The flashcards below were created by user
saunde86
on FreezingBlue Flashcards.
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what does stress do to lactating animals?
releases norepinephrine that blocks oxytocin, decreases capillary blood flow and constricts ducts (less milk production)
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What does oxytocin do to myopthilium?
contracts it and increases alveolar and intramamary pressure.
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what does oxytocin do to mammary ducts?
dilates the terminal and capillary ducts from the alveolus
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what effect does oxytocin have on blood flow?
it increases the cardiac output to the heart
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what is the timing of oxytocin?
from stimulus to contraction is about 20-60 sec. attach unit opne min after stimulus
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what is the reflex arc for milk ejection?
exteroceptive stimulus, CNS, cerebral cortex, hypothalmus, anterior pituitary, oxytocin action.
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what effect does photo period have on lactating animals?
extended photo period (16hrs per day) increases mamary output and persistency.
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what are targets for oxytocin?
myoepethilian cells, terminal ducts, and precappilary sphincter
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what factors effect milk yield?
Age, parity, pressure, photoperiod, and ambient temperature.
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why do long photoperiods effect milk yield?
light increases prolactin levels in serum, which allows for more milk production. (transcription of milk protein)
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what does a pregnancy do to milk yield?
it decreases yield as the number of cells starts to taper off.
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what is residual milk?
15-20% of milk product that cannot be gathered.
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what are the galactopoetic hormones?
prolactin, cortoicosteroids, oxytocin, and GH (IGF-1)
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what are the determining factors of galactopoeisis?
number of secretory cells, metabolic activity, and efficiency of milk ejection.
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what is galactopoiesis?
to enhance or sustain an established lactation.
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what are lactogenic hormones?
progesterone withdrawl, increase glucocorticoid/prolactin
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why is a dry period neccessary for lactation?
because without a dry period the subsequent milk yield would be around 30% less.
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what is involution?
natural regression of MG after peak lactation.
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for mammiogenesis what do estrogens do?
assist mammary duct growth.
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for mammiogenisis what what do progesterone & estrogen do?
assist lobular and alveolar growth.
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what is the blood:milk unit ratio?
500 units blood= 1 unit milk.
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what effect does over feeding have on mammary development?
critical period 3 months of age over feeding can increase extra parenchymal fat and decrease milk production (permanent effect) and parenchymal tissue growth.
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what is mamiogenesis?
growth and morphological development of mammary tissue.
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what is lactogenesis?
last stages of biochemical and structural differentiation of alveolar epithilial cells during periparturient period.
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what is the expected serving capacity for a yearling bull?
1-15 in 60 days.
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what is the expected serving capacity for 2 year old bulls?
25-30 in 60 days.
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what is the expected serving capacity for 3 year on older bulls?
40-50 in 60 days.
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Ram yearling serving capacity?
15-25 in 60 days.
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ram mature serving capacity?
30-50 in 60 days.
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boar serving 8.5-12 months age?
1 ejaculation per day, 7/week, 8-10 services per month.
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boar greater than 12 months serving?
2 ejaculations/day, 10/week, 10-12 services/ month
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