常分娩，包括胎膜滞留。
Forty-one cows of 3 dairy breeds were ovariectomized by laparotomy at 48-268 days of pregnancy to determine the effects on gestation length and parturition. No differences existed between bilateral ovariectomy and removing only the ovary containing the corpus luteum (unilateral), nor did breed differences exist. Twelve cows ovariectomized at 48-117 days of pregnancy aborted an average of four days after removal of the luteal tissue. Ovariectomy of eight cows at 139-174 days resulted in abortion an average of 23 days later. Twenty-one cows ovariectomized at 200-268 days of pregnancy terminated in 2-74 days (X = 33) at an average gestation length of 262 days. Based on previous history of these cows the expected gestation length was 278 days. Of the 41 cows, 36 had retained fetal membranes and 26 fetuses or calves died prepartum. Calving difficulties due to partial cervical dilation and uterine inertia, and postpartum metritis were common. The corpus luteum of pregnancy appeared essential for maintaining pregnancy in the bovine prior to days 165-180; there-after, a viable fetus was sometimes maintained in the absence of the gland. However, the corpus luteum was essential during late pregnancy to prevent shortened gestations and abnormal parturitions including retention of the fetal membranes.