Midterm 1 Flashcards
milk
the physiological secretion produced by the mammary gland of all animals
most valuable ingredients in milk
- protein
- calcium
biological value is the measurement of the ability of a food to
- provide nutrients necessary for nutrition ex. protein, energy (quantity)
- provide essential nutrients the body can’t produce itself (quality)
total biological value of milk vs. cereal
milk: 100
cereal: 60
cows turn low quality roughages into
high quality nutrition
key to avoiding dairy related health issues
moderation and diversity
lactose intolerant
- problem processing the sugars in milk (lactose)
- 25% of US pop
- not allergy to milk
what makes up lactose
glucose + galactose
how to reduce risk of heart disease
- dont smoke
- exercise
- lower stress
what contributes to high cholesterol
20% lifestyle choices
80% genetics
lactose free dairy products
- most cheeses
- butter
osteoporosis
weakening of bones resulting in increased probability of fractures
proteins and carbs - cal per gram
4 cal per gram
fat - cal per gram
9 cal per gram
milk allergy
- disappears with age
- 2-3% humans
- reaction to the protein component of milk
1 milk producing state
-19.5 % of nations milk comes from CA
top dairy breeds
87% Holstein
5.2% Jersey
which state has the most Dairies?
Wisconsin
which state has the most cows?
California
compared to last year we have less cows but _____ milk
more milk
how much does the average milk produced per cow go up per year?
200 lbs
holsteins
- largest dairy breed
- highest production
jerseys
- smallest breed, brown
- highest % fat and protein in milk (rich)
guernsey
-can’t convert beta carotene (yellow pigment) w/ enzymes into white (vitamin A)
5 most common dairy cows most common to least
- holstein
- jersey
- guernseys
- brown swiss
- ayrshires
how many pounds is the average cow
1000 - 2000 lbs
how many pounds is the average bull
2000 - 3000 lbs
when do cows mature physically?
5 years
sperm mature up to 7 years
requirements before breeding a cow
- 13 - 15 months old
- 50 inches tall
- 800 - 850 lbs
- multiple estrous cycles
estrous
21 day cycle
estrus
days / hrs in heat
standing heat / estrus
- time when cow will accept bull sexually
- will allow and jump cows
- 12-18 hrs
gestation period
- 278 - 287 days (9 months)
- deliver first calf around 24 months old
when do cows reach puberty?
6-9 months
how tall are cows
53-58 at withers
largest of four stomachs in the cow
rumen
rumen is designed to digest
high fiber, low quality feeds
length of standard lactation
305 days after calving
what makes up the udder
4 quarters
dry weight of an udder
60 lbs
how much milk does a cow produce per lactation
25,000 - 30,000 lbs/ lactation
how much blood is pumped per gal of milk
400 gal blood per 1 gal milk
how many pounds per gal of milk
8.6 lbs per 1 gal milk
what ligament controls the movement of the udder
median suspensory ligament holds udder up and relaxes to lower
milk letdown
process that allows for removal of milk once udder is properly stimulated
oxytocin
- short half life of 2 min
- acts on myoepithelial cells - contract in reaction to oxytocin and squeeze the milk out thought the duct
peptide based vs. steroid based hormones
- peptide: released from blood, bind to receptor leave body and clear out (ex. oxytocin)
- steroid: released by endocrine gland, long term (ex. estrogen, testosterone)
what does the vacuum do?
- reduces the atmospheric pressure by half
- atmospheric: 30 hg, 760 mm, 100 kPa, 14.7 Psi
- milking: 15 hg, 380 mm, 50 kPa, 7.4 Psi
milking parlor at CP
double 10 parallel
% fat in natural milk
3.7 %
% protein in natural milk
- 2 %
- caseins (cheese making)
- whey proteins
- 10 essential amino acids
- high in lysine and tryptophan
% lactose in natural milk
- 9 %
- milk sugar (only found in mammory gland)
% minerals (vitamins / ASH) in natural milk
.7 %
- calcium, phosphorus, potassium
- vitamins A, B, D, E, K
% water in natural milk
87.5 %
specific gravity of milk (measurement of density relative to water)
1.032
vitamin A
- vision
- fat soluble
vitamin D
- calcium absorption
- fat soluble
vitamin E
- blood clotting
- fat soluble
B complex vitamins
- good source of thiamine and riboflavin
- B1, B2, B6
colostrum
- thicker high protein milk
- given in first 2-5 days of lactation
average lactation curve
- 305 days / 10 months
- 2 year old’s first lactation curve will be flatter
peak in lactation
60 - 90 days
causes for daily milk production to go down
- nutritional fluctuation
- estrus / heat (distracted so eat less)
- disease
- excitement (cows like morning routine)
how old is a fully mature cow
5 yrs
mature equivalent of cow 2-5
2: 75%
3: 85%
4: 92%
5: 100%
photoperiod
- how much light per day
- longer days means more eating (therefore more milk)
cows preferred weather
- cool / cold
- 10-70 degrees
- generate heat internally
- -cow knows more she eats, warmer she gets
roughage to concentrate ratio
- 40 roughage (
- 60 concentrate (barely, corn, nuts)
- need vitamin A and D too
BST
- somatropin
- growth hormone
- RbGH is produced by lab
- causes 15% increase in milk production
how growth hormone / BST works
- binds to liver
- signals IGF1
- moves nutrients more effectively towards the mammary gland
3 conditions that determine if animal will respond to BST
- stage of lactation (at least 70 days in)
- body condition (too thin = less receptors)
- reproductive history (wait until cow gets pregnant)
BST is a peptide (protein based) hormone that contains 191 amino acids
True
BST may be produced using recombinant DNA technology that is identical to at least one of the naturally occurring forms
True
pasteurization
- goal: to kill microorganisms that cause disease (pathogens)
- heat / cook to kill bacteria
- heated by HTST
raw milk holding tank
- RMT
- chilled to 38 degrees
HTST
- high temp short time
- 161 degrees for 15 seconds
- milk run through thin plates allowing heat transfer
- regeneration, heating, and cooling sections
homogenized
-breaks up the fat globules in milk so that they become small enough to remain in suspension
HTST for ice cream
- more sugar = longer time
- 175 degrees for 25 sec
pounds milk per pounds cheese
10 lbs milk = 1 lbs cheese
100 lbs milk = 9-10 lbs cheese
rennet
- separates curds (solid) and whey (liquid)
- curds 30% protein, 30% fat, 30% water
ice cream prep mix
- 12% milk fat
- 11% milk solids not fats
- 16% sugar
- .3% stabilizer (holds shape)
over-run
- whipping air into ice cream mixture
- 50% air, 50% mix
cooked / feed milk
- cow’s feed flavor taste
- most common
sunlight activated / oxidized milk
-burned cabbage taste
high acid milk
-buttermilk taste
rancid milk
- curdle, old
- goaty, parmesan cheese taste
malty milk
-malted milk balls taste
flat milk
-added water
lactose free milk
- sweeter taste
- lactase added
whole milk
3.5 % fat
reduced fat milk
2 % fat
lite milk
1 % fat
skim milk
< .2 % fat
tri-process
- clarifies: filter
- separates: separates cream and skim w/ centrifuge
- standardizes: makes it 2%, 3.5% or skim
powder horn
adds chocolate powder to 2% milk
7 steps of milking procedure
- pre dip 30 sec
- squirt test and inspect milk
- wipe / clean teat
- attach machine
- watch machine 4-7 min
- dip all teats after machine falls off
- record time, cow #, lbs milk
alveolus
smallest organized unit of milk secreting cells
