Lactation

Question 1

Lactation

Answer 1

• the process of producing milk following parturition
• the defining feature of mammals
• provides nourishment of neonatal offspring

Question 2

milk

Answer 2

• secreted by cells contained in the mammary gland
• a balanced ration
• contains: water, protein, carbohydrate, fat, vitamins, and minerals

Question 3

milk components

Answer 3

protein (3.2% in cow milk)
-casine (80%) (cheese) and whey (20%)
carbohydrates (4.5%) in cow milk)
-lactose (glucose and galactose)
fat (3.5% in cow milk)
-triglycerides (butter)
minerals (Ca, P)
vitamins (all vitamins)
-vik k is low, commercial milk D fortified

Question 4

mammary glands

Answer 4

primary structure responsible for milk production = alveoli
huge blood supply required for delivery of
-glucose (lactose synthesis)
-amino acids (protein synthesis)
-acetate and long chain fatty acids (milk fat)

Question 5

myoepithelial cells

Answer 5

specialized muscle cells
respond to oxytocin
contract (a bit) to eject milk into ducts
called "milk let down"
-more correctly "milk ejection"

Question 6

mammary epithelial cells

Answer 6

linked together by tight junctions
absorb nutrients from blood (e.g. glucose and AA)
synthesize milk components (e.g. lactose, casein and milk fat)
secrete products into alveolar lumen
milk is stored into alveolar lumen until milk letdown

Question 7

stages of lactation

Answer 7

mammogenesis
lactogenesis
galactopoiesis (stage 3 lactogenesis)
mammary involution

Question 8

mammogenesis

Answer 8

development of the mammary gland

Question 9

lactogenesis

Answer 9

final differentiation of mammary epithelial cell
ability to produce milk
STAGE 1: immunoglobulin uptake, colostrum
STAGE 2: milk secretion begins

Question 10

galactopoisis

Answer 10

stage 3 lactogenesis

production and maintenance of milk production

Question 11

mammary involution

Answer 11

following cessation of lactation

Question 12

colostrum

Answer 12

first milk
concentrated nutrient supply
high in immunoglobulins (antibodies)
antibody transfer to neonate (very important in some species)
-passive transfer

Question 13

passive transfer

Answer 13

(of immunoglobulins)
extremely important in cow, mare, pig to provide early immunity to disease
less important in human, dog, rodent
-importance depends on ability of antibodies to cross placenta to fetus
colostrum must be delivered in 1st day of life or antibodies won’t be absorbed intact

Question 14

BST

Answer 14

bovine somatotropin aka bGH bovine growth hormone
results in 10-15% inc. in milk production
-cow inc. feed intake to meet demand
-thus extra milk is not free but is on top of maintenance requirements already being paid for

Question 15

beginning of lactation: the transition period

Answer 15

often associated w/ neg energy balance 
-mobilization of body reserves (fat)
-loss of body weight
metabolic disease - ketosis
mammary infection - mastitis 
parturition paresis - milk fever
-due to low levels blood Ca
-results in compromised ability of muscles to contract
           -muscle weakness