Follicle deviation and ovulatory capacity in Bos indicus heifers

The objectives of Experiment 1 were to determine the interval from ovulation to deviation, and diameter of the dominant follicle (DF) and largest subordinate follicle (SF) at deviation in Nelore ( Bos indicus) heifers by two methods (observed and calculated). Heifers ( n = 12) were examined ultrason...

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Bibliographic Details
Published in:Theriogenology 2008-04, Vol.69 (7), p.852-858
Main Authors: Gimenes, L.U., Sá Filho, M.F., Carvalho, N.A.T., Torres-Júnior, J.R.S., Souza, A.H., Madureira, E.H., Trinca, L.A., Sartorelli, E.S., Barros, C.M., Carvalho, J.B.P., Mapletoft, R.J., Baruselli, P.S.
Format: Article
Language:English
Subjects:
Animals
Bos indicus
calculated follicle deviation
Cattle - physiology
Cell Size - drug effects
diameter
dominant follicles
Drug Administration Schedule
Drug Implants - therapeutic use
Efficiency
Estrus Synchronization - methods
Estrus Synchronization - physiology
Female
Follicle deviation
follicle diameter
follicular development
Heifers
luteinizing hormone
Luteinizing Hormone - administration & dosage
Nellore
Nelore
observed follicle deviation
Ovarian Follicle - cytology
Ovarian Follicle - drug effects
Ovarian Follicle - growth & development
Ovarian Follicle - physiology
ovarian follicles
ovulation
Ovulation - drug effects
Ovulation - physiology
Ovulation Induction - veterinary
Ovulatory capacity
Pregnenediones - administration & dosage
Progesterone Congeners - administration & dosage
subordinate follicles
Time Factors
ultrasonography
zebu
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Summary:The objectives of Experiment 1 were to determine the interval from ovulation to deviation, and diameter of the dominant follicle (DF) and largest subordinate follicle (SF) at deviation in Nelore ( Bos indicus) heifers by two methods (observed and calculated). Heifers ( n = 12) were examined ultrasonographically every 12 h from ovulation (Day 0) to Day 5. The time of deviation and diameter of the DF and largest SF at deviation did not differ ( P > 0.05) between observed and calculated methods. Overall, deviation occurred 2.5 ± 0.2 d (mean ± S.E.M.) after ovulation, and diameters for DF and largest SF at deviation were 6.2 ± 0.2 and 5.9 ± 0.2 mm, respectively. Experiment 2 was designed to determine the size at which the DF acquires ovulatory capacity in B. indicus heifers. Twenty-nine heifers were monitored every 24 h by ultrasonography, from ovulation until the DF reached diameters of 7.0–8.4 mm ( n = 9), 8.5–10.0 mm ( n = 10), or >10.0 mm ( n = 10). At that time, heifers were treated with 25 mg of pLH and monitored by ultrasonography every 12 h for 48 h. Ovulation occurred in 3 of 9, 8 of 10, and 9 of 10 heifers, respectively ( P < 0.05). In summary, there was no significant difference between observed and calculated methods of determining the beginning of follicle deviation. Deviation occurred 2.5 d after ovulation when the DF reached 6.2 mm, and ovulatory capacity was acquired by DF as small as 7.0 mm.
ISSN:0093-691X
1879-3231
DOI:10.1016/j.theriogenology.2008.01.001