Animal Science 101 Lecture Notes PDF

K.Beltaire – Animal Science 101, UMass Pre-Vet and Animal Science Club What is iCons? The UMass Integrated Concentration in STEM Program...

K.Beltaire – Animal Science 101, UMass Pre-Vet and Animal Science Club What is iCons? The UMass Integrated Concentration in STEM Program (iCons) is a unique certificate program in real-world problem solving open to first and second-year students Wed (10/9) @5:30 pm in Hasbrouck 126 with science-intensive, STEM-adjacent, policy, and business majors where students work on diverse teams while researching student-directed real-world problems. Coveralls decorating night! Admission to iCons is by application only. iCons Application Bring your clean coveralls and creativity. The application deadline is 11:59 pm on Tues, 10/15. https://forms.gle/zg1YFE1gQj8YJMPy7 Paint pens will be provided. More info, please read: https://icons.cns.umass.edu/ Barn Chores Reproductive During Barn Chores, you are welcome to place Anatomy & Physiology Animal Science 101 your bookbags on tables in the Livestock Barn, but please place your shoes on chairs. Katherine A. Beltaire, DVM, DACT Thank you from Alice! [email protected] Animal Science 101 October 8, 2024 Source: PL Senger. Pathways to Pregnancy and Parturition. 2nd ed. Male: Hypothalamic-Pituitary-Gonadal Axis Path of Sperm Reproduction is regulated by inter- play between hormones secreted Testes: Seminiferous Tubules by the Brain and the Testes. Hypothalamus Ducts Hypothalamus: GnRH GnRH = Gonadotropin- releasing hormone Anterior Epididymis Pituitary Gland Anterior Pituitary Gland: Ductus deferens LH = Luteinizing hormone Ductus deferens FSH = Follicle-stimulating Head of Epididymis AG’s Body hormone Efferent ducts Urethra Testes: Leydig Cells = Testosterone Sertoli Cells = Estrogen Tail of Epididymis Students are not permitted to post, publish, or sell these lecture notes in any form to any entity during and after completion of the course. These are violations of both University policies and federal copyright laws. K.Beltaire – Animal Science 101, UMass Accessory Sex Glands Female Reproductive System - Species-variability - Development & maintenance depends on exposure to Testosterone Ovaries Species Ampulla Seminal Prostate Bulbourethral Oviducts Vesicles Glands Stud Dog - - + - Uterine Horns Tom Cat - - + + Uterine Body Boar - + + + Cervix Bull + + + + Vagina Ram + + + + Vulva Stallion + + + + Source: PL Senger. Pathways to Pregnancy and Parturition. 2nd ed. Oviducts versus Human Term = Fallopian tubes Ovaries Oviducts: Infundibulum – Ampulla – Isthmus Function: Ovary Between the ovaries and (1) Produce eggs the uterine horns (Oogenesis) - eggs develop Where fertilization occurs! in follicles (2) Follicles produce hormones: Muscle contractions and - Estrogen cilia guide oocytes (eggs) - Inhibin toward the uterine horns - Progesterone Uterus Cervix Smooth muscle sphincter between body of the Hollow muscular organ uterus and the vagina. Usually Y shaped Species-variability in structure. Normally closed, except during estrus (heat) Location of fetal and parturition (birth). development during pregnancy Source: PL Senger. Pathways to Pregnancy and Parturition. 2nd ed. Students are not permitted to post, publish, or sell these lecture notes in any form to any entity during and after completion of the course. These are violations of both University policies and federal copyright laws. K.Beltaire – Animal Science 101, UMass Vagina: Ovaries Muscular tube extends back from the Function: cervix and connects with the vulva (1) Produce eggs (Oogenesis) Vulva: (2) Ovarian follicles Composed of the vestibule, clitoris, and labia produce hormones – Urethra opens on the floor of the vestibule - Estrogen - Progesterone - Inhibin 4) Birth - Female has fixed Oogenesis number of 1°Oocytes (2N) that are have 1) Begins during fetal arrested in Prophase 1 development of Meiosis. 2) In fetal ovaries, Oogenesis primordial germ cells (oogonia, 2N) Oocyte development divide/multiply by occurs in ovarian Mitosis = stock the follicles. ovary. Oogenesis – stocks 3) Oogonium begins ovary, then what…. Meiosis but arrests until Puberty= 1°Oocyte (2N) 5) Puberty hits! Female: Hypothalamic-Pituitary-Gonadal Axis Oogenesis Reproductive (estrous) cycling is regulated by the interplay of 5) Puberty hits! Hypothalamus hormones secreted by the Brain (Hypothalamus & Pituitary Gland) GnRH 1° Oocytes complete and the Ovaries. Anterior Meiosis I to form a large GnRH = Gonadotropin- Pituitary Gland 2° oocyte and a small releasing hormone "polar body.