Real Science Exchange-Dairy

Dr. Nichols opens by outlining her background in protein nutrition research spanning Canada, the Netherlands, industry R&D, and now academia at UC Davis. Her research has focused on mammary amino acid metabolism, nitrogen efficiency, and the interaction between protein and energy supply in dairy cattle. (1:00–4:05)

Dr. Räisänen shares her path from Penn State to Finland, Switzerland, and now Aarhus University, where she is leading research within a large, multidisciplinary project focused on lifetime nitrogen efficiency in dairy systems. Her current work examines early lactation protein supply and rumen nitrogen balance. (7:32–10:07)

The discussion begins by establishing why protein nutrition plays a central role in sustainability. Ruminants are net protein producers, converting low-value feeds into high-quality milk and meat protein. However, inefficiencies in nitrogen utilization lead to urinary nitrogen excretion, contributing to ammonia emissions, nitrous oxide production, and nitrate leaching. Improving nitrogen efficiency, therefore, directly impacts environmental outcomes. (12:28–14:17)

The group discusses geographic differences in nitrogen regulation. European countries like the Netherlands and Denmark face intense scrutiny due to high livestock density on limited land. Similar regional challenges are emerging in concentrated U.S. dairy regions such as California’s Central Valley and parts of the Midwest. (15:17–18:19)

Dr. Nichols introduces the concept of metabolic flexibility—the ability of ruminants, and especially the mammary gland, to utilize different nutrients and metabolic pathways depending on supply. This flexibility helps explain why responses to protein supplementation are not always black and white, and why traditional limiting amino acid theory does not consistently predict milk protein responses. (24:58–26:23)

The conversation explores early lactation “protein boost” strategies inspired by post-ruminal amino acid infusion studies. Dr. Räisänen describes ongoing work using targeted concentrate supplementation to mimic infusion responses. Preliminary data suggest substantial early lactation milk yield responses, similar to infusion studies, when protein is delivered in a separate concentrate rather than blended into a TMR. (28:33–31:16)

Dr. Nichols discusses three key areas of flexibility highlighted in her webinar:

Energy source interactions (glucogenic vs. lipogenic supply),

 

Rumen nitrogen balance, and

 

Mammary gland amino acid metabolism. (32:21–33:50)

 

The panel explores how feeding systems may influence metabolic responses. PMR systems with separate concentrate feeding may allow temporal and metabolic “choice,” potentially improving efficiency compared to uniform TMR feeding. Robotic milking systems and automated concentrate feeders offer opportunities for more individualized protein nutrition strategies. (35:00–37:57)

Amino acid discussions highlight how flexibility challenges the traditional limiting amino acid model. Milk protein synthesis is not consistently limited by one amino acid, and mammary uptake patterns show that amino acids can serve multiple roles beyond direct incorporation into milk protein. Lysine, leucine, and histidine are discussed as examples of amino acids whose responses may vary depending on metabolic context. (41:07–45:25)

The group also examines energy source effects on nitrogen partitioning. Lipogenic diets (e.g., supplemental fats) may alter amino acid metabolism differently than glucogenic diets, but more research is needed to fully characterize these interactions. (49:24–53:11)

Dr. Räisänen emphasizes the importance of rumen microbial protein synthesis and improving prediction models for digestible amino acid supply. Better understanding and measurement of microbial protein output could significantly improve feed evaluation systems and nitrogen efficiency modeling. (54:04–56:05)

Dr. Nichols highlights endogenous nitrogen recycling and urea transport back to the rumen as another underexplored area. Improved mechanistic understanding of recycled nitrogen could refine models of rumen nitrogen balance and reduce overfeeding of dietary protein. (1:00:46)

The episode closes with a discussion of cow-to-cow variation in nitrogen efficiency and the potential for individualized feeding strategies to optimize the marginal efficiency of protein use. (1:02:00)

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Dr. Ricklefs-Johnson talks about bone health and the cardiovascular health benefits of cheese. Calcium, phosphorus, and vitamins D, K, and B12 are all important for bone health, and cheese is a good source of each. In the past, saturated fat in cheese would have been demonized, but research is finding that saturated fat isn’t created equally across all food types, and cheese has many unique fatty acids. Cheese consumption is associated with reduced risks of coronary heart disease, cardiovascular disease, and stroke. Cheese contains bioactive peptides that appear to help lower blood pressure. (4:18)

