Real Science Exchange-Dairy

Latest Episodes:

Legacy Series: Honoring Dr. Jim Drackley of the University of Illinois, Urbana-Champaign Feb 11, 2025

Show notes

In this episode, we honor and celebrate the remarkable career and contributions of Dr. Jim Drackley from the University of Illinois, a pioneer in dairy science and animal nutrition. Jim’s work has reshaped our understanding of dairy cow health, metabolism and nutrition. Dr. Cardoso, Dr. Overton, and co-host Dr. Jeff Elliott are former coworkers or graduate students of Dr. Drackley’s. (0:11)

Dr. Drackley begins by telling the audience about his background and how he became a dairy scientist. He talks about several of his mentors during his schooling. (9:20)

Speaking of mentors, Scott asks Dr. Elliot, Dr. Overton, and Dr. Cardoso to describe Dr. Drackley’s mentorship of them during teaching, graduate school and beyond. They praise Jim’s thoughtfulness and hands-off approach that taught them to think critically. (14:06)

When it comes to major contributions to the industry, Dr. Drackley names two that he is most proud of: expanding the knowledge of controlled energy dry cow programs using straw and corn silage to help control energy intake and his work in baby calf nutrition, specifically feeding more milk on-farm to calves. Dr. Overton adds that a visionary paper Dr. Drackley wrote in the late 1990s where he referred to the transition period as the final frontier as another important contribution. Dr. Cardoso also emphasizes Dr. Drackley’s excellent teaching skills as another achievement of note. (20:58)

Dr. Drackley says the teaching part of the job was the part that scared him the most when he started. Graduate school offers little formal teaching training and experience so one learns on the job. Jim describes his teaching style as organized, and he liked teaching in an outline fashion, working from the main topic down through the details. He worked hard to get to know the students, learn their names as soon as possible, and be approachable and empathetic. Later in his career, he used a flipped classroom approach for a lactation biology course and enjoyed it. (28:45)

The panel then reminisces about how much technology has changed from a teaching perspective as well as statistical analysis. Lecturing has moved from chalkboard to overhead projector to slide carousel to PowerPoint. Statistical analysis has moved from punch cards or sending data to a mainframe computer to performing real-time statistical analysis on your computer at your desk. (33:00)

Jeff, Phil, and Tom share stories and memories of their time with Jim. (37:30)

Scott asks Jim what challenges will need to be tackled in the future in the dairy industry. He lists environmental aspects (nitrogen, phosphorus, and greenhouse gases), increasing economic pressure on farms, and improving forage production and efficiency of nutrient use. Dr. Drackley’s advice for young researchers is to carve out a niche for yourself. (47:40)

Dr. Elliott, Dr. Overton, and Dr. Cardoso share some final thoughts paying tribute to Dr. Drackley and his accomplished career. (1:06:18)

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Three Strategies To Implement Today That Increase Milk Protein & Producer Profits with Dr. Mike Van Amburgh, Cornell University Feb 04, 2025

Show notes

This Real Science Exchange podcast episode was recorded during a webinar from Balchem’s Real Science Lecture Series. You can find it at balchem.com/realscience.

How can we increase milk protein and capture that income opportunity? Dr. Van Amburgh describes the seasonal drop in milk protein observed in the summer months. Heat stress may play a role in altering insulin sensitivity and how the cow partitions nutrients. What can we do to avoid that seasonal decline in milk protein? (0:01)

Simple things like cooling, fans, and sprinklers can reduce heat stress and increase cow comfort. Dr. Van Amburgh recommends promoting dry matter intake and lying time, with feed available 21-22 hours per day and more than 12 hours of lying time per day. (5:27)

Dr. Van Amburgh discusses basic formulation considerations for amino acid balancing including current feed chemical analyses that include NDF digestibility, characterizing the cows appropriately by using accurate body weights, understanding DMI and making sure actual milk lines up with ME and MP allowable milk, assessing body condition changes, and understanding the first limiting nutrient of milk production. Areas where mistakes are often made include using much lighter body weights than actual to formulate rations, not using actual DMI, and using feed library values instead of actual feed chemistry. (8:00)

Milk protein percentage and dietary energy are closely aligned. This is often attributed to ruminal fermentation and microbial yield. Sugars, starches, and digestible fiber sources drive microbial yield. While protein and energy metabolism are considered to be separate, that is an artificial divide and they should be considered together. Once adequate energy for protein synthesis is available, providing more dietary protein or amino acids can increase protein synthesis further. Dr. Van Amburgh provides some ranges of target fermentable non-structural carbohydrates, starch, sugar and soluble fiber appropriate for early peak and mid-lactation cows. He speaks about the benefits of adding sugars to the diet instead of trying to continue to increase starch. (11:15)

