Volume 8, Issue 15 (6-2017)                   rap 2017, 8(15): 138-143 | Back to browse issues page


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Effect of Gondaotropin Releasing Hormone Administration (GnRH) and CIDR Insert after Artificial Insemination on Fetus Loss, AI Interval and Conception . rap. 2017; 8 (15) :138-143
URL: http://rap.sanru.ac.ir/article-1-755-en.html

Abstract:   (290 Views)

The objective of this study was to investigate effect of different time of GnRH administration and CIDR insert after artificial insemination (AI) on fetus Loss, AI interval and conception rate in Holstein dairy cows. Multiparous high-yield dairy cows (> 30 Kg/d, n= 550) were randomly assigned into five groups. Groups were: 1- GnRH injection on day 5 after AI, 2- GnRH injection on day 11 after AI, 3- GnRH injection on day 13 after AI, 4- GnRH injection on day 5 and 11 after AI and 4- Controlled internal drug release (CIDR) devices were inserted on day 5 after AI and removed on day 14 after AI. Ultrasonography were used for consider ovary status and pregnancy diagnosis at d 32 after AI. Pregnancy was characterized by the presence of an embryo, corpus luteum and fluid in uterus horn. Cows diagnosed pregnant at 32 d were re-examined at 70 d after AI to confirm pregnancy. Pregnancy loss was considered to have occurred when a cow was diagnosed pregnant at 32 d after TAI and not pregnant at 70 d. Results showed percentage of cows that showed estrus at 19-24 d after AI was lowest in G5,11 (20.0 %) cows compared to GnRH injection on day 5 after AI (31.5 %), GnRH injection on day 11 after AI (25.7 %), GnRH injection on day 13 after AI (26.5 %) and CIDR group (32.7 %, P = 0.04). Percentage of cows that did not show estrus until day 34 after AI was lowest in CIDR group (20.6 %, P= 0.01) but there was no difference between other groups (average 42.6 %, P = 0.65). A greater (P = 0.01) percentage of cows that received GnRH injection on day 5 and 11 after AI were pregnant at 32 d (50.0) and 70 d (46.2 %) after AI compared to other groups. Pregnancy loss was lowest in CIDR group (P = 0.04). In conclusion GnRH injection on day 5 and 11 after AI compared to other methods improved pregnancy rates.

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Type of Study: Research | Subject: Special

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