“ LH = Luteinizing hormone FSH = Follicle-stimulating hormone 2° Oocyte arrests in Ovaries = Estrogen, Inhibin, Progesterone Metaphase II of Meiosis II until fertilization. Students are not permitted to post, publish, or sell these lecture notes in any form to any entity during and after completion of the course. These are violations of both University policies and federal copyright laws. K.Beltaire – Animal Science 101, UMass Hypothalamus Gonadotropin Releasing Hormone (GnRH) Anterior Pituitary Follicle Stimulating Hormone (FSH) OVARY A group of 1° oocytes in Follicles resume Meiosis Oocyte development inside a follicle is directed by hormone signals from the brain. In response to hormones from the brain, follicles produce two hormones: (1) Estrogen & (2) Inhibin Hypothalamus Ovulation GnRH Hormone surge (Luteinizing Hormone, Anterior Pituitary LH) results in rupture of the mature follicle LH to release the ovum. FSH Ovum is caught by the infundibulum of the OVARY oviduct. Inhibin A group of Estrogen Oocytes in Follicles Ovulation Empty follicle fills with blood (Corpus resume Meiosis Hemorrhagicum, CH). Corpus Luteum After ovulation, the collapsed follicle initially fills with blood and becomes a corpus hemorrhagicum. CH. After divisions of cells that line the CH, it Corpus Hemorrhagicum, CH. becomes a Corpus Luteum Luteum, CL.CL After multiplication cells that line the CH, the CH CL = Produces Progesterone. becomes a Corpus Luteum Luteum, CL. CL - for maintenance of pregnancy, if preg CL = Produces Progesterone. CL has a “fixed” lifespan unless the ovum is - for maintenance of pregnancy or diestrus fertilized and the resulting embryo implants in CL has a “fixed” lifespan unless the ovum is the uterus. fertilized and the resulting embryo implants in the uterus. Students are not permitted to post, publish, or sell these lecture notes in any form to any entity during and after completion of the course. These are violations of both University policies and federal copyright laws. K.Beltaire – Animal Science 101, UMass Hypothalamus Ovulation GnRH Anterior Pituitary Spontaneous ovulators: Ovulation occurs spontaneously in most species FSH LH as a result of rising levels of Luteinizing Hormone (LH). OVARY Inhibin A group ofCH to a Estrogen Corpus Oocytes in Follicles Ovulation Progesterone Induced ovulators: Luteum resume Meiosis Breeding/mating must occur to stimulate ovulation – Cat, Rabbit, Ferret, and Camelids (llamas and alpacas) Pregnancy Pregnancy Fertilized oocyte = zygote/embryo Correct timing of ovulation & breeding! Embryo moves down the oviduct and eventually enters the uterus (day of entry is species-dependent). No Pregnancy Estrous Cycle STAGES If fertilization has not occurred within roughly – Proestrus 12 hours of ovulation, the oocyte begins to – Estrus degenerate in the oviduct. CL has a “fixed” lifespan and will need to be – Metestrus (in some species) destroyed so that a new estrous cycle can begin. – Diestrus – Anestrus (in some species) Students are not permitted to post, publish, or sell these lecture notes in any form to any entity during and after completion of the course. These are violations of both University policies and federal copyright laws. K.Beltaire – Animal Science 101, UMass Estrous Cycles Proestrus Species Proestrus Estrus Metestrus Diestus Anestrus Follicles begin developing and growing Dog 9 days 9 days 60 days 3-5 months Output of Estrogen increases accordingly Pig 4 days 2-4 days 14 days Horse 7 days 14 days Short days (Fall-Winter) Sheep 1-1.5 days 14 days Long days (Spring- Summer) Cow 2 days 6-24 hours 2-4 days 14 days Estrus +/- Metestrus Not all species have a Metestrus Female is sexually receptive = heat Period during which the corpus luteum (CL) develops Estrogen (E2) production peaks (for most species) Progesterone (P4) produced by the CL temporarily +/- Ovulation (species-dependent) inhibits ovulation Lining of the uterus prepared for implantation of a fertilized ovum Diestrus “Luteal Phase” Diestrus
If no pregnancy occurs, the UTERUS releases
Corpus luteum at maximum size and exerting Prostaglandin F2a (PGF2a), (PGF2a) which causes the CL to maximum effect (Progesterone, P4) degenerate (i.e. luteolysis) at the end of diestrus.
If fertilized ovum implants in the uterus, CL is
Depending on the species, the female will either cycle retained well into the pregnancy back around into Proestrus or her ovaries will shut down and she
If pregnancy does not will go into Anestrus. occur, CL degenerates at the end of diestrus (i.e. luteolysis). Students are not permitted to post, publish, or sell these lecture notes in any form to any entity during and after completion of the course. These are violations of both University policies and federal copyright laws. K.Beltaire – Animal Science 101, UMass Not all species have Estrous Cycles +/- Anestrus an Anestrus Species Proestrus Estrus Metestrus Diestus Anestrus Dog 9 days 9 days 60 days 3-5 months Period of temporary ovarian inactivity Seen in seasonally polyestrus, diestrous, Pig 4 days 2-4 days 14 days and monoestrous animals Ovaries temporarily shut down Horse 7 days 14 days Short days (Fall-Winter) Sheep 1-1.5 days 14 days Long days (Spring- Summer) Cow 2 days 6-24 hours 2-4 days 14 days Students are not permitted to post, publish, or sell these lecture notes in any form to any entity during and after completion of the course. These are violations of both University policies and federal copyright laws.