This episode of the Real Science Exchange podcast was recorded during a webinar from Balchem’s Real Science Lecture Series.

Throughout the last 30 years, the dairy industry has moved to producing highly concentrated versions of milk proteins. In cows’ milk, about 80% of the protein is casein and 20% is in the serum or whey phase. These ratios vary by species. There are three major caseins in cows’ milk: alpha-S-casein, beta-casein, and kappa-casein. The first two are rich in phosphate for calcium binding. Kappa-casein is critical in a micellar structure that allows these structures to stay suspended in the milk. (1:21)

Whey proteins also differ by species. In cows’ milk, about 50% of the whey protein is beta-lactoglobulin. It’s rich in branched-chain amino acids, and it is not present in human milk so it is a focus of allergy research. Alpha-lactalbumin is found in all mammals and is a cofactor for lactose production. (10:34)

Caseins and whey proteins are different from one another and are in completely different classes of proteins. From structure, to size, to amino acid content, to solubility; these two types of proteins are yin and yang. (11:51)

When fluid milk or whey is concentrated by removing water, some sugars and other materials dissolve via evaporation or membrane filtration. It results in dried powders, milk protein concentrate, milk protein isolate, whey protein concentrate and whey protein isolates. Concentrates contain 80-85% protein and isolates contain more than 90% protein. (17:14)

What's driving the current and probably future popularity of these dairy proteins? One, is their versatility in many food applications, and the other is the superior nutritional quality of the proteins. Nearly half of the milk protein concentrate use is for mainstream nutrition and sports beverages. Similar trends have been observed for whey protein isolates. (20:05)

Dairy proteins are very rich in branched-chain amino acids (BCAA) like leucine. BCAAs help initiate protein synthesis, are important for muscle recovery, help with weight loss by maintaining blood glucose levels, are synergistic with exercise, and can promote healthy aging. Dr. Lucey gives several different examples of products utilizing dairy proteins. He predicts that the increased focus on nutrition products, interest in isolating individual proteins and improving export opportunities will continue to drive demand for dairy proteins in the future. (27:21)

All of the main milk proteins have genetic variants, which are minor amino acid differences in the same protein. Variants occur at different frequencies among breeds. Beta-casein has two variants, A1 and A2. There is one amino acid difference out of 209 total amino acids, located at position 67 where a histidine is found in variant A1 and a proline is found in variant A2. When histidine is present, the beta-casein is prone to cleavage at position 67, creating a fragment called beta-casomorphin-7 (BCM-7). When proline is present, it hinders the cleavage of casein at position 67. BCM-7 is an exogenous opioid peptide with the potential to elicit opioid activity on a range of tissues and organs. It’s known as a “bioactive peptide” and some others from milk and cheese have been implicated as anti-hypertensive. (35:26)

In the late 1990s, some researchers claimed that A1 milk was implicated in diabetes, coronary heart disease, autism, and schizophrenia. Subsequent reviews and investigations by significant international bodies found no evidence of these claims. (40:34)

In closing, Dr. Lucey answers questions from the webinar audience. He talks about the potential of breeding cows customized for the production of minor milk components, milk components as renewable bio-plastics, and the superiority of milk proteins compared to plant proteins. Watch the full webinar at balchem.com/realscience. (47:41)

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Dr. Overton presented on this topic in a Real Science Lecture series webinar on July 10, 2024. You can find it at www.balchem.com/realscience. This episode takes a deeper dive into the conversation.

Dr. Overton begins by reminding listeners of the vast number of changes occurring in the fresh cow during the first two to three weeks after calving. Body fat and protein mobilization, some systemic inflammation, the potential for elevated NEFAs and ketones, and calcium dynamics all play a role in how the fresh cow starts her lactation period. (7:31)

When consulting with clients, Dr. Faldet uses research to guide his decisions. He likes to implement a 14-day pen for fresh cows, ranging from 10-17 days. He evaluates things like stocking rates, lockup times, and cow comfort, along with fine-tuning a diet for each individual farm setting. (9:14)

The panel discusses the importance of increasing effective fiber along with starch in fresh cow diets. Without adequate effective fiber in the diet, the risk of acidosis increases, resulting in cows going off feed. There is no silver bullet; each farm’s fresh cow diet is going to be different due to different forage bases and timing in the fresh cow group. (13:02)

Both Dr. Faldet and Dr. Overton stressed the diet is only one component of a successful fresh cow program. Other critical pieces include stocking rate, availability of feed, water quantity and quality, and cow comfort. Dr. Faldet suggests that if you do all these non-diet factors right, you could probably maneuver closeup and fresh pens a little differently and make the diet work with the ingredients you have. Dr. Overton’s group is conducting survey work evaluating the variability in particle size in closeup diets. A pilot study showed that as particle size variability increased, so did fresh cow health issues and poor postpartum metabolic status. (19:10)

Protein requirements of the fresh cow were another topic of Dr. Overton’s webinar. He described a recent experiment evaluating standard and high metabolizable protein concentrations in the diet for closeup and fresh cows. The postpartum MP gave a big milk response, around 15-16 pounds per day for the first 21 days after calving, with a carryover effect of 11-12 pounds of milk for the next 20 days after all cows went back on the same diet. It’s important to note that lysine and methionine were fixed regardless of treatment, so it seems that other amino acids are probably involved in the mechanism of action. (23:06)

Dr. Overton described an experiment designed to evaluate starch and fiber in fresh cow diets where higher fiber digestibility and increased corn in silage resulted in less fiber and more starch than anticipated in the diet. Fresh cows were a bit of a trainwreck, but the problem was resolved once another couple of pounds of straw were added to the diet. On the other hand, you can go too far with increased fiber in fresh cow diets, which results in ketosis, lower intakes, and less milk production. (35:19)

The panel then discusses far-off programs, fat supplementation in fresh cow diets, and vitamin and mineral concentrations for fresh cows. (42:37)

In summary, each panelist shares their takeaways. Dr. Elliott reminds listeners that we should think about starch, fat, fiber, and protein together and how they influence each other rather than considering them individually. Dr. Faldet’s take-home message is to know what your targets and bookends are and really hone in and implement your fresh cow diets accordingly. Dr. Overton suggests that the industry will shift to evaluating fresh cow diets as their own thing rather than trying to tweak a few things from your high cow diet. Implementing fresh cow diets consistently and well is going to be important. (53:30)

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