AN SC 431 Nov 16 & 18

20 terms by amk5359 

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Superfetation =

tandem pregnancies → 2 offspring (or litters) are delivered at intervals equal to 1 or 2 estrous/menstrual cycles
* live offspring, normal birthweight, normal developmental signs

another word for tandem pregnancies


obstacles to superfetation (4)

1. ovulation during pregnancy
2. estrus, sperm transport through cervix, etc.
3. embryo transport to uterus
4. controlled contractions of uterus at 1st delivery

one possible explanation for superfetation

anatomical differences

problems associated with superfetation (3)

1. competition within the uterus
2. lactation
3. colostrum
*note: freemartinism is not a problem

goal of reproduction

to have offspring that will, in turn, reproduce

what is the term for the mammary gland and what type of gland is it?

mammae = breast or milk-forming gland → skin gland

phylogeny & class of lactating animals

kingdom: animal
class: mammalia

mammary glands are specialized glands that consist of...

a teat or nipple and their associated ducts & alveoli

mammary gland species variation:
1. cow
2. sow
3. human
4. mouse

1. 4 mammary glands; inguinal region
2. 14 teats; thor-abdom-inguinal region
3. 2 mammary glands; thoracic region
4. 8-10 glands; thor-abdom-inguinal region

relationships between lactation & reproduction (3)

1. lactation occurs after conception & pregnancy → ovaries affect MGs
2. lactational anestrus (varies among species)
3. endocrine changes during lactation lead to suppressed FSH & LH secretion and affect ovarian function

species variation in length of lactational anestrus

cow < ewe & mare < sow & rodents (entire length of lactation)

specific links between reproductive organs & mammary glands (3)

1. onset of puberty in female → increased mammary growth caused by E2 & P4 from ovaries
2. MGs grow & regress with each estrous cycle
3. most mammary cell mitotic division occurs during pregnancy (induced by E2, P4, PRL & PL (placental lactogen))

onset of milk secretion occurs when?

at parturition

mammary life cycle (4 stages + details)

1. mammogenesis → development of MG to point where it can secrete milk
2. lactogenesis → beginning of milk secretion
3. galactopoiesis → maintenance of milk secretion once it begins
4. involution → regression of MG to non-functional status ("dry period")

why do newborns need milk? (5)

1. milk has readily digestible energy for homeothermy
2. colostrum: immunoglobulins for passive immunity
3. milk is easily digested
4. acts as a probiotic
5. hormonal effects and more...

composition of milk: notable feature in...
1. human
2. mare
3. porpoise

1. high lactose
2. high protein
3. low water & high fat → important for warmth

benefits of breast feeding in humans (5)

1. maternal-infant psychological bonding
2. economical (very important for poor people)
3. reduces later development of bovine milk allergies
4. provides mom with some protection against breast cancer
5. decreases likelihood of obesity in child

lactation can be induced by... (3)

1. neurological stimulation
2. hormonal
3. psychosomatic

lactation problems (5)

1. agalactia → failure to produce milk
2. mastitis → inflammation/infection of MG (sometimes associated with metritis → uterine infection)
3. behavioral issues with dam → lactating, but won't let young nurse
4. precocious lactation → causes loss of colostrum
5. insufficiency

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