الفهرس 
Introduction
Reproductive cycleOnly 14 pages are availabe for public view
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Abstract
Studies on different aspects of reproduction of the camels are urgently
needed to disclose the possibilities of improving reproductive and productive
capabilities of this important species. The current work aimed to study the
follicular wave pattern, hormonal profiles and to investigate the efficacy of
inducing ovulation using GnRH analogue. In addition, the changes in blood
vasculature of the ovarian follicles and corpus luteum during different
developmental stages were studied.
Three reproductively sound, non pregnant, non lactating female
dromedary camels were used in the present study. The animals were
examined ultrasonographically, in a daily basis, using B-mode and color
Doppler to detect the changes in ovarian structures and their blood
vasculature, respectively, for 22 follicular cycles. Camels were bled daily to
trace the hormonal changes relative to the structural changes of the ovary.
During each follicular cycle, the interwave interval, day of emergence,
deviation, and ovulation, maximum diameter of the dominant follicle,
detection and regression of the CL were determined. Blood area and
percentage were determined in the ovarian structures. A single injection of
GnRH analogue was used to induce ovulation for dominant follicles over 0.9
cm. E2 and P4 were assayed during each studied reproductive phase during
the present study.
The results showed that, three phases of follicular development were
noticed during each follicular wave including, growth (11.6 ± 0.8 days),
mature (6.9 ± 0.6 days) and regression (13.3 ± 1.3 days) phases. The mean
total number of recruited follicles was 16.5 ± 1.8. The follicular wave lasted
for 35 ± 2.3 days. In approximately 70.8 % of the studied waves, the
dominant follicle reached a mean maximum diameter of 21.6 ± 0.6 mm
whereas in the other 29.2 % of the waves, the follicle continued to grow
until it reached a mean maximum diameter of 40.6 ± 3.2 mm. Estrous
behavior was unpronounced and highly variable in duration and intensity.
The mean diameter of the DF at the day of emergence was 4.6 ± 0.2 mm
versus 4.1 ± 0.3 mm for the subordinate. The day of deviation was
determined on day 6.1 ± 1.08. The mean diameter of the DF at the day of
deviation was 9.9 ± 0.4 mm versus 8.3 ± 0.4 mm for the subordinate follicle.
The mean maximum diameter of the subordinate follicle was 8.6 ± 0.3. The
regression of subordinate follicle started on Day 8.1 ± 1.3.
An ovulation rate of 100 % was recorded with the GnRH treatment
when the maximum size of the dominant follicle measured between 9.2–18.9
mm. Treatment was noticed to shorten the interwave interval from 17.03 ±
0.8 to 11.7 ± 1.7 days. Ovulation occurred within 24–32 h of treatment in
92.3 % of trials and within 32–40 h of treatment in 7.7 % of trials. The
induced CL attained its maximum diameter on day 9.9 ± 0.9. The corpus
luteum lasted for 24.2 ± 1.9 days.
Estradiol increased from basal levels of 27.4 ± 0.4 pg/ml to peak
concentrations of 134.4 ± 47.5 pg/ml as the follicle reached a diameter of
13.2 mm then decreased until the next wave of follicular growth. Peripheral
concentrations of progesterone remained low (less than 0.4 ng/ml)
throughout the follicular wave. Following induction of ovulation,
concentrations of progesterone increased gradually to reach a mean peak
concentrations of 15.9 ± 7.3 ng/ml by day 9 and decreased thereafter until
the complete regression of the CL.
The blood flow of ovulatory follicles detected for the first time when
the diameter was 6.9 ± 0.8 mm (day 4.0 ± 0.5). The vascularized area
increased gradually with the growth of the follicles. At 8 hr before ovulation,
the maximum diameter of the follicle was 15.8 ± 0.7 mm, with BA and
BA% of 0.19 ± 0.04 cm2 and 9.8 ± 2.6 %, respectively. BA and BA%
decreased gradually with regression of the follicles to disappear completely
on day 27 ± 1 when the diameter of the DF was 16.1 ± 0.5 mm. The blood
flow to the oversized follicle wall increased gradually till reached the
maximum value of 0.34 ± 0.05 cm2 when the size of the follicles was 26.7 ±
4.6 mm, but the BA% was decreased till reached 4.1 ± 0.2 %. Then both the
BA and BA% decreased for few days inspite of the follicle continued to
grow.
Blood circulation in the CL was detected in all ovulations starting
from day 1 after ovulation. The blood flow to the CL rose distinctly after
ovulation till reached the maximum when the CL was 13.8 ± 1.01 mm in
diameter (day 5) while the maximum BA noticed when the CL was 18.1 ±
0.4 mm in diameter (day 7). On day 10 both, the BA and BA% decreased to
0.33 ± 0.01 cm2 and 19.8 ± 6.7 %, respectively concomitant with beginning
of regression of the CL, then both, the BA and BA% decreased gradually
before completely disappeared on day 22.
On the scope of the present study we concluded that
1. The follicular wave pattern in dromedaries consists of well defined,
but individually variable, periods of growth, maturity and regression.
2. The dominant follicle is larger than that of subordinate follicle in the
day of emergence (with few exceptions) and deviation.
3. Ovarian follicles best respond to induction of ovulation using GnRH
analogue when their size ranges from 9-19 mm. No ovulation
occurred from follicles larger than 30 mm diameter.
4. There is a close temporal relationship between luteal diameter and
serum progesterone concentration after induced ovulation.
5. Doppler ultrasound could provide new information on the
development of the follicle towards ovulation, allowing visual
observations of the blood flow in a delimited area in the walls of
preovulatory follicles and CL in camels.