Lactation Flashcards Preview

ANSC exam 3 (last part before final) > Lactation > Flashcards

Flashcards in Lactation Deck (41):

what is the mammary gland

milk secreting structure
1. teat
2. duct system
3. lobes


what is the udder

complex organ made up of a series of systems


what are the different systems in the udder

supportive system
secretory system
duct system
blood, lymph and nerve systems


describe the udder of a cow

1. two separate halves
2. 4 separate mammary glands
3. it is an exocrine gland


When is the greatest growth of the udder and when does the growing stop

1. greatest growth between 1st and 2nd lactation
2. stops growing after 5 years of age


describe 4 things about the mammary gland

1. specialized skin glands
2. produce colostrum
3. present in males and females
4. number and appearance differs among species


what are the 2 parts of the mammary gland support system and describe them

1. Lateral Suspensory Ligament (LSL)
-extends along both sides of udder to midline
-connects to MSL
2. Medial Suspensory Ligament ( MSL)
-provides most support and elasticity
-creates 2 distinct halves between left and right


in what species do two glands drain to 1 teat

sows (10-14 teats)
mares (2 teats)
queens (10 teats)
bitches (8-12 teats)


what is a function of a teat besides excretion of milk

main barrier against infection


how many glands per teat in cows and ewes

1 gland per teat


what are the 6 parts of a mammary gland

1. streak canal
2. teat cistern
3. gland cistern
4. duct system
5. lobule
6. alveoli


what is the streak canal

first part of the teat
1. milk passes before expulsion
2. keratin plug will form to prevent entrance of bacteria
3. surrounded by teat sphincter muscle to prevent leaking


what is the teat cistern of milk prior to suckling or milking
2. holds 100-400 mL of milk


what is the gland cistern

common pooling area for milk from duct system


what is the duct system

1. TRANSPORTS milk from lobule to gland cistern
2. consists of 1st and 2nd degree ducts
3. non secretory


what is the lobule

each lobule contains 150 to 220 alveoli
This is the place where milk is actually produces


what are alveoli and what are their 3 functions

they are the producers of milk

1. remove nutrients
2. transform into milk
3. discharges into duct system


What makes up the alveolus

1. lumen: opening of alveolus that collects milk
2. epithelial cells: secreting cells of alveolus
3. duct: transports milk from the alveolus to the gland cistern
4. myoepithelium: muscle cells that contract in response to oxytocin
5. arterioles and venuoles: provide blood flow
-brings substrates for milk production


how many liters of blood must flow to the udder to make 1 liter of milk



describe mammary gland before birth

very immature gland
duct system is initiated
non functional teats present


describe mammary gland at birth

glands and teats are present
streak canal
teat and gland cistern
rudimentary collecting ducts


describe mammary gland from birth to puberty

1.immature gland grows in size and function
2. grow at similar rate to rest of body
3. growth initiated by growth hormones release from pituitary gland


describe mammary gland from puberty to pregnancy

1. glands grow with each additional estrous cycle
2. sex hormones (progesterone and estrogen) produces by ovary simulate growth
3. growth is more rapid than the rest of the body


mammary gland during pregnacy

1. progesterone produced by placenta stimulates lobular development
2. preparation for nursing by young


mammary gland during lactation

1. high levels of prolactin secreted by pituitary gland time of birth
2. lobules grow substantially
3. prolactin initiates and maintains milk secretion by mammary gland


mammary gland during involution

1. at end of lactation or weaning the gland returns to normal state and size


what is colostrum

1. first milk produced
2. provide extra nutrients and immune fuction
-nonfat solids
- immunoglobins


what is passive immune transfer with relation to colostrum

1. immune system develops after birth
2. contains immunoglobins or other antibodies
3. inadequate intake increases sickness and death


absorption of colostrum

1. only 24 hours after birth
2. gut starts to close not allowing proteins to be absorbed
*requires about 5% of body weight in colostrum


in the production of milk, what are the screening components of blood and what is synthesized in cellular metabolism

1. screen components
2. synthesis of cellular metabolism


what hormone is released for milk let down

oxytocin (stimulates myoepithelial cells of alveolus


how long does it take for the gland to be refilled with milk

6 hours


what are the main components of milk



describe Milk Carbs

1. lactose primary sugar
2. synthesized by epithelial cells of alveoli
3. glucose and galactose (disaccharide)
4. broken down in small intestine by enzyme lactase


describe milk proteins

1. casein primary protein
-80% of milk protein
2. milk serum proteins (larger than casein)
-18% proteins-whey
3. provide high levels of amino acids to consumers


describe casein

1. primary milk protein
2. synthesized by epithelial cells of alveoli
3. found in the form of casein micelles
4. negatively charged
5. pulls calcium of of the blood
6. essential for cheese making process


describe milk lipids

1. % varies by species
2. triglycerides make up more than 90% of solids
-source of fatty acids


what percent of milk lipids do dairy cows and seals have

1. cows milk consists of 3.5%
2. seals 50%


describe milk fat

1. fat content of milk influenced by diet
2. high fiber diets-more acetate- increase milk fat %
3. milk fat % receives lower emphasis than milk production
4. cows are fed to maintain adequate milk fat (3.5%)


minerals in milk

excellent source of calcium
estrogen important for protecting bone matrix


one problem with high producing cows

more calcium pulled from blood can mean milk fever