Dr. Van Amburgh details an experiment using more byproduct feeds in a lactation diet to successfully increase intake and subsequently, milk protein content. (24:04)

Milk protein increases with higher DCAD in diets, independent of protein level. Increasing DCAD can also lead to increased DMI, probably through better fiber digestion. The mechanism is not completely understood, but perhaps some rumen microbes have a higher requirement for potassium. In another study, feeding higher DCAD resulted in an 11% increase in milk protein yield and a 26% increase in milk fat yield. (32:39)

Feeding fatty acids may also improve milk protein via insulin signaling pathways. A 5.6% increase in milk protein was observed when the ratio of palmitic acid to oleic acid was around 1.5:1. (36:21)

Dr. Van Amburgh encourages the audience to pay close attention to digestibility of dietary ingredients and shares an analysis of ten different sources of feather meal that varied in digestibility from around 50% up to 75%. (40:10)

Dr. Van Amburgh details an experiment targeting optimum methionine and lysine levels for improved milk protein. In an example with 60 Mcals of ME in the diet, the targets were 71 grams of methionine and 193 grams of lysine. (42:00)

Questions from the webinar audience were addressed. They included information about the best type of sugars to add to diets, if protozoa are preferentially retained in the rumen, BMR vs conventional corn silage, amino acid supply when dietary crude protein is around 14-15%, using metabolizable energy instead of net energy, variability of animal protein blends, and methionine to lysine ratios. (48:23)

To end this podcast, Dr. Jose Santos steps in to invite everyone to the Florida Ruminant Nutrition Symposium in Gainesville held February 24-26.

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Milk production responses of dairy cows to fatty acid supplements with different ratios of palmitic and oleic acids in low- and high-fat basal diets with Dr. Adam Lock, Michigan State University; Dr. Bill Weiss, Professor Emeritus, Ohio State University Jan 28, 2025

Show notes

In this study, two basal diets were fed, one low-fat and one high-fat. The low-fat diet contained cottonseed meal and cottonseed hulls and the high-fat diet contained whole cottonseed. This balanced fiber and protein to try and make the difference between the basal diets and just the fatty acids. Basal diets were supplemented with two different fat supplements that had different ratios of palmitic and oleic acids. The applied question at hand was “Does fat need to be supplemented to a high-fat basal diet?” (5:32)

The low-fat diet contained 1.93% fatty acids and the high-fat diet contained 3.15% fatty acids. Fatty acid supplements were fed at 1.5% of dry matter and replaced soyhulls. The palmitic acid supplement contained 80% palmitic acid and 10% oleic acid. The palmitic + oleic acid supplement contained 60% palmitic acid and 30% oleic acid. Thirty-six cows were used in a split-plot Latin square design, with half the cows on each basal diet. Under each split-plot, cows were allocated to a 3x3 Latin square, evaluating a control treatment (no fat supplement), palmitic acid supplement, and palmitic + oleic acid supplement. (8:46)

Bill, Adam, and Clay discuss the increase in milk components the industry has experienced recently due to the powerful combination of genetics and nutrition. Hoard’s Dairyman reported that 2024 was the first year that the U.S. had averaged over 4% milk fat going back to 1924 when records began. (13:01)

Both fat supplements increased milk yield in low-fat and high-fat basal diets, but the magnitude of the increase was larger in the low-fat diet. The high palmitic acid diet increased milk yield more in cows fed the low-fat basal diet than the palmitic + oleic supplement did. High-fat basal diet cows had similar milk yield responses to both fatty acid supplements. The panel discusses the industry emphasis on milk components and if/when a threshold in performance might happen given the advancement of genomics and nutrition. (15:51)

Clay asks Adam to remind the listeners about the relationship between fatty acids and crude fat or ether extract. Adam recommends moving away from ether extract and focusing solely on fatty acid content. Bill, Adam, and Clay talk about the variability in the fatty acid content of various feedstuffs. (25:33)

Bill asks if the feed efficiency improvement with the fat supplementation was due to more of a gross energy or digestible/metabolizable energy effect. Adam suggests it may be a little of both. The diet is more energy-dense, but we also know now that some of those specific fatty acids have specific effects. Improvements in NDF digestibility are consistently observed with palmitic acid supplementation. Oleic acid improves fatty acid absorption and has an impact on adipose tissue metabolism and insulin sensitivity. Bill and Adam go on to talk more philosophically about the best way to measure feed efficiency in dairy cows. (29:02)

If Adam could do this experiment over again, he would have pushed the basal fat levels a bit more and had both lower-producing and higher-producing cows in the experiment. This leads to a discussion of how the results might have differed if distiller grains or soybeans were used instead of cottonseed in the experiment. Listeners should be careful not to extrapolate the results from this experiment to other fat sources. (33:55)

