Milk: From Cow to Carton

By The Dirt To Dinner Team July 11, 2017 | 11 MIN READ

Global Food


Milk: From Cow to Carton


Health and Nutrition

By The Dirt To Dinner Team July 11, 2017 | 11 MIN READ

The D2D team got their introduction to dairy farming on a visit to Evergreen Farms, run by the 2nd generation Harpster brothers in Spruce Creek, Pennsylvania.

dirt-to-dinner team

Evergreen Farms comprises 8,000 acres of land and is one of the largest and most productive dairy farms in Pennsylvania.

They manage 7,000 animals, and milk close to 3,000 cows three times per day.

A team of 85 employees, animal nutritionists, and veterinarians care for the animals and the land they farm on.

The Beginning: A Calf is Born

The average Holstein calf is born weighing from 70-100lbs. With their familiar black and white markings, Holsteins are the most common dairy cow because they are the best producers of milk. They consume high levels of food and tend to be larger in size from other breeds.

A Jersey calf may be 40-50 pounds. Jersey cows, are tawny in color, are smaller and lighter eaters but they produce the milk which is high in butterfat and protein.

After birth, the males are either sent to a feedlot or used for breeding, while the females will stay on the dairy farm.

Newborn calves are moved to individual hutches, which are placed next to each other so the calves can begin bonding. They are bottle-fed a combination of the mother’s colostrum (for one to two days), whole milk, and a milk replacer (like Enfamil). They grow so quickly that it is imperative that they are cared for with a nutritious diet of fatty acids, proteins, vitamins, and minerals. During their stay in the hutches, the calves are de-horned as well. Yes, female cows also grow horns.

dairy farm, Milk: From Cow to Carton

Did you know that calves…

Require passive transfer of immunity from their mother’s first milk or colostrum?

Drink two gallons of whole milk each day?

Double their birth weight in the first two months of life, from 90 to 180 pounds?

The calves will outgrow the bottle feeding after 6-8 weeks and will transition to a grain-based diet. At this point, the youngsters will be moved to larger pens or pasture, where they can roam and socialize together. Throughout this ‘growing’ phase, and up to three years old, these animals are referred to as heifers.

Cows are very social animals. They make friends in the calf pens and stay with those friends for life, even going back and forth to the milking parlor together.

Breeding the Cows

At 15 months, the heifers start ovulating and are ready to be bred. This is almost always done through artificial insemination. The average gestation period is roughly 281 days. At any given time on a farm such as Evergreen, there can be 300 or so cows preparing to calve. This phase of preparation is called “springing” for heifers and “dry period” for mature cows. During this time the cow’s nutrition, veterinary, and socializing needs are met but she is not yet a part of the milking herd. Once the calf is delivered, she produces milk and becomes an important part of daily milk production on the farm.

The average milking cow produces 65-75lbs of milk per day, which is about 130 glasses of milk. High performing dairy farms, like Evergreen farms, produce anywhere between 90 -100lbs of milk a day.

cows at a feeding trough

Evergreen Farms produces approximately 10 million gallons of milk per year, which means four to five times a day, a 7,000-gallon tanker truck rolls up to the milking parlor to collect the raw milk. On a smaller farm, the trucks may fill up every other day.

Roughly 100 days after delivering a calf, the cow will be impregnated again while she is still part of the milking herd. Her lactation cycle (days she produces milk) is about 310 days. She is taken out of production eight weeks prior to delivering a calf. Again, this ‘time off’ from lactating is called the “dry period.” During this dry period, she takes a break from milking and is often let out into the pasture with the heifers. Her diet is specially formulated to meet the needs of the developing calf and prepares her for her next lactation.  This birthing/milking cycle continues for approximately 8 years.

Technology and the Dairy Barn

It is important to constantly monitor a cow’s health and production. The tags in their ears are unique identifiers that can be scanned to tell a farmer all of the details of her heritage, when she was last milked, and how much milk she is producing. The system also tracks her health record and at what stage she is in her lactation.

Cows have a good life. They eat about 12 times per day, are milked 2-3 times, require 16 hours of light, and rest between 11-13 hours.

Happy Cows Make More Milk

Dairy farmers take good care of their cows because happy cows make more milk.

A comfortable, quiet environment, playing music in the barns, incorporating cooling fans and sprinklers and scratching brushes, and treating them with respect are important factors for happy cows.


  • have a 360 degree vision – like an owl.
  • produce 125 pounds of saliva…a day. Saliva aids in the digestion process.
  • can walk upstairs, but don’t bend their knees to walk downstairs.
  • are colorblind. They charge at a waving blanket– not the color red, as you might think!

