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Reproduction and Breeding (Hormonal control of male RS (LH - Action…
Reproduction and Breeding
Function of males sex organ & hormones
Major organs & function
Ducts : store & carry sperm & seminal to penis
Penis : deposit sperm into vagina
Accessory organs : produces fluids which carries sperm to penis
Testis : produces sperm (spermatogenesis) & sex hormones (streoidogenesis)
Adaptation of Reproductive system
Fish
Bisexual
Hemaphroditism- synchronous (left gonad-ovary, right gonad- testis./ vice versa), asynchronous (start w 1 sex, then switch to aonther )
Unisexual- dev of young w/o fertilization. female only produce female offspring.
Freshwater fish- demersal egg, long inc period, small no of egg spawn.
Marine fish- buoyant/pelagic egg, short inc period, large no of eggs
Marine animals
Short life cycle
Rapid turnover of generation
Reduce larval form
unusually large, unprotected surface, direct insemination, protective dormant stage
Freshwater animals
Asexual & sexual
ovotestis- produce both male & female gamete at the same time
direct sex change- pandalid, prawn, clown
Birds
1 left ovary & 1 left oviduct (red body size, inc survival of fragile eggs)
Ovary- enlarge during breeding season
Testes- grow larger during breeding season
Cloacal protuberance- keep sperm at optimal T
Altricials 50% less productive than precocials
Female- need Energy for egg production, less E for ness building & parental caring
non-migrants less 14% productive than migrants
Pelagic seabirds less 40% productive than bird feeding at other habitat
Egg yolk- provide nutrient. Albumen- water supply & shock cushion
Sex determination of various animal
Signs of Estrus (When the female is in heat)
Cow will be mounted by other cows, increased activity, bellowing, thin clear mucus flowing out of vagina
Mare in estrus- breeding stance (hind legs spread, pelvis tilted). Will also teased by stallion, evert clitoris and express urine(urine)
Animal in estrus accept mounting by male
Gilt / Sow in estrus will stand rigid with erect in presence of boar
Bitch , attracted available dogs. Has a sanguineous(bloody) discharge from swollen vulva. (Due to bursting of blood cappilary in endometrium not due to shedding like in primates)
Function of females sex organ & hormones
Menstruation, menstrual cycle, fertilization, pregnancy, lactation, birth control
Follicular growth
Prenatal stage > oogonia multiplication >1st meitotic div, oocyte (remain until puberty) >resting phase , 1st follicles (grow in size) > 2nd follicle (grow & put on a layer of cells, granulosa cells with zona pellucida around them.
Final outcome either ovulation / atresia
Factor involve in reproduction & breeding
Hormonal control
Pineal gland respond to changes in photoperiod
By producing melatonin
Photoperiod & breeding season
Control by hypothalamus through GnRH
Involve hormones such FSH & LH
FSH - stimulate follicle + estrogen
LH - corpus luteum + progesterone
Other factor
Social factors
Communication - pheromones & vocalization
Male effect
Nutrition
Adequate nutrition :check: for optimum reproduction
Reproductive senescence
Menopause :red_cross: end of ovarian act.
Greatly increase in LH secretion
Estrogen & Progesteron greatly diminished
Major difference between between male and female germ cell production
Normal replenished of male germ cell in contrast to a continuing decreases in oocyte production of female throughout the reproductive life.
Mitosis continue to greatly increase the no. of spermatozoa in male while mitosis ceases in female after birth
Estrus vs Menstrual Cycle
Menstrual cycle
Depicts uterine events in large apes & human
Characterized- obvious bleeding
Bleeding- result of shedding of wall of the vascularised of the uterus
Estrus cycle > ovarian activity
Estrus - period of sexual receptivity (to copulate)
Metestrus - period of corpus luteum fully function
Proestrus - period of follicular growth
Hormonal control of male RS
LH - Action indirect; Leydig cell -> testosterone (stimulated) -> sertoli cells (stimulated)
FSH - Action direct to sertoli cells->inhibin produced
Testosterone- Development and Maintenance of libido, general body feature of male body
Steroidogenesis- Leydig cells produce testosterone if stimulate by LH
Feedback mechanism - Testosterone inhibit LH secretion, Testosterone and estrogen inhibit FSH secretion
Development of testes
90% seminiferous tubules, 10% connective tissue, blood vessels, Leydig cells
Testes descendent -> scortum - Most rodent & some carnivores (breeding season), mammals (fetal early postnatal life)
Abdominal testes- ellephant, dolphin, whales
Gametogenesis
Sperrmatogonia(Seminal tubule) -> spermatocytes -> spermatids -> spermatozoa
Testicular fluid - transport of sperm out of testis
Sertoli cells - support & sustain spermatogonia
Male infertility
Low sperm count- decreaseFSH n LH stimulation, blockage in rete testis, epididymis, vas deferens
Impotency - penis failed to erect due to : physical damage, health, physiological problem
birth control - neutering & spaying, chemical castration, immunization.
