Estrus cycle of bitch

Reproductive cycle of bitch

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

2. 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

3. 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.

4. STAGES OF ESTROUS CYCLE Four stages : Proestrus Estrus Diestrus Anestrus

5. Canine Estrous Cycle

6. 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.

7. 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.

8. 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

9. 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 .

10. 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 .

11. -10 -6 -4 -2 0 2 4 8 12 14 Hormonal Patterns During Estrous Cycle of Bitch Arbitrary Plasma Concentrations Days from LH Peak Estrogen LH Progesterone Ovulation Fertile Period Completion of Meiosis I Fertilization

12. Diestrus B itch becomes refractory to breeding D iminishing attraction of male dogs. Vulvar discharge diminishes E dema slowly resolves. The appearance of vaginal mucosal folds becomes flattened and flaccid .

13. Diestrus Estrogen levels are variably low P rogesterone 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.

14. 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

15. 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.