The Journal of Research ANGRAU

POSTPARTUM OVARIAN FOLLICULAR DYNAMICS AND ESTRUS ACTIVITY
presence of high FSH receptors (Knopf et al. 1989).
Kulick et al. (2001) opined that the slower average
growth rate of the dominant follicle of the second in
two wave cycle was compensated by taking a longer
period for reaching maximum diameter and ovulation.
The maximum diameter of dominant follicles
of first and second waves in two wave cycles reached
on 5.13 + 0.63 and 18.50 + 0.50 days and in three
wave cycles, 6.45+ 0.88, 12.89+3.06 and 20.44+1.42
days and regression started on 10.80+ 1.10 in first
wave in two wave cycle and 7.12+ 0.74 and 15.15+
2.26 days in first and second waves of three wave
cycle, which were in agreement with the Figueiredo
et al. 1997) and Gaur et al. (2007) in Nellore cows.
Statistical analysis of the data of diameter
of dominant follicle in two wave cycles revealed that
the diameter of the first wave dominant follicle was
significantly (P< 0.01) smaller than the second wave
dominant follicle (ovulatory follicle). The growth rate
of second wave dominant follicle was faster than its
counterpart in the first follicular wave.
The regression of dominant follicles of first
wave in two wave cycle and first and second waves
in three wave cycle occurs between 7-15 days
observed in the present study were similar to the
findings of Figueiredo et al. (1997) and Gaur et al.
(2007) in Nellore cows. The mean regression rate of
first wave in two wave cycle was 1.41+0.20 mm per
day and in three wave cycle 1.20 + 0.33 and 1.48 +
0.33 in first and second waves respectively.
The mean duration of phase of regression
of dominant follicles in first wave of two wave cycles
was recorded as 6.50+ 0.56 days and in three wave
cycles 7.13 + 1.86 and 4.72 + 1.42 days respectively
in first and second waves. The mean period of static
phase was 1.20±0.26 days in first wave of two wave
cycle and 1.80±0.34 and 1.67±0.67 days for first and
second waves of three wave cycles, respectively.
The mean ovulation in natural estrus in postpartum
lactating Ongole cows was recorded as 20.90 ±0.46
and 22.20±0.37 respectively in two wave and three
wave estrous cycles. The mean duration of first and
second wave in two wave estrous cycles in
postpartum lactating Ongole cows were 14.20±0.40
and 9.10±0.45, respectively. Where as in three wave
estrous cycles the duration of first, second and third
waves were 11.20±0.37, 10.60±0.40 and 6.0±0.31
days, respectively. In the present study, in natural
cycle, the corpus luteum grew to a maximum
diameter of 15.93 + 0.37 and 17.8 + 0.37 mm in two
and three wave cycles on the day 13.1+1.50,
14.60+0.56 and remained static up to 14.60+ 1.50
and 15.90+0.45 days of the estrous cycles,
respectively.
The above results were almost comparable
to that observed by Figueiredo et al. (1997) in Nelore
cows 15.56 + 0.44 and 17.69+0.80 mm in two and
three wave cycles, respectively. But Mayra et al.
(1999) and Rhodes et al.(1997) reported higher size
in zebu cows.
The mean period of first exhibition of
postpartum estrus was recorded as 109.50 + 4.56
days. The incidence of estrus was recorded as 32.50
% and 62.50 % during day and night time respectively.
These findings were in corroboration with the report
of Venkat Naidu et al (2010)
It may be concluded that the knowledge
about the follicular dynamics in postpartum lactating
Ongole cows helps in planning and designing of the
synchronization protocols and reducing the service
period, inter calving period etc, for improving
reproductive performance.
ACKNOWLEDGEMENT
The authors express their sincere gratitude
to the SVVU, Tirupati for providing facilities to carry
out the research work at Cattle Project, Live Stock
Research Station, Lam Farm, Guntur.
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Marcatti Anderson George of Assisi-2003.
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