Adam emphasizes that we shouldn’t be afraid of feeding high-fat diets, either basal or supplemental fatty acids, especially to high-producing cows. We should be very mindful about where those fatty acids are coming from. We could provide the same nutrients by feeding either cottonseed or distillers grains, but how those ingredients feed out could be very different. (38:38)

In summary, Clay agrees we should take a fresh look at how much fat we’re feeding cows in basal diets and underlines the importance of the source of supplemental fatty acids. Bill concurs and commends Adam’s group for basically making cottonseed without fat in the low-fat basal diet, which allowed for very clean interpretations of the fatty acid supplement results. Adam underlines that we can feed higher fat diets, but the fatty acid profile of all of those ingredients we might use is going to be key. In addition to fatty acids in diets and supplements, de novo synthesis of milk fat from acetate is the other half of the equation. Bringing those together might be a strategy to keep up with genetic improvements and drive higher milk fat yield. (47:43)

You can find this episode’s journal club paper from JDS Communications here: https://www.sciencedirect.com/science/article/pii/S2666910223001114

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Methyl Donor Nutrition in the Transition Dairy Cow with Dr. Joe McFadden, Cornell University Jan 21, 2025

Show notes

This Real Science Exchange podcast episode was recorded during a webinar from Balchem’s Real Science Lecture Series. You can find it at balchem.com/realscience.

Feeding rumen-protected choline in early lactation has consistently increased milk yield and energy-corrected milk yield, which is more pronounced when cows are fed diets low in metabolizable methionine. Choline feeding also increases milk fat and protein yield, minimizes body condition loss in early lactation, and reduces postpartum disease incidence. Dr. McFadden presents three topics about choline biology in the dairy cow. (01:45)

Why should we consider fatty acid feeding when feeding methyl donors like choline and methionine?
Choline degradation in the rumen and small intestine, focusing on the role of triethylamine oxide
Why should we consider lysophosphatidylcholine as an immunomodulator in fresh cows and preweaning calves?

Fatty acid nutrition to optimize methyl donor efficiency. (4:02)

Fatty liver is a concern for fresh cows because of its relationship with ketosis, poor fertility and compromised milk production. Cows with fatty liver exhibit low circulating concentrations of phosphatidylcholine, which is a component of very low-density lipoproteins (VLDL) that transport triglycerides out of the liver. Feeding rumen-protected choline lowers liver triglyceride deposition by supporting the synthesis of phosphatidylcholine and thus, VLDL.

Dr. McFadden goes on to explain the two different pathways for phosphatidylcholine in the liver and how those interact with fatty acid metabolism. He describes several experiments that have investigated how rumen-protected choline and supplemental fatty acids interact in lactating cows.

Low phosphatidylcholine supply is a key feature of fatty liver in dairy cows, likely due to low polyunsaturated fatty acid (PUFA) and low choline supplies. Delivery of post-ruminal PUFA may support phosphatidylcholine synthesis with accompanying improvements in insulin sensitivity, body condition maintenance, and inflammation, but interactions with dietary fatty acid digestibility should be considered. Dr. McFadden gives a list of considerations for fresh cow diets incorporating fat and choline supplementation.

Gastrointestinal choline degradation and trimethylamine N-oxide (TMAO) (16:58)

Unprotected choline is almost totally degraded in the rumen. Microbes convert choline into trimethylamine (TMA) which is then converted to TMAO in the liver. Rumen-protected choline allows for a large proportion of choline to reach the small intestine intact. However, research shows that choline can also be degraded by microbes in the small intestine in the same pathway, limiting choline bioavailability. Plasma TMAO accumulation is associated with non-alcoholic fatty liver disease, inflammation, insulin resistance, obesity, oxidative stress, and cardiovascular disease in rodent and human models. Little research was available regarding if the relationship between TMAO and poor health was causative or just associative. Dr. McFadden’s lab infused cows intravenously with TMAO and found that TMAO did not modify milk production or glucose tolerance in early lactation cows.

TMAO does not appear to influence energy metabolism or health in early lactation cows. Choline is subject to both ruminal and lower-gut degradation to TMA, and that influence on choline bioavailability needs to be defined. Data in non-ruminants suggests that unsaturated fatty acid feeding can shift the gut microbes to slow TMA formation.

