Nutritional Balance Of Grass-Fed Grazing Is Key To Abundant, Quality Milk Supply
Madison—Creating a nutritional balance of grain and forage in grass-fed cows is essential for creating quality milk and subsequently, quality cheese.
The American Cheese Society (ACS) recently hosted a webinar entitled “From Grass to Vat: The Impact of Feed on Milk Quality & Components,” which highlighted the logistics of pasture grazing.
This is a very timely topic, not only in terms of conversations happening in the broader market like how to source grass-fed cheeses and what that means, as well as how to label them in stores, said Zoe Brickley of Jasper Hill Farm, Greensboro, VT.
The first week that the cows of Jasper Hill Farm go out on pasture is a celebration, Brickley said. We have long winters here, and the day that there’s finally enough grass for them to get the nutrition they need has come, and the cows literally kick up their heels and celebrate.
“Protein gets turned into the unique complexity of aroma.Not only is nutrition important for the cow’s functioning, but can also impact particular aromas of cheese...”
—Zoe Brickley, Jasper Hill Farm,
The topic of cow’s feed is complex, Brickley said. This is definitely an area of expertise at the farm, and our herd managers have the most technical job – right up there with our cheesemaking team.
There’s universal standards of quality when it comes to milk harvesting, but there’s also some really unique approaches and everyone has their own way of doing things, Brickley said.
First off, the most important ingredients in cheese are actually ingredients in milk, she said.
We have milk protein, which is bundled into groups of proteins held tightly together by minerals. All dairy animals are going to have casein bundles, Brickley said. The size and shape vary from species to species, but it’s something they all have in common.
For a cow to get all the nutrients she needs, means getting all of the essential amino acids – half of which must come from feed and can’t be made by the body.
When individual amino acids are broken down during cheese aging, they turn into aroma, Brickley said.
“Protein gets turned into the unique complexity of aroma,” she said. “Not only is nutrition important for the cow’s functioning, but can also impact particular aromas of cheese down the line.”
Fat – which has a major impact on potential flavor – is another big consideration when we think about feeding cows, she said.
Flavors associated with goatiness, sheepiness and cowiness – species-specific flavors – are associated with flavors that happen when fat gets broken down, Brickley said, the same when protein gets broken down during aging.
“Cows aren’t out there eating really fatty foods and turning it into butterfat. They have a very complex digestive system that turns cellulose and other nutrients from grass into fats,” Brickley said.
“Making sure the cow has all the nutrition she needs is the best way to make sure your milk is as rich in butterfat as possible,” she said.
During a cow’s nine- to 10-month lactation cycle, levels of protein and butterfat are going to vary. Milk will be richer and less watery at certain times, and it will have more water and fewer solids at other times.
Lactose – which gets metabolized by starter cultures during cheesemaking – also varies during lactation.
“It’s another element that needs to be balanced by herd managers to make sure cows get the proper nutrition to do their jobs,” Brickley
We ask a lot of cows. To have a balanced milk that’s going to lend itself to really good cheesemaking, you have to then supplement or enhance nature’s ability to feed the cow, she said.
“This isn’t saying that it’s not possible to make good cheesemilk on pasture alone – it just takes a particular skill and expertise to do it,” Brickley continued.
What Makes Milk Different
Obviously, the species is going to have a lot to do with what differentiates milk, Brickley said. Goat, sheep and cow have the broadest, biggest, most drastic changes at the civilian level – someone shopping in a cheese store switched up the
species on their favorite cheese – they’re probably going to notice.
“They all have the same ingredients, but those ingredients are in different proportions and different physical arrangements,” Brickley said.
Different species and breeds are also going to have different nutritional needs, she said.
In very sophisticated dairies that have the money to invest in the most state-of-the-art equipment, there’s automatic milking parlors and automatic feeding parlors. The cows are tagged and will walk up to a feeding wall and a specially-balanced ration of hay, silage, grasses and grains will be dispensed, balanced exactly to that cow’s nutritional needs, Brickley said.
“A good herd manager is tuned in to all levels. Not only are you managing individual animals, but you’re also managing individual species,” she said. “It’s a very technical problem.”
Grass-Fed As A Reaction To Industrial-Scale Food Systems
A big reason people are concerned with grass-fed is because of the exposé-type journalism and greater understanding of what industrial-scale food systems look like to the general public, Brickley said.
The industrial-scale system seems to the average person to be very unnatural and an off-putting situation, she said.
“I think a lot of the problems identified in that model are somewhat unique to the beef industry, but the concerns have carried over to the dairy industry,” Brickley continued.
“With a dairy cow, you’re not looking to keep that cow around for just a season. You want a dairy cow to be productive for years on end, and you want her to be extremely healthy so she’s able to give as much of the richest milk possible every day,” she said.
Dairy farmers – regardless of scale – are much more tuned in to keeping the feed balanced, Brickley said. Any herd manager worth their salt is trying to balance fibrous feed and grain feed.
Other studies show that milk from a cow whose diet is primarily derived from grass sources is higher in omega 3 fats and conjugated linoleic acids (CLA), she continued.
Microbial Balance In Milk
Wherever a cow is hanging out – a muddy barn or a dry barn, a muddy pasture or a nice, dry pasture – all of those environmental factors are going to determine the microbial balance of whatever is outside of the udder, Brickley said.
About 80 percent of raw milk microflora comes from the skin of the udder, she said.
The microbial balance of the cow’s gut is teeming with bacteria. What’s inside the cow’s gut is really important for her ability to digest her feed, and a sterile gut would not be able to make the amount or quality of milk than one that has the proper balance of microflora, Brickley continued.
“It’s important to know that microflora comes in at the point of milking – whatever microbes get into the udder. It’s more environmental factors rather than what’s coming from her gut,” she said.
When we talk about grass-fed milk, we tend to think about no grains at all, Brickley said. I only know of two cheesemaking dairies in the country with recognizable brands – Trader’s Point Creamery and Maple Hill Creamery – that do not give any grain to their cows.
“Pasture-based dairies like Jasper Hill Farm have the cows on grass when there’s grass to eat, give cows hay when it’s wintertime and they’re inside, but throughout both seasons, we’re using grain as a tool to maximize nutrition,” she said.
“It’s not our way of changing nature or stressing the cow to make more milk,” she said. “It’s our way of avoiding body stress in the only capacity that we have.”
Grains are a source of starch, and they’re providing the cow more energy than she’d be getting on grass alone in most circumstances, Brickley said. When the cows aren’t getting enough, there’s an energy deficit and they can become unhealthy.
Too much corn and not enough forage can also cause problems, including sugar imbalance and the leaching of calcium from bones and hooves, she said.
On the grass side, if you’re 100 percent grass-based and you don’t have the tool of adjusting your grain ration, you can adjust the types of grasses in your pastures, but this is not a quick fix, she said.
“It’s about crafting a pasture that has a starchier nutrient balance with more energy,” she said.
If you want to do 100 percent grass-based, you’ve got to be really scientific about it. For instance, grass in full sun has more sugars and a better source of energy. However, cows often feel hot and exhausted, and want to lay in the shade and not eat as much, she said.
“The cows will be in the shady spot, not eating the sugar that you desperately need them to get,” she said. “You need to rope off your pasture in a very particular way, giving them enough time in sunny spots. It takes very intensive management and it’s possible, but it takes expert management to achieve.”