Erection and ejaculation

Question 1

3 stages on the timeline of male reproductive behaviours are:

Answer 1

• precopulatory (searching, courtship, arousal, erection)
• copulatory (mounting, ejaculation)
• post-copulatory (dismount)

Question 2

What general things are involved in the pre-copulatory courtship behaviours in males overall?

Answer 2

• Flehmen response → detects pheromones → curl upper lip aspirating fluid into vomeronasal organ
• vulva sniffing
• circling
• calling
• neck biting (cats)
• foaming at mouth (pigs)
• excitement (horses)

Question 3

Describe what occurs during the arousal stage of pre-copulatory phase in males when mating, and what does arousal lead to physiologically/physically? (?

Answer 3

• Sexual arousal includes physiological responses to visual/auditory/olfactory/tactile stimuli
• Arousal leads to:
  
  • elevation in testes
  • increased blood flow
  • increase scrotal cirumference (vasocongestion)
  • eretion and penile protrustion

Question 4

Briefly describe what occurs in erection stage of pre-copulatory mating phase in males → specifically for neural reflexes

Answer 4

• requires neural and vasomotor reflexes
• neural: sensory stimuli → activation of hypothalamic behaviour centre → stimulation of parasympathetic nerves → nerve terminals release nitric oxide → nitric oxide drives vasomotor process

Question 5

Briefly describe what occurs in erection stage of pre-copulatory mating phase in males → specifically for vasometer reflexes

Answer 5

• Nitric oxide (NO) causes relaxation of corporal sinusoids and BV dilation
• increased blood pressure in corporal sinusoids
• collapse of emissary veins
• contraction of ischiocavernosus and bulbospong. muscle block venous return
• peak cavernous blood pressure

Question 6

What occurs during erection in musculocavernous penis?

Answer 6

• increased blood flow
• relaxation of retractor penis muscle if present
  
  • significant increase in length and diameter

Question 7

explain what happens to fibroelastic penis during erection

Answer 7

increased blood flow

relaxation of retractor penis muscle

straightening of sigmoid flexure → not an increase in length or diameter like musculocavernous

Question 8

Copulation phase of mating: explain mounting and intromission phase of this (touching on 2 things that good mounting relies on)

Answer 8

• mounting occurs prior to intromission (entrance of penis into vagina)
• mounting is key element of breeding soundness
• Mounting reliant on: good male conformation allowing mating, and female receptivity

Question 9

Explain what emission and ejaculation are in the copulatory phase of male mating:

Answer 9

• Emission: movement of sperm from cauda epididymis to vas def, emptying of SP (seminal plasma) into pelvis urethra
  
  • gets everything ready to go
• Ejaculation: expulsion of semen from the penis

Question 10

What drives emission - para or sympathetic stimulation mainly?

Answer 10

• driven by sympathetic stimulation of SM in:
  
  • cauda epididymis
  • vas def
    
    • accessory sex glands

Question 11

What drives ejaculation; is it para or sympathetic stimulation?

Answer 11

• parasympathetic stimulation of:
  
  • ischiocavernosus m
  • bulbospongiosus m
  • urethralis m
• SM in the bladder neck contracts to prevent backflow into the bladder

Question 12

What occurs in the post-copulatory - refractory period in male mating

Answer 12

• they are unresponsive to further stimuli
• end of refractory period indicated by renewed response / interest in stimuli

Question 13

What is refractory period influenced by and why do we care about refractory period length in bulls/rams?

Answer 13

• influenced by:
  
  • species, amount of sexual rest, male age, novelty of female
• The shorter the refractory period, the more cows bulls/rams can get pregnant/mate with (higher reproduction rate)

Question 14

What measures might you include for assessing bull for breeding soundness?

Answer 14

• Semen assessment*
• circumference of the scrotum → larger area = higher sperm produced
• overall health/diseases in male for semen quality
• conformation of bull

Question 15

Mating behaviour in the bull → general mating signs in pre-copulation to post-copulation (how long copulation takes etc.)

Answer 15

• pre copulation: flehmen, chin resting, test mounting, nuzzling vulva
• copulation: 1-2 seconds, 1 large pelvic thrust, ejaculate into the vagina
• post-copulation: 20 ejacs to satiation- paddock joining

Question 16

mating behaviour in rams: explain some behaviours from pre-copulation to post-copulation (similar to cows)

Answer 16

• precopulation: flehmen, nudging ewe, pawing
• copulation: 1-3 seconds, 1 large pelvis thrust, ejaculate at external cervical os
• post-copulation: 10 ejacs to satiation- paddock joining

Question 17

mating behaviour in horses - explain some behaviours they show in pre-copulation to post-copulation

Answer 17

• pre-copulation: flehmen, excitement
• copulation: 20-60 seconds, multiple pelvis thrusts, tail flagging, ejaculate into uterus
• post-copulation: 3 ejacs to satiation (not as much as cows/rams)

Question 18

mating behaviour in pigs: explain some behaviours shown in pre-copulation to post-copulation

Answer 18

• pre-copulation: nuzzling sow, teeth grinding, foaming at mouth
• copulation: 5-20 mins, rapid pelvis thrusting until cervix engages, then drowsiness during slow ejaculation → ejaculate into cervix and uterus
  
  • post-copulation: about 10 ejacs so higher than horse and similar to cow/ram

Question 19

Mating behaviour of dogs- explain brief behaviours shown in pre-copulation to post copulation

Answer 19

• pre copulation: roaming, sniffing/licking vulva
• copulation: 2 mins (first stage) - up to 45mins (Second stage where bulbus glandis creates a tie - stuck together until erection is lost*)
• post copulation: not sure how many ejacs to satiation

Question 20

Mating behaviour in cats: pre-copulation to post-copulation

Answer 20

• pre-copulation: spraying, prowling, neck biting
• copulation: 1 min, 1 large pelvis thrust, ejaculate into vagina
• post-copulation: 6-15 ejacs

Question 21

Viagra prolongs vasodilatory effect of nitric oxide. What would happen if you gave viagra to a bull in absence of any sexual stimuli?

Answer 21

• He would not get an erection due to the absence of sexual stimuli
  
  • all viagra does is prolong that physiological response to nitric oxide → but an erection REQUIRES sexual stimuli to kick the process off.

Question 22

two methods of semen collection are:

Answer 22

• Artificial vagina
  
  • electroejaculation

Question 23

Briefly explain artificial vagina method of collecting semen

Answer 23

• Ejaculate into artificial vagina
• collect physiological semen sample
• male must be trained though so can’t use all of the time

Question 24

Briefly explain electroejaculation in collecting semen from males:

Answer 24

• male restrained or anaesthetised
• rectal probe used to stimulate ASG’s
• Neg: may include excess seminal plasma and urine contamination (close to bladder)
• Positive: can do it on any male/don’t have to be trained