Lysophosphatidylcholine and immunomodulation (28:45)

Dr. McFadden gives an overview of neutrophil activation and the oxidative burst that contributes to pathogen killing. The ability to elicit the oxidative burst is diminished in pre-weaned calves and transition cows. When cows were given endotoxin to cause an immune response, circulating lysophosphatidylcholine was decreased. In rodent models, lysophosphatidylcholine promotes the oxidative burst and suppresses long-term inflammation in response to bacterial infection. Dr. McFadden cultured neutrophils from pre-weaned calves with lysophosphatidylcholine and observed an enhanced oxidative burst.

Immunosuppression is characterized by low circulating lysophosphatidylcholine concentrations in dairy cows. In vitro data suggests lysophosphatidylcholine can activate neutrophils, and rumen-protected choline increases circulating lysophosphatidylcholine. Future research is likely to define an immunomodulatory role for choline.

Dr. McFadden takes questions from the webinar audience. (38:07)

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Dr. Laura Hernandez and Dr. Tom Overton: The role of the mammary gland in calcium metabolism Jan 14, 2025

Show notes

Dr. Hernandez recently presented a Real Science Lecture series webinar on this topic. You can find the link at balchem.com/realscience.

Dr. Hernandez begins with an overview of how she came to study calcium metabolism in the mammary gland. Over the past number of years, she has worked on research to manipulate what’s happening in the mammary gland in the prepartum period to ensure adequate endocrine, nutritional, reproductive, and immunological status. (5:55)

The panelists discuss how “normal” has changed when it comes to transition cow health. Dr. Overton reminds listeners that 25 years ago, 6-8% of fresh cows in a herd having clinical milk fever was pretty typical. Now, we accept none of that. Subclinical hypocalcemia was not on the radar then, and we thought we had calcium all figured out. Dr. Hernandez’s work shows that this was not the case. She is pleased that a synergism of producers, veterinarians, and academics have been working together to understand the mechanisms of calcium metabolism to find solutions for individual farms based on their situation. (9:22)

Dr. Hernandez then discusses various interventions used in the industry, including low-potassium diets, negative DCAD diets, and zeolite clays. The clays are new to the US, and it seems that they work primarily through a phosphorus reduction mechanism and are best limited to feeding 10-14 days pre-calving. (18:14)

Dr. Overton asks Dr. Hernandez about a point in her webinar that cows are in negative calcium balance through 150-200 days in milk. She confirms that there are approximately 8.5 kilograms of calcium in the bones of a cow, but we don’t know how much of that she loses each lactation. Her dream scenario would be a CT scanner large enough to fit a dairy cow in to evaluate how her bones change throughout lactation. This leads to a discussion of whether or not we should be including higher rates of calcium in dairy cow diets. Dr. Hernandez would like to learn more about what’s happening with calcium absorption in the gut in real-time with endocrine status and stage of lactation, which is a challenging task. (23:17)

Co-host, Dr. Jeff Elliott, asks if the reason multiparous cows are more prone to milk fever is because they’re not as efficient at calcium resorption to the bone. Dr. Hernandez doesn’t have a definitive answer, but it could be due to less effective gut absorption with age, or it may be related to the influence of estrogen on bone density. She also mentions it could be endocrine-controlled or even stem cell-related. (28:59)

Dr. Hernandez’s hypothesis has always been that you have to have a calcium decrease to trigger the negative feedback loop involved in calcium metabolism. Her advice is to wait until 48 hours to take a blood sample to analyze calcium. This aligns well with epidemiological research on the veterinarian side regarding delayed, persistent, transient, and normal hypocalcemic animals. (33:04)

Dr. Overton asks about a calcium-chelation study that Dr. Hernandez’s group conducted and whether or not chelating calcium had an impact on colostrum production. It did not in that experiment. Dr. Hernandez was surprised at how much chelating agent was needed to overcome the draw of the mammary gland, but that further underlines how much of a priority lactation is in metabolism. (41:45)

Scott asks both panelists their views on what the priority should be for research in this area. Dr. Hernandez’s ideas include more research on how zeolite clays work biologically, finding out what’s happening in the gut, mammary gland, and bone of a dairy cow at different stages of lactation. She emphasizes that research should be conducted at different stages rather than just extrapolating from one stage to another because lactation is incredibly dynamic. Dr. Overton seconded the idea of a better understanding of zeolite clays and their feeding recommendations, as well as research defining what happens to and where all the calcium is pulled from the bone during lactation. (45:32)

In closing, Jeff, Tom, and Laura share their take-home thoughts. Jeff is excited to learn more about how zeolite clays work and if other products may come to the forefront to help in calcium metabolism management. Tom commends Laura on her work and how it has dovetailed so well with the epidemiological research from the veterinary side. Laura reminds listeners that the mammary gland is running the show and is thrilled that her work as a basic scientist is having an applied impact on the dairy industry. (51:17)

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Assessing Mineral Availability and Real-World Implications with Dr. Bill Weiss, Professor Emeritus, The Ohio State University Jan 07, 2025

Show notes

Please note the recording was before the new NASEM model was released. However, there is still a lot of good information from Dr. Weiss beyond those recommendations. This Real Science Exchange podcast episode was recorded during a webinar from Balchem’s Real Science Lecture Series. You can find it at balchem.com/realscience.

