Nutritionists are often blamed for transition cow problems like high NEFAs, clinical and subclinical ketosis, and subclinical hypocalcemia. Dr. Baumgard suggests these symptoms are a result of one of two situations: 1. These are highly productive, healthy, and profitable cows; or 2. The symptoms are the metabolic reflection of immune activation, likely stemming from metritis, mastitis, pneumonia, or GI tract inflammation. In the first scenario, the nutritionist deserves a raise; in the second, these are mostly management issues not caused by nutrition. (1:26)

If listeners are interested in more detail on this topic, Dr. Baumgard suggests reading this 2021 review in the Journal of Dairy Science: “ Invited review: The influence of immune activation on transition cow health and performance—A critical evaluation of traditional dogmas.”

Link: https://www.sciencedirect.com/science/article/pii/S0022030221006329

Dr. Baumgard highlights key concepts that underpin his thinking regarding transition cows: The best indicators of health are feed intake and milk yield, it’s too easy to overthink the immune system, Mother Nature is rarely wrong, and inconsistent or non-reproducible data should create doubt. He goes on to review the incidence of metabolic disorders in early lactation and the energy balance dynamics of the transition period. (4:29)

For decades, we’ve had the assumption that NEFAs and ketones are causing many of the health issues in transition cows. NEFAs, BHBs, and calcium have been correlated and associated with negative outcomes. However many other studies do not find these negative correlations or associations. Plasma NEFA is markedly increased following calving in almost all cows, yet only 15-20% get clinical ketosis. Dr. Baumgard suggests that it’s presumptuous and reductionist of us to assume we can use one metabolite to diagnose the disease. Little mechanistic evidence exists to explain how these symptoms cause metabolic disease issues. (10:29)

If hyperketonemia, high NEFA, and subclinical hypocalcemia are causing disease, then therapeutically treating these disorders would improve overall cow health. NAHMS data does not back that up. Dr. Baumgard dissects the dogma of ketosis. In short, mobilization of adipose tissues and partial conversion of NEFA to ketones is essential for maximum milk yield. (18:35)

High-producing cows are more hypoinsulinemic compared to low-producing cows, and transition period insulin concentrations are inversely related to whole lactation performance. Low insulin concentrations coupled with insulin resistance allow for fat mobilization. (29:02)

Post-calving inflammation occurs in all cows. Sources include the mammary gland, the uterus, and the gut. Severe inflammation precedes the clinical presentation of the disease. In one experiment, all cows exhibited some inflammation in very early lactation. However, cows that were culled or died before 100 days in milk were already severely inflamed during the first few days of lactation. Dr. Baumgard thinks inflammation is the simplest and most logical explanation for why some cows don't eat well before and after calving. (31:13)

While clinical hypocalcemia (milk fever) is pathological and requires immediate intervention, is subclinical hypocalcemia detrimental to health, productivity, and profitability? (36:33)

Dr. Baumgard’s paradigm-shifting concept suggests that increased NEFA and hyperketonemia are caused by immune activation-induced hypophagia, and hypocalcemia is a consequence of immune activation. He goes on to use a high-producing, a low-producing, and a sick cow to illustrate this concept. (43:26)

In summary, the metabolic adjustments in minerals and energy during the transition period are not dysfunctional and don’t need to be “fixed.” The real fix is to prevent immune activation in the first place to prevent the cow from going off feed. Profitable production is a consequence of wellness. (52:19)

Dr. Baumgard takes a series of engaging questions from the webinar audience. Watch the full webinar at balchem.com/realscience. (56:04)

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The Balchem technical team selected abstracts of interest from the 2024 American Dairy Science Association meetings to feature on this episode of the Real Science Exchange.

Whole Cottonseed and Fatty Acid Supplementation Affect Production Responses During the Immediate Postpartum in Multiparous Dairy Cows

Guests: Jair Parales-Giron and Dr. Adam Lock, Michigan State University (0:58)

The experiment had four treatment groups: no fat supplement, 10% of the diet from whole cottonseed, a 60:30 mix of calcium salts of palmitic and oleic acid at 1.5% of the diet dry matter, and a combination of both whole cottonseed and fatty acid supplement. Energy-corrected milk was increased by almost six kilograms in cows fed the whole cottonseed diet, with a similar increase of more than five kilograms in the fatty acid-supplemented cows during the first 24 days of lactation. However, no further improvement was observed when both whole cottonseed and fatty acids were fed together. The increase in milk production was not accompanied by increased weight loss or loss of body condition.

Effect of Close-Up Metabolizable Protein Supply on Colostrum Yield, Composition, and Immunoglobulin G Concentration

Guests: Dr. Trent Westhoff and Dr. Sabine Mann, Cornell University (17:06)

In this study, cows were assigned to one of two diets 28 days before expected calving: one that provided 39 grams of metabolizable protein (MP) per pound of dry matter and one that supplied 51 grams of MP per pound of dry matter. This represents about 100% of the MP requirement and 140% of the MP requirement, respectively. Diets were formulated to supply equal amounts of methionine and lysine. Cows entering their second parity who were fed the elevated MP diet produced two liters more colostrum than second parity cows fed the control MP diet. This effect was not observed in cows entering their third or higher parity. Overall, higher MP supply did not impact colostrum quantity or quality. Dr. Westhoff also highlights an invited review he authored regarding nutritional and management factors that influence colostrum production and composition. The MP research has also been published; links to both are below.

