Body condition influences maintenance of a persistent first wave dominant follicle in dairy cattle
Body condition influences maintenance of a persistent first wave dominant follicle in dairy cattle
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DOI：
10.1016/s0093-691x(98)00024-7
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发表时间：
1998-03-01
期刊：
影响因子：
2.8
通讯作者：
Thatcher, WW
中科院分区：
文献类型：
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作者：
Burke, JM;Hampton, JH;Thatcher, WW
本研究的目的是确定在低体状态(LBC，体况评分[BCS]1=瘦，5=胖[2.3+/-0.72，n=4])与高体况(HBC，BCS=4.4+/-0.12，n=4)奶牛相比，体内药物释放装置(CIDR)的血浆孕酮(P-4)浓度是否足以维持持续的第一波优势卵泡(FWDF)。在发情周期的第7天(第0天=发情)，给奶牛注射前列腺素F(2α)(25 mg im Lutalyse，下午(R)，第8天上午)。用过的含P-4(1.2g)的CIDR装置插入阴道直到排卵或第16天。从第5天至第18天(或排卵)采集血浆进行P-4和雌二醇(E-2)测定，并每天进行卵泡超声监测。在第5至7天，HBC奶牛的血浆P-4平均浓度高于LBC奶牛(4.6>；3.4+/-0.37 ng/ml；P<；0.04)。所有LBC奶牛均保持第一波优势卵泡，并在去除CIDR装置后排卵(18.3+/-0.3d，n=3；第4头奶牛在第11天失去CIDR装置并于第15天排卵)，而HBC奶牛排卵发生在CIDR暴露期间(11.3+/-0.3d；n=3；第4头奶牛在第19天出现黄体化第一波优势卵泡，但未排卵)。平均发情日数，LBC(n=3)为17+/-0.4，HBC(n=3)为10+/-0.4。LBC奶牛血浆E-2的持续浓度(12.9+/-2.8pg/ml；第8至17天)反映了活跃的持续第一波优势卵泡的存在。BCS和血浆P-4浓度(y=ng/ml)的差异通过回归方程的差值(P<；0.01)反映出来：Y(LBC)=19.9-3.49x+0.166x(2)vs Y-Hbc=37.3-7.04x+0.340x(2)(x=周期天数，7~12天)。虽然在第8天之前，HBC奶牛的P-4浓度较高，但在没有CL的情况下，从CIDR设备释放的血浆P-4的清除量更大会改变卵泡动力学，导致HBC奶牛过早排卵。在LBC奶牛中维持了更高的基础浓度的P-4，这使得持续的第一波优势卵泡得以维持。(C)1998年，爱思唯尔科学公司。
The objective of this study was to determine whether plasma concentrations of progesterone (P-4) from a controlled internal drug releasing (CIDR) device (similar to 2 ng/ml) were adequate to sustain a persistent first wave dominant follicle (FWDF) in low body condition (LBC, body condition score [BCS] 1 = lean, 5 = fat [2.3 +/- 0.72, n = 4]) compared with high body condition (HBC, BCS = 4.4 +/- 0.12, n = 4) nonlactating dairy cows. On Day 7 of the estrous cycle (Day 0 = estrus), cows were treated with PGF(2 alpha) (25 mg im Lutalyse,(R) P.M., and Day 8 A.M.) and a used CIDR device containing P-4 (1.2 g) was inserted into the vagina until ovulation or Day 16. Plasma was collected for P-4 and estradiol (E-2) analyses from Day 5 to Day 18 (or ovulation), and ovarian follicles were monitored daily by ultrasonography. Mean concentrations of plasma P-4 were greater in HBC than LBC cows between Days 5 and 7 (4.6 > 3.4 +/- 0.37 ng/ml; P < 0.04). All LBC cows maintained the first wave dominant follicle and ovulated after removal of the CIDR device (18.3 +/- 0.3 d, n = 3; Cow 4 lost the CIDR device on Day 11 and ovulated on Day 15), whereas in the HBC cows ovulation occurred during the period of CIDR exposure (11.3 +/- 0.3 d; n = 3; a fourth cow developed a luteinized first wave dominant follicle that did not ovulate during the experimental protocol on Day 19). Mean day of estrus was 17 +/- 0.4 for LBC (n = 3) and 10 +/- 0.4 for HBC (n = 3) cows. Sustained concentrations of plasma E-2 (12.9 +/- 2.8 pg/ml; Days 8 to 17) in LBC cows reflected presence of an active persistent first wave dominant follicle. The differential effect of BCS an concentrations of plasma P-4 (y = ng/ml) was reflected by the difference (P < 0.01) in regressions: y(LBC) = 19.9 - 3.49x + 0.166x(2) vs Y-HBC = 37.3 - 7.04x + 0.340x(2) (x = day of cycle, Days 7 to 12). Although P-4 concentration was greater for HBC cows prior to Day 8, a greater clearance of plasma P-4 released from the CIDR device in the absence of a CL altered follicular dynamics, leading to premature ovulation in the HBC cows. A greater basal concentration of P-4 was sustained in LBC cows that permitted maintenance of a persistent first wave dominant follicle. (C) 1998 by Elsevier Science Inc.