Feeding the Herd

Cows require a lot of food to produce milk. Their stomachs have four separate compartments, each with a specialized duty in the digestive process. They eat their food quickly, burp it up as cud, and chew it again. Digestion of feed ingredients occurs in the second compartment called the rumen. It takes about two days to process the food into milk.

holstein dairy cattle in field with blue sky

Producing 100lbs of milk a day takes as much energy as running a marathon. Cows are fed a complete nutritional mix of corn silage, haylage, corn, soy, canola, high-protein, high fiber grains, vitamins, and minerals — where each bite is perfectly balanced. High milk-producing cows such as those at Evergreen Farms consume over a 100lbs of food a day.

Feed varies depending on the cow’s age— whether they are first- lactation cows or mature cows. Each dairy farm is different and requires their unique formula, adjusted as often as needed.  The dairy nutritionist uses sophisticated computer models to create diets.  Feed analysis takes place each week.  Cows have food available 24 hours a day.

Cows need sugars in their diet. Evergreen Farms collects unsold candy from Hershey and mixes it in with the feed giving cows an added treat in their feed. (This also reduces food waste at Hershey.)

In order to feed the cows, many acres of land are needed to grow grain crops (corn and soybeans) and forage (grass and alfalfa). These crops are specific to optimize digestibility and energy and protein intake. At Evergreen Farms, 96% of the feed for the animals is home-grown or locally produced by neighbors. This is a typical sustainable model for most dairy farms.

Evergreen Farms goes through 170 tons of silage a day to feed all their animals.

What happens to the cow waste?

Manure is a resource. Farmers recycle the manure back to the crops using best management practices which include application timing and soil/crop nutrient analyses.

Barns are hosed down daily and the manure is separated into solids and liquid. Special processing equipment repackages the wastewater for irrigation use on the farm.

Manure creates a nutrient-rich, moisture-retaining soil that is essential for crop growth.

The Milking Parlor

A cow actually looks forward to the milking because her udder becomes full — and she will happily walk into the milking stall. Since they are creatures of habit and appreciate a routine, milking is scheduled at the same time each day for each group of cows. A cow is milked about every eight hours.

dairy farm, Milk: From Cow to CartonToday’s milking machines can milk a cow in about 7 minutes. First, the cow’s teats are cleaned with an iodine and water solution, then dried. Then rubber-lined cups are attached to the teats, and milk will flow into the milk tank. The pumping action of the cups imitates a sucking calf so it does not hurt the cow.

Milk exits a cow’s udder at a little over 100 degrees and is cooled immediately to 35 degrees by flowing through a series of stainless steel plates called a plate cooler. It is then stored in large stainless steel tanks to await the tanker truck pick up.

Milk is cooled immediately after leaving the cow to eliminate the possibility of bacterial contamination.

The milking parlors are cleaned after every milking session. With a large herd of cows, the process of moving cows to and from the milking parlor is a constant activity.

The Milk Market, Organic Milk and Antibiotic Use In Dairy Cows

Milk Pricing

Unlike most businesses that will price their products based on what it costs to make that product, and include some sort of profit, dairy producers are paid per 100lbs of milk, called a hundredweight (cwt), and are subject to prices set monthly by the U.S. Department of Agriculture. Pricing per cwt will vary according to the supply and demand for the milk and milk products in that region and will take into consideration the export market as well as any supplies of milk products waiting to be sold.

What is Raw Milk?

Raw milk is milk fresh from the cow. It is neither pasteurized nor homogenized. Both the FDA and CDC assert that raw milk can run the risk of being unsafe to drink because certain bacteria forming enzymes remain in the milk and can grow easily and quickly.

rBST & Marketing Misconception

The “rBST free” label often found on milk cartons has created a bad reputation for a growth hormone that is in reality no longer used in dairy farming.

Oakhurst Dairy Milk labelno rbST milk label

BST is a growth hormone that is created naturally by the cows’ pituitary gland and rBST at one time was used in dairy farming to help increase the cows’ milk production. Several organizations have created fear regarding the safe use of this hormone and because of the consumer backlash, it has not been used in U.S. dairy farming since roughly 2000.