Most ration formulation software uses the 2001 NRC mineral equations. The basic concept of the 2001 NRC mineral requirements is to feed enough absorbable minerals to maintain adequate labile body stores and fluid concentrations. Minerals are lost each day via excretion in feces and urine, milk production, and incorporation into tissues or the fetus in the case of growing or pregnant animals. We have decent data to predict mineral concentrations of milk, growth, and the fetus; however, the endogenous loss in feces is much harder to capture. Absorption coefficients (AC) for most minerals are exceedingly difficult to measure. (0:29)

The NRC requirements are the means of several experiments. Feeding to the mean results in half the cows being fed adequately or in excess, and half are not fed enough. In human nutrition, recommended daily allowances for vitamins and minerals are calculated as the mean plus two standard deviations, which statistically meets the requirement for 97% of the population. Since the standard deviation of the requirement is hard to acquire, human nutrition uses the same standard deviation for energy metabolism, around 20%. Dr. Weiss feels this is a reasonable safety factor for minerals for animals as well. He recommends feeding about 1.2 times the NRC requirement while keeping an eye on the maximum tolerable limit for the mineral in question. (4:59)

How do we measure absorption? We measure the minerals in the diet, we apply AC, and we get grams or milligrams of absorbed minerals available for the animal to use. Dr. Weiss details some of the complex methodology involved in trying to obtain AC. Feces contain not only unabsorbed dietary minerals but also endogenous/metabolic minerals (e.g., intestinal cells, enzymes, etc.) and homeostatic excretion of minerals (e.g., dumping excess minerals). In the 2001 NRC, the endogenous fecal for almost every mineral is a function of body weight, which is incorrect. It should be a function of dry matter intake. (8:40)

Endogenous fecal losses can also be measured using stable or radioactive isotopes. This method is extremely expensive and if radioactive isotopes are used, management of radioactive waste becomes an issue. Thus, most of the AC for trace minerals that used these methods are 50-60 years old. (15:33)

Dr. Weiss details some of the issues with calcium requirements in the 2001 NRC leading to overestimation of calcium absorption for many calcium sources and overestimation of the maintenance requirement due to endogenous fecal being calculated using body weight. Organic and inorganic phosphorus have different AC, so partitioning between organic and inorganic will give a more accurate estimate of the requirement. (16:33)

Potassium has a linear antagonistic effect on magnesium. You can feed more magnesium to overcome this antagonism, but you won’t ever eliminate it. If you feed a few percent added fat as long-chain fatty acids, Dr. Weiss recommends feeding 10-20% more magnesium to account for soap formation in the rumen. (19:17)

It’s much more difficult to measure AC for trace minerals due to multiple antagonists, interactions among different minerals, and regulated absorption. In addition, AC for trace minerals is very low, which means a small change in the AC can have a huge impact on diet formulation. All feeds in the NRC system have the same AC for each trace mineral and we know that’s not right. (25:39)

Dr. Weiss gives an overview of different trace mineral antagonisms and interactions and details his approach to formulation if he has absorption data for a particular ingredient. He also gives his estimates of revised AC for several minerals. (28:07)

In summary, the factorial NRC approach only fits 50% of the population. Feeding an extra 10-20% above the NRC requirement includes about 97% of the population. We need to continue to account for more sources of variation in AC. Interactions need to be top of mind when considering mineral requirements and diet formulation. (37:39)

Dr. Weiss takes a series of questions from the webinar audience. (40:50)

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Understanding Dairy Cow Behavior to Optimize Nutritional Management with Dr. Trevor DeVries, University of Guelph Dec 17, 2024

Show notes

This Real Science Exchange podcast episode was recorded during a webinar from Balchem’s Real Science Lecture Series. You can find it at balchem.com/realscience.

