5Bulbis glandis (dog only) Bulbis glandis (dog only)Responsible for the tie or coital lockPenile spines (tom only)Responsible for inducing ovulationDependent on testosterone productionFind penile spines picture
7Dog reproduction Estrus length 7-13 days Ovulation type Spontaneous Breeding days fromstart of estrusGestation daysLitter sizeLitters / year 2Weaning weeks
8Reproduction Estrus every 6-8 months Estrus lasts 21-22 days Ovulation about 10th dayPseudopregnancy common
9Canine Estrous Cycle Stage Duration in days External signs Proestrus 4-14(9 days)Enlarged Vulva w/ bloody discharge, restlessness, no courtship w/ maleEstrus4-21(10 days)Clear to pink vulva discharge, female turns hindquarters towards him, raises pelvic region, waves tail, male acceptance and courtshipDiestrus60Vulva shrinks, no discharge, non-acceptance of male, terminates with parturationAnestrus100 +Inactive ovaries, no vulva discharge, low steroids
10Ovarian Cycle is Divided into Four Stages A. Pro-estrusPhysical turgid swelling of vulva and appearance of a bloody discharge.Vaginal cytology will change with very early non-cornified epithelialcells increasing towards end of proestrus. Behavior - bitch is restlessand secretes pheromones but is aggressively negative towards malebecoming more passive towards start of estrusB. EstrusVulva swelling will soften and discharge will be slightly pink to straw-colored. Some females will still have a bloody discharge in estruswhich is normal. Vaginal cytology will have a high concentration ofcornified epithelial cells with little debris. Behavior - bitch seeks maleturns hindquarters towards him, raises pelvic region, waves tail to oneside and finally stands for mating by male.
11C. Metestrus D. Anestrus Pseudopregnancy Loss of vulva swelling and no discharge. Vaginal cytology is nocornified cells and high numbers of White Blood Cells. Behavior -non-acceptance of maleD. AnestrusPeriod of ovarian inactivity and no vaginal dischargeWill not return to heat again until at least 4 monthsPseudopregnancyExtension of metestrus period in which progesterone concentrationsremain elevated. Female will have nest building behavior and enlargedmammary glands.
14Provides sexual posturing Changes During Estrus of BitchVulva Swollen and EnlargedBloody dischargefrom vulvaCopulationAggressivetowards MalePassiveProvides sexual posturingto male for copulationProestrus EstrusIndicates Day ofPeak in LH
16Ovulation: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.
17LH PeakThe greatest number of ovulations occur 24 to 72 hours after the LH peak.Breeding can be timed from the LH Peak to the fertile period 4 to 7 days later.Plasma Progesterone (P4)Plasma P4 concentrations rise prior to ovulation- follicles will start luteinization before ovulationMeasurement of serum P4 can be used as a means to determine day of ovulation and breeding- can be highly variable
18Hormonal Patterns During Estrous Cycle of BitchFertile PeriodOvulationFertilizationEstrogenCompletionof Meiosis IArbitrary Plasma ConcentrationsProgesteroneLHDays from LH Peak
19Control of Estrus in the Bitch A. AndrogensMiboleroneMode of Action:Administration:B. ProgestinsOvaban(UpJohn) - MethytestosteroneNegative feedback on FSH and LHInitiate 30 days prior to expected onsetProestrus(Schering) - Megestrol Acetate- Negative feedback on FSH and LHDepends upon stage of estrous cycle.Lower dosage needed if given 7 days prior to proestrus.A much larger dosage is needed to block ovulation if givenduring proestrus.
20Induction of EstrusGnRH Administration:Estrus induction can be used to treat bitches that failto cycle or have silent heats. Response of fertile estrus ishighly variable.Anestrus is the result of low FSH and LH. GnRH can beused to successfully induce estrus in the bitch. However,it requires frequent (every 90 min) administration over10 to 11 days. Specialized infusion pumps (mini-pumps)can be utilized to deliver the pulses of GnRHGnRH analogs can be used to induce fertile estrus in thebitch without giving frequent injections.
22Intromission by vigorous thrusting of the hindquarters. BreedingIntromission by vigorous thrusting of the hindquarters.Swelling of bulbus glandis swells (6X4 cm) in the vaginaVulva sphincter muscles contract around the penis formingthe copulatory “tie”.First Stage of CoitusThe “Turn”Second Stage of Coitus
23Hormone Concentrations During Pregnancy and Parturition MatingProlactinProgesteroneCorticosteroidsArbitrary Plasma ConcentrationsTotal EstrogensDays of Pregnancy
25Signs of Impending Parturition Behavior of bitch is one of nest building, restlessness andseeking quiet, out of sight areas. Vulva becomes swollen,edematous and may have some vaginal discharge.Relaxation of pelvic and abdominal muscles is a consistentsign of impending parturition. Presence of milk in mammarygland is not an accurate sign.Decrease in body temperature from 38 to 37oC just beforeparturition.
26Parturition First Stage of Labor Averages 4 hours but can last 6-12 hoursPeriod in which the cervix dilatesBitch will be uneasy, refuse food, pant, vomiting andfrequently looking at flank.Second State of LaborVisible straining of bitch in the sitting positionPlacental membrane will break and there will be fluid discharge from vulva.Membrane will rupture spontaneously or through licking of dam.After the start of labor first fetus cannot be expected to survive more than 6 hours in the uterus.Fetuses should be delivered within 2 hours of each other.Usually interval between puppies is about 30 minutes.
27Third Stage of LaborPassage of fetal membranes should take 5 to 15 minutes.DystociaDefinition: Any problem with delaying normal birth of fetus.SymptomsAbnormal fetal presentation, position or postureStrong and persistent labor for 20 minutes withoutdelivery of fetus.Weak and infrequent contractions for 2 to 3 hoursMore than 4 hours from delivery of last fetus (if not last one)Most common problem is uterine inertia (weak contractions),size of fetus and birth canal.
29Contraception in Bitch Surgical:Physical: Intravaginal DeviceSilastic and polyethylene tubing placedin vestibule and vagine. 50% of bitchescan still tie and get pregnant.Adding copper ring increases effectivenessHormonal:Progestogens : Medroxyprogesterone - MAPMegesterol Acetate – MGAAndrogens : Implants – MiboleroneImmunological : Immunize against LHAnti-ZP3 - anti-zona vaccineOvariectomyHysterectomyTubal Ligation
30Contraception in Male Surgical : Chemical Agents : Immunization : Castration - Correct behavior such as wanderingfighting, and urine markingVasectomy - Tie Vas DeferensChorhexidine - injected into epididymisImmunize against LH