PP13 Male Behavior

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PP13Male Behavior Libido TraitsChapter 11
pg 240-265ANS 3319Dr. Michael J.
FieldsUniversity of Florida
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Libido

• Definition - sex drive or willingness and
  eagerness of a male to mount and attempt service
  of a female
• Sex drive has a genetic component
• Within twins, libido is very similar
• Heritability (h2) 0.6

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Libido Measurement

• Can be measured
• Pubertal measurement reflects life time of
  performance
• Libido is related to pregnancy rates
• Sex drive or Testosterone is NOT related to
  Scrotal Circumference
• Scrotal Circumference is related to production of
  sperm numbers

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Libido Terms

• Flehman lip-curl
• Split in upper lip leads to Vomeronasal Duct
• Tongue up towards upper palate
• Tongue compression stroke
• Not in pigs
• Tarbogen - inverted U
• Greatest single stimulus to mount and serve is an
  immobile rear end structure

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Flehman Lip Curl
E.S.E. Hafez
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Libido Measurement in Bulls

• Reaction Time
• Time from male introduction to mating
• Libido Score 1 - 10
• 1 no interest (FSU)
• 10 2 matings (pimp-daddy)
• Serving Capacity
• Number of matings in a given time
• Mounting ability

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Libido Measurement in Bulls

• A study in 2005 observed the effects of
  sequential female introduction in estrus vs.
  group introduction to the bull and the incidence
  of mounting and mating.

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Bailey et al (2005)
Group
Sequential
Greater initial flehman response with a group of
females vs. sequential introduction of females.
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Bailey et al (2005)
Group
Sequential
More females in estrus allowed more mounts when
they were in groups, rather than sequential
addition of females in estrus.
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Bailey et al (2005)
More mean copulations occurred with a group of
females in estrus vs. sequential addition of
females in estrus.
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Libido Measurement in Stallions

• Test Breeding
• Length of time it takes a stallion to cover a
  mare
• Used more for a breeding management tool than to
  test fertility
• More time spent on a stallion that takes 30 min
  to mount a mare vs. an aggressive stallion that
  only takes 2 min to mount

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Libido Female Role

• Bulls are polygamous - distribute their services
  among receptive females
• Will service as many females as possible
• Females in late Proestrus and Estrus tend to form
  a sexually active group
• Females travel to male
• Females newly in heat are most attractive to
  bulls

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Libido Female Role

• Female urination
• Ungulates the presence of male will stimulate
  urination
• Females who are sexually receptive to male
  urinate towards a potential mate
• Sign of estrus in mares

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Libido Livestock Differences

• Bull and Horse
• Eyesight is most important cue to find receptive
  female
• Olfaction less important than eyesight
• Ram
• Olfaction important
• Boar
• Lordosis and Olfaction important

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Libido Social Dominance

• Physically dominant bull inhibits sexual
  performance
• 1 bull can dominate over 4 bulls
• Age and seniority are most important factors
• Breed effects
• Bos taurus dominates Bos indicus

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Libido Rams

• Ram Effect
• Goat and Ram Effects are interchangeable
• Androgen derived but not yet identified
• Olfactory system major role
• Pheromones cause either a direct immediate
  effect or lasting change on recipient
• Wool scent major vector
• Effect on LH release within 20 min
• Rams become more aggressive at end of breeding
  season and tend to injury each other

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Factors Affecting Libido (Summary)

• Age and experience
• Temperament
• Highly aggressive Low libido
• Body condition
• Very fat Low libido

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Factors Affecting Libido (Summary)

• Environment
• Extreme temperature
• Night and Day
• Housing
• Short Day Breeders (Sheep) vs. Long Day Breeders
  (Horses)
• Effect of length of day on hypothalamic-pituitary
  axis (reduction on function and output)
• Genetics
• Breed and species difference
• Social effects