Feeding behavior of dairy cows is inherently tied to their dry matter intake (DMI) which is tied to milk production. If we want to change a cow’s DMI, it must be mediated by changing her feeding behavior. (00:23)

In a multi-variable analysis, Dr. DeVries found that DMI was most associated with feeding time and meal frequency. It’s important to allow the cow to maximize the amount of time she can spend at the bunk eating, as well as the number of times she can get to the bunk each day. In one study, about 30% of the variability in milk fat content in cows on the same diet was explained by their meal frequency, where cows who had more meals per day had higher milk fat. Dr. DeVries also talks about the impacts of feeding behavior on cow efficiency and rumen dynamics. (2:13)

As soon as a cow sorts the TMR put in front of her, she consumes a diet that’s variable in composition to what we expect. Cows who sorted against long feed particles had lower milk fat and milk protein concentrations. In another study, Dr. DeVries retrospectively analyzed cows with a low vs high risk of ruminal acidosis. Cows in both groups had similar DMI but a tendency for high-risk cows to have lower milk yield and numerically lower milk fat. Combining these resulted in significantly lower fat-corrected milk for the high-risk cows. Given that the diets and DMI were similar, the difference was attributed to sorting, which can have quite negative impacts on individual and herd-level production. (10:00)

Cows spend nearly twice as much time ruminating as they do eating. Rumination reduces feed particle size and increases surface area, leading to increased rates of digestion and feed passage. In a recent study, Dr. DeVries’ group calculated the probability that cows were ruminating while lying down using automated monitoring data from previous experiments. Cows with a higher probability of ruminating while lying down had higher DMI, milk fat, and milk protein than cows who ruminated while standing. This highlights that cows need not only time to ruminate but also space for sufficient rest. (16:44)

Diets and diet composition should be formulated to encourage frequent meals, discourage sorting, and stimulate rumination. Forage management factors including forage quality, forage quantity, forage type (dry vs ensiled), and particle size all play important roles. In a study with fresh cows, Dr. DeVries’ lab fed two different particle sizes of straw: 5-8 cm vs 2-3 cm in length. While DMI was the same over the first 28 days of lactation, cows fed the long straw spent more time with rumen pH below 5.8 because they were sorting against the straw. This also resulted in a yield difference, as the short straw-fed cows produced about 165 pounds more milk over the first 28 days compared to the long straw group. Dr. DeVries also comments on the use of feed additives on rumen stability and feeding behavior (22:54)

More frequent feed delivery should generate more consistent consumption and better feeding behavior, and improve rumen health and milk component concentration. Shifting feed delivery away from return from milking, while still ensuring cows have abundant feed available, results in more consistent eating patterns. Dr. DeVries emphasizes that we push up feed to make sure it’s present at the bunk, not to stimulate cows to eat. We want to make sure that eating behavior is driven by the cow: when she's hungry and goes to the bunk, we need to make sure feed is there. (30:02)

Dr. DeVries indicates we want to minimize the time cows are without feed completely. An empty bunk overnight plus a little overcrowding resulted in negative impacts on rumen health, including more acidosis and reduced fiber digestibility. Increased competition in overcrowding scenarios results in cows having larger meals, eating faster, and likely having a larger negative ruminal impact. In another study, every four inches of increased bunk space was associated with about 0.06% greater milk fat. Herds with high de novo fat synthesis were 10 times more likely to have at least 18 inches of bunk space per cow. (40:04)

In closing, Dr. DeVries’ biggest takeaway is that how cows eat is just as important as the nutritional composition of the feed in ensuring cow health, efficiency, and production. Collectively, with good quality feed and good feeding management, we can gain optimal performance from those diets. Dr. DeVries ends by taking questions from the webinar audience. (43:40)

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Perspective and Commentary: Variation in nutrient composition of feeds and diets and how it can affect formulation of dairy cow diets with St-Pierre & Weiss Dec 10, 2024

Show notes

Dr. Weiss and Dr. St-Pierre co-authored this episode’s journal club paper in Applied Animal Science (ARPAS Journal). Bill and Normand share a career-long interest in how feedstuffs and diet variation impact cows. (6:31)

Bill and Normand discuss sources of variation, which they divide into true variation and observer variation. True variation means the feed has changed: a different field, change during storage, etc. Observer variation includes sampling variation and analytical variation. Some feeds may exhibit a lot of true variation and others may exhibit a lot of observer variation. And some feeds are high in both types of variation. Highly variable feeds should be sampled more frequently. Some feeds are so consistent that using book values makes more sense than sending in samples for analysis. Bill and Normand go on to give some examples and share sampling and analysis tips for different types of feedstuffs. (12:41)

Bill would often be asked if users should continue to average new samples with older ones or just use the new numbers from the most recent sample. He and Normand debate the pros and cons of the two approaches as well as discuss the use of a weighted average where recent samples would be weighted to contribute more. (26:02)

Next, our guests discuss how multiple sources of a nutrient reduce the TMR variation for that specific nutrient. For example, alfalfa NDF is more variable than corn silage NDF on average. Yet if you use a blend of these two ingredients, you end up with less variation in NDF than if you used all corn silage. Normand details the mathematical concepts behind this relationship. Both Bill and Normand emphasize that diets must be made correctly for the best results. (32:26)

