Studied by 33 people
Inheritance
Feed management
Demand of milk (from calf)
Gender of calf
Age
What factors affect milk production
True
Milk production is affected by progeny (T/F)
Male
(blank) calves have a higher milk demand
slowly
Inbred calves grow more (blank) than crossbred calves
5-6 years
What age do cows tend to be at peak lactation
quality and quantity
adequate (blank) of feed is essential for good milk production
They use their own body reserves
What do cows do if they have inadequate nutrients during parturition and lactation
Mastitis
Inflammation of the udder
Dirty or poorly adjusted equipment
Poor milking practices
Injuries to cows
What causes mastitis
Mastitis
What is the most costly disease in the dairy industry
Clots or flake in milk
Udder is sensitive to touch
Swollen or hot to the touch
Symptoms of Mastitis
Antibiotics is injected into the infected quarter
How is mastitis treated
Increase
We (blank) milking in cows with mastitis
Colostrum
First milk, provides passive immunity
Lactoferrin
Binds iron in milk and acts as a antimicrobial
Lysozyme
Hydrolyzes bacteria cells
Immunoglobulins (Ig)
Present in colostrum, antimicrobial
24 hours
How long does intestinal absorption of Ig last
After calving
When does the greatest variation in milk composition occur?
3-5 days
How long does it take for a cow to produce regular milk instead of colostrum
11th milk
After what milk can the milk be sold
Antibodies
Vitamin A & D
Fat
Protein
Minerals
Composition of milk
False
Lactation can continue at peak production indefinitely (T/F)
Mammogensis
structural development or growth of \n mammary gland
Lactogenesis
associated with the end of pregnancy & \n parturition; tissues change from nonlactating to lactating \n state
Milk secretion
synthesis of milk by epithelial cells
Milk removal
passive removal from cisterns and ejection \n of milk from alveolar lumen
Lactation
milk secretion + milk removal
Galactopoiesis
maintenance of lactation
Lactation
What is the distinguishing feature of mammals
Provide nutrients to offspring
Source of passive immunity for offspring
Functions of mammary gland
Hair
Mammary glands
Nurture offspring
Traits of mammals
Mammary gland
Modified sweat gland controlled by hormones, provides sustenance to offspring
4 glands
4 terminate teats
Cow udder structure
4 glands
2 teats
Mare udder structure
2 glands
2 teats
Sheep and goat udder structure
Multiparous
Multiple mammary glands in rows along abdominal wall
True
Sows are multiparous animals
Gland
Secreting organ
Epithelial cells in tissues consisting of alveoli
Where is milk synthesized and secreted
Exocrine gland
Gland that secretes fluid into a duct
Endocrine
Ductless glands that secrete hormones
88% water 12% solids
Dairy cattle milk composition
Suspension
Maintains udder attachment to the cow
Median suspensory ligament
Separates left and right halves of udders, forms mammary groove
Lateral suspensory ligament
Supports outer wall of udder
Teats
Area where milk is secreted
Consist of hollow tubes of skin, muscle, and erectile tissueS
Includes sphincter muscle that controls milk flow
Fore quarter attatchment
Area of the udder that is attached to the abdominal wall
Rear quarter attachments
Area of the udder that is attached at teh rear below the tail
Mammary groove
Groove that separates the left and right side of the udder in the rear
False
Milk can move between quarters (T/F)
60%
Rear quarters produce (blank) of milk
Streak canal
Bottom openings of teats
True
Cows can have extra teats (T/F)
Gland cistern
Cavity within the mammary gland
Teat cistern
Cavity within the teat
Alveolus
Sac-like structure
Basic unit of milk production
Lumen lined with layer of epithelial cells
Epithelial cells
Cells that manufacture milk
Remove nutrients from blood to transform into milk
Myoepithelial cells
Cells that surround epithelial cells that contract and eject milk
alveolus lumen, oxytocin
Milk collects in the (blank) until triggered to release by the hormone (blank) at the time of milking
Allow for sensation of temperature and pain
Helps to signal lactation when offspring nudge the udder
Why do teats have sensory nerves
500, 1
(blank) gallons of blood are needed for (blank) gallon of milk
Build-up of intramammary pressure
What triggers milk production to fall
~45 sec
How long does it take for milk let down to occur
Oxytocin
What hormone causes contraction of the myoepithelial cells
Negative pressure
Suction from milking machine or calf
Positive pressure
Hand milking
Suckling
A combination of positive and negative pressure created by the calf that triggers lactation
Milk “hold-up”
If cows are stressed milk letdown can be disrupted
Epinephrine
Adrenalin, can override oxytocin and pause milk let down
Redirects blood to muscles
True
Teats, cisterns, and glands all exist at birth (T/F)
Isometric growth
First 2-3 mo after birth
Growth rate same as general body growth
Allometric growth
2-3 mo to 1 yr
Growth rate faster than rest of the body
Puberty
Occurs at ~7-9 mo
Some allometric growth
Jersey
Which cow has the highest butterfat
During pregnancy
When does the greatest degree of structural development occur
Estrogen
Which hormone stimulates growth of mammary duct system
Progesterone
Which hormone stimulates growth of alveoli
Somatotropin
Growth hormone produced by pituitary, helps increase milk yield
Prolactin
Helps initiate milk secretion
ACTH
Acts on the adrenal gland to produces stress hormones
Corticosteroids
Stress hormones
TSH
Acts on the thyroid to create thyroid hormones
Involution
Young no longer needs milk, cycle starts again with new pregnancy
4-6 weeks
When does peak lactation occur
Persistency of lactation
Measure how much milk production is maintained compared month to month; usually 90-92%
False
Milk removal is not required for maintenance of lactation (T/F)
Milking/suckling
Alveoli are distended when what has stopped
2 month
How long do you want a cow to be dry
Note
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