Exam 4 - Lactation Flashcards
Lactation
A strategy to nourish offspring
Lactation stages
1. __________ – development of the mammary gland
2. ___________ – initiation of milk synthesis and secretion
3. __________ – maintenance of milk secretion
4. ___________ – regression
- Mammogenesis
- Lactogenesis
- Galactopoesis
- Involution
Mammogenesis
Development of the mammary gland, prenatal, peri-pubertal, post-conception
Lactogenesis
Begins with colostrum and involves the initiation of milk synthesis and secretion
Secretory epithelial cells can transfer components directly to the lumen or further process/convert to milk-specific products
In Lactogenesis epithelial cells of the alveoli have three main functions what are they?
- Absorption of nutrients and milk precursors from the blood
- Synthesis of milk specific nutrients
- Transfer of milk components to the lumen of the alveoli
Caseins
Unique to the mammary gland
Pulls calcium with it
Lactose
Regulates water concentration
Along with galactose, unique to the mammary gland
Triglycerides
Given that dietary fiber is the original source of VFAs and VFAs are used to form milk triglycerides that means that dietary fiber regulates milk fat
Immunity
The ability of the body to defend against foreign invaders
Three types of immunity
- Innate
- Adaptive
- Passive
Passive immunity
Ready-made antibodies received by the animal passively (i.e. animal’s own immune system did not have to do the work of making the antibodies)
Passive immunity can be ________ or _______
Natural or artificial
Passive immunity’s protective effect is _________, but antibodies are used up/broken down over time therefore protection is only __________
Immediate; transient
Colostrum
‘first milk’, containing a high concentration of antibodies (i.e. immunoglobulins, IgG)
Species vary in their reliance on _________ __________ ________ as a result of morphological differences of the placenta
Colostral antibody transfer
Ability of the newborn to absorb intact colostrum _________ is a consequence of the maturity of the digestive system; ___________ with age
Proteins; decreases
Antibodies are ______ molecules and absorption must occur ________ intestinal lining becomes impermeable to large proteins. Time of the intestinal closure is ________ _________ but in general the ________ the better.
Large; before; species dependent; earlier
Galactopoesis
Maintenance of milk secretion
Regulation of Milk Movement requires coordination between the ________ and _________ __________
Brain; mammary systems
Milk composition
Contains all the major classes of nutrients and is variable by species and even within species
Involution
Regression of mammary structures
Alveolar tissues collapse with loss of secretory function, but persist with much smaller lumens
Retention of milk in the alveoli ________ as young require less milk and suckle less therefore this leftover milk in the lumen serves as a ________ __________ ________ to the process of milk production
Increases; negative feedback mechanism
What is a dry period
Stage in the lactation cycle when cows are no longer being milked
The absence of a dry period interferes with the increase in cell numbers that normally occurs during the early stages of ________ and would result in substantial ________ in _____ yield
Lactation; decrease in milk
An animal that relies on colostrum
Horses, porcine, goats, bovine, swine
An animal that doesn’t rely on colostrum and have placental antibody transfer
Humans, dogs, mice
If an animal is highly stressed out, what hormone inhibits oxytocin/decreases milk let down?
Epinephrine
_____ contains all the major class of nutrients
Milk
Minerals - the ratio of dietary __ to _ is most important
Ca to P
Major classes of nutrients in milk
Water, lipids, proteins, lactose, minerals, vitamins
Lipids
Globules, mostly triglycerides, lighter than the rest of milk
Milk price is affected by ____ ________
Fat content
Proteins in milk
Casein, whey and immune globulins
Casein
Coagulates at low pH, insoluble, majority of milk protein
Whey
Serum proteins, minority of milk proteins, soluble
Immune globulins
Very small amount in milk, no IgG absorption but IgA acts as a surface protectant for mucosal lining
Lactose
Synthesized only by cells of lactating mammary glands, aqueous, sweet flavor
Amount of lactose produced determines _____ _______
Milk volume
Lactose is broken down by bacteria into _____ ____ and is important in _________ dairy product
Lactic acid; fermented
Lactose intolerance
A sensitivity to lactose caused by greater lactose concentrations present than the body is able to digest, sensitive to the milk carbohydrate, occurs in GI system, regional occurance
Milk allergy
An allergic reaction to milk proteins, triggered by the immune system, should avoid all milk and milk products
The ratio of dietary Ca to P is most important - : to :
1:1 to 1:2
_______ and ___________ are important for growth/maintenance of skeleton
Calcium and phosphorus
Vitamin A in milk
Varies by breed and by environment/feeding practices, green feed increases carotene and therefore vitamin A, less in jerseys and guernseys but more in Holstein, light can destroy vitamin A
Vitamins are necessary for _______ _______
Tissue metabolism
Vitamin D in milk
Not a great source naturally but milk is often fortified with vitamin D
Why is milk fortified with vitamin D
Because vitamin D is needed for proper Ca and P metabolism/absorption of Ca
Milk is a poor source of vitamin __ and __ and generally a good source of vitamin __
E; K; B
Processing steps of milk
Milk is cooled to at least 39 degrees, transported to processing plant, heated to 161 degrees, quickly cooled back down.
