mammary physiology quiz 3

Question 1

subclinical mastitis symptoms

Answer 1

• milk udders appear normal
• milk contains high SCC
• infections are long, sometimes with bouts of clinical symptoms

Question 2

clinical mastitis symptoms

Answer 2

• visual abnormalities in milk
• ## short term infections

Question 3

Effects and treatment of gram negative bacteria

Answer 3

• LPS of cell wall is released along with endotoxins after bacterial death
• not treatable with antibiotics
• more of these cases become clinical

Question 4

Effects and treatment of gram positive bacteria

Answer 4

• contain lipotechoic acid, typically are host adapted
• longer duration infections
• most remain in subclinical state

Question 5

what two pathogens affect the milk, ducts, and parenchyma

Answer 5

strep spp. and S. aureus

Question 6

what three pathogens affect the milk and ducts?

Answer 6

coryne, s. agalactiae, staph spp.

Question 7

what pathogen affects the cow?

Answer 7

mycoplasma

Question 8

what pathogen affects the milk, ducts and cow?

Answer 8

coliforms

Question 9

what type of resistance occurs at a genus/species leve and involves the target organism lacking a binding site?

Answer 9

intrinsic resistance

Question 10

what type of resistance involves a previously susceptible strain of bacteria that becomes resistant due to a mutation or DNA acquisition and causes the potential spread to humans?

Answer 10

acquired resistance

Question 11

what are the three D’s to guide antibiotic therapy decisions

Answer 11

Detect (when was the cow infected?does this require immediate treatment?); Diagnose (is active bacteria still present?); Decision (will antibiotics help this cow?

Question 12

inflammation persist in milk for ______ days with or without a biological cure

Answer 12

3-5

Question 13

antibiotics are rarely useful for cows with previous diagnosis of _________, > or = 3 previous treatments for ____, >4 months of SCC> ________ cells/mL, and chronic clinical or subclinical mastitis in previous lactations

Answer 13

refractory pathogen; CM; 200,000

Question 14

what are the 5 non-antibiotic treatment options?

Answer 14

• watchful waiting
• dry off affected gland
• divert cow to beef market
• segregate cow and use 1/4 milker
• early dry off of cow

Question 15

Which of the following would most reduce persistency?

a. Fostering a newborn on another dam

b. Missing one milking in a dairy herd milked 3 times per day

c. Late pregnancy (7 months) in a dairy cow

d. Providing a dry or nonlactating period between lactations

e. All of the above would be equivalent

Answer 15

c. Late pregnancy (7 months) in a dairy cow

Question 16

Increased frequency of milking or suckling

a. Reduces metabolic activity of mammary epithelial cells

b. Stimulates daily milk yield

c. Stimulates mammary epithelial cell loss

d. Stimulates the involutionary process

e. All of the above

Answer 16

b. Stimulates daily milk yield

Question 17

Exogenous growth hormone would increase milk yield in cows only if

a. given during the first lactation of a dairy cow’s life

b. a dairy cow is in “positive energy balance”, or has sufficient nutrients available to support increased milk production

c. given during the first week of a cow’s lactation

d. it was given as an oral protein in her feed

Answer 17

b. a dairy cow is in “positive energy balance”, or has sufficient nutrients available to support increased milk production

Question 18

Milk yield is equal in two cows through day 30 of lactation. Beginning on day 31, cow A is injected daily with a high dose of cortisol and cow B is not treated. One week later….

a. Compared to cow B, milk yield would decrease in cow A

b. Compared to cow B, milk yield would increase in cow A

c. Relative to cow B, milk yield would be unaffected in cow A

d. Relative to cow B, endogenous secretion of cortisol would most likely be decreased in cow A

e. More than one answer is correct

Answer 18

e. More than one answer is correct

Question 19

Exogenous estrogen administration has been shown to

a. reduce milk yield in a variety of species

b. inhibit lactation by disrupting myoepithelial cell function

c. affect milk production regardless of whether progesterone is also administered

d. all of the above

Answer 19

d. all of the above

Question 20

Proven strategies for evaluating milk yield in various species include

a. weigh-suckle-weigh

b. litter growth index

c. measurement of total RNA in mammary parenchyma

d. all of the above

Answer 20

d. all of the above

Question 21

In cattle, shortly before milking, most milk is stored where?

Answer 21

within the lumen of the alveoli

Question 22

stimulation of the milk ejection process involves release of a hormone from the…

Answer 22

posterior pituitary gland

Question 23

when is intramammary pressure the greatest?

