ANS 431: Reproductive Behavior
I. Sequences of Sexual Behavior
1. Components of copulatory patterns
A. Precopulatory stage
a. Search for sexual partner (sexual arousal)
b. Courtship (sexual display)
c. Erection
d. Penile protusion
B. Copulatory stage
a. Mounting
b. Intromission
c. Emission & Ejaculation
C. Postcopulator stage
a. Dismounting
b. Refractoriness
c. Memory
2. Male Courtship
A. Sniffing & Licking
B. Flehmen reaction
C. Nuzzling of rump & back--Ruminants
D. Biting neck--Stallion
E. Noses flanks, Grind teeth, Foams at Mouth--Boar
F. Increased vocal and motor activity
3. Female Courtship
A. Restlessness
B. Increased Vocal activity
C. Sniffing of male (or other female) genitals
D. Circling
E. Mock Fighting
F. Frequent Urination
G. Mount other females--cows, goats, pigs
H. Tail wagging--sheep & goats
I. Vulva "winking"--horses
4. Mating
A. Female allows for mating to take place
B. Stands immobile--Lordosis
C. Prepares for male to mount
5. Erection and Protrusion
A. Parasympathetic signal
B. Vasodilation of arteries supplying cavernous bodies
--especially the crura
C. Ischiocavernosus muscle pumps blood into crura
& corpus cavernosum
--causes stiffening & straightening
D. Sigmoid flexure distends, retractor muscle relaxes
E. In Ruminants & Boars elongation occurs
with little dilation
F. Prepuce everts at protrusion in bulls
6. Mounting
A. Alignment
B. Mounting
C. Fixes forelegs and grasps female
D. Rhythmic pelvic thrusts
7. Intromission--Insertion of Penis in Vagina
A. Male must be erect
B. Bull
a. Lasts 2 seconds
b. Penis spirals at ejaculation
C. Boar
a. Last up to 7 minutes
b. Spiraled penile end, becomes more
Corkscrewed during intromission
D. Stallion
a. Lasts for several minutes
b. No Spiraling
E. Ram
a. Short intromission
b. Urethral Process disperses semen
at ejaculation
8. Emission
A. Movement of spermatic fluid along
vas deferens and pelvic urethra
B. Mixes with accessory gland fluids
C. Brought about by smooth muscles under
ANS (sympathetic) control.
9. Ejaculation
A. Passage of semen along penile urethra.
B. Brought about by striated muscles (urethralis)
under control of somatic efferent
sacral nerves (deep perineal nerve).
--Sympathetic Response
C. Bulbospongiosus muscle compresses
penile blood to increase blood pressure
along corpus spongiosum in a wave-like manner.
D. Wave action along penile urethra causes transport
of ejaculate.
E. Cattle, Sheep, & Goats--Quick (seconds)
--Bulls leap
--Rams & Billys throw head back
F. Boar--5 minutes (3-20)
--Trance
G. Stallion--40 seconds
--Bites females neck
10. Refractoriness
A. Period of time between ejaculations
B. Variable, Increases with each ejaculation
with the same mating
12. Frequency of Copulation (to exhaustion)
A. Bull--20 (60-80)
B. Ram--10 (30-40)
C. Boar--3 (8)
D. Stallion--3 (20)
IA. Dog and Cat Sexual Behavior
A. Dog
1. Precopulatory Behavior
a. Search
i. Bitch–Roaming
ii. Dog–Roaming around territory
b. Courtship
i. Bitch–Immobile Stance
ii. Dog–Sniffing and licking of vulva
c. Consummation
i. Bitch
A. Tail deflection to one side
B. Urination in presence of male
C. Affectionate head rubbing
ii. Dog
A. Erection
B. Protrusion of Penis
C. Mounting
2. Copulatory Behavior
a. First Stage Coitus
i. Mounting and intromission by a few thrusting movements
ii. 1st and 2nd fractions of semen are ejaculated
A. 1st Fraction–Pre-sperm
1. Seminal fluid from prostate
2. 0.5-5 ml
B. 2nd Fraction–Sperm Rich
1. 300 million to 2 billion sperm
2. 1-4 ml
iii. 1-2 minutes
b. “The Turn”
i. Transition phase
ii. After ejaculation, dog lifts one leg and turn
around while lifting one leg over the bitch
iii. Penis remains in bitch vagina
iv. Lasts 2-5 sec.
c. Second Stage Coitus, “The Tie”
i. Animals stand with hind quarters in contact
and their heads facing opposite directions
ii. 3rd fraction of semen is ejaculated
A. Post-sperm fraction
1. Seminal fluid from prostate
2. 1-80 ml
3. Forced cranially to push sperm-rich fraction
into the uterus.
iii. Encourages Uterine rather than Vaginal insemination
A. Penis stays engorged and acts as plug
iv. Lasts 5-45 minutes
B. Cat
1. Precopulatory Behavior
a. Search
i. Queen–Vocalization (calling)
ii. Tom–Prowling
b. Courtship
i. Queen
A. Croaching
B. Affectionate head rubbing
C. Rolling
ii. Tom–Bitting queen on dorsal neck
c. Consummation
i. Queen
A. Elevation of rear quarters and hyperextension of neck (Lordosis)
B. Presentation of vulva
C. Tail deviation
ii. Tom
A. Mounting
2. Copulatory Behavior
a. Mounting (1-3 min.)
i. Queen
A. Lordosis
B. Treads hindlegs
ii. Tom
A. Neckbitting
B. Mounts with forelegs
C. Mounts with hindlegs
D. Rakes with forelegs
E. Treads with hindlegs
F. Arching of back
b. Coitus (5-10 sec.)