How do feedstuffs and diet variations impact cows? Both guests describe different experiments with variable protein and NDF concentrations in diets. Some were structured, like alternating 11% CP one day and 19% CP the next for three weeks. Some were random, like randomly alternating the NDF over a range of 20-29% with much higher variation than we’d ever see on-farm. The common thread for all these experiments is that the diet variations had almost no impact on the milk production of the cows. (38:04)

Clay asks how variation in dry matter might affect cows. Bill describes an experiment where the dry matter of silage was decreased by 10 units by adding water. Cows were fed the wet silage for three days, twice during a three-week study. To ensure feed was never limited, more as-fed feed was added when the wet silage was fed. It took a day for cows on the wet silage treatment to have the same dry matter intake (DMI) as the control cows and milk production dropped when DMI was lower. However, when switching abruptly back to the dry silage diet, DMI increased the day following the wet silage and stayed high for two days, so the cows made up for the lost milk production. Bill and Normand underline that it is critical for the cows not to run out of feed and described experiments where feed was more limiting, yielding less desirable outcomes. (46:17)

In the last part of the paper, our guests outlined seven research questions that they feel need to be answered. Normand shares that his number one question is how long will cows take to respond to a change in the major nutrients? He feels that we spend an inordinate amount of money on feedstuffs analysis, and there are some feeds we should analyze more and some feeds we should quit analyzing. Bill’s primary research question revolves around controlled variation. What happens if you change the ratio of corn silage and alfalfa once a week? Will that stimulate intake? Data from humans, pets, and zoo animals indicate that diet variation has a positive impact and Bill finds this area of research intriguing. (50:43)

In closing, Clay encourages listeners to read this paper (link below) and emphasizes the take-home messages regarding sampling and research questions. Normand advises that if you are sampling feed, take a minimum of two samples, and try as much as you can to separate observer variation from true variation. He also reminds listeners to concentrate on a few critical nutrients with more repeatability for analyses. Bill encourages nutritionists to sit down and think when they get new data - before they go to their computer to make a diet change. If something changed, why did it change, and is it real? Take time to think it through. (1:01:38)

You can find this episode’s journal club paper from Applied Animal Science here: https://www.appliedanimalscience.org/article/S2590-2865(24)00093-4/fulltext

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The Dual Essentiality of Choline and Methionine with Dr. Heather White, University of Wisconsin-Madison Dec 03, 2024

Show notes

This Real Science Exchange episode was recorded during a webinar, which was part of a series. Watch all the presentations from this series here: https://balchem.com/animal-nutrition-health/resources-categories/real-science-lecture-series/previous-lectures/page/10/

Early in lactation, the cow is incapable of eating enough to meet her dramatically increased requirements. As the cow’s intake decreases near calving, there are fewer nutrient contributions from dry matter intake and she must alter nutrient partitioning to meet her increased needs by mobilizing fat and muscle stores. (1:18)

Triglycerides from fat stores are broken down into non-esterified fatty acids (NEFA) and glycerol. NEFA has two different fates in the postpartum cow: to the mammary gland as a precursor for milk fat synthesis, or to the liver to be oxidized for energy production. Glycerol enters the gluconeogenic pathway in the liver as a glucose precursor. (4:41)

The capacity for the liver to use NEFA for energy is limited by the capacity of the TCA cycle. When the TCA cycle is at capacity, excess NEFA can either undergo incomplete oxidation to ketones or be repackaged back into triglycerides. If the capacity for other tissues to use ketones for energy is exceeded, then blood concentrations of ketones rise and negative outcomes from subclinical and clinical ketosis can occur. If triglycerides accumulate in the liver, negative outcomes associated with fatty liver can occur. Triglycerides can be transported out of the liver via very low-density lipoprotein (VLDL) export; however, VLDL export does not keep up with triglyceride concentration during the transition period in dairy cows, largely because of a limiting amount of phosphatidylcholine. (5:51)

Dr. White describes a series of experiments in her lab using liver cells in culture to investigate the relationship between choline supplementation and VLDL export. As choline supplementation to the cell culture increased, so did VLDL export from the cells into the media. In addition, increasing choline supplementation to the cell culture also decreased cellular triglyceride content. (10:54)

Using gene expression and radiolabeled tracers over a series of experiments, Dr. White’s group found that as choline supplementation increased, so did complete oxidation of NEFA to energy. This was accompanied by decreased incomplete oxidation to ketone bodies and decreased accumulation of lipids in the liver cells. Glucose and glycogen were also increased with increasing choline supplementation to the cell culture, and a decrease in reactive oxygen species was observed. In addition, choline-supplemented cultures exhibited an increase in metabolic pathways associated with methionine regeneration and methyl donation. (15:29)

