Exam 2: Mammary Gland Flashcards Preview

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Flashcards in Exam 2: Mammary Gland Deck (88)
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1

Herd average milk production for Holstein cows in

US corn silage based systems is _______ lbs per day

65‐85lbs

2

 At the peak of lactation cows may produce ______ lbs of milk per day

100‐140 lbs

3

During milking up to a ______of milk/minute passes through each teat end.

quart

4

The cow has _____ udder(s) and four quarters!   

one

5

The _________ is the most important support structure

and supports and separates the two lateral halves of the udder

median suspensory ligament

6

There is no _________of the duct system between quarters

no crossover

7

The front teats are usually a little _____than the rear teats

larger

8

Teat skin condition, teat end condition and the

_______lining of the streak canal are important factors

in protection against new intra‐mammary infections.

keratin

9

With the exception of some ________infections, which may be seeded into mammary tissue by hematogenous spread,

all mastitis causing bacteria enter through the teat canal (streak canal).   

Mycoplasma mastitis

10

The internal structures of the udder include the

__________consisting of grape‐like clusters of myo‐epithelial alveolar tissue

which express milk under the influence of oxytocin,

the ducts which lead from the secretory tissue,

and the cisterns, including the gland cistern, which opens into the teat cistern.

secretory parenchyma

11

Milk available in the cisterns between milkings amounts to _____ mL in each quarter

100‐400 ml

12

Mammary  tissue develops in the udder at an accelerated rate compared to the tissues of the rest of the body between about 3 months of age and puberty (9 ‐ 11 months).  

This is known as the period of _______ growth.

allometric

13

Underfeeding in this period impairs udder development.  

More importantly, overfeeding during this period can lead to the

deposition of excess fat in the udder and

reduce milk secretion capacity in adult life

Allometric growth period

14

___________is the predominant hormone governing synthesis of milk in cattle (vs.  prolactin in non‐ ruminants)

Growth hormone

15

 Milk ejection (as opposed to milk synthesis) is under the influence of the pituitary hormone _______. 

oxytocin

16

The delay between oxytocin secretion from the pituitary gland and

ejection of milk in the mammary gland

is between 60 and 90 seconds.  

This is known as the _______ time

milk let‐ down time

17

 _______secretion is triggered by stimulation of the mammary gland and teats, and also by other situational triggers, such as entering the milking parlor

Oxytocin

18

The _______is the main barrier to infection entering the tissues of the udder

teat canal

19

Polymorphonuclear leucocytes (known as ______cells) constitute the major cellular response to bacterial infection in the udder, but do not trigger immune memory.

somatic

20

Antibody levels in milk are much ________than those in plasma

lower

21

Although there is an effective vaccine against _____mastitis,

no effective vaccines have been produced

against the other major mastitis pathogens including

environmental streptococci, Streptococcus agalactiae, Staphylococcus aureus and Mycoplasma bovis.

coliform (E.coli)

22

What 3 organisms can cause contagious mastitis?

Staphylococcus aureus

Streptococcus agalactiae

Mycoplasma bovis

23

Mastitis infections are transferred from

teat to teat by ______ (blow‐back of milk droplets into the teat end)

teat‐end impacts

24

________mastitis is transmitted during the milking process as a result of contamination of milking equipment with milk containing mastitis bacteria

Contagious

25

This used to be the most prevalent contagious mastitis organism.  The Five Point Mastitis Control Program was introduced in the 1960’s to control this infection, primarily because of its negative impact on cheese yield.

Streptococcus agalactiae (contagious mastitis)

26

T/F:

 

Streptococcus agalactiae infections

penetrate deeply into the mammary stroma

FALSE

27

T/F:

 

streptococcus agalactiae is commonly resistant to antibiotics

FALSE

28

Recently there has been a resurgence of Streptococcus agalactiae infections because of the movement of infected cattle into _______ herds. 

rapidly expanding

29

Once Streptococcus agalactiae was controlled

________became the most important cause of contagious mastitis.  

Staph aureus

30

Staph aureus causes subclinical and clinical mastitis.  

Some strains cause an acute _______ mastitis which can result in sloughing of the affected quarter.

gangrenous