Reproductive cycle of bitch

2. Reproductive Cycle Of Bitch
Dr. Muhammad Awais
Department of Theriogenology

3. Estrous Cycle
 Cyclic or recurrent set of physiological and behavioral
changes that takes place from onset of one estrus period
until onset of the next estrus is called estrus cycle.
 Interval from cycle to cycle varies among breeds
and can be affected by environmental causes
 Range: 4 to 13 Months
 Average: 7 Months

4.  The onset of the first estrous
cycle (puberty) of an
individual bitch is expected
between 6 and 10 month of
age but may not begin until
she has reached 2 years of
age.

5. STAGES OF ESTROUS CYCLE
 Four stages:
1. Proestrus
2. Estrus
3. Diestrus
4. Anestrus

6. Canine Estrous Cycle

7. Proestrus
 Proestrus lasts from 9 days average.
 Estrogen rises from basal anestrous levels (2-10 pg/mL) to
peak levels (50-100 pg/mL) at late proestrus.
 Progesterone remains at basal levels (<1ng/mL)
 FSH and LH levels are low during most of proestrus, rising
during the preovulatory surge.

8. Proestrus
 During proestrus, the bitch becomes attractive
to male dogs but is still not receptive to
breeding.
 Vulvar discharge of uterine origin is present,
and the vulva is mildly enlarged.
 The vaginal mucosal folds appear edematous,
pink, and round.

9. Changes During Estrus of Bitch
-8 -4 0 +4 +8 +12
Proestrus Estrus
Aggressive
towards Male
Passive Provides sexual posturing
to male for copulation
Bloody discharge
from vulva Copulation
Vulva Swollen and Enlarged
Indicates Day of
Peak in LH

10. Estrus
 Accept male for matting
 Estrus lasts 3 days to 3 weeks, with an average of 9 days.
 Estrous behavior precede or follow the LH peak
 Primary oocytes ovulate 2 days after the LH peak, and
oocyte maturation is seen 2-3 days later.
 the life span of secondary oocytes is 2-3 days.

11.  Ovulation:
Ova are released from the follicles approximately two to
three days following initiation of LH surge.
 Fertilization:
 Ovulated ova are not ready for fertilization (must complete
Meiosis I) and therefore are not fertilized until Day 4 to 7
following the LH surge.

12. -10 -6 -4 -2 0 2 4 8 12 14
Hormonal Patterns During Estrous Cycle
of Bitch
ArbitraryPlasmaConcentrations
Days from LH Peak
Estrogen
LH
Progesterone
Ovulation
Fertile Period
Completion
of Meiosis I
Fertilization

13. Diestrus
 Bitch becomes refractory to breeding
 Diminishing attraction of male dogs.
 Vulvar discharge diminishes
 Edema slowly resolves.
 The appearance of vaginal mucosal folds becomes
flattened and flaccid.

14. Diestrus
 Estrogen levels are variably low
 Progesterone levels steadily rise to a peak of
15-80 ng/mL before progressively declining in
late diestrus.
 Diestrus usually lasts 2 month in the absence of
pregnancy.

16. Anestrus
 Period when female does not experience cycles
 Mean levels of FSH are moderately elevated, and those of LH
slightly elevated during anestrus.
 Basal LH is low (<1–2 ng/ml) between sporadic, variable-
height and often-large pulses (3–30 ng/ml) at intervals of
7–18 h or longer

17. Anestrous
 At late anestrus, the pulsatile release of LH
increases, causing the proestrous folliculogenesis.
 Estrogen levels are basal(2-10 pg/mL)
 Progesterone levels (<1 ng/mL) at late anestrus.