MP paper: https://www.sciencedirect.com/science/article/pii/S0022030224010774

Invited review: https://www.sciencedirect.com/science/article/pii/S0022030224000341

Colostrum—More than Immunoglobulin G (IgG): Colostrum Components and Effects on the Calf

Guest: Dr. Sabine Mann, Cornell University (41:23)

Dr. Mann presented this abstract at an ADSA symposium titled “Colostrum: The Role It Plays In Calf Health, Development, and Future Productivity.” Her focus was to give credit to the importance of IgG while reminding the symposium audience of the importance of other colostrum components like bioactive factors and nutrients. There is potential that measuring IgG could be a marker for all the other colostrum components that have been transferred as well. We have excellent and cost-effective ways to measure IgG calf-side, but very few bioactive factors can be measured as easily. Heat treatment of colostrum to control bacterial contamination has a detrimental effect on many of the non-IgG components of colostrum. More data is needed to learn how impactful this may be to the calf. Dr. Mann details parts of the heat treatment process that farmers can check to make sure heat treatment is having as little impact as possible. She also would like to have a way to measure the antimicrobial activity of colostrum and the concentrations of insulin and IGF-1 in colostrum on-farm. Lastly, she reminds the audience that we can focus a lot on making the best quality colostrum via transition cow management and best management practices for colostrum harvest, but we still need to get it into the calf. Colostrum must get into calves cleanly and safely, at an adequate amount, and at an optimal temperature.

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

Shakespeare wrote, “The eyes are the windows of the soul.” Dr. Ollivett believes the lungs are the window to calf health management. The lungs are an indicator organ: respiratory disease is a symptom of management failure. Failure of passive transfer, diarrhea, septicemia, poor nutrition, a dirty environment, and heat or cold stress can all negatively impact the lungs. Often, this can manifest as subclinical pneumonia, where the lungs are abnormal but the calf externally appears completely normal. (3:51)

Dr. Ollivett reviews the defense mechanisms of the airway. When a veterinarian takes swabs to assess a respiratory disease problem, the bacteria and viruses that live in the nasopharyngeal area just ahead of the trachea are the most representative of those bacteria and viruses that are present in the lungs. The bacteria and viruses in the lower nasal passages are unreliable indicators of what is present in the lungs. (6:28)

Is coughing a good predictor of pneumonia? Research shows that if calves are coughing, it is highly likely they will test positive for a respiratory pathogen. One study showed that coughing was the best predictor of observing pneumonia on lung ultrasound, but only 37% of calves with pneumonia on ultrasound also had a cough. Dr. Ollivett observed similar results in commercial settings, where only about 10% of calves with pneumonia on ultrasound had an accompanying cough. This suggests that a cough is not a good early warning tool for pneumonia. (10:29)

Dr. Ollivett believes respiratory disease exhibits an iceberg effect, where considerably more subclinical respiratory disease exists than clinical respiratory disease. She provides examples of necropsied lungs from dairy calves to emphasize the point that calves can appear completely normal, but have the same or more damage to their lungs compared to calves exhibiting clinical signs of pneumonia. In her work, Dr. Ollivett has found that the sensitivity of lung ultrasounds to find lung lesions in animals with subclinical disease is 88%. (16:32)

What does it take to perform a lung ultrasound? Dr. Ollivett gives an overview of the process and describes what normal and affected lungs look like. Depending on the farm, 50-80% of cases can be subclinical for one to two weeks before we see signs of pneumonia. With lung ultrasounds, you can treat affected animals sooner while also getting a good assessment of where management can improve to better prevent pneumonia cases in the future. (27:37)

The prevalence of the disease is roughly equal to the incidence of the disease times the duration of the disease. Prevention of disease reduces the speed at which disease occurs, thus decreasing the incidence of disease and lowering its prevalence. On the other hand, identifying sick calves sooner should reduce the duration of the disease, also lowering its prevalence. In addition, effective treatment that reduces the duration of disease supports antimicrobial stewardship. Dr. Ollivett details criteria to evaluate treatment failure in your operation, as well as discusses antibiotic therapy in conjunction with lung ultrasounds. (34:29)

Dr. Ollivett emphasizes the impact that the gut has on the lungs on most dairy farms. She feels that as an industry, we are far too comfortable with abnormal manure in 7- to 14-day-old calves. After any abnormal manure, calves are more likely to have abnormal lungs in the next couple of weeks. Ensuring good passive transfer and maintaining a clean environment will reduce lung lesions. (50:50)

To keep calves breathing easy, Dr. Ollivett shares recommendations to reduce management failures before, at, and after birth. These can include clean and adequate space in maternity, clean calf bedding and equipment, the excellent establishment of passive transfer, adequate average daily gains in early life, and routine lung ultrasounds. (53:21)

Dr. Ollivett answers questions from the webinar audience about evaluating treatment protocols for effectiveness, technicalities and landmarks of performing lung ultrasounds, how soon after birth to begin lung ultrasounds, using lung score to determine when to treat with antibiotics, and if lung ultrasounds could be used to cull animals with lung damage before they enter the milking herd. Watch the full webinar at balchem.com/realscience. (55:44)

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