LEC 1_241008_STG411 (3) PDF

Faculty of Veterinary Medicine Level 4: Theriogenology (STG 411) LEC 1: Female Reproductive Physiology Dr. AHMED HASSANEEN Date: 07/10/2024 1  Estimated world livestock numbers From 1990...

Faculty of Veterinary Medicine Level 4: Theriogenology (STG 411) LEC 1: Female Reproductive Physiology Dr. AHMED HASSANEEN Date: 07/10/2024 1  Estimated world livestock numbers From 1990 to and human population 10 2024 Number in billion 8 How much increase 62.9 % ▪ Cattle: 30 % 6 from 1990 to 2012 ? ▪ Sheep goats: 29% 1990 2000 ▪ Pigs: 21% 4 20.6 % 2012 2 16.5 % 13.8 % 0 ▪ Human population: 86% Cattle Sheep Pigs Human Goats Food and Agriculture Organization of the United Nation (FAO), http://www.fao.org/ag/againfo/themes/en/meat/backgr_sources.html 2  Cow fertility 80 70 Decreasing Cow fertility (%) 60 France Spain 50 Ireland 40 Canada 30 United Kingdom 20 Sweden 10 Japan (Beef) 0 New York, USA Heriberto R. Martinez et al. Trends of fertility decrease, (2013), Lucy MC. Reproductive Loss in High-Producing Dairy Year cattle. J Dairy Sci. 2001; 84: 1277-1293, Data : Livestock Improvement Association of Japan.inc. 3 Consumption and production of beef cows in Egypt (2011 – 2015) Number in thousand The Cattle Site (2016) USDA GAIN: Egypt livestock and products annual 2015. Retrieved from http://www.thecattlesite.com/r eports/ ?id=4350 Year 4 Consumption and production of beef cows in Egypt (2016 – 2023) The Cattle Site (2024) USDA GAIN: Egypt livestock and products annual 2023. Retrieved from http://www.thecattlesite.com 5  Functional anatomy Brain Hypothalamus Pituitary gland Ovary Ovary 6 Reproduction is regulated by two main systems: A. Nervous system: Central nervous sys. Cow brain B. Endocrine System 1- Hypothalamus: - Small part at the bottom of the brain Anterior - Located around 3rd ventricle and in-between pituitary the optic chiasma and mammillary body Preovulatory LH Pulsatile surge release gonadotropin release - Produce gonadotropin releasing hormone GnRH with two mode of Ovary release tonic and surge 7 2- Pituitary gland: - Consists of 3 parts; anterior, intermediate and posterior - Located in a bony depression under the base of the brain Anterior part (adenohypophysis) - Produce FSH, LH, TSH, GH, PRL, ACTH Posterior part (neurohypophysis) - Release some neuroendocrine hormones such as oxytocin 8 Neural & neuroendocrine reflex (Senger, 2003) 9 3- Pineal gland: - Located as a neuro-epithelial evagination from the roof of the 3rd ventricle - Act as a neuroendocrine transducer that receive neuronal Stimuli concerning the changes of photoperiod - Produce a monoamine hormone called melatonin - Melatonin secretion controlled by period of lightening 1- Dark-light cycle 2- Seasonal cycle (short and long day) 10  Ovary 4- Gonads “ovaries”: - Production of ova - Secretion of sex steroid hormone “estrogen, progesterone” - Secretion of inhibin and activin - Secretion of oxytocin. 11  Reproductive hormones Biochemical classification: 1- Proteins Peptides “gonadotropin and oxytocin” Glycoproteins “FSH and LH” 2- Lipids From cholesterol as Steroids hormones “progesterone and estrogen” From Arachidonic acid “Prostaglandins” 3- Monoamine “melatonin” 12  Reproductive hormones Classification according to mode of action: 1- Neural communication Through synapses such as neurotransmitter 2- Endocrine Through blood 3- Paracrine Affecting neighboring cells 4- Autocrine Affecting the same cell 13  A- Hypothalamic Hormones: 1- Gonadotropin releasing hormone “GnRH” 1. It is a decapeptide secreted from preoptic area, suprachiasmatic nucleus, and median eminence 2. Has two mode of release 1. Tonic mode “stimulate tonic LH and FSH” 2. Surge mode “stimulate surge LH” 3. Clinical application: 1. Synchronization 2. Inactive ovaries 3. Delayed ovulation 4. Cystic ovaries 14  A- Hypothalamic Hormones: 2- Gonadotropin inhibiting hormone “GnIH” 1. It is a peptide hormone known as RF-amid related peptide 2. Originally known in birds and recently identified in mammals including ruminants 3. It inhibit the release of LH and FSH 15  