Dr. White then details the complexity of the metabolic pathways that intersect between choline and methionine. In similar experiments supplementing cell cultures with increasing amounts of methionine and choline, there were no effects of methionine on lipid export, oxidative pathways, or glucose metabolism. The main benefit of methionine was a marked increase in glutathione production. It’s important to note that no interactions between choline and methionine were observed in this series of experiments. (19:37)

There seems to be a clear biological priority for different sets of pathways for choline and methionine. Choline seems to be influencing lipid, glucose, and oxidative pathways, while methionine is primarily serving its role as an essential amino acid for cellular protein structure and generation, acting as a methyl donor, and impacting inflammation. Importantly, both the choline and methionine results observed in cell culture are paralleled in transition dairy cow studies. (24:14)

Dr. White’s lab further investigated the impact of methionine on inflammation. When cells were challenged with LPS to provoke an inflammatory response, methionine mitigated the inflammatory response. Similar results have been observed in liver tissue samples of transition cows. Methionine mitigated inflammatory markers and increased glutathione but did not influence reactive oxygen species. Conversely, choline decreased reactive oxygen species but did not change glutathione. (27:47)

Choline and methionine are both essential nutrients, there are biological priorities for them as methyl donors, and they are not mutually exchangeable. The lack of interaction between choline and methionine in vivo or in vitro supports the idea of different biological roles for these nutrients. (32:09)

Dr. White takes questions from the webinar audience. (34:53)

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ADSA Industry of Interest Research, Part Two Nov 26, 2024

Show notes

In part two of a two-part series, the Balchem technical team selected industry research of interest from the 2024 American Dairy Science Association meetings to feature on this episode of the Real Science Exchange.

Smart Cows, Smart Farms: Unleashing the Potential of Artificial Intelligence in the Dairy Sector

Guest: Dr. Jeffrey Bewley, Holstein Association USA (1:58)

Dr. Bewley is the Dairy Analytics and Innovation Scientist at Holstein Association USA, where part of his role is collaborating with Western Kentucky University at the WKU Smart Holstein Lab. The group works with more than 30 technologies, including wearable, camera and machine vision, milk analysis, and automation technologies. At ADSA, Dr. Bewley’s presentation was part of a symposium titled “Applications of AI to Dairy Systems.” His talk focused on cow- and farm-level technologies using artificial intelligence. He anticipates a continued massive increase in the availability of technologies for dairy farms to assist with automating processes that are often monotonous tasks. One example of this is the wearable accelerometer technologies that allow for the assessment of estrous behavior, as well as rumination and eating behavior. In the future, camera-based technologies may become more commonplace for things like body condition scoring. Cameras may also be able to monitor rumination and eating behavior, and even perhaps dry matter intake. Dr. Bewley also sees an opportunity on the milk analysis side to be able to measure even more biomarkers to better manage for improved health, reproduction, and well-being. He reminds listeners that animal husbandry will continue to be a critical piece of dairy farming even with advancing technology. He gives examples of current and cutting-edge technologies on the horizon for dairy farms. On his wish list of technologies for the future, he includes dry matter intake measurement and inline measurement of somatic cell count, hormones, and metabolites in the milk. In closing, Dr. Bewley encourages listeners to be excited yet cautious about artificial intelligence and gives examples of how technology can collect phenotypic data to use in genetic evaluation.

Explaining the Five Domains and Using Behavioral Measures in Commercial Systems

Guest: Dr. Temple Grandin, Colorado State University (26:48)

Dr. Grandin’s presentation was also part of a symposium, titled “The Animal Behavior and Wealthbeing Symposia: Evaluating Animal Comfort and Wellbeing Using the Five Domains.” The five domains approach is gaining popularity. Previous guidance documents emphasized preventing suffering, cruelty, and discomfort. The five domains are nutrition, environment, health, behavior interactions, and the emotional state of the animal. Much of the information available is very theoretical. Dr. Grandin’s goal for this presentation was to gather easy-to-download scoring tools to assist in auditing the five domains in the field. She emphasizes the importance of good stockmanship for animal well-being and cautions that while artificial intelligence technologies can be used to assess the five domains, good stockmanship will always be necessary. Dr. Grandin recommends a three-legged audit: internal, independent third-party, and corporate representatives. She cautions against farming all audits out to a third party and anticipates that it has the potential to cause major supply chain disruptions. Lastly, Dr. Grandin recommends simple yet effective outcome measures for audits that can be taught in a short training session that includes practice audits.

View her five domains paper here: https://pubmed.ncbi.nlm.nih.gov/36290216/

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