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Register a new userMonitoring the ovarian follicular activity with relative to puberty in growing Shami heifers
رصد نشاط الجريبات المبيضية و علاقته بالبلوغ الجنسي في عجلات البقر الشامية
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استخدمت 12 أنثى من عجلات البقر الشامية النامية في محطة بحوث دير الحجر لتحسين البقر الشامية، متوسط أعمارها 178 ± 4 يوماً، و متوسط وزنها 115 ± 3 كغ لرصد ديناميكية نمو الجريبات المبيضية و خصائصها ( العدد اليومي، القطر، عدد الموجات و طولها، معدل النمو و التراجع ). فُحص كل مبيض بمفرده يومياً عدة مرات بوساطة جهاز راسم الصدى Ultrasound لتتبع نمو الجريبات المبيضية و تراجعها. أظهرت النتائج وجود جريبات مبيضية نامية في مبايض العجلات الشامية النامية و هي بعمر 6 أشهر، و أنها تتطور على شكل أمواج ينمو خلالها نحو 4 إلى 7 جريبات صغيرة ( 2 - 5 مم) معاً ثم تصبح إحداها سائدة و يكون مصيرها التراجع خلال فترة ماقبل البلوغ من دون وجود فرق معنوي في متوسط عدد الجريبات المبيضية و حجمها بين المبيضين الأيمن و الأيسر.
Twelve growing Shami heifers available in Dier-Al-Hajar Station for improving Shami Cattle weighing 115±3 kg and 178±4 days old were used to monitor the daily growth of ovarian follicles (daily numbers, size, length and number of waves, rate of growth and regression) using Transrectal Ultrasound Echo System (7.5 MHz probe) in 6-14 months-old heifers. Results indicated that ovarian follicles developed in a wave pattern in all Shami heifers when they were 6 months old and no significant differences in the number and size of ovarian follicles were found between right and left ovaries. A cohort of 4 to 7 small follicles with a diameter 2-5 mm developed together and one of them was selected for continual growth, became dominant and later regressed during the pre-pubertal stage.
References used
Adams, G. P., A. C. Evans and N. C. Rawlings. 1994. Follicular waves and circulating gonadotrophins in 8-month-old prepubertal heifers. J. Reprod. Fertil. 100: 27-33
Alvarez, P., L. J. Spicer, C. C. Chase, Jr., M. E. Payton, T. D. Hamilton, R. E. Stewart, A. C. Hammond, T. A. Olson and R. P. Wettemann. 2000. Ovarian and endocrine characteristics during an estrous cycle in Angus, Brahman, and Senepol cows in a subtropical environment. J. Anim. Sci. 78:1291–1302
Bergfeld, E. G. M., F. N. Kojima, A. S. Cupp, M. E. Wehrman, K. E. Peters, M. Garcia-Winder and J. E. Kinder. 1994. Ovarian follicular development in prepubertal heifers is influenced by level of dietary energy intake. Biol. Reprod. 51: 1051-1057
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Twelve growing Shami heifers available in Dier-Al-Hajar Station for
improving Shami Cattle weighing 115±3 kg and 178±4 days old were used to
determine the weekly hormonal concentrations of progesterone (P4) and
estradiol 17-β (E2) during the pre-
and puberty stages (6-14 mos). Blood
samples were collected weekly from the Jugular vein using vacutainer tubes
supported with K3EDTA.
Twelve growing Shami heifers available in Dier-Al-Hajar Station for
improving Shami Cattle during 2005-2007 weighing 250±11 kg and 400±21
days old were used to monitore the growth of dynamic of ovarian follicles (daily
numbers, size, length and nu
mber of waves, rate of growth and regression) and
characteristics of estrus cycle (length, time of dominancy, diameter of Graffian
follicle and estrus and ovulatory times), length of corpus luteum (CL) during
the estrous cycle. Heifers were maintained under uniform conditions and fed
according to their daily growth. Transrectal Ultrasound Echo System (7.5 MHz
probe) was used to study the ovarian structures and to monitor the daily
development and regression of ovarian follicles, the formation and regression of
corpus luteum in the left and right ovaries during the estrus cycle. Results
indicated that the growth turnover of ovarian follicles was observed and
developed in a wave pattern in all Shami heifers and no significant differences
in the number and sizes of ovarian follicles were found between right and left
ovaries. A cohort of 5 to 7 small follicles with a diameter 2-5 mm developed
together and one of them was selected to continue growing and becomes
dominant and later on being regressed or ovulated during the estrus cycle. One
to five follicular waves were observed per cycle and each wave was
characterized by the development of one large (dominant) follicle and a
variable number of smaller follicles. The estrus cycle with one follicular wave
occurred only in heifers exhibited the first post pubertal cycles with an average
length equaled to 8.67±0.33 days. Frequency of estrus cycle according to the
number of follicular waves was 8.4, 25.3, 44.2, 20 and 2.1% in cycles having 1,
2, 3, 4 and 5 follicular waves, respectively. Furthermore , the length of estrus
cycle was also related to the number of follicular waves and it was 21.87±0.62,
22.44±0.74, 26.4±0.72, 26.50±3.50 days in cycles having 2, 3, 4 and 5 follicular
waves, respectively with significant differences (P < 0.05) in cycles with 2 or 3
vs. 4 and/or 5 waves. The functional duration of CL was extended to 9, 12 and
15 days in a short (17-19 days), intermediate (20-24 days) and long estrus cycle
(≥ 25 days). The maximum diameter of dominant follicles in ovulatory waves
was significantly larger (P < 0.05) than that of dominant follicles in nonovulatory
waves. In conclusion, this study showed that the development of
ovarian follicles in Shami heifers occurs in waves and the most common pattern
is three waves per estrous cycle.
Fifteen Shami cows available in Dier-Al-Hajar Station for improving Shami
Cattle were used during 2009-2010 to evaluate the ovarian response of cows for
gonadotropin releasing hormone (GnRH) or human chorionic gonadotropin
(hCG) injected on day 5
of the estrus cycle during which dominant follicle is
growing in the first follicular wave. Animals were divided randomly into three
groups of five cows. Group 1 was left as a control and received no treatment
while Groups 2 and 3 received on day 5 of the estrous cycle a single i.m.
injection of 8 ?g of a GnRH agonist (Buserelin) and 3000 IU hCG, respectively.
Transrectal ovarian ultrasonography was performed daily to monitor ovarian
follicular dynamics and corpus luteum.
This study was carried out at Camel Research Station, Deer Al-Hajar,
Directorate of Animal Wealth Research, General Commission of Agricultural
Scientific Research to measure the testicular dimensions, TDs (Length, TL;
width, TW; Circumference, TC)
; the relationship between these parameters
and to use them as an indicator to determine the puberty age in Shami camel
males. Twenty five camel raised in the station were equally divided, according
to their age, into five groups: G1, almost one year,G2, G3, G4, and G5 were 2,
3, 4 and 5 years old, respectively.
The ovary of a laying hen contains follicles in the rapid growth phase
which have advanced from a pool of follicles in the resting stage of about
٦-٨ mm in diameter. Little is known about mechanisms regulating follicular
transformation from the re
sting stage to the rapid growth phase. One potential
regulator of this transformation may be Follicle Stimulating Hormone
(FSH). In addition, there are accumulating results indicating that a negative
relationship between inhibin and FSH may be existed.
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