LU6: REPRODUCTION & BREEDING
LU6: REPRODUCTION & BREEDING
Factors involve in reproduction & breeding
Interaction between sexes by
: The onset of puberty often fasten due to exposure of female to male abruptly at peripubertal period.
Interaction between females facilitates sexual development.
Presence of male enhance the signs of estrus.
Sufficient nutrition needed for optimum reproductive efficiency.
Insufficient nutrition cause loss of body condition postpone the beginning of puberty & recycling.
Photoperiod & breeding season
: react to changes in photoperiod by increase the melatonin secretion.
: decides the beginning of breeding season.
Eg: sheep & goats ("short day breeder") due to :arrow_down: photoperiod while horses & cats ("long day breeder") due to :arrow_up: photoperiod.
: End of ovarian activity.
Not responsive to GnRH, estrogen & progesterone secretion is diminished.
Hormonal Changes in estrous cycle
Temperature & humidity
Hot & humid environment depresses reproduction especially dairy cows & sows ( :arrow_down: estrous detection & conception).
Anterior pituitary gland releases
follicular stimulating hormone (FSH)
luteinizing hormone (LH)
: stimulates follicle to grow & produce
gonadotrophin releasing hormones (GnRH)
: stimulate corpus luteum to produce
Estrogen & progesterone maintains uterus & secondary sexual characters & exert feedback control over hypothalamus & pituitary gland.
Female Reproductive Organs Structure
: Implantation & pregnancy
2 uterine horns, 2 cervices, & 1 vagina.
Eg: rabbits, rodents, marsupials.
Larger uterine body with smaller uterine horns ( for mare), for cow, ewe, & doe (smaller uterine horns)
2 long uterine horns, common uterine body, & 1 cervix
. Eg: dogs, pigs, elephants, whales, dolphins, tarsiers, lemurs, lorises, etc.
: No uterine horn, all uterine body. Eg: humans
: Protects from external disturbance
: Transport of ovum
: Organ of copulation
: Produce ova & hormones
: External opening to reproductive organs
: Period of sexual receptivity.
: Period of corpus luteum formation.
:Period of follicle growth.
: Period of corpus luteum is fully functional.
Describe ovarian activity.
Testosterone & inhibin exert -ve feedback control over hypothalamus & anterior pituitary & regulate level of testosterone in blood.
: Testosterone inhibits LH secretion; Testosterone + estrogen inhibits FSH secretion.
: stimulate anterior pituitary to secrete FSH & LH;
: stimulate Sertoli cells to produce sperm & inhibin;
: stimulate Leydig cell to produce testosterone.
: Low sperm count due to :arrow_down: gonadotrophin stimulation, blockages in the rete testis, epidydimis // vas deferens.
Male Reproductive Organs
: Produce fluids (carries sperm to penis).
: Store & carry sperm & seminal fluids to penis.
: Produce sperm (spermatogenesis) & sex hormones (steroidogenesis).
Also controlled by hypothalamus via GnRH.
90% made up of hundred meters of
& 10% made up connective tissues, blood vessels, &
: Deposit sperm into vagina.
Sign of estrus in farm animals
Cows mounted by another cows & show signs of bellowing, thin clear mucus flow out of vagina, & increased activity.
: hind legs spread, pelvis tilted, tail diverted, evert the clitoris, & express small amount of urine.
: Stand rigid with ears erect in presence of boar.
: Sanguineous discharge from swollen vulva due to burst of blood capillary in endometrium.
Characterized by obvious bleeding.
Bleeding: Result of shedding of vascularised wall of uterus.
Describe uterine events in
large apes & human
Birth Control of farm animals & pet
Neutering & Spaying
Hermaphroditism (both female & male sexes)
(1 ovary, 1 testis)
(switch to female or male sex) Eg: clownfish, wrasses//gobies)
Unisexuality // parthenogenesis
Bisexuality // gonochorism
demersal eggs, long incubation period, small no. of eggs spawn, larger & less vulnerable larvae. Direct insemination (save sperms).
To protect eggs against risk of freezing // low salinity of surface water.
Bouyant // pelagic eggs, short incubation period, large no.of eggs spawn, vulnerable larvae.
Marine animals: use asexual & sexual modes of reproduction, mostly invertebrates are hermaphrodite, have direct sex change.
Birds Reproductive Adaptation
1 left ovary
1 left oviduct
. Benefits: reduce female body size // weight, & :arrow_up: survival chances of fragile eggs.
Ovary enlarge significantly as it approach breeding season & male testes are paired but appeared absent through out the year.
Most male birds have
to keep sperm at optimum temperature.
Most birds lacks a penis, so, brief copulation act known as "cloacal kiss".
less productive than precocials;
less productive than biparental;
less productive than migrants;
Pelagic sea birds
less productive than birds feeding at other habitats
Female: need large amount of energy for eggs production, so less time & energy for nest building, & subsequent parental caring.
Egg yolk provide nutrient for embryo. Albumen acts as primary water supply & act as shock cushion.
) :arrow_right: primary (46n) & secondary (23n)
:arrow_right: differentiates to
: A penis fails to become erect. Causes: physical damage, health & medication, & psychological problem. Treatment: cognitive behavioral therapy & medicine.