Lactation

Question 1

Lactation

Answer 1

the production of milk by the mammary gland

Question 2

What gland is the mammary gland?

Answer 2

exocrine gland

Question 3

What does the mammary gland produce?

Answer 3

the external secretion of milk transported through a series of ducts

Question 4

What is the udder supported by?

Answer 4

horizontally and laterally by suspensory ligaments

Question 5

What is the purpose of lactation?

Answer 5

-provide nutrition to offspring
-passive immunity source

Question 6

How many teats do cows have?

Answer 6

4 - each with their own mammary gland

Question 7

Alveoli

Answer 7

-secretory tissue of the mammary glands
-appear as sac like structures
-lined with epithelial cells that produce milk
-millions within each mammary gland
-each has its own blood supply

Question 8

Epithelial cells

Answer 8

secretory cells that produce milk during lactation
-line the alveoli

Question 9

Where does alveoli empty the milk produced into?

Answer 9

ducts that eventually lead to the gland cistern

Question 10

Orifice

Answer 10

-opening to the papillary duct
-normally held closed by the sphincter muscle in the wall of the teat and elastic tissue
-invasion here is the primary route inf most cases of mastitis

Question 11

Streak canal

Answer 11

-located at the end of each teat
-1/4-1/2 in long
-made up of extensions of the skin that lie close together
-held closed by sphincter muscles
-prevents the escape of milk between milking
-acts as a barrier to the entry of bacteria

Question 12

Teat cistern

Answer 12

-final storage area of milk
-base of the udder
-large collection area
-milk letdown

Question 13

Gland cistern

Answer 13

-bottom of udder
-located just above the teat cistern
-acts as a milk reservoir

Question 14

Supramammary lymph glands

Answer 14

act as filters that destroy and remove bacteria from the udder

Question 15

Supernumerary teats

Answer 15

-50% heifers
-extra teats (functional)
-usually removed

Question 16

What happens when a cow is milked?

Answer 16

1.sphincter muscles relax
2. the orifice opens
3. the streak canal opens and remains open for one hour after milking

Question 17

Estrogen function in mammary growth

Answer 17

responsible for the growth of the primary and secondary ducts and teat and gland cisterns

Question 18

Progesterone in mammary growth

Answer 18

stimulates the growth of the alveoli

Question 19

What is responsible for the initiation of lactation?

Answer 19

growth hormone, adrenal corticoids, and prolactin

Question 20

Oxytocin role in mammary growth

Answer 20

released by suckling reflex; contraction of the myoepithelial cells in the alveoli

Question 21

What happens when milking/suckling stops?

Answer 21

alveoli distend and the capillaries fill with blood

Question 22

Factors affecting milk production

Answer 22

-inheritance/genetics
-feed
-management
-health
-sex of offspring (increased for male; decreased for female)
-# of offspring (increased for more offspring)
-age (really young or really old is a decreased milk production)

Question 23

Colostrum

Answer 23

-first milk females produce after calving
-milk obtained during the first milking
-it contains more proteins, minerals, and milk fat
-less lactose

Question 24

Transition milk

Answer 24

the next several milking after the colostrum

Question 25

Immunoglobulins

Answer 25

-involved in passive immunity
-necessary for the fetal immune system to survive
-sometimes they are transferred in utero through the bloodstream
-usually transferred through colostrum
-give protection from harmful microorganism that invade the body and cause illness

Question 26

Milk fat

Answer 26

-mixture of lipids existing as microscopic globules suspended in milk
-fat soluble vitamins are components
-contains more flavor

Question 27

Carbohydrates

Answer 27

-lactose is the predominant carb in milk
-milk is the only natural source of lactose
-synthesized in the mammary gland
-4.8% of milk is lactose
-accounts for 30% of total calories in milk
-1/6 as sweet as sucrose

Question 28

Proteins

Answer 28

-high quality
-3.3% protein
-22% of the calories in whole milk
-Casein is the main protein (only found in milk)
-contains whey proteins lactalbumin and lactoglobulin

Question 29

Vitamins

Answer 29

all vitamins essential for humans nutrition are found in milk

Question 30

Minerals

Answer 30

rich source of calcium and a good source of phosphorus and zinc