The Onset of Reproductive Activity

Question 1

reproductive quiescience?

Answer 1

not very active reproductive tract

Question 2

oestorus cycles?

Answer 2

shows when ready to mate

Question 3

puberty?

Answer 3

the ability to accomplish reproduction successfully

Question 4

meaning of puberty in males?

Answer 4

fertilisable spermatozoa in the ejaculate

Question 5

meaning of puberty in female?

Answer 5

pregnancy supported without deleterious effects

Question 6

pre-pubertal?

Answer 6

hypothalamic neurones and HPG established but quiescent

Question 7

peri-puberty?

Answer 7

acquire ability to receive information from pre-synaptic neurones to increase frequency and promote GnRH secretion

Question 8

puberty - GnRH?

Answer 8

increased frequency and amplitude of GnRH secretion

Question 9

loads of food early on - hens laying?

Answer 9

lots of eggs but smaller

Question 10

less food? - hens laying

Answer 10

fewer eggs but bigger
(start laying around 4 months)

Question 11

timing of puberty for male and female bovine?

Answer 11

m: 11 months (7-18)
f: 11 months (9-24)

Question 12

timing of puberty for male and female equine?

Answer 12

m: 17 months (10-24)
f: 18 months (12-19)

Question 13

timing of puberty for male and female ovine?

Answer 13

m: 7 months (6-9)
f: 7 months (4-14)

Question 14

timing of puberty for male and female porcine?

Answer 14

m: 7 months (5-8)
f: 6 months (5-7)

Question 15

timing of puberty for male and female canine?

Answer 15

m: 9 months (5-12)
f: 12 months (6-24)

Question 16

timing of puberty for male and female feline?

Answer 16

m: 9 months (8-10)
f: 8months (4-12)

Question 17

timing of puberty influenced by?

Answer 17

season
genetics
nutrition
social cues
housing density

Question 18

brain puberty is dependent on?

Answer 18

on ability of hypothalamus to secrete sufficient GnRH to stimulate pituitary gonadotropin secretion

Question 19

brain puberty is independent of what?

Answer 19

of gonadal and anterior pituitary status
- can induce ovulation in pre-pubertal animals by exogenous GnRH administration

Question 20

what centre are we dependent on for puberty?

Answer 20

the tonic centre

Question 21

why do many of the animals we eat get sent to abattoir around puberty time?

Answer 21

body mass is highest during puberty and fattest

Question 22

GnRH neurons?

Answer 22

they release GnRH into portal system which travels to anterior pituitary - they do this with the input of Kisspeptin neurons

Question 23

more fat stored - the more?

Answer 23

leptin stored

Question 24

what does leptin do?

Answer 24

input of of neuropeptide Y neurons
stimulates onset of cyclicity

Question 25

anorexia?

Answer 25

less fat less sugar suppresses reproductive cycling

Question 26

improve nutrition does what to reproductive cycling?

Answer 26

augments it higher number of follicles recruited ovulate more oocytes larger no. of lambs as a consequence

Question 27

when do sheep typically breed?

Answer 27

in the autumn in with a bang out with a fool ram in on bonfire night and usually get lambs on april fools

Question 28

long day summer melatonin

Answer 28

less produced and over a shorter time hypothalamus is sensitive to it later in the day so less likely to react as less melatonin produced when hypothalamus is sensitive to it

Question 29

short day winter melatonin

Answer 29

more produced and over a longer period - overlaps with when hypothalamus is sensitive to melatonin this is how we tell the difference between seasons (sensitivity to melatonin)