Connecting the Dots for a Sustainable Future

Since the mid-20^th century, advancements in nutritional chemistry/biochemistry, feed formulation and management, and new research techniques used to study the various effects on animal health have improved the efficiency and optimization of meat, milk, and egg production significantly. (Harmon, 2024) Feed intake, growth rate, feed efficiency, quantity, animal well-being and quality improvements remain the definitions of productivity success. It follows that, given a positive productivity state, animals must also be in a positive state of health perhaps in spite of diagnostic measurements that say otherwise (Baumgard L. H., 2024). Despite the observed gains in production, a thirst remains to solve for those factors that may be constraining the rate of productivity advancements of the various species industries.

One of the most significant challenges in animal nutrition is understanding the asymptomatic/subclinical issues that are known to negatively affect productivity but are not often seen.

(Reinhardt, Lippolisa, McCluskey, Goff, & Horst, 2011) ( McArt, Nydam, & Oetzel, 2012) (Ruegg, 2017) (Rishniw, White, & Mueller, 2021) Prime examples of this include, but are not limited to, certain subsets of subclinical hypocalcemia (SCH) in dairy cows, subclinical ketosis (SCK) and subclinical mastitis (SCM). Efforts towards diagnosing, identifying and predicting subclinical issues and what that means for overall health and productivity, most certainly advances our understanding of these often unseen problems. Furthermore, the primary objective is to predict and mitigate the progression to advanced pathological conditions that are readily apparent and have severe consequences. As a result of these efforts and understanding, prophylactic nutritional strategies can be developed to potentially reduce the risk of occurrence and help alleviate these subclinical conditions. In this paper, we first develop a non-comprehensive review of existing research which is presented to evaluate current advancements in the underlying causes of subclinical conditions for various species. Then, the authors seek to connect the dots between what appears to be highly conserved root causes and potential nutritional strategies which could be part and parcel to a holistic approach for increasing better health outcomes and therefore productivity in the 21^st century.

Subclinical conditions in dairy cows significantly affect herd health, productivity, and economic efficiency, often presenting without overt clinical symptoms. (Goff, 2008) (Oetzel, 2013) (Baumgard, Collier, & Bauman, 2017) (Cascone G. , et al., 2022) (Seminara & McArt, 2025) In a recent study, a global economic simulation across 183 milk-producing countries estimated the financial impact of 12 dairy cattle diseases, including milk fever, mastitis, lameness, ketosis, and metritis. ( Rasmussen, et al., 2024) The effects of the various diseases and conditions on milk yield, fertility, and culling were standardized, meta-analyzed, and adjusted for co-morbidities to prevent overestimation. Monte Carlo simulations, which incorporated country-specific data, estimated total global losses at US$65 billion annually. According to the study, the costliest diseases were subclinical ketosis (US$18B), clinical mastitis (US$13B), and subclinical mastitis (US$9B). Subclinical hypocalcemia was not included in the study as one of the factors. However, Milk Fever was included, and the estimated annual adjusted loss was reported at approximately US$0.75B. If these simulations are even remotely close to reality, and there is no reason not to think so, the magnitude of the inefficiency is clear.

In a study on the prevalence of periparturient disease and their effects on fertility, it was revealed that 59.0% of grazing dairy cows in the study had at least one subclinical health issue. (Ribeiro, et al., 2013)

The most common conditions included subclinical hypocalcemia (43.3%), subclinical ketosis (35.4%), subclinical endometritis (SCE) (15.3%) and elevated non esterified fatty acids(NEFA) concentration (20.0%) which may be a complication but not necessarily a subclinical issue. This study did not mention subclinical mastitis but did reference 15.3% for the disease mastitis.

In another global meta-analysis, 38 studies from six continents determined the global prevalence of subclinical ketosis (SCK) in dairy cows using a random-effects model. (Loiklung, Sukon , & Thamrongyoswittayakul, 2022) SCK is a common metabolic disorder, which arises from negative energy balance (NEB) following calving. This condition negatively impacts milk production, reproductive performance, and immune function. Early detection through blood or milk ketone testing is crucial for effective intervention and prevention of more severe complications. The findings showed that the global SCK prevalence was 22.7%. There were no significant differences in SCK prevalence that were observed a) across continents, b) diagnostic techniques, c) cut-off values (i.e. ?1.0, ?1.2, ?1.4 mmol/L BHB), d) sample types (milk vs. blood), or e) parities. Holsteins (19.8%) had a significantly lower prevalence than mixed breeds (23.7%). Indoor barns (27.8%) had a higher prevalence compared to pasture and unspecified housing. Meta-regression showed no association between SCK prevalence and study years or days in milk. Cumulative evidence indicated that SCK was linked to various risk factors, emphasizing the need for global efforts to reduce SCK prevalence in dairy farms. This analysis did not account for feed management practices (e.g., total mixed ration, partial mixed ration, body condition score) or milk yield in subgroup analyses. Overall, the study highlighted the high global prevalence of SCK and the need for improved management strategies to mitigate its impact on dairy cow health and productivity. SCK root cause and diagnostic complexities notwithstanding, there appears to be a real opportunity to help with reduction strategies for SCK.

