Induction of follicular wave emergence for estrus synchronization and artificial insemination in heifers

The objective was to synchronize follicular wave emergence among cattle for synchronization of estrus and ovulation, and to determine pregnancy rate after AI at observed estrus. At random stages of the estrous cycle, a controlled internal drug release device (CIDR-B) was inserted intravaginally (Day...

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Bibliographic Details
Published in:Theriogenology 2000-09, Vol.54 (5), p.757-769
Main Authors: Martinez, M.F., Adams, G.P., Kastelic, J.P., Bergfelt, D.R., Mapletoft, R.J.
Format: Article
Language:English
Subjects:
Animals
artificial insemination
Cattle - physiology
CIDR-B
Estradiol - administration & dosage
Estrus Synchronization
Female
follicular wave
Gonadotropin-Releasing Hormone - administration & dosage
heifers
Insemination, Artificial - veterinary
Male
Ovarian Follicle - physiology
Ovary - diagnostic imaging
Ovary - physiology
Pregnancy
Progesterone - administration & dosage
Prostaglandins F - administration & dosage
Ultrasonography
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Summary:The objective was to synchronize follicular wave emergence among cattle for synchronization of estrus and ovulation, and to determine pregnancy rate after AI at observed estrus. At random stages of the estrous cycle, a controlled internal drug release device (CIDR-B) was inserted intravaginally (Day 0) in 67 cross-bred beef heifers, and they were randomly allocated to receive either no further treatment (Control; n = 18); 5 mg of estradiol-17β and 100 mg of progesterone im (E/P; n = 16); 100 μg im of GnRH (GnRH; n = 16); or transvaginal ultrasound-guided follicular ablation of all follicles ≥5 mm (FA; n = 17). All heifers received a luteolytic dose of PGF (repeated 12 h later), and CIDR-B were removed on Days 9, 8, 6 or 5, in Control, E/P, GnRH or FA groups, respectively, so the dominant follicle of the induced wave was exposed to exogenous-progesterone for a similar period of time in each group. Mean (±SEM) intervals (and range, in days) from treatment to follicular wave emergence in these groups were 3.5 ±0.6 (−2 to 8), 3.4 ±0.1 (3 to 4), 1.5 ±0.3 (−1 to 4), and 1.0 ±0.1 (0 to 2), respectively. Although the interval was longest (P
ISSN:0093-691X
1879-3231
DOI:10.1016/S0093-691X(00)00388-5