Answer 23

during the initial phase of milking

Question 24

oxytocin is synthesized in ribosomes of the

a. Herring bodies

b. Neurophysins

c. Paraventricular nucleus of the hypothalamus

d. Posterior lobe of the posterior pituitary

e. Supraoptic nucleus of the hypothalamus

f. More than one answer but not all are correct

Answer 24

f. More than one answer but not all are correct

Question 25

Efficient milk ejection relies on a. contraction of myoepithelial cells following cortisol binding b. interaction of offspring and mother c. normal blood flow to the gland d. estrogen priming of receptors e. more than one but not all of the above are correct

Answer 25

e. more than one but not all of the above are correct

Question 26

Milk ejection a. can be initiated by a single piglet in between regular bouts of nursing by the rest of the litter b. occurs at regular intervals that differ by species c. always occurs within the half-life of oxytocin (1 minute) following beginning of stimulation of the teat d. none of the above

Answer 26

b. occurs at regular intervals that differ by species

Question 27

Mastitis affects the mammary gland and body by what two modes?

Answer 27

- causing epithelial cell apoptosis and decreasing their activity - elevating number of leukocytes

Question 28

what organism cases clinical mastitis most often?

Answer 28

coliforms

Question 29

factors influencing the risk for acquiring mastitis include: (4)

Answer 29

- environmental cleanliness - exposure to bacteria - health of animal - virulence of pathogen

Question 30

why is mastitis risk higher at the time of dry-off? give two reasons

Answer 30

- intramammary pressure increasees with the end of milk removal - milking helps flush out bacteria from teat

Question 31

apoptosis describes the process whereby ________ during ________

Answer 31

epithelial cells die; involution

Question 32

Milk synthesis depends on intracellular milk synthesis in the ___________, as well as the passage of milk from the __________ into the ________

Answer 32

alveolar epithelium; cytoplasm; alveolar lumen

Question 33

galactopoieses is the...

Answer 33

maintenance of milk secretion

Question 34

what factors cause active vs. passive milk withdrawal

Answer 34

- active: oxytocin stimulation - passive: suckling

Question 35

maintaining lactation requires the maintenance of what three factors?

Answer 35

- number of mammary cells - cellular synthetic activity - milk ejection efficiency

Question 36

persistency is...

Answer 36

the degree to which milk yield is maintained; function of mammary cell number

Question 37

when insulin is elevated, nutrients are partitioned more toward _____ and not ____

Answer 37

body tissues; milk

Question 38

estradiol inhibits lactation in women by

Answer 38

disrupting myofibrils in myoepithelial cells

Question 39

the inhibition of milk secretion that accompanies increasing intra-mammary pressure is probably caused by a chemical inhibitor called the

Answer 39

Feedback inhibitor of Lactation (FIL)

Question 40

nerve transmissions - afferent _____, efferent _____

Answer 40

arrives, exits

Question 40

increasing milking frequency ______ intramammary pressure and _______ milk yield

Answer 40

decreases; increases

Question 41

oxytocin is synthesized in the _________ and _______ of the hypothalamus

Answer 41

PVN (paraventricular nucleus); SON (supraoptic nucleus)

Question 42

There are two ways milk ejection is inhibited. ______ involves decreased oxytocin release from the posterior pituitary gland; _____ involves decreased oxytocin at the mammary gland mediated by release of epinephrine and norepinephrine from the adrenal glands

Answer 42

central inhibition; peripheral inhibition

Question 43

name the four stages of milk ejection

Answer 43

massage phase, non-nutritive sucking phase, nutritive phase, post-massage phase

Question 44

______ may initiate an irreversible involution of mammary epithelium in that lactation

Answer 44

delay in milk removal

Question 45

mammary epithelium is increasingly sensitive to ____ with advancing lactation

Answer 45

oxytocin

Question 46

involution - changes in epithelial cells

Answer 46

- decrease in metabolic activity, alveolar size/shape, and volume/number of alveoli - increased visibility of connective tissue - cessation of milking -> increased intra-alveolar pressure -> increased presence of lysosomes -> more phagoctyosis - secretions contain more immune cells and lactoferrin - by the end of involution, gland resembles that of a virgin animal

Question 47

remodeling/involution occurs in what three phases?

Answer 47

active involution, steady state, mammogenesis/re-development

Question 48

changes in alveolar fluid compounds

Answer 48

- concentrations of lactose, casein, and milk fat decline - lactoferrin increases - immunoglobulins and serum albumin increase

Question 49

continuously milked cells _____ turnover of cells

Answer 49

decreases