dairy

Question 1

why is there an increase in jersey cows and other breeds in recent years?

Answer 1

there has been a cultural shift from drinking fluid milk to eating cheese products

Question 2

how long is the lactation cycle

Answer 2

305 days

Question 3

how long is a cow’s gestation period?

Answer 3

283 days

Question 4

what are the 60 days before calving referred to as?

Answer 4

drying

Question 5

what is the purpose of drying?

Answer 5

to renew the udder for lactation with the calf

Question 6

what are the parts of an internal udder structure

Answer 6

lobules (containing the alveolis) –> duct system -> gland system –> gland cistern –> teat cistern –> streak canne

Question 7

internal alveoli structure

Answer 7

epithelial cells (responsible for milk synthesis and secretion)
lumen (responsible for milk components and water)
myoepthelial (responsible for milk ejection)
capillary system (responsible for supplying milk components)

Question 8

how are grades of milk determined

Answer 8

somatic cell count and bacterial count

Question 9

grade a means

Answer 9

scc < 100,000 –> likely not an infection
<1,000,000 bacteria/ml

Question 10

grade b means

Answer 10

scc > 250,000 –> likely an infection
> 1,000,000 bacteria/ml

Question 11

classes of fluid milk

Answer 11

1. fluid milk
2. soft products (yogurts, ice cream, sour cream)
3. cheese
4. butter

Question 12

what is pasteurization

Answer 12

rapid heating and cooling to kill bacteria

Question 13

what is homogenization

Answer 13

separating the fat into smaller equal sized pieces so that it doesn’t rise to the top

Question 14

what are the percentages of average milk composition

Answer 14

water –> 87.7%, fat –> 3.6%, protein –> 3.2%, lactose –> 4.8%, ash/minerals –> .7%

Question 15

what is mastitis

Answer 15

the inflammation of the udder, caused by an infection

Question 16

what are the types of mastitis

Answer 16

clinical –> with visible symptoms
subclinical –> without visible symptoms

Question 17

what is the main test used in diagnosing mastitis?

Answer 17

CMT (california mastitis test)
combine milk with reagent and swirl, it should become very thick and bright purple

Question 18

what is butter

Answer 18

water in fat

Question 19

what is buttermilk

Answer 19

fat in water

Question 20

how is yogurt made

Answer 20

bacteria ferments the milk

Question 21

what is the DHIA and what is it for

Answer 21

Dairy Heard Improvement Association
serves as a record system

Question 22

what is a sire summary

Answer 22

explains the genetic disposition to specific traits (mother and grandmother have higher or lower milk production than the average of the population)

Question 23

why is sexing semen important

Answer 23

can get female sperm because females are more desired

Question 24

what is the average herd size in the US

Answer 24

115

Question 25

where are the most dairy herds located in the US

Answer 25

Wisconsin - 11,000 herds

Question 26

Who produces the most milk in the US

Answer 26

California - 1,500 herds

Question 27

what has been relationships of herd size to production?

Answer 27

herd size is decreasing while production is increasing

Question 28

what are the main trends of milk products

Answer 28

fluid milk consumption has decreased while cheese consumption has increased

Question 29

how has dairy trends affected herds

Answer 29

Holstein herds have decreased, while jersey herds have become more favored bcs of cheese production. crossbreeds are becoming more common

Question 30

what are the steps in milk processing?

Answer 30

pasturization and homogenization

Question 31

how does milk let down occur?

Answer 31

oxytocin is responsible for it touch of udder is a nerve impulse calf/milking machine releases oxytocin

Question 32

key events in a lactation cycle

Answer 32

early lactation, mid lactation, late lactation

Question 33

what aspects are contributing to success in dairy industry

Answer 33

AI, trait selection, maximizing production, DHIA

Question 34

when are calves first bred?

Answer 34

15 months

Question 35

at what age do heifers give birth for the first calf?

Answer 35

24 months

Question 36

after the first calving, when are the cows rebred

Answer 36

at day 80

Question 37

what is the repro cycle of cows

Answer 37

1st calving, 80 days later rebreeding, gestation is 283/5 days, 60 day drying period (365 days)

Question 38

when does early lactiation occur

Answer 38

0-50/60 days in milk

Question 39

when does mid lactation occur

Answer 39

60-175/180 days in milk

Question 40

when does late lactation occur

Answer 40

180-305 days in milk

Question 41

what are the alveoli responsible for

Answer 41

milk synthesis and secretion -- houses the epithelial cells

Question 42

lumen

Answer 42

collects milk components and water

Question 43

myoepithileial cells

Answer 43

milk ejection

Question 44

capillary system

Answer 44

supply milk components

Question 45

how is cheese made

Answer 45

coagulation and separation of curds and whey add rennet, which is a coagulation enzyme remove whey (H2O, lactose, whey protiens)

Question 46

low fat milk

Answer 46

1-2% milk fat

Question 47

skim milk

Answer 47

0% milk fat

Question 48

whole milk

Answer 48

3-4.5% milk fat

Question 49

1/2 & 1/2

Answer 49

18% milk fat

Question 50

heavy cream

Answer 50

35% milk fat