L22- Milk Prod and Ketosis (#4) Flashcards
3 general developmental processes culminate in milk secreiton- what are they?
- Mammogenesis
- Lactogenesis
- Galactopoiesis
What is mammogenesis?
Mammary gland development
What is lactogenesis?
Induction of milk syntehsis
What does lactogenesis involve?
Regulation of gene expression and protein synthesis within the milk secreting epithelial cells
A few of genes turned during lactogenesis code for what 3 things?
- a-lactalbumin (required for lactose synthesis)
- Casein
- Several enzymes needed for Fatty acid synthesis
What is galactopoiesis?
The final stage of lactogenesis and refers to the mainteance of milk synthesis until it is no longer needed during an established lactation
Milking stimulates the release of _______(bST) which helps maintain milk produciton
Bovine somatotropin
Cows are in ________ during the first 12-14 wk of laction
Negative energy blaance
During the first month, cows may obtain one third of their energy needs from body stores resulting in a ______
50-100 lb wt loss!!
AA from lost muscle of cows during demands of milk production are used for _____ and _______
protein synthesis and
Gluconeogenesis
The ______ pathway for plasma components and leukocytes is open ONLY during pregnancy, involution, and inflammatory states like mastitis *
Paracellular*
Step 1 of pathway for milk secretion and synthesis by the mammary epithelial cell
I: Exocytosis of secretory vesicles containing milk protein, lactose, and other components of the aqueous phase
Step 2 of pathway for milk secretion and synthesis by the mammary epithelial cell
II: Milk fat secretion via the Milk fat globule (MFG)
Step 3 of pathway for milk secretion and synthesis by the mammary epithelial cell
III: Direct movement of the monovalent ions and water across the apical membrane of the cell
Step 4 of pathway for milk secretion and synthesis by the mammary epithelial cell
IV: Transcytosis of components of the interstitial space (immunoglobulins)
Step 5 of pathway for milk secretion and synthesis by the mammary epithelial cell
The paracellular pathway for plasma components and leukocytes. pathway V is only open during pregnancy, involution, and in inflammatory states such as mastitis
What is colostrum?
Special milk after parturition that is very high in proteins to act to improve the immune function of the calf
What are milk proteins?
Synthesizes on the RER and move onto the Golgi stacks where they are decorated with oligosacchardies and phosphorylated, etc
Class of milk proteins- describe the 1) solubility in acid, 2) protein(s), and 3) function(s) of WHEY** (vs caseins)!!
Whey (20% of total milk proteins):
-Soluble in acid
-Proteins: B-lactobulin (60% of total whey proteins)
a-Lactalbumin (25% of total whey proteins)
- Function:
B-lactobulin: no clear function possible a dietary protein
a-lactablumin: requred for lactose synthesis
Class of milk proteins- describe the 1) solubility in acid, 2) protein(s), and 3) function(s) of CASEINS** (vs whey)!!
Caseins (80% of total milk proteins): -Insoluble in acid -Proteins: Caseins (a,b,k) - Function: Slows gastric emptying after precipitation, increases bioavailability of Calcium
Casein increase what in milk?
Bioavailability of calcium in milk (15% of calcium in milk is assoc with casein)
Whey proteins have a much higher _____ than casein
Biological value