臺灣博碩士論文加值系統

同期化中使用GnRH誘導排卵具有穩定且集中的排卵時間，因此，能與定時人工授精配合進行繁殖管理，而人絨毛膜促性腺激素(hCG)雖能作用於LH受體並誘導濾泡排卵，其在排卵誘導時間的效果卻仍未有文獻提出。本試驗目的在於比較hCG和GnRH在泌乳牛排卵誘導上的差異，並同時探討在週期5.5至6.5天或9至10天，使用兩劑低劑量PGF2α溶解黃體搭配排卵誘導的效果。本試驗納入產後50至70天的牛隻(n = 19)共進行22次的同期化以確認牛隻週期，並依照產次將同期化成功的牛隻隨機分入不同週期時間的cross-over試驗組別。於Stage 1時，牛隻會在排卵後9至10天(G組及H組)或5.5至6.5天(OvG組及OvH組)給予第一劑PGF2α (375 µg)，並定義為Day 0，並間隔一天給予第二劑PGF2α (250 µg)。在Day 2會使用GnRH (250 µg)或hCG (3000 IU)誘導牛隻排卵，並從Day 3開始進行超音波連續觀察以確認濾泡排卵時間。在Stage 1以GnRH誘導排卵的牛隻，不論Day 0位於排卵後9至10天(G組)或5.5至6.5天(OvG組)，進入Stage 2時則改為使用hCG誘導排卵(H組及OvH組)，反之亦然。試驗結果顯示，G組在黃體溶解過程比OvH組有較低的黃體剩餘面積比，顯示較好的黃體溶解反應，但整體而言，各組使用兩劑低劑量PGF2α皆能達到高比例且相近的黃體完全溶解率。各組間不論是在排卵時間、排卵率及濾泡大小皆沒有顯著差異，而合併組別比較GnRH與hCG在排卵誘導的效果時，雖然使用hCG具有比GnRH顯著較晚的排卵時間(33.4 ± 2.7 v.s. 29.2 ± 0.5 h)，兩者皆有高比例的排卵誘導率。結論，本試驗證實了在週期早期和中期使用兩劑低劑量PGF2α配合hCG或GnRH誘導排卵的可行性，且能有高比例的黃體溶解率、排卵誘導率及穩定的排卵時間，而在牧場配合定時人工授精進行繁殖管理。

The use of gonadotropin-releasing hormone (GnRH) has been shown to benefit timed artificial insemination (TAI) with stable and concentrated ovulation time in dairy cows. On the other hand, human chorionic gonadotropin (hCG) can also be used for induced ovulation due to its LH-like effect; however, its efficacy on induced ovulation time has never been described. The aim of this study is to compare the effect of hCG with GnRH on induced ovulation during early and middle diestrus in dairy cows. A total of 19 lactating cows were synchronized using modified Ovsynch-48 protocol for 22 estrous cycles. Synchronized cows (n = 16) were randomly assigned to groups of early or middle diestrus that received PGF2α administration (Day 0) on 5.5 to 6.5 days or 9 to 10 days after synchronized ovulation. In stage 1, cows were treated with 375 and 250 µg PGF2α on Day 0 and Day 1, respectively, then administered with 250 µg GnRH or 3000 IU hCG in groups of 9 to 10 day (G and H group) and groups of 5.5 to 6.5 day (OvG and OvH group) on Day 2. Ovulatory response was consecutively monitored by ultrasonography on Day 3. In stage 2, cows were treated in the same manner converse to that in stage 1. The result demonstrated that 96.6% of the cows showed complete luteolysis, while only one cow failed in the OvH group. Although there was no significant difference in time of ovulation among four groups, the ovulation time after hCG injection (33.4 ± 2.7 h) was later (P < 0.01) than that of GnRH administration (29.2 ± 0.5 h). Ovulation rate was 93.1% (27/29) in total and had no significant difference among groups. To sum up, though hCG group had later time of ovulation compared to that in GnRH group, both hormones were effective for the fixed time of induced ovulation during early or middle diestrus in dairy cows.

目次

摘要.................... i
Abstract.................... ii
目次.................... iii
表次.................... v
圖次.................... vi
第一章 前言.................... 1
第二章 文獻探討.................... 2
第一節 牛隻的動情週期.................... 2
一、 濾泡的消長.................... 2
二、 濾泡的排卵.................... 2
三、 黃體的消長.................... 3
第二節 同期化與定時人工授精.................... 3
一、 發情誘導與偵測.................... 4
二、 排卵誘導與定時人工授精.................... 4
三、 同期化的排卵時間.................... 5
四、 同期化程序的改良.................... 7
（一） 濾泡的日齡.................... 7
（二） 前同期化(Presynchronization) .................... 7
（三） 外源性PGF2α的作用與劑量.................... 8
第三節 hCG於臨床上之應用.................... 10
一、 hCG的作用.................... 10
二、 同期化中使用hCG.................... 11
（一） 使用hCG取代第一劑GnRH.................... 11
（二） 使用hCG進行排卵誘導.................... 12
三、 配種後使用hCG增加P4濃度.................... 12
四、 使用hCG治療卵巢囊腫.................... 13
五、 使用hCG造成的免疫反應.................... 13
第三章 材料與方法.................... 14
第一節 試驗動物.................... 14
第二節 試驗設計與流程.................... 14
一、 動情週期同期化(Synchronization) .................... 14
二、 Stage 1和Stage 2.................... 15
第三節 超音波掃描紀錄及分析.................... 16
一、 超音波影像測定.................... 16
二、 超音波連續觀察.................... 16
第四節 血液樣本採集與分析.................... 16
第五節 黃體溶解及同期化成功判定.................... 17
第六節 牛隻生理紀錄.................... 17
第七節 數據統計分析.................... 17
第四章 結果.................... 18
第一節 動情週期同期化.................... 18
第二節 Stage 1 & 2的黃體溶解反應.................... 19
一、 黃體面積變化.................... 19
二、 黃體剩餘面積比.................... 20
三、 血清P4濃度.................... 21
四、 黃體完全溶解比例.................... 22
第三節 Stage 1 & 2的排卵反應.................... 22
一、 濾泡動力學.................... 22
二、 排卵率、排卵濾泡直徑與排卵時間.................... 23
第四節 其他.................... 25
一、 中空黃體.................... 25
二、 特殊案例紀錄.................... 25
第五章 討論.................... 27
第一節 hCG和GnRH排卵誘導的效果.................... 27
第二節 不同週期時間的排卵誘導反應.................... 29
第三節 黃體溶解反應.................... 30
第四節 其它.................... 31
第六章 總結.................... 33
參考文獻.................... 34

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