کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
10892389 1082100 2012 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Effect of intrauterine administration of gonadotropin releasing hormone on serum LH concentrations in lactating dairy cows
موضوعات مرتبط
علوم زیستی و بیوفناوری علوم کشاورزی و بیولوژیک علوم دامی و جانورشناسی
پیش نمایش صفحه اول مقاله
Effect of intrauterine administration of gonadotropin releasing hormone on serum LH concentrations in lactating dairy cows
چکیده انگلیسی
The objectives were to compare: (1) preovulatory serum LH concentrations, and (2) synchronization of ovulation, after im or iu administration of the second GnRH treatment of Ovsynch in lactating dairy cows. Lactating cows (N = 23) were presynchronized with two injections of PGF2α given 14 days apart (starting at 34 ± 3 days in milk), followed by Ovsynch (GnRH-7 d-PGF2α-56 h-GnRH) 12 days later. At the time of the second GnRH of Ovsynch (Hour 0), cows were blocked by parity and randomly assigned to 1 of 3 groups: (1) control group (CON; N = 7) were given 2 mL sterile water im; (2) intramuscular group (IM; N = 8) received 100 μg of GnRH im; and (3) intrauterine group (IU; N = 8) had 100 μg GnRH infused in the uterus (2 mL). Blood samples for serum LH concentrations were collected at Hours 0, 0.5, 1, 1.5, 2, 3, and 4. Furthermore, ultrasonography was performed twice daily (12-h intervals) from Hours 0 to 60 to confirm ovulation. The LH concentrations were greater (P < 0.05) in the IM than IU and CON groups at Hours 0, 0.5, 1, 1.5, 2, 3, and 4. Although LH concentrations were numerically higher in the IU group, LH concentrations within the IU and CON groups did not change over time. More cows ovulated in the IM (8/8) and IU (7/8) groups within 60 h after the second GnRH administration compared with the CON (2/7) group. In summary, serum LH concentrations were lower in the IU versus IM group, but the proportion of cows that ovulated within 60 h was similar between these two groups. Therefore, iu administration of GnRH may be an alternative route of delivery to synchronize ovulation in beef and dairy cattle.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Theriogenology - Volume 78, Issue 6, 1 October 2012, Pages 1390-1397
نویسندگان
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