LH surge in response to the treatment with GnRH analog or estradiol in ovariectomized buffaloes with or without progesterone pre-exposition

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• 作者：Jos茅 Octavio Jacomini ; Gustavo Guerino Macedo ; Nelcio Ant么nio Tonizza de Carvalho ; Jos茅 N茅lio de Sousa Sales ; Pietro Sampaio Baruselli
• 关键词：Buffalo ; Endocrine ; Luteinizing hormone ; Reproduction ; Synchronization ; Ovulation inducer
• 刊名：Livestock Science
• 出版年：February, 2014
• 年：2014
• 卷：160
• 期：Complete
• 页码：194-198
• 全文大小：467 K

文摘

The aim of the present study was to evaluate the LH surge after EB (estradiol benzoate) or GnRH administration with or without P4 (progesterone) pre-exposure in ovariectomized (OVX) buffalo cows. Females were randomly assigned to receive an intravaginal P4 device (D0-D9). They were then given EB 24 h or GnRH 36 h post-P4 device removal (factorial 2脳2, n=6 per group). Blood collection for LH measurement began 36 h after the P4 device removal and continued at 3 h intervals. The area under the LH curve (AUC; 30.2 ng² and 13.41 ng²; P=0.007) and the area of the LH peak (AP; 19.0 ng² and 8.9 ng²; P=0.009) were greater for EB than GnRH. We did not observe an effect of P4 pre-exposure on the AUC and AP. Furthermore, there was no interaction between P4 pre-exposure and EB or GnRH treatment on the AUC and AP. However, there was an interaction (P<0.01) between P4 pre-exposure and the type of inducer (EB or GnRH) to release a preovulatory-like LH surge at the beginning (BP), final (FP) and time (TP) of the LH peak. The P4 pre-exposure anticipated the BP (2.5 and 7.4 h), TP (6.0 and 12.0 h) and FP (11.5 and 17.1 h) when EB was used to induce a preovulatory-like LH surge (P<0.01). However, there was no effect of P4 pre-exposure on BP (0.4 and 0.4 h), TP (3.0 and 3.0 h) and FP (5.9 and 6.1 h) with GnRH treatment. There was also no effect of the pre-exposure to P4, type of inducer or interaction on the amplitude of the LH peak. We concluded that EB therefore led to greater LH release than GnRH, and pre-exposure to P4 before EB administration anticipated the preovulatory-like LH surge in buffalo cows.