Class X Graduate Paper

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Class XGraduate Paper

• Role of mother-young interactions
• in the survival of offspring
• in domestic mammals
• Nowak et al

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Care of young essential for the survival of
mammals Pattern of mother-young interactions
vary according to developmental status of neonate
and litter size Altricial young large litters,
not fully developed, interactions do not imply
mutual recognition Precocial young small
litters, fully developed, inter-individual
recognition Intermediate type functional
sensory systems, but inefficient thermoregulation
and limited locomotor capabilities
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Mothers face common and specific
problems Comparing Altricial rabbit Precocial
ruminants (sheep, goats, cattle) Intermediate
pig
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Parental investment Individuals who produce a
large number of surviving, reproductively capable
offspring pass on more of their
genes Mammals effective reproduction more
than fertilization, gestation and birth! ?
Neonates are entirely dependent upon the care and
resources provided by the mother
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Offspring care substantial cost expenditure
of metabolic energy for milk production, thermal
regulation, and increased risk of
predation Natural selection favors mechanisms to
ensure that offspring benefit of parental
investments and not unrelated young ? when young
are likely to intermingle, mothers rapidly
develop the ability to recognize their offspring
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Young born in isolation ? little need for the
mother to recognize her offspring Communication!
? of needs Recognition of mother in species
where adults reject, react aggressively to, or
even cannibalize strange offspring
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Mother young interactions Onset related to
onset of birth ? facilitate maternal
responsiveness Not periparturient or lactating
aggressive towards young or avoiding
them Parturient rabbit, sow and ewe rapid
change in ovarian steroids plasma progesterone
?, oestradiol ?, prolactine ?, oxytocin ?
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Hormones involved in maternal behaviors, such as
nest building in rabbit and sows, not in sheep
and goats ? vagino-cervical stimulation
(expulsion of the fetus) important for
development of maternal behavior in sheep and
goats
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Behavioral aspects Rabbits digging a burrow and
collect straw and grass, pulling hair to line the
nest Sows building a nest of grass and small
branches Nest aiding in thermoregulatory
abilities
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Rabbits born small, lack fur, have reduced
thermoregulatory abilities Birth mother licks
her young, ingests placenta and engages in
nursing Pigs free themselves from their fetal
membranes without assistance Sows rudimentary
maternal care, devours placenta but does not lick
neonates and doesnt assist them in teat-seeking
activity
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Goats, sheep, cattle pre-birth females isolate
themselves from the flock important for
mother-young bond ? protects from disturbances
and facilitates early interactions Birth
mother licks the neonate and fetal fluids, birth
membranes are consumed Buffalos and wildebeests
give birth within the herd Suppression of visual
or auditory cues from the lamb, and licking or
nursing is without consequences ? Suppression of
olfactory cues is detrimental for maternal
acceptance
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• Grooming
• Fetal membranes around head may lead to
  suffocation
• Removal of birth fluids may help dry the coat
  and reduce heat loss
• Licking may stimulate teat-seeking activity and
  contribute to early bonding
• Placentophagia minimizes risk of predation by
  removing olfactory traces
• Also improved milk production
• Vocalizations orient the young towards the
  maternal body and provide cues for later
  recognition

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• Teat seeking and nursing behavior
• Immediately after birth neonate starts exploring
  mothers body
• Contact with sensory cues facilitate location of
  the udder
• Rabbits mother emits odor signal from ventrum ?
• Triggers nipple-searching behavior
• Mother-young interaction only during nursing,
  once a day, 3-5 min

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• Pigs mother remains recumbent, allowing the
  young to follow the surface of the body until
  they reach the ventrum
• Sows olfactory, tactile and thermal cues to
  locate the udder
• Piglets move with the direction of sows hair
  growth
• Up to 12 h after parturition piglet can obtain
  milk continuously
• After 12 h release of milk becomes cyclic and
  sow develops a regular lactation sequence

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Teat order after 4 days ? is maintained when
supply is adequate Sight, smell and recognition
of neighbors involved in location of the
teat Lambs (ruminants) are attracted to their
mother by sight and hearing First contact is made
with her chest of flank ? Udder seeking by
thermotactile and olfactory cues ? Touch on the
face activates oral exploration and head
movements warm, smooth, non-wooly surfaces
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First day after birth lambs are allowed to suck
at any time and for as long as they
wish Afterwards ewes restrict the frequency and
duration by walking away from the lamb
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• Recognition between mother and young
• Preferential treatment of biological offspring
• Ability of parent to discriminate between own and
  alien young
• In some species true recognition is lacking
• Parental behavior spaced proximity ? animals
  respond to all others found within the location
• Ground-squirrels and altricial young before
  leaving the nest

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• Sows cannot recognize their litter in the days
  after parturition but do identify nest site
• Recognition of litter by 7 days after birth,
  exclusively by smell
• At 9 days sow abandons nest and piglets
• Sow does not respond to piglets that remain in
  nest and makes not attempt to fetch them ?
• Sow recognizes litter but not piglet
• Piglets recognize maternal odors and grunts by 36
  h

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• Ruminant mothers recognize young rapidly and
  reject alien offspring (2-4 h after birth)
• Olfactory clues but also vision and audition
  (recognizing at distance)
• Lambs recognize mothers by visual, vocal and
  behavioral cues (1 day)

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• Inadequate parent-young interactions
• Offspring mortality highest in first few days
  after birth ? transition from intrauterine life
  to extra-uterine life
• Birth process ? dystocia
• After birth ? survival of newborn mainly
  dependent on mother

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• Abnormal maternal behavior of inexperienced
  mothers is possible cause of mortality
• Rabbits improve nests with successive
  parturitions, visit nest more often (wounding and
  soiling of the nest) ? pup survival
• Primiparous ewes show temporary delays in
  expression of maternal care
• Primiparous sows may show aggressive behavior
• Rabbits and sows cannibalism

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• Litter size
• Ungulates with more than one offspring show more
  maternal care but not twice as much
• Higher chance of loosing half a twin in a field
  situation
• Risk of uneven maternal bonding
• Strength of bonding improves with experience

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• Behavior of neonate
• Major survival factor maintaining homeothermy
• Early access to the udder/nipple for colostrum
  intake (immunoglobulins)
• Delayed ingestion of colostrum high incidence
  of loss of mother-young contact
• Pigs competition among litter mates
• More efficiently stimulating piglets at the cost
  of other piglets