Lactation

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