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Monitoring 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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 Publication date 2014
and research's language is العربية
 Created by Shamra Editor




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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 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.


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Research summary
تستعرض هذه الدراسة نشاط الجريبات المبيضية وعلاقته بالبلوغ الجنسي في عجلات البقر الشامية. استخدم الباحثون 12 عجلة من البقر الشامية بمتوسط عمر 178±4 يوماً ووزن 115±3 كغ. تم رصد نمو الجريبات المبيضية باستخدام جهاز راسم الصدى يومياً. أظهرت النتائج أن الجريبات المبيضية تتطور على شكل موجات تبدأ من عمر 6 أشهر، حيث تنمو مجموعة من الجريبات الصغيرة معاً ثم تصبح واحدة منها سائدة وتتراجع قبل البلوغ. لم يكن هناك فرق معنوي بين المبيضين الأيمن والأيسر. في الشهر الأول قبل البلوغ، كانت متوسطات طول الموجة، القطر الأعظمي للجريب السائد، وعدد الجريبات اليومية أكبر مقارنة ببقية الأشهر. استنتج الباحثون أن البلوغ الجنسي يحدث عند أول إباضة للجريب السائد وتشكيل الجسم الأصفر عند متوسط عمر 400±21 يوماً ووزن 250±11 كغ.
Critical review
تقدم هذه الدراسة فهماً عميقاً لديناميكية نمو الجريبات المبيضية في عجلات البقر الشامية وعلاقتها بالبلوغ الجنسي. ومع ذلك، يمكن الإشارة إلى بعض النقاط التي قد تعزز من قوة الدراسة. أولاً، كان من الممكن تضمين عينة أكبر من العجلات لزيادة دقة النتائج وتعميمها. ثانياً، لم يتم التطرق بشكل كافٍ إلى العوامل البيئية والتغذوية التي قد تؤثر على نمو الجريبات والبلوغ الجنسي. أخيراً، كان من الممكن تقديم مقارنة مع سلالات أخرى من الأبقار لتوضيح الفروقات والميزات الخاصة بالبقر الشامي بشكل أوضح.
Questions related to the research
  1. ما هو الهدف الرئيسي من الدراسة؟

    الهدف الرئيسي من الدراسة هو رصد ديناميكية نمو الجريبات المبيضية ومواصفاتها في عجلات البقر الشامية النامية منذ عمر 6 أشهر حتى البلوغ الجنسي.

  2. ما هي الأدوات المستخدمة لرصد نمو الجريبات المبيضية؟

    استخدم الباحثون جهاز راسم الصدى (Ultrasound) بوساطة مسبار تردد 7.5 ميغاهرتز لرصد نمو الجريبات المبيضية يومياً.

  3. ما هو العمر والوزن الذي تصل فيه عجلات البقر الشامية إلى البلوغ الجنسي؟

    تصل عجلات البقر الشامية إلى البلوغ الجنسي عند متوسط عمر 400±21 يوماً ووزن 250±11 كغ.

  4. هل كان هناك فرق معنوي في عدد الجريبات بين المبيضين الأيمن والأيسر؟

    لم يكن هناك فرق معنوي في متوسط عدد الجريبات المبيضية وحجمها بين المبيضين الأيمن والأيسر.


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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