Transcript Reproductive behavior

Reproductive and parental
behavior
A.J. Zanella
ANS 305
Objective
 To discuss reproductive behavior in
domestic mammals
Pre-copulatory and copulatory
behavior
 Courtship
– Motivational aspects
• Enhance sperm production
• Enhance fertilization
• Increase litter size (pigs)
 Copulatory responses
– Consummatory responses
• Most of the current information is on males
• Exception dogs and cats
Variability in sexual behavior
 Males
– Courtship is highly variable
• Licking & sniffing the female genitalia
• Nudging
• Vocalizations
– Copulation is less variable than courtship
Variability in sexual behavior
 Females
– Courtship (proceptive behavior)
• Mounting behavior (cows)
• Urination (mares & ewes)
• Seeking out & selecting males
 Copulatory behavior
• Receptive behavior
• Passive responses (?)
– Exceptions: cats & dogs
Domestic mammals (females)
 Cyclic nature
 Display no interest in males and will not be
receptive outside the estrous period
 Olfactory, auditory and visual stimuli
produced by females have “attractive”
qualities to males
 Females display preferences for sexual
partners
– Sows; ewes; bitches & female cats
Mate choice and timing of mating
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
Free ram
Tethered ram
% of marked females (52 days)
The evolution of seasonal
breeding
 Domestic species evolved in temperate
climates
– Reduce risk of predation
– Avoid delivery at the times when resource are
limited
 Domestication has altered seasonal
reproductive behavior in several species
Species Estrous cycle
Length
Duration
Dog
Monoestrous
1 cycle/season (2x)
7-10 days
Cat
Seasonally
polyestrous
3 weeks
1-4 days
7-10 days
Horse
Seasonally
polyestrous
3 weeks
5-6 days
Cattle
Polyestrous
3 weeks
10-12 hours
Sheep
Seasonally
polyestrous
16-18 days
36 hours
Goat
Seasonally
polyestrous
3 weeks
12-24 hours
Swine
Polyestrous
3 weeks
2-3 days
Behavioral signs of estrus
 Sensory and motor activity
– Increase in general activity
• Ovulation in women (Morris & Udry, 1970)
 Increase in sensory acuity
 Neuronal “re-organization”
– Visual
– Olfactory
– Spatial memory
Behavior of estrus females
towards males
 Proceptive behavior
– Females will seek males
 Standing behavior
 Vocalizations
 Urination
– Mares, sheep and goats
Female responses during
copulation
 Limited data ?
– Copulation causes an increase in uterine
motility
– Uterine motility follows nuzzling and mounting
by a bull
– Female cats, 5 to 10 seconds post-intromission,
becomes very aroused (eyes dilate, they may
turn and hit the male)
Behavior of estrus females
towards other females
 Agonistic interactions
– cows; pigs; mares
 Increase in vocalizations
 Attempts to mount other animals
– cows; bitches; sows
 Standing while mounted by other animals
– Cows (56 times over a 15 hours period)
• PRESENCE OF MALES MAY ELICIT MORE
PRONOUNCED BEHAVIORAL RESPONSES
Sexual behavior of males
 Pre-copulatory behavior is highly variable
– Beef bulls have a more elaborated courtship
display than dairy bulls
– Male broiler breeders (domestic fowl) are more
aggressive towards females than commercial
laying strain males (Millman et a,, 1999)
Sexual behavior of males
 Investigate the genitalia of the female
 Flehmen behavior may follow
 Play behavior (dogs)
 Mounting
 Attempt copulatory intromission by pelvic
thrusting
Stallion
Reaction time Pre-coital
behav ior
Manner of
intromission
Averages about 5
minutes
One to four moun ts
Several pelvic
oscillations
Terminal inactive
phase
Noses genital
region
Genital olfactory
reflex
Bites croup region
Penis erect fully
Bull
Reaction time Pre-coital
behav ior
Manner of
intromission
Mode 2 minutes
Noses vulv a
Mean 12 m inutes Genital olfactory
Beef breeds 12 min reflex
Alignm ent
Licks h indquarters
Single pelvic thrust
coordinate with
clasp reflex
Boar
Reaction time Pre-coital
behav ior
Manner of
intromission
1-10 minutes
Short protusions o f
spiral penis
repeated till
intromission o ccurs
Pelvic oscilations
followed by
somnolent phase
App roaches sow
giving series o f
grunts
Noses vulv a
Champs jaw and
froth at mouth
Ram
Reaction time Pre-coital
behav ior
Manner of
intromission
30 s ec to 5 minut es Noses vulv a
Very qu ick single
Genital olfactory
pelvic thrust with
reflex
fore limb clasping
Paws with fore foot
Goat
Reaction time Pre-coital
behav ior
Manner of
intromission
12-60 s econds
Very qu ick pelvic
thrust
Bleating, stamping
with fore foot,
rapid licking
Genital olfactory
reflex
Olfactory stimuli
 Pheromones
– Substance produced by one animal which
conveys information to other individuals by
olfactory means
 Vaginal secretions
 Urine
 Preputial gland
 Salivary glands
Pheromones
 Hamsters
– Dimethyl disulfide in vaginal secretions
 Dogs
– Methyl-p-hydrobenzoate in urine of bitches
 Pigs
– Androgenic steroids is saliva of boars
Detection of pheromones
 Olfactory system
– Volatile substances
 Vomeronasal organ
– Flehmen behavior: head elevation and curling
of the upper lip.
– Non-volatile substances
– Primarily performed by males
– Females may show the behavior towards newborn animals
or amniotic fluid.
Flehmen behavior
 Fluid is drawn from the oral cavity through
the nasopalatine duct and to the posterior
part of the vomeronasal organ.
Inclusive reproductive fitness
 Males may help close relatives (horses)
 Females may support sisters when they are
not able to breed
– Wolf packs:
• only the dominant females have pups
• their female relatives help to look after the young
Sexual suppression
 Females
– Honey bees
– Some primates
– Naked mole rats
 Males
– Stallions
– Some primates
Monogamy
 Domestic dogs are the only domestic
species that retain “some” indicative of
monogamous behavior