Sexual Cycle and heat detection Flashcards
oogenesis and what hormones are involved
it is the process of creating ova. it starts before puberty, where the oogonium undergo mitosis until its doubled and this phase is called the primary oocyte.
after puberty the primary oocyte continues to undergo mitosis and is released until it encounters sperm during ovulation. After fertilisation meiosis continues producing a fertilised egg.
Hormones invlovled: FSH +LH =>trigger the ovarian cycle
spermatogenesis and what hormones are involved
germ cells develop into spermotocytes which then turn into spermatozoa. it starts with the spermatogonium dividing into two producing primary spermatocytes that then develop into 4 haploid spermatids-sperms.
Hormones involved: GNRH+ FSH+LH+INHIBIN+TESTOSTERONE
Puberty
occurs when animals weight is from 40-60% of adult weight
female cycle can be categorised as
follicular phase,ovulation and luteal phase
Ovulation can last up to
35-36 hours in women,
11-12 h in rabbits
some animals can have a sexual period thats continuous or seasonal
for continuos:
cow,rabbit,pigs
for seasonal:
horses(spring),sheeps(autumn),goats(autumn)
spontaneous ovulation
GNRH AND Lh secretions are induced by the oestrogen mature follicle (positive feedback)
induced ovulation
GnRH secretion is induced by coitus, sexual inter course triggers gnrh
Main stages of the Oestral cycle
oestrus-meteotrus-dioestrus-prooestrus
Oemediopro
Ovarian cycle
Follicular, ovulation and luteal cycle
(heat) Oestral cycle
oestrus-meteotrus-dioestrus-prooestrus
can be catergorised as the follicular phase and luteal phase
only occurs in animals
Ovulation is triggered by
the surge in LH after follicular phase
During luteal phase
progesterone,estradiol promote thickening of the endometrium, corpus luteum is at its peak development.
Uterine menstrual cycle
can be divivded into mentstrual flow phase,,roliferative phase and secretory phase
Folliculogenesis is defined as
when corpus luteum decreases
Puberty in sheep is between
6-7 months
Puberty of cow starts around
9-11 months
Mare’s puberty begins
18 months
Sows undergo puberty around
6-7 months
OOcytes number at birth differ by species
cows=30
woman=400-500
sheep=60
sow=205-600
Sertoli cells provide ….during cell differentiation in ….
- nutirents
2. spermatogenesis
Sexual Cycle can be summarised as the
ovarian cycle and oestral cycle
Sexual phases can be summarised as the
Follicular and luteal phase
when is it best to inseminate animals (artificially or naturaly)
During the first day of heat
Melatonin stimulates what hormone secretion by the hypothalamus?
GnRH
what happens when you miss a heat detection for cows?
delayed fertilisation by 3 weeks. a delayed fertilisation means delayed birth dates between two calfs
There are types of heats signs at each stage of the heat cycle (early signs, late signs, and signs during mating )
early signs: nervousness and increased activity.
signs during mating: clear mucus at vulva, ingestion decreased, milk production decreased.
Late signs: trying to mate with other cows, tangles tail hair with mucous, blood in mucous after heat
Discrete signs of heat in cows include
mooing, licking the vulva, sniffing
in what animal is the no relation between oestrus and ovulation?
mare
cows are more prone to show signs of oestrus during which times of the day?
Morning and night
Heat detection tools:
- Automated heat detection
2. colour coding
Factors that can affect heat detection include
- reproduction technique
- Health
- Livestock Building
- start of lactation