The panel discusses the mechanisms of action of cheese consumption on cardiovascular health, how much cheese is recommended daily, and whether different cheeses have different health benefits. Dr. Ricklefs-Johnson explains that the protein in cheese is primarily in the form of casein, rather than whey. Casein had been less utilized as it was thought harder to digest, but more research is showing the benefits of casein in muscle recovery and helping with sleep. (8:27)

Research supports that calcium from cow milk sources is more bioavailable compared to supplements or fortified calcium in plant milks. Cheese is also unique as a dairy food that contains vitamin K, which works in conjunction with vitamin D and calcium for maintaining bone mass. (15:07)

The panel visits about some of the other presentations at the symposium, including feeding cows to influence vitamin K or fatty acids in the milk and how to get the word out about the health benefits of cheese. (19:16)

Panelists share their take-home thoughts. (26:29)

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Dr. Rico’s presentation was titled “Of cows and bugs: Using insects as alternative feeds in dairy cattle nutrition.” He gives an overview of his presentation, noting that while insects are not a major focus of US dairy nutrition, they are of interest in other parts of the world as a protein source to substitute for soybean or fish meal. (2:12)
Dr. Dou’s talk was “Alternative feed for livestock: Opportunities and challenges to support a circular food system.” She explains that a typical agriculture/food system is linear: take, make, and waste, which generates a lot of food residues. Her research aims to recover and recycle some of the food residues from other industries and evaluate their suitability for livestock feeding. (3:51)
Dr. Pinotti’s presentation was titled “Alternative foodstuffs in dairy ruminant nutrition: Basic concepts, recent issues, and future challenges.” His research focuses on using “former food” for livestock feeding and feeding insects not only as a protein source but also as a potential mineral source. (5:38)
Dr. Pinotti talks about the challenges around variability in alternative feedstuffs. He goes on to describe some of the bakery byproducts he has used in research rations. He calls them fortified versions of cereal. They contain quite a lot of starch and also contain a lot of fat. These ingredients are ideal for young monogastric animals and also have utility in lactating dairy cow diets. The panel discusses the EU animal protein ban and whether similar restrictions exist for animal fats. (10:16)
Dr. Rico notes that insects contain between 40 and 70% protein, depending on the type of insect. Crickets, mealworms, and black soldier fly larvae are the most popular. The fly larvae have a higher fat content compared to crickets and are a good energy source for monogastrics like pigs, chickens, or fish. Less is understood about the feeding value of insects in ruminant diets, and Dr. Rico’s lab has been conducting experiments to help define this in dairy cattle. He notes the chitin content of insects is a unique challenge due to its indigestibility. It comes out in the NDF fraction in a nutrient analysis, but it is animal fiber, not plant fiber. (21:27)
The panel talks about the scalability of insects as a protein source and confirms that the theory that insects are a cheap protein source is different from reality at this time. The group talks about small-scale insect projects at universities and in Africa. (27:17)
Dr. Pinotti explains that insects are quite good at accumulating minerals, bad and good. His group conducted an experiment using sodium selenite as the substrate and the insects made selenocysteine and selenomethionine. Future research will include zinc as well as selenium in the substrate, and insects will be fed in an in vivo trial to verify bioavailability. He does not envision issues with chitin interfering with bioavailability since the insects incorporate the minerals into amino acids. (34:27)
Dr. Rico talks about the amino acid and fatty acid profiles in insects. Essential amino acid content is relatively similar to other common protein sources. Insects contain higher levels of lauric and myristic acids than other common sources which could pose a challenge for lactation diets. He explains that there is a low-fat source of black soldier fly larvae with around 12% fat, compared to 30% in the full-fat version. The panel talks about variability in protein and fat content by insect type and the substrate the insects were grown on. (37:35)
Dr. Dou describes some of her circular feed research using fresh cull fruit (kiwi, citrus, apples; delivered daily) blended into the TMR. Later, she also ensiled the fruit with dry hay in an effort to preserve the fruit before spoilage. Dr. Pinotti notes that he has used cull material from a salad plant as feed as well.  (44:31)
Dr. Dou reports that one-third of food produced for human consumption never makes it to the human stomach. Globally, it’s estimated that 1.6-1.9 billion tons of food are lost and wasted each year. The panel talks about the biggest challenges keeping us from using more former food products in livestock feeding. (50:54)
Panelists share their take-home thoughts. (59:51)
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This episode’s guests were speakers on a Hot Topic Panel titled “Farm Management for the Future - Managing for Health, Welfare, and Performance” at the 2025 ADSA annual meeting. 
Dr. Nelson gives some background on how the Hot Topic Panel idea came to be and introduces the rest of the guests. (1:07)
