کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
2454379 | 1110387 | 2009 | 6 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Use of Gonadotropin-Releasing Hormone at Fixed-Time Artificial Insemination at Eighty or Ninety-Seven Hours Post Prostaglandin F2α in Beef Cows Administered the Long-Term Melengestrol Acetate Select Synch
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کلمات کلیدی
موضوعات مرتبط
علوم زیستی و بیوفناوری
علوم کشاورزی و بیولوژیک
علوم دامی و جانورشناسی
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چکیده انگلیسی
In a 2-yr trial, the pregnancy response of 549 Angus-based cows (BCS 5.1 ± 0.56, postpartum interval 69.7 ± 19.1 d) was evaluated when estrous cycles were synchronized by feeding melengestrol acetate for 14 d with gonadotropin-releasing hormone (GnRH) given on d 26 and prostaglandin F2α (PG) on d 33. Of all cows, those observed in estrus within 72 h after PG were inseminated 9.5 ± 4.01 h after estrus was first observed. The remaining cows were fixed-time inseminated (TAI) and randomly assigned to receive or not receive GnRH at TAI, and randomly assigned to be inseminated at 79.7 ± 2.26 h (early) or 96.6 ± 1.94 h (late) post-PG. There were no GnRH à year (P = 0.47) or GnRH à time of TAI (P = 0.96) interactions. Cows that received GnRH at TAI had a greater (P < 0.001) pregnancy rate than those receiving no GnRH. There was a tendency (P = 0.07) for a year à time of TAI interaction. In yr 1, late TAI cows had a greater (P = 0.01) pregnancy rate than early cows; however, in yr 2, pregnancy rate was not different (P > 0.10) between early and late cows. Results indicate that within the long-term melengestrol acetate Select Synch protocol, pregnancy rate of cows not observed in estrus within 72 h of PG could be increased by adding a second GnRH injection at TAI, whereas the effect of delaying time of TAI until 97 h post-PG on pregnancy rate was inconsistent.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: The Professional Animal Scientist - Volume 25, Issue 3, June 2009, Pages 256-261
Journal: The Professional Animal Scientist - Volume 25, Issue 3, June 2009, Pages 256-261
نویسندگان
J.K. Ahola, G.E. (Jr.), J.C. (Pas),