Animal Science > Lactation > Flashcards

Lactation Flashcards

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1
Q

3 main classes of mammary

A

monotremes
marsupials
placental mammals

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2
Q

monotremes

A

egg laying mammals
lack teats
milk is secreted from tubular glands onto stiff mammary hairs where it is consumed by the young
no storage of milk

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3
Q

marsupials

A

pouched animals
although not all have pouches
short gestation- 13-40 with very simple placental development
live young are born and travel to pouch where they attach to a teat and lactation is stimulated

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4
Q

Abdominal teats

A

teats on the abdomin, ex dogs, pigs

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5
Q

pectoral teats

A

teats on the chest, ex. humans, chimps, elephants

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6
Q

inguinal teats

A

between the rear legs, ex. cows, horses, sheep goats

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7
Q

what % of milk do the rear quarters on a cow produce

A

55-65%

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8
Q

how much does an udder on a cow weigh

A

25-60lbs

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9
Q

What is the mammary gland

A

modified skin, and it lies outside the body cavity

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10
Q

cow udders support system

A

skin, connective tissue, and suspensory ligaments

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11
Q

suspensory ligaments

A

-lack of ligament, no intramammary groove, heavy sagging udder
-median suspensory ligament forms intramammary groove
-lateral suspensory ligament

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12
Q

coarse areolar connective tissue

A

-forms fore udder attachment to abdominal wall

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13
Q

teats

A

no hair or sweat glands on the teats
usually 4,sometimes more

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14
Q

supermammary teats

A

extra teats (>4), mostly non functional

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15
Q

average teat length, front and rear

A

front: 6.6 cm, rear: 5.2 cm

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16
Q

average teat diameter, front and rear

A

front: 2.9 cm, rear: 2.6

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17
Q

Streak/teat canal

A

-barrier between the outside world and the sterile world of the udder, main barrier against infection
- the name of the opening by which milk exits the teat
-lengths by a small amount with subsequent lactations

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18
Q

what is the streak filled with?

A

keratin

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19
Q

what does keratin in the streak canal do?

A

this keratin plug seals the canal and has antimicrobial properties

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20
Q

teat cistern

A

-storage cavity
-space between the annular folds and streak canal

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21
Q

annular fold

A

between teat and gland cistern

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22
Q

secretory tissue

A

-alveoli (alveolus)= basic milk production unit (storage of milk)
-1 mill/cubic in
-bill/udder
-separate blood supply to each alveolus

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23
Q

gland cistern

A

-opens to teat cistern
-storage structure for milk

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24
Q

myoepithelial cells

A

-contractile cells that squeeze the alveoli
-are responsible for milk let down
-respond to oxytocin(tells animal to release milk)

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25
how many units of blood does it take to produce 1unit of milk
500 units
26
myo means what
muscle
27
true or false? the udder is very vascular
true
28
how much blood makes up the body in a lactating cow
8%
29
what hormones peak to stimulate mammary glands to milk
prolactin and oxytocin
30
lactogenesis
proccess of milk production during pregnacy and after birth
31
what is produced first?
colostrum, (colostrumgenesis)
32
colostrum
most nutritious, vitamins and minerals, high immunoglobulin levels, only source of passive transfer of antibodies in some species
33
antibodies passed on through what
either the placenta or colostrum
34
Antibodies
Antibodies are made by the dam’s immune cells as a response to an antigen * Fungi * Bacteria * Viruses Antibodies are specific for different antigens and attack the antigen when it is recognized Just before parturition antibodies accumulate in the mammary gland
34
35
when is peak lactation in dairy cows and goats
cows:50-70 days post calving-in excess of 100lbs of milk/day goats:30-45 days post kidding- 9.4lbs
36
what is galactopiesis
maintenance of milk
37
what is galactopiesis determined by
Determined by genetics, nutrition, disease, frequency and completeness of milking (more frequently milk has makes higher milk production)
38
what hormones are involved in galactopiesis
prolactin, growth hormones (bovine somatatropin (BST)), thyroid hormones
39
what is BST
bovine somatatropin, a protein hormone that cows naturally produce in their pituitary glands to regulate growth and milk production
40
milk ejection/let down
-most of milk stored in alveoli -w/out proper stimulation this milk is not let down -a smaller portion of milk is stored in the cistern and this milk does not need to be let down
41
what is the key hormone of milk let down
oxytocin
42
what is oxytocin produced in and released from
produced in the hypothalamus and stored and then released from the posterior pituitary
43
milk let down reflex
-udder stimulation or other stimulus -nerve impulses from the spinal cord to the brian -release oxytocin from the posterior pituitary
44
how is oxytocin carried
in the blood to myoepithelial cells in the mammary gland -myoepithelial cells contract -milk forced into the cistern -pressure of milk in the cistern increases oxytocin release
45
milk let down reflex, neural stimulation
primary stimulation is tactile stimulation of the teats -pre stripping -calf bucking at udder and suckling the teat
46
milk let down reflex, visual and auditory clues
-seeing a calf -entering the parlor -hearing the sounds in the parlor
47
how long does it take oxytocin to respond after stimulation
1-2 minutes
48
what is the half life of oxytocin
30s-3.5 minutes
49
what does stress do to milk production
inhibits milk ejection by causing release of stress hormones from the adrenal gland
50
epinephrine
adrenalin, hormone produced when stressed or scared
51
norepinephrine
noradrenaline, chemical/hormone released when stressed or scared
52
what does blood do during a fight or flight response
redirected to the extremities and away from the myoepithelial cells
53
what happens to the myoepithelial cells during stress
they do not receive the chemical signal to contract = no milk let down
54
stress hormones also inhibit release of _________ from the posterior pituitary
oxytocin
55
what is involution
-decrease weight, volume and productivity of the mammary gland -starts following peak lactation -decrease in alveoli size in dairy cattle
56
what happens during the approach of the next parturition
regrowth of mammary gland
57
lactation curve
graphic plot of milk volume over time
58
how long does the teat spincter remain open for after milking
15-60 minutes
59
mastitis effects
clots and flaky teats, high somatic cell count, may cause death, treatment is antibiotics, then milk must be dumped
60
prevention of mastitis
keep a cleaned and sanitized environment to minimize infection, decrease stress, pre and post milk dip
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