The production of milk by a cow is a biological response to having given birth to a calf. Even if the calf is not suckling on the cow, this production of milk can continue if the cow is regularly stripped of the milk being produced in her udder. Not removing all the milk from the cow's udder at each milking session can impact her long-term production and health.
Decreased Milk Production
When too much milk is left in a cow's udder, her body begins to signal that less production is needed. This is the main reason why dairy farmers prefer to separate newborn calves from their mother cow. A newborn calf requires much less milk than a dairy cow is capable of producing when her udder is drained twice a day as is the industry standard.
A cow that is under milked is susceptible to getting mastitis. This is a painful condition in which the udder becomes hot to the touch, is swollen and often takes on a reddish color. The udder becomes hardened as the cow's body releases white blood cells to fight off the infection. This process turns her formerly whitish and free-flowing milk to more of a cottage cheese consistency. Under milking can lead to mastitis because the warm liquid left in the udder is of the perfect temperature for bacteria to thrive. A cow's udder is vulnerable to bacteria after being milked because the end of the teat duct releasing the milk takes time to close.
An average milking cow can produce up to six gallons of milk per day. Carrying that around in her udder between her hind legs produces a tremendous amount of pressure. Dairy cows become adjusted to daily milkings and will moo excessively if the farmer is tardy in accomplishing this task.
Wasted Milk/Wasted Time
When a cow has a bacterial infection in her udder, she often is given antibiotics. These are administered directly to the udder via the end of the teat canal. The presence of antibiotics in a cow's milk automatically disqualifies her milk for consumption by humans or other animals. On commercial dairy farms where hundreds of cows are used for milk production, this also creates a time waster for the farmer who must disconnect the milking machine from the main milking system and hook it up to a separate container to ensure the milk from the infected cow does not enter the main milk holding tank. For a hobby dairyman only milking the cow for personal use, infections in the cow's udder means a temporary lack of home-grown milk.
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Amy M. Armstrong is a former community news journalist with more than 15 years of experience writing features and covering school districts. She has received more than 40 awards for excellence in journalism and photography. She holds a Bachelor of Arts in communications from Washington State University. Armstrong grew up on a dairy farm in western Washington and wrote agricultural news while in college.