Dairy Cattle (ANISCI EXAM #3)

Bos taurus

Bos indicus

European origin → adapted to colder environments

Indian origin → adapted to hotter environments

pasturization

1864 → Louis pasteur: microbe work

1893 →1st commerical pasteurizer

1908 →1st pasteurization passed

artificial insemination

• aquisition of high quality semen from bull

• detect estrus in female or synchronization of estrus and/or ovulation

• deposition of semen in cow’s uterus

greater than 60% of dairy cattle are bred by artificial insemination

• <10% of beef cows

units of milk is measured in

pounds

in 2024, 9.3 mil cows made

24,000 lbs of milk

trends in U.S dairying

there are fewer dairy farms but they have larger herds of cattle

milk production per cow increases

trends in milk and cheese

1975-2022 → fluid consumption of milk in a decrease

• health consideration, environment, milk alternatives

cheese consumption in an increase

economic impact of dairying

dairy products provide ~10% of annual cash receipts from agriculture

22% of beef consumed in U.S comes from cull dairy, dairy steers, and calves

2010s - 2020s: 12-18% of dairy productions are exported/sold to other countries

geographic distribution of cows

1. california

2. wisconsin

3. idaho

small farms/small herds

most dairy farms have less than 100 cows

• family owned + operated

• grown own feed

• raise own youngstock

• house cows on pasture/in barns

big farms/large herds

most milk comes from cows on large farms

• family owned

• hired labor

• grow & purchase feed

• raise their own youngstock or contract to raise offsite

• house cows in barns/dry lots

dairy breeds

1) Holstein → milk

2) jersey → fat in milk (butterfat)

3) brown swiss

4) ayrshine

5) guernsey

breeding cycle

nonseasonally polyestrous

dairy calves - ensuring a safe delivery

• born year round

• monitor in close up pens

• keep maternity area clean

• assist with deliveries as needed

• after delivery → checking airway, breathing, circulation

• allow the cow to lick the calf or dry it off

• dip navel (umbilicus) w/ iodine or chlorhexidine in order to prevent infection and promote healing of umbilical cord

• calf should stand (15-20 min) and nurse (30 min)

• bottle feed or tube feed →passive transfer of immunity

dystocia

difficult birth

• most costly reproductive condition

• increase calf mortality

• decrease milk production

• decrease conception rate

• increase days open (not pregnant)

colostrum (liquid gold)

initial milk coming from mother containing more protein (esp antibodies/immunoglobins), fat, minerals and vitamins than milk that is produced later

allows for passive transfer of immunity

failure of passive transfer of immunity

higher rate of disease/death

housing of calves

calf hutches/pens

housed individually so they cna’t pass pathogens

management goal: clean, dry, well ventilated, without draft

dairy calves feeding

more than 2 days = milk replacer, water, calf starter

• from birth → weaning = gain 1.5-1.8 lbs a day

processing - dairy calves

• ear tag

• disbud/dehorn less than 6 weeks

  • horns attach to the skull at ~ 8 weeks

• castrate less than 2-3 months

• remove extra teats less than 2-6 weeks

  • supernumerary teats

weaning

transition from milk based diet to concentrates & forage based diet

usually starts @ 4-8 weeks

• timing of weaning should not be based on age, but rather be based on feeding age

ex. Holstein calves should consume 3 lbs of calf starter (grain) per day for 3 consecutive days before weaning

weaned heifers

housing: alone, in groups in pens/barns, on pasture

feeding: goal is to reach 55% of projected adult weight by 13-15 months (puberty @ 9-11 months)

lactation curve

• milk production increases over the first 40-100 days

• most cows produce 50% of milk in the first 110 days

• during lactation, cows will be bred again so that they calve on a 12-15 month calving schedule

why the 12-13 month calving interval?

it is desirable because the cows that calve every 12-13 months give more milk than cows that have longer intervals

• the closer the lactation periods are together, the more time is spent at peak milk production and less time is spent at low milk production at the end of the lactation curve

dry cows

~ 45-60 days prior to calving, cows are removed from milking herd to allow for completion of calf development and for repair/regeneration of udder tissue

present day dairy farming

1) feed

• feed accounts for 45-70% of all the farm’s total operating costs

2) cow is milked

3) milk goes to bulk tank and cooled to 40 deg F

4) milk gets put in milk truck

• driver takes a sample of milk

milk sample in testing

safety

• temperature

• antibiotics? drug residues?

• somatic cell count

• bacterial count

quality

• % milk fat

• % protein

• milk urea nitrogen

average composition of whole/raw milk

87% water + water soluble vitamins ( B + C)

4% milk fat (500 fatty acids→ 48% calories, flavor, fat soluble vitamins - A , D , E, + K)

9% skim solids → proteins, carbohydrates, minerals (calcium, phosphorus, zinc)

milk processing: separation

milk is spun to remove debris, some bacteria and to separate heavier milkfat from the lighter milk fat

milk processing: standardization

fat content is adjusted

milk processing: fortification

addition of vitamin A & D

pasteurization

HIGH TEMP, SHORT TIME → kills harmful bacteria

• milk is heated as it flows through pasteurizer to 161 deg F for 15 sec

homogenization: hot milk is pressurized to 2500-3000 psi by a multiple cylinder piston pump & forced through very small passages in an adjustable valve

• break down fat particle

rapid cooling to 40 deg F

packaging

labelled with nutritional content and dated distribution