Dairy Cattle

Cattle parturition term

calving

Cattle intact male term

bull

Cattle castrated male term

steer

Cattle female term

cow

Cattle young male term

bull calf/bullock

Cattle young female term

heifer

Cattle all young term

calves

Changes in dairy industry

number of farms decreasing but average herd size increasing, milk production increasing

Top milk producing states in the US

1. California

2. Wisconsin

3. Idaho

4. Texas

5. New York

Dairy cattle breeds

Holstein, Jersey, Guernsey, Brown Swiss, Ayrshire

Holstein dairy breed

superior in pounds per milk, fluid milk, 90% of US cows

Jersey dairy breed

Superior in % milk fat, milk used for butter, creamy cheese, ice cream

Geurnsey dairy breed

golden milk due to B-carotene, milk used for cheese

Brown Swiss dairy breed

milk has desirable fat to protein ratio, milk used for cheese

Ayrshire dairy breed

have good udder conformation, milk used for butter, cheese, yogurt

Calving interval definition

time in between a cows 2 consecutive calves

Ideal calving interval

365 days

Events of calving cycle

Parturition, rebreeding, gestation, dry period, parturition

Rebreeding day number

day 80

Cattle length of gestation

285 days

Dry period definition

last 60 days of gestation, remove cow from milking herd, allows cow to focus energy on fetal growth, part of gestation period

Lactation cycle start and ending events

time from parturition until the cow is dried off

Ideal lactation cycle length

305 days, would allow for calf every year

While calves are separated

fed colostrum within 24 hours, placed into individual hutches or pens, fed milk replacer, fed some grains for rumen development

Length of time calves are in individual hutches or pens

6-8 weeks

Average dairy cow first calves at

25 months of age

Average dairy cow calves every

13.1 months

Average dairy cow produces ___ milk per lactation

24,000 lbs of milk per lactation

Average dairy cow produces milk for ___ years

5 years

Reasons to cull

reproductive failure, udder breakdown, low milk yield, mastitis, foot and leg problems

Lactation phases

Cow calves and enters lactation, fresh cow phase, peak milk phase, mid lactation phase, late lactation, far away dry phase, close up dry phase

Cow calves and enters lactation phase day

day 0

Lactation fresh cow phase days

day 0 - day 20

Lactation peak milk phase days

day 21 - day 100

Lactation peak milk phase characteristics

highest milk production, rebreed animal

Mid lactation phase days

day 101 - day 200

Mid lactation phase characteristics

gradual decrease in milk production

Late lactation phase days

day 201 - day 305

Late lactation phase characterstics

continual gradual decline in milk production

Far away dry phase days

day 306 - day 345

Far away dry phase characteristics 

stop milking cow, prioritizes fetal development

Close up dry phase days

day 346 - day 365

Close up dry phase characteristics

prepare for calf

Milk componants

water, lactose, minerals (Ca, P), fat, protein

Udder structural componants

Alveolus/alveoli, ducts, gland cistern, teats (teat cistern, streak canal)

Alveolus/alveoli purpose in udder

produces milk

Ducts purpose in udder

transport milk

Gland cistern purpose in udder

hallow area that stores the milk

Teat purpose in udder

where milk flows out of udder

Teat cistern purpose in udder

collects milk from gland cistern

Streak canal purpose in udder

narrow tube at tip of teat that is the main barrier to infection, opening for milk to exit

Alveolus components

epithelial cells, myoepithelial cells, capillary system

Epithelial cells purpose in alveolus

secrete milk into lumen (hallow inside) of alveolus

Myoepithelial cells purpose in alveolus

surround epithelial cells and contract for milk secretion into ducts

Cappilary system purpose in alveolus

surround entire alveolus and supply milk components to alveolus

Milk let down definition

release of milk triggered by stimulation

Stimulation types for milk let down

touch of udder, sight of calf, sound/sight of milking machine

Result of stimuli for milk let down

release of oxytocin from posterior pituitary

Result of oxytocin for milk let down

causes teat cistern to fill

Types of milking parlours

Tandem, herringbone, parallel, rotary

Tandem milking parlour

cows stand nose to tail

Herringbone milking parlour

cows stand at 45º angle

Parallel milking parlour

cows stand in parallel with eachother

Rotary milking parlour

cows stand on circular platform that rotates slowly 

Good quality raw milk must be free of

debris and sediment, off-flavors, abnormal colors and odor, chemicals

Good quality milk must be

low in bacterial count, of normal composition and acidity

Grade A milk is used for

liquid milk and manufacturing

Grade A milk perimeters

<100,000 colony forming units (cfu/mL), <75,000 somatic cells/mL, and no drug residues

Somatic cells are made of

epithelial cells and immune cells

What does a high somatic cell count indicate

infection

Grade B milk is used for

manufacturing

Grade B permameters

<1,000,000 cfu/mL, <750,000 somatic cells/mL, no drug residues 

Mastitis definition

Inflammatory response of the udder tissue in the mammary gland caused by physical trauma or microorganism infections

Mastitis can result in

a high somatic cell count

California Mastitis Test (CMT)

collect milk, combine with reagent, read results, mastitis milk thickens

Types of milk treatment

Pasteurization and homogenization

Milk pasteurization process

Heat milk to above 161ºF for 15 seconds and cooled to 39ºF quickly, kills harmful bacteria

Milk homogenization process

breaks fat particles into tiny pieces that stay in solution, prevents seperation of cream and water in milk

Types of fluid milk products

Whole milk, 2% milk, 1% milk, skim milk, half and half, whipping cream, heavy cream

Other dairy products

Cheese, butter, yogurt, ice cream

Cheese is made by

coagulation of casein protein and seperation of whey

Butter is made by

seperation of milk fat

Yogurt is made by

fermentation of milk

Ice cream is made by

freezing cream/milk

Reason for success in the dairy industry

DHIA, limited number of selected traits, adaptation to technology

DHIA purpose

national association that helps dairy producers create and manage records and data about cows

Bovine somatotropin (bST)

Growth hormone that naturally occurs in cows

Administration of more bST will

increase milk production as well as need for more nutrients, not change milk composition