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Pregnancy rates after fixed-time artificial insemination of Brahman heifers treated to synchronize ovulation with low-dose intravaginal progesterone releasing devices, with or without eCG.
- Source :
-
Theriogenology [Theriogenology] 2011 Nov; Vol. 76 (8), pp. 1416-23. Date of Electronic Publication: 2011 Jul 28. - Publication Year :
- 2011
-
Abstract
- The objective was to determine whether eCG in an ovulation synchronization protocol with an intravaginal progesterone (P(4))-releasing device (IPRD) containing a low dose of P(4) improves pregnancy rate (PR) to fixed-time AI (FTAI) in Bos indicus heifers. Day 0, 2 y old Brahman heifers were allocated to either eCG+ (n = 159) or eCG- (n = 157) treatment groups. All heifers were weighed, body condition scored (BCS), and ultrasonographically examined to measure uterine horn diameter and presence of a CL. On Day 0, all heifers received a low-dose IPRD (0.78 g P(4)) and 1 mg of estradiol benzoate (EB) im. On Day 8, the IPRD was removed, all heifers received 500 μg cloprostenol im, and those in the eCG+ treatment group received 300 IU of eCG im. On Day 9, all heifers received 1 mg EB im. All heifers were FTAI 52 to 56 h after IPRD removal. Ten days after FTAI, heifers were exposed to bulls. Heifers were diagnosed as pregnant to FTAI, natural mating, or not detectably pregnant (NDP) 65 d after FTAI. Treatment with eCG+ as compared to eCG- did not affect PR to FTAI (28.9 vs 30.6%; P = 0.590), natural mating (51.3 vs 47.7%; P = 0.595), or overall (65.4 vs 63.7%; P = 0.872). Mean live weight gain from Days 0 to 65 d post-FTAI was higher in heifers pregnant to FTAI (72.29 ± 4.26 kg; P = 0.033) and overall (66.83 ± 3.65 kg; P = 0.021), compared to heifers that were NDP (60.03 ± 3.16 kg). Uterine diameter group, 9-11, 12-13, and 14-20 mm (26.2, 31.3, and 33.3%; P = 0.256), presence and absence of CL (29.8 vs 29.4%; P = 0.975), AI technicians 1, 2, and 3 (32.6, 28.8, and 22.4%; P = 0.293) and sires A, B, and C (23.9, 36.0 and 27.0%; P = 0.122) had no effect on PR to FTAI, natural mating, or overall. In conclusion, treatment of primarily cycling Brahman heifers with 300 IU eCG in conjunction with a low P(4)-dose (0.78 g) IPRD and EB to synchronize ovulation, did not improve PR after FTAI, natural mating, or overall.<br /> (Copyright © 2011 Elsevier Inc. All rights reserved.)
- Subjects :
- Administration, Intravaginal
Animals
Body Composition
Chorionic Gonadotropin administration & dosage
Cloprostenol administration & dosage
Cloprostenol pharmacology
Female
Insemination, Artificial methods
Ovulation Induction methods
Pregnancy
Pregnancy Rate
Progesterone administration & dosage
Weight Gain
Cattle physiology
Chorionic Gonadotropin pharmacology
Insemination, Artificial veterinary
Ovulation Induction veterinary
Progesterone pharmacology
Subjects
Details
- Language :
- English
- ISSN :
- 1879-3231
- Volume :
- 76
- Issue :
- 8
- Database :
- MEDLINE
- Journal :
- Theriogenology
- Publication Type :
- Academic Journal
- Accession number :
- 21798584
- Full Text :
- https://doi.org/10.1016/j.theriogenology.2011.06.010