Crawford County 4-H Dairy Skills
17 year old
The Milking Process
The ultimate goal for your 4-H dairy project is to have her reach maturity, have a calf
and produce milk. Milk production is a complex biological event involving specialized secretory
(milk producing) cells in a cow’s udder. A cow’s udder is organized into four independent
glands called quarters each with their own teat. Each quarter contains millions of milkproducing cells that are organized into tiny hollow grape like structures called an alveolus.
Surrounding each alveolus are special muscle cells called myoepithelial cells. Milk is produced
and stored in the lumens of thousands alveolus where at the appropriate time it is squeezed
out and flows down a system of tubes and ducts into a collecting area just above the teat. The
phenomena which causes milk to be squeezed out of the alveolus is called milk let down. Milk
let down occurs when a hormone called oxytocin is released by the brain in response to a calf
nuzzling a cow’s udder or in response to the stimulation of udder preparation just prior to
milking.
Whether it is one or a thousand cows, the goals of the milking process are fundamentally
the same. They are extracting milk from the cow’s udder in the shortest period of time with the
least amount of risk to the cow in terms of physical injury and mastitis. Properly milking a cow
involves a cascade of events, each dependent upon the other for success. To further explain,
the milking process can be subdivided into five distinct steps.
1. Cattle Handling: The half hour prior to milking is a critical component of the milking
process. How you handle a cow during this period sets the mood for milk extraction. If
a cow becomes anxious and excited, she releases a hormone called adrenalin. This
hormone prevents oxytocin, the milk let down hormone, from working properly for up
to 30 minutes. For this reason it is important to avoid loud noises and any activity that
could potentially elicit the “fight or flight” response from a cow. Dogs, sticks, rubber
hoses, and cattle prods should never be used to herd cows into the holding area.
2. Udder Prep: The goals of udder preparation are twofold; first is sanitizing the teat and
second is stimulating milk let down. Teat sanitization requires the use of an approved
pre-dip and at least 30 seconds of contact time. Milk let down requires 10 to 20
seconds of manual teat stimulation. Combining these two processes is the most
efficient way to accomplish udder preparation. First dip all teats with pre-dip. This is
best accomplished using a cup. Your goal is to cover the entire teat up to the base of
the udder with pre-dip. Second, using gloved hands, massage and fore strip each teat.
After 30 seconds contact time, wipe dry each teat using a single service towel.
3. Unit Attachment: Unit attachment should take place in approximately 60 seconds after
the initiation of teat stimulation. Milk let down should occur in about 30 to 40 seconds.
When the teats are plump with milk, it is time to attach the milkers. Unit attachment
should take place as quickly as possible with a minimum of air leakage. Once attached,
the unit should be aligned squarely under the udder. This prevents liner slips or air
leaking between the teat and the rubber liner.
4. Unit Detachment: When little milk can be felt in the area of the udder above the teats
and milk flow is low, the unit should detach. To do this the vacuum must be first turned
off and then the unit should be gently pulled away. If you have automatic detachers,
this will be done for you at a predetermined milk flow.
5. Post Dip: Post dipping should be done as soon as possible after the unit is detached.
Like pre-dipping this is best accomplished by using a teat dip cup. The purpose of post
dipping is to prevent the growth of bacteria in the thin film of milk left on the teat.
Questions:
1. What are alveolus? ______________________________________________
2. What is milk let down? ___________________________________________
______________________________________________________________
3. What hormone prevents the milk let down hormone from working properly?
_______________________________________
4. What are the two goals of udder preparation? __________________________
________________________________________________________________
5. When is the proper time to attach the milkers? __________________________
6. What must be turned off before you detach the milker from the udder?
_________________________________________
7. The purpose of post dipping is to prevent bacteria from growing in the milk
_______________ left on the teat.