A- Hypothalamic Hormones: 3- Prolactin inhibiting factor PIF 1. It is secreted from the arcuate nucleus in the hypothalamus 2. It is a peptide hormone like dopamine and catecholamine 3. It regulate the secretion of prolactin 4- Prolactin releasing factor “PRF” 1. It is a peptide hormone 2. It stimulate the release of prolactin 16  B- Anterior pituitary Hormones: 1- Follicle stimulating hormone “FSH” 1. It is a glycoprotein hormone 2. It stimulate the growth and maturation of ovarian follicles 3. It act with LH to stimulate estrogen release from the follicles 4. Clinically used in superovulation 5. Commercially available from pituitary extract and equine chorionic gonadotropin hormone 17  B- Anterior pituitary Hormones: 2- Luteinizing hormone “LH” 1. It is a glycoprotein hormone released in 2 modes 2. It stimulate theca cells growth and function in the ovarian follicles 3. It act with FSH to stimulate estrogen release from the follicles 4. Clinically used in treatment of cystic ovaries and delayed ovulation 5. Commercially available from pituitary extract and human chorionic gonadotropin hormone 18 Two cells two gonadotropin secretions of estradiol 19  B- Anterior pituitary Hormones: 3- Prolactin hormone “PRL” 1. It is a polypeptide hormone. 2. It stimulate the milk secretion 3. It has a luetotrophic function 20  C- Posterior pituitary Hormones: 1- Oxytocin hormone 1. It is a polypeptide hormone 9 amino acids. 2. It is secreted from hypothalamus and released from posterior pituitary. It is also secreted from regressing corpus luteum in the ovary. 3. It stimulate contractions of myoepithelial cells, Myometrium “during estrus and labor” 4. Clinically used in treatment of uterine inertia 21  C- Pineal glands Hormones: 1- Melatonin hormone 1. It is a monoamine hormone. 2. It is secreted and released from pineal gland. 3. Its secretion greatly increased during darkness and inhibit gonadotropic activity in mare 4. It stimulate the onset of breeding season in short day breeder 22  D- Gonadal Hormones: 1- Estrogen hormone (E2) 1. It is a steroid hormone. 2. It is secreted from the follicles. 3. Animal estrogen includes estradiol, estrone, and estriol and plant estrogen found in legumes as clover and alfa alfa 4. It stimulate the sexual behavior, secondary sex character, development of uterine glands, duct sys of the udder, uterine contractions 5. Clinically used in uterine inertia 23  D- Gonadal Hormones: 2- Progesterone hormone (P4) 1. It is a steroid hormone. 2. It is secreted from the corpus luteum. 3. It stimulate the maternal behavior, maintain of pregnancy, alveolar part of the udder, inhibit uterine contractions 4. Clinically used in estrus synchronization 24  D- Gonadal Hormones: 3- Relaxin hormone 1. It is a polypeptide hormone. 2. It is secreted from the corpus luteum uterus and placenta during late pregnancy. 3. It stimulate the dilatation of cervix and separation of pelvic symphysis before labor. 25  D- Gonadal Hormones: 4- Inhibin hormone 1. It is a glycoprotein hormone. 2. It is secreted from the granulosa cells of the follicles. 3. It selectively inhibit FSH release. 5- Activin hormone 1. It is a glycoprotein hormone. 2. It is secreted from the granulosa cells of the follicles. 3. It stimulate FSH release. 26  E- Uterine Hormones: 1- Prostaglandin hormone (PGF2α) 1. It is derived from arachidonic acid “unsaturated fatty acid”. 2. It is secreted from the endometrium. 3. It stimulate uterine contractions, has a natural luteolytic function. 4. Clinically used in estrus synchronization and destruction of corpus luteum 27  F- Placental Hormones: 1- Equine chorionic gonadotropin hormone “eCG” or “PMSG” 1. It is glycoprotein secreted from the endometrial cups from day 40 - 85. 2. It is circulated in blood and not excreted in urine. 3. It has FSH and LH biological activity with more FSH like function 4. Clinically used in superovulation 28  F- Placental Hormones: 2- Human chorionic gonadotropin hormone. 1. It is glycoprotein secreted from the trophoblast cells and reach beak from day 50 - 70. 2. It is circulated in blood and excreted in urine. 