8. Sexual Behaviour - M2 Flashcards
What are 2 main roles of odour?
- Odour has a stimulatory value in initiating male sexual behaviour
- pheromones
- boar odour and the odour of estrus sows can advance and synchronize puberty in gilts
- evoke the lordosis response during estrus - Odour has a large role in the establishment of the strong bonds between mother and offspring
What is the principal means of early recognition? How does visual recognition fit in?
Odour is the principal means of early recognition, but visual recognition takes over as the secondary means of mutual identification
Photoperiods and reproductive behaviour
Relative length of the light period of each day helps determine timing of breeding behaviour in some domestic animals
What are the 2 principal ways in which photoperiodism operates?
- Reproduction during that part of the year where day length is long
- eg. horses breed commencing int he spring (light becoming longer and stronger) and continues through the summer - Reproduction during that part of the year when day length is at a minimum
- eg. sheep and goats commence breeding in the fall when the photoperiod is less than the dark period and the light period is diminishing further day after day
Refractory period
When the photoperiod fails to provide adequate stimulation, a refractory period develops in which breeding performance is arrested
- just as photoperiod determines the onset of reproductive behaviour, it also impacts when it stops
How does visual stimuli promote mounting behaviour in bulls and boars?
- Will mount a dorsal surface with supports (eg dummy)
- simple form of the mounting releaser (cue that stimulates activity) - Also stimulated by seeing other mount
- rams are not stimulated this way
3 seasonal and climatic breeding responses
- Temperature effects
- even with non-seasonal breeders, temperature can affect reproductive behaviour
- cold weather: in cattle, cold weather will drop the number of cows in estrus however in sheep, it hastens the onset of repro activity
- warm weather: in bulls and boars, it decreases sexual libido - Inherent rhythm
- the enviro acts as a “zeitgeber” or timer
- the better the inherent rhythm is developed, the more the zeitgeber functions to synchronize events - Daily patterns
- sexual behaviour in several species tends to occur at particular periods of the 24h day
- eg. sheep mate most around sunrise and sunset, behavioural estrus onset most often occurs at sunrise, and rams will circulate through a pen to check ewes every 20-40min
What 3 characteristics of the female are important for the likelihood of successful mating behaviour?
- Attractiveness
- measured by the extent to which sexual response is evoked
- depends on various factors: pheromones, visual cues, etc - Proceptivity
- the extent of invitation behaviour (eg female seeks out male)
- ewes are known for exhibiting proceptive behaviour - Receptivity
- willingness to accept courtship and copulatory attempts (eg lordosis)
What is behavioural estrus?
The state during which the female seeks and accepts the male
- estrus behaviour is in synch with physiological changes
- increase in locomotion, investigative, and vocalizations, while there is a decrease in eating and resting
- in ewes, sows, cows, and mares, the first behavioural estrus tends to be “silent:
Sheep estrus behaviour
- Silent heats more common and usually need a ram to detect
- Ewes are very proceptive and will seek out the male during estrus, rub herself against the ram, and shake her tail in the ram’s direction
Goat estrus behaviour
- Marked behavioural estrus with rapid tail waving (“flagging”) repeated bleating, decreased eating, and a tendency to roam
Cattle estrus behavior
- Estrus lasts for ~12-24 hrs
- General restlessness (increased activity), raising and switching of the tail, arching or stretching of the back, increased licking of others, jerky movements of the vulva region, roaming and bellowing
- Mutual riding takes place btw the estrus subject and closest social associates (eg female-female mounting)
Horse estrus behaviour
- Mare in estrus adopts a “urination stance” or “straddling” with small amounts of urine
- Tail elevated and mare displays rhythmic clitoral “flashing” or “winking”
- May seek out the male adopt a stationary stance; some will have a temper and kick forcefully upon being mounted by the stallion
Pig estrus behaviour
- Adopt a lordosis stance in response to pressure on the lumbar region on the back; standing period is well-defined and lasts less than a day
- Sows in estrus may be ridden by other sows, but not as common as in cattle
What is the Whitten effect?
When the presence of a male synchronizes estrus in a group of females
- use of teaser rams in a flock of ewes
- boars engage in elaborate nudging and vocalizations along with the secretion of pheromones
