Milkfat has been on a historic run over the past decade. Better genetics, nutrition and understanding of what drives milkfat have helped push tests higher in many herds.
Protein, however, hasn’t kept pace. And for processors, the difference is becoming harder to ignore.
Cheese plants want more protein, while ultrafiltered milk and other high-protein products are also driving demand. Meanwhile, some of the milk coming into those plants is carrying more fat than processors were built to handle.
So, where’s the protein?
In a recent episode of Cornell Cow Convos, Cornell dairy nutritionist Mike Van Amburgh discussed how milk components have changed, why fat has been easier to increase than protein and what it could take to move protein higher.
“We essentially had a national herd that was milkfat depressed,” Van Amburgh says. “Then genomics started in 2009 and really took off around 2013. Ten to 13 years later, you can really see the effect. It’s a combination of the nutrition information we have now and genomics.”
How Fat Started Climbing
Van Amburgh points to two developments behind the milkfat climb: better nutrition knowledge and genomics.
For years, dairy rations included plenty of unsaturated fat, and researchers learned more about how those fatty acids could interfere with the cow’s ability to make milkfat.
“We realized we were overfeeding unsaturated fats,” Van Amburgh says. “We were feeding a lot of them, and they were causing milkfat depression. Understanding CLA and how all of that worked was the first step toward overcoming milkfat depression.”
Genomics added another piece to the puzzle. As genomic testing became more widely used, farmers had a better way to identify animals with the genetic potential for higher component production.
His group also began looking more closely at amino acids and how they influence milk production. Lysine, methionine and histidine became a major focus because the right balance can affect how the udder makes both fat and protein.
“We realized we needed to meet the cow’s requirements for lysine, methionine and histidine,” Van Amburgh says. “When we meet those requirements, the cow increases the activity of the enzymes involved in making milkfat. The first thing we see is the cow increasing milk fatty acid synthesis.”
In one study, the response was far beyond what researchers expected.
“We had two extraordinary cows,” he says. “They started at 4.6% fat and averaged about 5.3% to 5.4% for the entire treatment. We had a bunch of cows in the 8% to 10% range. Our focus was reducing nitrogen excretion, and those cows showed us just how much potential they had.”
Protein is a Different Puzzle
Van Amburgh says the protein problem isn’t necessarily a lack of genetic potential. The cow may have the ability to make more, but she needs the right amino acids to do it.
“It’s not a lack of genetic capacity,” Van Amburgh says. “That’s the positive part, but it’s also frustrating. The cows have the potential. The problem is they need different amino acids, and those are the ones we don’t have enough of.”
Lysine, methionine and histidine are well understood, but once those requirements are covered, other amino acids become limiting.
“Once you meet the requirements for lysine, methionine and histidine, you need more isoleucine, leucine, valine, arginine and proline, along with more lysine,” he says. “Those become the most limiting amino acids. The only way to meet those requirements with our current feeds would be to grossly overfeed protein, and we don’t want to do that.”
For dairy nutritionists, simply adding more crude protein isn’t a good answer. It costs more and can increase nitrogen losses without giving the cow the specific amino acids she needs to make more casein.
“I get frustrated when I see articles saying we can just feed against fat and feed for more protein,” he says. “If it were that easy, I’d have cows at 5% or 6% protein right now.”
Individual cows can produce impressive protein tests in herds making genetic progress, but getting an entire herd there is another challenge.
“There are cows that can hit 4% protein,” he says. “But as a general population, we can’t do it. We might learn how to do a little more as we get different genetics, but it’s really difficult right now because we don’t have enough of the amino acids the cow needs to make casein.”
Processors are Feeling it, Too
The changing milk composition is creating headaches beyond the farm. Processors built plants around a certain type of milk, and today’s milk doesn’t always fit those systems.
Plants making ultrafiltered milk are dealing with higher-fat milk than expected. Cheese plants want protein because it drives yield, but they don’t necessarily need all the extra fat.
“Everybody making Fairlife and similar products is frustrated because their system was built around 4% butterfat and 3% protein,” Van Amburgh says. “They can’t work with the milk the same way anymore. The system is essentially broken. Cheese makers have the opposite problem. They want the protein. They don’t need all the extra fat.”
Van Amburgh recalls Barbano’s reaction when he first saw some of the milk coming out of their research.
“He called me and asked, ‘What are you doing to these cows?’” Van Amburgh says. “In the first study, he said, ‘Those have to be Jerseys. They can’t be Holsteins.’ When we got the lysine, methionine and histidine right, the Holsteins started behaving like Jerseys.”
“In the last study, we went beyond even that,” he says. “When you get to 8%, 9% or 10% fat, you’re in water buffalo territory.”
“The processors are upside down on milk composition,” Van Amburgh says. “The cheese makers looked at Dave and me and said, ‘We always wanted higher-component milk, but now it’s a little out of balance. You better fix it.’”
Building a Better Component Profile
For producers, the research raises a practical question: How much protein can a dairy realistically produce today?
Van Amburgh points to herds producing 3.5% to 3.6% true protein in the bulk tank and considers those strong numbers when they are achieved without loading the ration with crude protein.
“I’ve had the privilege of working with herds where the bulk tank can hit 3.5% to 3.6% protein,” he says. “If you’re at 3.5% to 3.6% true protein, you need a lot of cows close to 4%. You’ll also have some below it. That’s just how it works.”
Getting cows to reach their potential still starts with the fundamentals: cow comfort, lying time, forage quality, rumen fill and stocking density.
“It’s cow comfort and lying time,” Van Amburgh says. “It’s getting the most digestible forages we can get and keeping the rumen full of NDF. The cow doesn’t care where the NDF comes from. She wants digestible NDF and enough of it.”
He also points to overcrowding as an issue in high-producing herds.
“Overcrowding is a big one,” he says. “We need 12 to 13 hours of lying time for these cows if we want them to perform.” On the ration side, Van Amburgh says producers shouldn’t chase components by simply adding more fat.
“Don’t feed too much fat,” he says. “We’re seeing fatty acids around 4.4% to 4.5% and total fat around 4.7% to 4.8%. I don’t want to go above 5%. Once we get above 5%, we start losing feed efficiency.”
“In all of our diets, we stay below 5% fat,” he says. “Then feed enough amino acids and let the cow do what she’s supposed to do.”
For now, Van Amburgh sees 3.5% to 3.6% true protein as a realistic target for many herds. Getting beyond that will require more than adding crude protein. Genetics will continue to play a role, but researchers also need to learn how to provide the amino acids needed to support more casein production.
The industry is looking for more protein, and Van Amburgh believes amino acids could be part of the answer.
“Everybody in the world now wants protein,” he says. “We just need to show these amino acids work. We’re going to have to get the industry to understand these amino acids aren’t feed additives. They’re requirements.”
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