Also, subclinical mastitis (SCM) is among the most prevalent conditions and by some estimations, found in over 37 percent of dairy cows. (Chen, et al., 2022) SCM is a hidden inflammation of the udder in dairy cows that doesn’t show visible symptoms like swelling, redness, or abnormal milk, making it tricky to detect without testing. Although it does not exhibit visible signs, it can be detected through somatic cell count analysis and may lead to reduced milk yield and increased susceptibility to clinical mastitis. It is a widespread and economically significant issue that compromises milk quality and production.

Moreover, SCM, like all subclinical conditions, poses a significant diagnostic challenge on dairy farms due to lack of visible clinical symptoms. Infected cows often go unnoticed, allowing the condition to persist and impact milk quality and yield without immediate detection.

Despite its subtle presentation, SCM is substantially more common than CM, with prevalence estimates ranging from 15 to 40 times higher. (Pilla, et al., 2013) This disparity underscores the need for targeted management strategies to mitigate economic losses associated with undetected infections. Heikkila et al. reported  “notable” reductions in milk yield due to mastitis. (Heikkilä, Liski, Pyörälä, & Taponen, 2018). They searched and measured the pathogens that might be responsible for the inflammation and milk yield decreases. It was suggested that pathogen-specific strategies are essential for effective mastitis management and that targeting E. coli and Staph. aureus could yield the greatest gains in production. Pathogen invasion is the most common trigger for subclinical mastitis, but it’s not the only one. Abiotic stressors can mimic microbial insult. While pathogen insult is the usual suspect, it’s not a universal prerequisite for mastitis. However, infection can lead to immune activation, elevated somatic cell counts (SCC), and subtle milk yield losses without visible symptoms. (Mezzetti, Carpenter, Bradford,, & Trevisi, 2024). As with SCK, inflammation mediation strategies may contribute to health and productivity improvements.

Similarly, subclinical (i.e. no apparent signs of the disorder) ruminal acidosis (SCRA) also known as SARA or subacute ruminal acidosis is a disorder characterized by periods of low ruminal pH, disrupting ruminal fermentation and leading to secondary complications such as increased systemic inflammation, reduced feed efficiency, milk fat depression, and weight loss. The ruminal pH drops leads to the death and lysis of gram-negative bacteria. This releases lipopolysaccharide (LPS), also known as endotoxin, into the rumen. LPS can translocate through the rumen wall into the bloodstream, triggering systemic inflammation. It was shown that SARA is often associated with elevated levels of cortisol (stress hormone) along with haptoglobin and lipopolysaccharide-binding protein (LBP) which are acute-phase proteins that increase during inflammation. NEFA also increases during metabolic and inflammatory stress. (Guo, et al., 2022)

SARA is one of the most prevalent metabolic disorders in lactating dairy cattle, impacting a large percentage of cows in early to mid-lactation. (Garrett E. F., 1997) (Oetzel G. R., 1999) (Christodoulopoulos, 2025).

In a comprehensive review, Plaizier et al. highlighted SARA’s detrimental effects on dairy cow performance and health, noting reductions in feed intake and fiber digestion, along with clinical signs such as milk fat depression, laminitis, diarrhea, liver abscesses, and systemic inflammation. (Plaizier J. C., 2008) More recently, Burhans et al. proposed that SARA’s ability to trigger endotoxemia, much like severe heat stress, may intensify inflammatory responses in cows already challenged by high environmental temperatures thereby potentially compounding their physiological stress. (Burhans W. S., 2022) Nutritional management plays a critical role in preventing this condition and maintaining optimal rumen function. Like SCK and SCM, inflammation seems to be at the core of this sub-clinical condition.

Hypocalcemia is widely considered a metabolic disorder affecting calcium homeostasis, often occurring in a subclinical form before progressing to more severe symptoms(i.e., milk fever).

Even in its subclinical state, hypocalcemia can impair muscle function, reduce feed intake, and negatively impact reproductive performance.

