ADSC 2010 Lecture 26Outline of Last Lecture I. UterusA. Uterine HornsB. Uterine BodyC. CervixII. VaginaA. CapacitationIII. VulvaIV. ClitorisV. Reproduction- Ovarian CycleA. Follicles1. Primary2. Secondary3. Tertiary4. GratianB. OvulationC. Corpus LuteumD. Fertile Life of Ova and Sperm1. Ova2. SpermE. FertilizationVI. Reproduction- Embryonic DevelopmentA. Blastocyst1. Inner cell massa. Endodermb. Mesodermc. Ectoderm2. Trophoblast3. Blastocyst CavityVII. Reproduction- ImplantationA. ImplantationB. Implantation TimesVIII. Reproduction- PlacentaA. Placenta1. Chorion2. Allantois3. AmnionB. Placental AttachmentC. Functions of the Placenta1. Respiration2. Nutrition3. Waste Removal4. Protection5. Hormone ProductionIX. Reproduction- PregnancyA. Hormonal Changes During PregnancyOutline of Current Lecture I. Reproduction- Gestation LengthII. Reproduction- ParturitionA. Preparatory StageB. Expulsion of FetusC. Expulsion of PlacentaIII. Factors Influencing Fetal Size1. Genetics2. Age and Size of Dam3. Nutrition4. Litter Size5. Ambient Temperature6. Fetal HormonesCurrent Lecture: I. Reproduction- Gestation Length- Cow: 275 days or 9 months- Ewe/Dow: 147 Days or 5 months- Sow: 114 days or 3months 3 weeks and 3 days- Mare: 336 days or 11 monthsII. Reproduction- ParturitionA. Preparatory Stage- Dilation of cervix – relaxin- Increased uterine contraction – oxytocin- Rupture of chorio-all antois* Cow: 2-6 hours* Sow: 2-4 hours*Mare: 2-3 hoursB. Expulsion of Fetus- Passage of fetus through cervix into vagina- Rupture of fluid sacs- Reflex contractions push fetus through birth canal* Cow and Ewe: .5-1 hours* Sow: 1-4 hours*Mare: 10-20 minutesC. Expulsion of Placenta* Cow and Ewe: 4-5 hours* Sow: 1-4 hours* Mare: .5-3 hoursIII. Factors Influencing Fetal Size1. Genetics- Heritability for birth weight is about .402. Age and Size of Dam- Older/larger dams produce a larger fetus3. Nutrition- Majority of fetal growth occurs in the last trimester (1/3) of pregnancy- Nutrition during this time is important4. Litter Size- Larger litters = smaller fetuses5. Ambient Temperature- High temperatures result in smaller fetuses- Lower temperatures result in larger fetuses6. Fetal Hormones- Insulin and growth
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