Dr. Devries describes his research program in dairy cattle behavior and nutrition, particularly using behavior as a metric for understanding nutrition and housing management and using automated tools. He has particular expertise in automated milking systems. He envisions incremental adoption of various automated tools to replace human labor in the manufacturing of milk. He predicts this will manifest not only in automated or robot systems, but also in increased automation in a traditional parlor system as well. (5:01)
Dr. Boerman, a nutritionist, collaborates with Dr. Amy Reibman, an engineer, at Purdue to research the use of video analytics on dairy farms. Projects include video prediction of cow intake and cow body weight combined with milk production information in an effort to make improvements in feed efficiency. She emphasizes that technology needs to be used across a large number of farms without disrupting the farm. The panel talks about what technologies are currently available, challenges in identifying individual cows, and specific issues created for technology in a dairy farm environment. Dr. Boerman notes that a collaborative effort with colleagues of different expertise leads to the most optimal outcomes. (15:42)
Dr. Giordano talks about monitoring systems for reproduction, health, and welfare. Wearable sensors are a good example of a technology that can be used to monitor both reproduction and health, as well as aspects of nutritional management. The goal of many research programs in this area is to touch cows as little as possible, yet intervene as early and intensely as possible with cows who truly need intervention. An intervention could be a treatment to ameliorate or reduce clinical signs, or it could be a preventative intervention that prevents the cow from developing a clinical health disorder. More work is needed to refine algorithms and integrate data, as well as distilling the data into what is most valuable to make the best predictions at the most reasonable cost.  (34:08)
The panel further discusses the challenges of data integration, adequate internet and power access on farms, human error for manual data entry, and future training challenges for dairy farm and allied industry employees.(38:32)
Panelists share their take-home thoughts. (52:26)
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Genetic resilience and the dynamics of inbreeding and diversity in dairy breeding. Dr. Maltecca (6:43)
The main issues in managing genetic diversity in dairy cattle include inbreeding depression and continuing selection without exhausting the available variability in the population. These are difficult to investigate in a breeding population, as there is not a model algorithm where there is the luxury of designing an experiment. Dairy cattle closely resemble one another, so it is difficult to distinguish between the effect of selection from the effect of drift and the effect of deleterious mutation accumulation in the population. Researchers find proxies to estimate inbreeding and inbreeding depression because we don’t have good estimates of dominance effects.
Identifying genetic diversity within indigenous and highly commercialized breeds for improved performance and future preservation. Dr. Huson (12:24)
Dr. Huson covered four steps of thinking about genetic diversity in cattle: characterization of the genetic diversity, biological understanding of why we should preserve diversity, utilizing our understanding of diversity in breeding programs, and preserving and reassessing diversity over time. 
Harnessing indigenous African breeds for sustainable dairy production: Opportunities for crossbreeding to accelerate genetic improvement. Dr. Mapholi (16:52)
Dr. Mapholi emphasized the importance of tick and disease resistance for the sustainability of the African dairy industry. The indigenous African breeds had been overlooked due to small frame size and the perception they were not suitable for commercial farming, but they have excellent tick and disease resistance. Exotic breeds from the US and Europe struggled with the harsh environment. Crossbreeding indigenous and exotic breeds is allowing for simultaneous improvement in milk production and disease resistance. Genomics is particularly helpful to identify the best candidate breeds for crossing.
Genomic- versus pedigree-based inbreeding: 2 sides of the same coin. Dr. Macciotta (24:19)
It was thought that genomic selection would help in slowing the increase of inbreeding because we were looking at the DNA of the animal, not their pedigree. However, the traditional top animals were the population from which genomic selection began, and genomic selection shortens generation interval, so inbreeding continues to increase at a faster rate. Genomics offer new tools for investigating inbreeding, but there are 10-15 options to calculate inbreeding, all of which could provide a different answer. With pedigree selection, there is only one measurement of inbreeding. We are still investigating the best method for calculating inbreeding using genomic tools.
Managing genetic diversity: Strategies for sustainable livestock improvement. Dr. Baes (27:53)
Genomic selection has increased the speed at which animals become more related. There are negative implications of inbreeding, but today, the genetic and economic gains achieved through the current intense directional selection still far outweigh the inbreeding issues. No one knows where the edge of the cliff is, however. Dr. Baes envisions an international system one day where academia, AI companies, and producers all work together to understand and manage genetic diversity in livestock.
The panelists discuss key takeaways they got from the other speakers’ presentations and give perspectives on the topic of genetic diversity for their particular country and field of study. (34:58)
Panelists share their take-home thoughts. (46:10)
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