i. Queen
A. Copulation scream
B. Turns on tomcat upon withdrawl
ii. Tom
A. Pelvic thrust
B. Erection
C. Intromission
D. Ejaculation
E. Withdrawl
c. Post-Coitus “After reaction”
i. Queen
A. Hisses and Strikes at Tom for 1-10 minutes
B. Rolls
C. Licks forepaws
D. Views Tom
E. Re-encourages Tom
ii. Tom
A. Licks penis
B. Licks forepaws
C. Waits for Queens call
d. Repeat Breedings
i. Up to 30 times in 24 hours
ii. After-reaction increases each coital contact
II. Mechanisms of Sexual Behavior
1. Hormonal
A. Programmed during Prenatal Development
a. Testosterone causes masculinization of brain
b. AFP binds to estrogen so it can't cross
blood-brain barrier
c. Feminization is default pathway
B. Gonadal Steroids
a. Estrogen + Progesterone = Female Behavior
b. Testosterone = Male Behavior
2. Central Nervous System
A. Sensory
a. Initiates behavior
b. Types
i. Olfaction
ii. Vision
iii. Audition
iv. Tactile
c. Olfaction
i. Pheromones
--Chemical attractants detected
by olfaction
--Females from urine and
vaginal secretions
--Males from Preputial pouch,
carpal gland (boars),
Saliva (androgen metabolites)
ii. Vomeronasal organ
--Accessory olfactory organ
--Detects less volatile pheromones
(Fluid-borne)
--Connects oral cavity
by nasopalatine ducts
iii. Flehman reaction aspirates vasonasal
organ
--Head elevation and curling of lip
d. Auditory
i. Long range signal
f. Visual
i. Close range signal
ii. Signalling of receptiveness
g. Tactile
i. Grooming, biting, nuzzeling, etc.
B. Hypothalamus
a. Reacts to sensory signals
and sex steroid hormones
b. Neurons produce behavior specific peptides
(neurotransmitters)
C. Mid-brain
a. Receive hypothalamic peptides
b. Speed up impulses
D. Medulla
a. Integrates postural adaption for lordosis
and mounting
E. Spinal cord
a. Signal specific muscles for lordosis
and mounting
III. Factors Affecting Sexual Behavior
1. Psychosocial Aspects
A. Females
a. Matriarchal herds
b. Pecking order
B. Males
a. Solitary
b. Dominant male with herd
2. Genetic
A. Breed Differences
a. Bull Libido: Dairy > Beef > Brahman
b. Boars Training: York better than Duroc
B. Differences within breed
3. Environmental
A. Coolidge Effect
a. Novel female stimulates male
B. Nonspecific Stimuli
a. Change environment for sluggish males
C. Presence of other males
a. Stimulates male
D. Season & Climate
a. Seasonal Breeders
b. Hot weather lowers activity
4. Experience (Memory)
A. Practice makes perfect
B. Need social contacts during development
a. mixed sex > unisex > isolation
5. Precoital stimulation
A. Increases copulation efficiency
B. Teasing
c. Sterile Matings
6. "Abnormal" Behavior
A. Homosexuality
a. Common, especially females
b. Can be a problems with males
B. Hypersexuality
a. Nymphomania--Female
--Cystic Ovaries
b. Satyriasism--Male
C. Hyposexuality
a. Impotency a physical problem in animals
b. Physical or mental with humans
D. Autoeroticism
a. Masturbation
b. Most common in Stallions & Bucks
c. Also seen in Bulls on High Protein Diets
IV. Maternal & Neonatal Behavior
1. Suckling
A. Milk is letdown in response to suckling
B. Young will try to suckle what ever nose comes
in contact at first, learns with experience
2. Parent-Young Interaction
A. Imprinting
B. Continuous contact important
C. Placentophagy
D. Maternal Grooming
3. Sheep
A. Prepartum Period
a. Grazing ends
b. Seeks Isolation
c. Will lamb where fetal fluids first spill
B. Lambing
a. Ewe usually recumbent--lying down
b. Placenta delivered in 2-5 hours
c. Eaten in some breeds
C. Postpartum Behavior
a. Lamb is cleaned and groomed
b. Lamb stands withing 15 min after birth
c. Lamb finds teat by trial & error
D. Mutual Recognition by Ewes and Lambs
a. Ewe recognizes lambs bleat
b. Color pattern
c. Smell
E. Suckling Behavior
a. Times per day
--first 4 days-30
--midlactation-15
4. Cattle
A. Similar to Sheep
a. Cows eat afterbirth more often
b. Calves stand after 45 min
c. 1st suckle 2-5 hr
5. Horses
A. Prepartum
a. Restless
b. Waxing & milk letdown
B. Foaling
a. Mares stay recumbent longer postpartum
C. Postpartum
a. Foal stands--approx. 1 hr
b. First suckle within 3 hr
6. Pigs
A. Prepartum
a. Nesting
b. Increase Vocal activity
B. Farrowing
a. Usually occurs after sunset
b. Sow on side
c. Piglets must escape fetal membranes
d. Duration: 3 hours
d. Mother stands to urinate
e. Lies down again
--Piglets prown to getting squished
C. Postpartum
a. Piglets immediately mobile
b. Find teats within 5-30 minutes
D. Suckling
a. Teat order established
b. Frequency: 18-28 times/day
c. Duration: 4-8 min
ANS 431 Homepage
~~~~~Revised 3/1/98~~~~~ TAW