Seasonal Effect, Sexual Behavior Flashcards
Affect of Season
Daylight hours
many wildlife and some domestic species are seasonal breeders at temperate latitudes
Horse and Sheep
Mare foals in the spring: approximately 10.5-12 mo gestation, conceive in spring
Ewe lambs in spring: approximately 21 week gestation, conceive in fall
Seasonal Breeders
Show seaonal pattern of prolactin secretion. Peak concentrations in spring summer (long days), nadir in autumn or winter (short days)
If light is detected during a specific tiem period, the day is preceived as long
Melatonin is secreted by pineal gland at night
The exact method of influence on the Hyppthalamic-pituitary- gonad axis is not known
Equine
during anestrus
GnRH concentration in hypothalamus is low
LH and FSH secretion by the antuitary pituitary are reduced
Ovaries are inactive
Steroid production is low
Same result in males
Equine
Spring transition
GnRH concentrations begin to increase shortly after winter solstice
FSH levels rise as GnRH increase
Numner and size of ovarian follicles increses
FIrst few large follicles do not ovulate
First ovulatory follicle is accompanied by and estradiol surge and LH surge - leading to ovulation
Transition takes 6-12 weeks
Breeding during this time is unsuccessful
Equine
Breeding mares early
Many breed associateion observe January 1 as the official birth date of foals
Therefore - advantage to competition borses born near January 1
Increasing day length with artificial lights will return seasonally anestrous mares to reproducitve competence
Light therapy doesn’t shorten the transtion phase - it just moves ti early in theyear
Strategy - add artificial light during evening hours starting in Nov and Dec
Ovine
the pattern of light formt he summer solstice to the autumnal equinox is most critical
Follicular waves continue during anestrus - follicles reach ovulatory size, but do not ovulate
Estrogen production is low during anestrus
The first LH surge of the season is not followed by ovulation - but progesterone form luteninized follicles rises
The second LH surge of the season is accompanied by ovulation and estrus
Ovine
Breeding sheep out of season
Sheep gestation and length and speed of lamb growth should allow for two pregnancies per year
Some breeds are easier to “trick” into breeding during shorter days
Block exposure to morning or evening light by housing in light-tight barns
Expose to addtional artiicial light for 8-12 weeks, followed by 8-12 weeks of short days
Or melatonin implants for 4+ weeks
Rams need to be exposed to light treatment also
Withhold contact with rams until ready to breed
Treat with CIDR P4 sponge for CIDR for 12 days with eCG injection at P4 removal
Sexual Behavior
Male sexua behavior
Courtship
Copulation
Both are under the control of testosterone
The brain undergoes sexual differentiation during a short period of time near puberty - necessary for normal sexual behavior
Sexual Behavior
Primary Stimulated by visual cues
bovine, equine
Sexual behavior
Primarily stimulated by olfactory cues
Males -effect on females
Procine, Ovine, Equine
male rodents, swine, sheep, and other species can stimulate earlier puberty, induce ovulation, and increase the speed of sperm transport in the female tract
Sexual behavior
Primarily stimulated by olfactory cues
Female-effect on males
Identification ont he presence of females in estrus
Pheromones
air-borne chemicals released by urine or feces or secreted by cutaneous glands tha elicit a response
Flehmen response
is a particular type of curllng of the lips in ungulates, felids, and amny other mammals
THe pose, which is adopted when examining scents left by other animals of the same species, helps expose the vomeronasal organ and draws senct molecules back toward it
Sexual Behavior
Female Sexual behavior
Estrogens
necessary for mating behavior
high around the time when a follicle is mature and able to ovulate a viable egg
Sexual behavior
Female sexual behavior
Progestogens
inhibit mating behavior
high during pregnancy and during stages of the estrous cycle without fertilization egg
Bovine Behavior
Bull
Libido isthe desire to mate
mating ability is the ability to successfully mate
both appear to be influenced by genetics
Bulls housed in groups will establish dominance heirarchy very quickly
Bovine Behavior
Cow/Heifer
Females play the major role in soliciting sexual partners
Form sexually acitve group that stays in visual contact with bulls
Bovine Behavoir
Mating activity
Bulls will “sham mount” a female to test her willingness to “stand” to be mated
The greatest stimulus to a bull is a female (or any large, similarly-shaped object) that is immoble
Equine Behvior
Stallion
Vocalization, olfactory and tactile investigation, and the flehmen response
when brought toa mare - stallions will begin sexual behaviors within 2 minutes
stallions can have phychological breeding issues
Almost all stallions respond more vigorously when provided with more than one stimulus mare
Equine Behavior
Mare
Estrus in a pasture setting - will approach stallion and exhibit sexual behavior: urination, deviation of tail, standing still
Diestrus in pasture setting - will avoid approaching stallion and exhibit aggression if he persists
will allow close contact with stallion during diestrus for non-sexual social behaviors
Mares will occasionally exhibit estrous behaviors during the anovulatory protions of the year
Porcine behavior
Boar
When placed near females - boars will “chant”, salivate profusely, nuzzle the flank and head-rest on the back
When breeding for the first time - the experience needs to be very pleasant (calm, quite, good footing)
Confidence - intimidation by a group of gilts or being beat-up by a larger sow can ruin a young boar for future mating
Young boars should be exposed to one gilt of similar size that is in strong standing heat
do NOT hurry the first mating
Porcine Behavior
Sow/Gilt
Male presence is necessary for females to show obvious estrus behavior
Take the female to the male - she assumes the major role in searching for the male
Even when in heat - the female may run away fromt he boar and he will follow her
Mating stance - sows/gults will adopt a “mating stance” (standing immobile with back arched and ears erect)
Canine Behavior
Dog
mating should be done int he male’s territory
The dog will be attracted to any female in proestrus, estrus, or diestrus - approach and investigate the anal-genital area
Penile erection occurs after penetration
Canine Behavior
Bitch
if not receptive tot he male (proestrus/diestrus)
bitch will sit down when approached
If receptive - will “flag” her tail and assume the mating stance
Canine Behavior
The “tie”
After ejaculation - the dog dismounts bt the penis is “locked” in the vaginal vault by the swollen bulbus glandis and the mascular vulva
The dog and bitch position themselves posterior-to-posterior
THe “tie” lasts from a few minutes to over an hour