3. It has LH like activity 4. Clinically used in delayed ovulation, cystic ovaries 29  F- Placental Hormones: 3- Placental lactogen hormone (human chorionic somatropin “hCS”). 1. It is a protein secreted from the trophoblast cells. 2. It is circulated in blood until the last trimester. 3. It regulate the metabolism of protein and carbohydrate to fetus 4- Protein B. 1. It is a pregnancy specific protein 2. It prevent the regression of CL in early pregnancy 30  Biochemical Hormone Source Action in female Effect on ovary classification Decapeptide Hypothalamus Release FSH and LH Follicular development; GnRH ovulation Glycoprotein Pituitary Stimulates ovulation and Formation of CL LH P4 secretion Glycoprotein Pituitary Follicular development, E2 Development of follicles FSH synthesis Progesterone Steroid CL, placenta Maintenance of pregnancy Inhibits GnRH release Steroid Follicle, Sexual behavior, uterine Estradiol placenta contraction, vasodilatation hCG Glycoprotein Chorion ovarian P4 synthesis eCG Glycoprotein Chorion Formation of accessory CL’s PGF2a Prostaglandin Endometrium Destruction of CL (Luteolysis) Glycoprotein Granulosa Inhibits FSH secretion and inhibit follicle development Inhibin cells 31  A. Reproductive cycles: Each reproductive cycle is related to various phenomena: 1. Puberty and sexual maturity 2. Breeding season (seasonal breeders) 3. Estrous cycle ❑ Estrus detection 4. Physiological anoestrus 32 B. Reproductive processes: 1. Follicular growth (folliculogensis) 2. Follicular dynamics (F. waves) 3. Oocyte maturation 4. Ovulation 5. Luteolysis 6. Fertilization 7. Maternal recognition of pregnancy 33  1. Puberty and sexual maturity The age at which the animal is capable of sexual production, in female, it means the age at which the female shows the signs of heat and sexual receptivity Sexual maturity is the time at which the female has a full reproductive capacity for pregnancy and parturition. The animal showed be used in breeding after the sexual maturity 34 1.Species Factors affecting time of puberty: Diff acc to the species (see table) 2.Breeds Small breeds “Jersey” earlier than heavy “Friesian” Dairy earlier “11-12 ms” than Beef breeds “14-15 ms” 3.Body weight Increase body weight hasten the puberty Cow 340 kg, ewe 30 kg, doe 25 kg, queen 2.5 kg 4.Environmental factors Such as photoperiod in seasonal breeder Ewe born in Jan reach puberty 8 months old while ewe born in April reach puberty 5-6 months old 35 36  Endocrine mechanism of puberty: 1.Activation and maturation of GnRH neurons 2.Increase sensitivity of the ovarian receptors to gonadotropin 3.Decrease sensitivity of Hypothalamus and GnRH neurons to negative feed back of ovarian estradiol During pre-pubertal period the hypothalamus is highly sensitive to estradiol leads to low GnRH and subsequently low FSH and LH. 37  2. Breeding season “seasonal breeder” Cows has no seasonality Sheep, goats, horse, camel shows seasonality The photoperiod affect breeding by: 1. Direct action on Hypothalamo-pituitary axis through melatonin 2. Change sensitivity of CNS “hypothalamus” to negative feed back of steroids 38  2. Breeding season “seasonal breeder” Goats: in Egypt polyestrous with high incidence during December Ewe: seasonal shortday breeder in winter and autumn/fall Mare: polyestrous with high tendency as long day breeder from February to August and highest fertility from mid April to July She-camel: polyestrous with high tendency in winter and 39 spring 40  Estrus: It is period of sexual receptivity Lasts for one days. It is characterized by high threshold levels of estrogen that stimulate more FSH, LH, ------ increase inhibin ------------ selective inhibition of FSH ----------- Surge LH ----------- Ovulation Characterized by presence of dominant mature Graafian follicles with absence of CL. 41  4. Physiological anestrus: Condition when the female does not exhibit estrus Anestrus may caused by 1. Gestational anestrus because of high P4 levels 2. Seasonal anestrus 3. Lactational anestrus: suckling stimulate maternal center and inhibit GnRH 42