Podcast
Questions and Answers
What is the typical copulation duration for a stallion?
What is the typical copulation duration for a stallion?
Which breeding method is recommended for heifers that have reached full growth?
Which breeding method is recommended for heifers that have reached full growth?
What common risk is associated with copulation in younger heifers?
What common risk is associated with copulation in younger heifers?
During which phase does meiosis I begin in ovogenesis?
During which phase does meiosis I begin in ovogenesis?
Signup and view all the answers
What is metrorrhagia in the context of coitus?
What is metrorrhagia in the context of coitus?
Signup and view all the answers
What occurs to the secondary oocyte if fertilization takes place?
What occurs to the secondary oocyte if fertilization takes place?
Signup and view all the answers
What is the role of the zona pellucida surrounding the oocyte?
What is the role of the zona pellucida surrounding the oocyte?
Signup and view all the answers
What is the primary role of Growth Differentiation Factor 9 (GDF9) in folliculogenesis?
What is the primary role of Growth Differentiation Factor 9 (GDF9) in folliculogenesis?
Signup and view all the answers
Which structure is the final product after the ovulation of a mature Graafian follicle?
Which structure is the final product after the ovulation of a mature Graafian follicle?
Signup and view all the answers
What effect does increasing estrogen levels have during estrus?
What effect does increasing estrogen levels have during estrus?
Signup and view all the answers
Study Notes
Coitus
- Coitus involves the insertion of the erect penis into the vagina, followed by ejaculation.
- The location of semen deposition varies depending on the animal: cattle, buffalo, mare, sow, and ram each have distinct areas.
- The ram's urethral process forces semen distribution, ensuring its effectiveness despite low volume.
Duration of Coitus
- Cattle and sheep have brief copulation lasting only a few seconds.
- Stallion copulation lasts 15-30 seconds.
- Dogs have a copulatory tie that can last 15-30 minutes.
- Swine exhibit a copulatory tie for an average of 3-8 minutes.
- Failure to ejaculate is common in swine.
Dangers of Coitus
- Young heifers can experience uterine injuries with overly large bulls.
- Lacerations and trauma can lead to post-coital swelling, bleeding, and straining.
- Artificial insemination is preferred for heifers' growth, while natural breeding is recommended for mature heifers.
- The first insemination should be natural to allow for size compatibility between the bull and heifer.
- Foreign breed pairings can lead to dystocia and oversized embryos.
- Artificial insemination is advised for situations where natural breeding poses risks.
Metrorrhagia
- Metrorrhagia is bleeding after coitus.
- While sometimes normal, it can indicate underlying issues.
Ovulation
- The maturation of an oocyte is known as ovogenesis.
- Meiosis I begins during fetal development, while meiosis I is completed after puberty, producing a secondary oocyte and the first polar body.
- The secondary oocyte then begins meiosis II.
- If fertilization occurs, meiosis II is completed, resulting in an ovum and a second polar body.
- Without fertilization, meiosis II doesn't complete.
Folliculogenesis
- The process starts with a primordial follicle and progresses through stages: primary, secondary, mature Graafian follicle, corpus luteum, and corpus albicans.
- The mature Graafian follicle houses the secondary oocyte and the first polar body.
Cumulus Oocyte Complex
- The cumulus oocyte complex comprises the oocyte, follicular fluid, zona pellucida, and corona radiata cells.
- These cells play a vital nutritive and protective role.
Zona Pellucida (ZP)
- The zona pellucida is a tough, acellular glycoprotein layer surrounding the oocyte and produced by the oocyte itself.
- It acts as a barrier to sperm penetration and has species-specific receptors to prevent fertilization by sperm of other species.
Corona Radiata
- The corona radiata is the outermost layer of cells around the oocyte.
- It's composed of cumulus oophorus cells.
Regulation of Follicular Growth
- Growth differentiation factor 9 (GDF9) is a protein produced by the theca cells, acting as a paracrine factor to stimulate granulosa cells.
- Growth differentiation factor 9B (GDF9B) is produced by both granulosa and theca cells, acting as an autocrine inhibitor for follicular growth.
- Activin is a hormone produced by granulosa cells, acting as a paracrine factor to enhance the growth and maturation of the dominant follicle.
Mechanism of Ovulation
- Estrogen levels rise during estrus, triggering LH release.
- The pre-ovulatory LH surge causes the expansion of the cumulus cell layer, separating the oocyte from the follicular wall.
- This surge also increases blood supply to the ovary and follicle, leading to vascular permeability.
- Plasminogen and prostaglandins enter the follicle through the increased permeability.
- Plasminogen activation converts plasminogen into plasmin, which degrades collagen and weakens the follicular wall.
- Prostaglandin E and F synthesis and release further contribute to muscle contraction and expulsion of the oocyte.
Fimbria
- Fimbria are finger-like projections on the fallopian tube's infundibulum.
- They move and contract for guiding the oocyte into the fallopian tube.
- Estrogen increases their activity.
Time of Ovulation
- Various animal species have different ovulation timings: cows (10-12 hours after estrus), mares (2 days before the end of heat), ewes (6-12 days before the end of heat), goats (4-6 hours before the end of heat), sows (24-48 hours after estrus), cats (induced 24 hours after coitus), and camels (induced 24-36 hours after coitus).
Fertilization
- Fertilization involves the union of a mature sperm and ovum to form a zygote.
Factors Facilitating Fertilization
- Sperm maturation in the epididymis, sperm capacitation, and the acrosomal reaction are essential.
- Sperm transport to the egg is a complex process influenced by fallopian tube length, location, and sperm motility.
- Ovum transport relies on fimbriae, follicular fluid, cilia, and muscle contractions.
Mechanisms of Sperm Transport
- Fertilization occurs at the ampullary-isthmic junction.
- Ejaculation in the dorsal fornix of the vagina, estual mucus for sperm movement through the cervix, and selection of sperm in the uterus are crucial steps.
- Oxytocin and prostaglandin in semen contribute to contractions for sperm transport.
- Sperm await the ovum at the ampullary-isthmic junction.
- Abnormal sperm are either phagocytized or lost via the cervix.
Cervical Mucus
- It protects, nourishes, and has antimicrobial properties.
Sperm Attachment to Fallopian Tube
- Temporary attachment to the fallopian tube epithelium for protection and capacitation.
Barriers to Sperm
- The cervix is a challenging barrier, due to mucus and the annular ring.
- The cortical reaction hardens the zona pellucida, preventing further sperm entry.
Syngamy
- Fusion of male and female pronuclei to form a zygote.
Abnormal Fertilization
- Polyspermy (multiple sperm penetration) leads to a triploid zygote, typically ending in death.
- Polygyny (maturation of the egg without the second polar body expulsion) also results in a triploid zygote.
- Gynogenesis (non-development of the male pronucleus) leads to a haploid embryo that dies.
- Androgenesis (non-development of the female pronucleus) results in a haploid embryo that doesn't develop.
- Ovum wandering can occur internally or externally, and is common in bitches.
- Superfecundation involves impregnation by two different males.
- Superfetation is the gestation of fetuses from separate ovulations, a rarer phenomenon.
Twins
- Identical twins (monozygotic) form when a single zygote splits into two, sharing the same sex and DNA.
- Fraternal twins (dizygotic) result from fertilization of two eggs by two sperm, sharing half of their DNA like regular siblings.
- Twin incidence rises with maternal age.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
This quiz covers the mechanics and duration of coitus in various animals, along with potential dangers associated with natural breeding. Learn about species-specific copulation times, injury risks, and the role of artificial insemination in reproductive health.