Antibiotics and Antibiotic Testing

No matter if a cow is raised on an organic or conventional farm, the use of antibiotics is accepted to treat a sick animal. In both cases, an animal treated with antibiotics is taken out of the milking parlor until all traces of the antibiotic are gone from her milk. Milking a cow not withheld for the full FDA mandated period after receiving antibiotics is a serious business. Every tanker of milk organic and non-organic milk is tested three times: by the farm, the dairy processing plant, and the USDA. If the milk tests positive for antibiotic residue the entire batch is thrown out immediately, the farmer receives no payment and is fined and put on notice by the USDA.

Organic Milk

stonyfield yogurt cups on a grocery shelf

According to the strict guidelines in place by the USDA, organic milk must come from a cow that has not been treated with antibiotics or any type of growth hormone and has been fed at least 30 percent of its diet on pasture.


Cheese production in this country is big business and accounts for about 40 percent of the milk fat and 15 percent of skim solids from farm milk..

Mozzarella takes the greatest share of the cheese market. Cheddar is a close second. It takes 10 pounds of milk to make 1 pound of cheese. That’s good business for dairy farmers!

Processing the Milk

In order to see how raw milk is processed, the D2D team visited the Cornell Creamery, where they use milk from their local cows to create delicious ice cream, yogurt, and milk.

Raw milk is collected from the dairy storage tanks into a large, refrigerated tanker. It is re-tested for safety and then taken to a dairy processing plant. At the processing plant, the milk is retested again and then processed either into beverage milk or other dairy products. After it leaves a processing plant, it may go to a distribution center and will be delivered to the grocery store within 1-3 days.

From the udder to your cup, the U.S dairy industry follows strict government regulations to ensure that milk and milk products are safe for consumption.

Milk Safety research continues: Cornell University and IBM recently announced a joint research project that will use genetic sequencing and big-data analyses to help keep the global milk supply safe.

“As nature’s most perfect food, milk is an excellent model for studying the genetics of food,” said Martin Wiedmann, the Gellert Family Professor in Food Safety and Cornell Institute for Food Systems faculty fellow.

To make various dairy products, raw milk is spun to separate out the fat. The fat is then added back in depending on the product that is being created: skim, 2%, or whole fat milk.

Why is milk pasteurized? To make your milk safer to drink. Pasteurization kills bacteria and makes enzymes inactive so you can drink it and not get sick. It does not hurt the nutritional value. Chilled raw milk is heated by passing it between heated stainless steel plates until it reaches a temperature of at minimum 161F for a time of at least 15 seconds. It is then quickly cooled to best practice temperature of under 40F. Some milk is ultra-high temperature processed (UHT) and is heated to 280 degrees for two seconds. UHT will make a milk product more shelf-stable because it is completely sterilized. This process will also make your milk more expensive.

dairy farm, Milk: From Cow to Carton

Why is milk homogenized?  Homogenized milk is smooth with an even texture, and is more consumer-friendly — you don’t have to fuss with mixing the cream in yourself.  Milk that isn’t homogenized has a layer of cream at the top.

What is the “shelf life” of milk? The shelf life of milk is based on the quality of the milk produced on the farm and the level of excellence in sanitation practices at the processing plant. Ideal storage temperatures for milk and dairy products are 34-38°F. Under these conditions, the shelf life of milk can range from 15 to 18 days. “Sell by” dates are based on the shelf life. Most pasteurized milk will remain fresh for 2-5 days after its sell-by date. When in question, the “smell test” is a good idea. Fresh milk smells, well fresh. While drinking sour milk is not necessarily harmful, it is best to not drink it. Ultra-Pasteurized milk (and products) can have a longer shelf life of 60-90 days, depending on the packaging, but only until it is opened. After opening, Ultra-Pasteurized milk should be kept well refrigerated (34-38°F) and consumed within 7-10 days for the best quality and taste.

Beyond the Carton

We don’t just drink milk, we use it for butter, cheese, yogurt, cream cheese, and ice cream! And there are nifty other uses for milk as well, from soothing itchy skin to fixing fine china. Glass for glass, milk is one of nature’s most nutritious foods. So grab a glass and enjoy a milk fix today.

Follow milk’s journey from farm to table in this video by Midwest Dairy:

Dirt-to-Dinner is grateful to the Harpster family for letting us into their dairy barns and educating us on all things dairy. We also thank Chris Canale and Kevin Campbell, Cargill Animal Nutrition, the Cornell Dairy Processing team and the faculty at Cornell University College of Agriculture and Life Sciences.

Unless otherwise sourced, the images in this post were taken by D2D or contributed.

Other resources we used: Washington Dairy FarmersNew England Dairy and Food Council American Dairy AssociationUSDA