Dairy Operation

Lecture 5

California’s share of total US milk supply

19%

Top milk producing county in California

Tulare

Top 5 milk producing counties in California output share

72.4 %

general structural trends in the US dairy industry

increase average heard size and decreasing total number of dairies

percentage of US dairy farms that are family owned

97%

dry lot housing systems

outdoor pens with shade structures where cows are exposed to weather and pen surfaces require routine maintenance

freestall housing system

covered barn housing with individual stalls for lying down, concrete alleys, and mechanical or flush manure removal

pasture housing system

system offering grazing access but heavily constrained by land availability, seasonal growth, and water resources

daily time budget for dairy cow (lying/resting)

12 hours per day

daily time budget for dairy cow: eating & other activities

5 hours per day

daily time budget for dairy cow: milking & movement

3 hours per day

impact of extra waiting time in milking parlor holding pens

reduces: lying/resting time. leading to lower milk yields,

increases fatigue & higher lameness risk

Sand as bedding material

in organic material providing excellent lying comfort and low bacterial growth but difficult to separate from manure systems

organic bedding materials

straw, sawdust, recycled manure solids

absorbent materials that require careful moisture and hygiene management to prevent bacterial proliferation & mastitis

Thermal neutral comfort zone for dairy cattle

20-70 F

primary biological consequences of heat stress

decrease dry matter intake, reduce milk production, altered rumination & compromised reproductive performance

convective heat transfer in dairy cooling

transfer of heat from skin via moving air currents generated by ventilation fans

evaporative heat transfer in diary cooling

loss of heat through liquid water turning to vapor → sweat, panting, or water soakers/misters

conductive heating in diary housing

direct physical heat exchange between the cow’s body and a cooler contact surface, such as ground or stall bedding

Radiative heat loss

Emission of thermal infrared energy into the surrounding atmosphere/sky without direct contact

the core function of soakers at the feed bunk

soaking cow hide to the skin so fans can evaporate the water, pulling heat directly out of the body

TMR

mixed blend of forages, concentrates, minerals, & vitamins designed so every bite provides a balanced diet

feed sorting and its negative impact

cows selecting tasty concentrates over fibrous forage, leading to inconsistent nutrients intake and increased risk of subacute rumen acidosis

Enteric methane source

methane generated during microbial fermentation of feed in the cow’s rumen released mainly through eructation (burping)

Manure methane formation pathway

anerobic (oxygen-deprived) decomposition of organic matter in liquid manure storage lagoons by methanogenic microbes

anaerobic digester function

captures biogas (CH4) emitted from decomposing liquid manure to produce renewable natural gas (RNG) or electricity

what’s the perfect ratio for crops/ good fertilizer

NPK= nitrogen phosphorus potassium