Professors McArt and Neves investigated how different patterns of subclinical hypocalcemia (SCH) in early postpartum Holstein cows affect health outcomes and milk production. (Neves J. A., 2020) They grouped 407 cows by parity (primiparous vs. multiparous) and calcium levels in early lactation into four categories: Normocalemic (NC), transient SCH (tSCH), persistent SCH (pSCH), and delayed SCH (dSCH). Dyscalcemic was the term coined for pSCH and dSCH. They found that tSCH cows, especially multiparous ones, produced more milk than other groups and had similar or slightly elevated disease risk compared to NC cows. They also found that pSCH and dSCH cows showed significantly higher risk of adverse events (e.g., metritis, displaced abomasum, herd removal) regardless of parity compared to NC and tSCH cows. The milk yield of tSCH cows outperformed all other groups which suggested better metabolic adaptation. The possibility remains that there may have been a greater ability to adapt to inflammation or less inflammation in those tSCH cows. Professor Lance Baumgard et al. wrote about inflammation and subclinical hypocalcemia. (E. A. Horst, 2021). The transition period from gestation to lactation involves major physiological, metabolic, and inflammatory changes that critically affect a cow’s health, future productivity, and survival in the herd. Traditionally, issues like excessive fat mobilization, ketone production, and subclinical hypocalcemia were believed to cause transition related disorders by suppressing immune function. However, despite decades of research, transition problems remain widespread. Emerging evidence now suggests that immune activation and inflammation are normal (and possibly primary) drivers of the metabolic changes seen postpartum. Inflammatory signals originating from the mammary gland, gut, and calving related tissue damage can reduce feed intake, induce hypocalcemia, and increase NEFA and ketone levels. Baumgard argued that these metabolic markers (NEFA, ketones, calcium) might not be causal but rather reflect either healthy metabolic adaptation or pathological immune response. In essence, the cow’s immuno-metabolic balance, not just traditional biochemical markers, may be the key to understanding transition success. In 2023 Neves suggested that a central debate emerged around the question:

Is SCH a causal disorder, or is it a symptom of deeper physiological stress, such as systemic inflammation?

Though immune activation has been proposed as a potential trigger for low calcium levels, the potential mechanisms linking inflammation to hypocalcemia remain poorly understood.  Inflammation may be involved in some HC but it clearly is a complicated disease and has multiple factors. The use of DCAD or even binders to reduce HC does not fit neatly into the inflammation theory (Weiss, 2025).  Neves and McArt also suggested that rather than treating SCH as an isolated calcium deficiency, researchers should focus on the degree, timing, and duration of low blood calcium to understand its broader metabolic significance. This position underscored that systemic inflammation, especially sterile inflammation, may play a central role in causing subclinical hypocalcemia (SCH) in postpartum dairy cows. While multiple mechanisms linking inflammation to reduced plasma calcium have been identified, substantial knowledge gaps remain. (Neves R. C., 2023) The multifaceted nature of this subclinical condition most likely necessitates a comprehensive nutritional approach that addresses all potential contributory factors.

The chemistry of these conditions has garnered increasing attention within the scientific community and Chemlock Nutrition, reflecting a broader interest in their underlying mechanisms. Bauman and Currie examined the biochemical and physiological processes involved in nutrient transformation within mammals, emphasizing the cyclical nature of sustenance. (Bauman & Currie, 1980) They described a process whereby nutrients are ingested, digested, absorbed, and subsequently utilized by body tissues for maintenance, growth, and the establishment of metabolic reserves, including lipids, glycogen, and amino acids. Moreover, they asserted that a substantial portion of nutrients was directed toward pregnancy and lactation (i.e. essential physiological processes) to ensure species survival. Homeostasis and homeorhesis are the two distinct regulatory mechanisms by which nutrient partitioning is governed.

Homeostasis refers to the maintenance of physiological equilibrium, ensuring stable internal conditions such as body temperature and nutrient levels. In contrast, homeorhesis involves coordinated metabolic adjustments that prioritize nutrient distribution to support specific physiological states, such as gestation and lactation.

These physiological states impose substantial metabolic demands, often necessitating homeorhetic adaptations that may lead to metabolic disorders if regulatory mechanisms fail to respond adequately. In 2017, Baumgard et. al suggested in their 100 year review that it is the inadequate coordination of nutrient utilization or the presence of metabolic imbalances that compromise cow health and performance (Baumgard, Collier, & Bauman, 2017). Optimal and efficient milk production was attained under conditions of minimal or absent physiological stress where stress also elevates maintenance costs and adversely affects overall well-being. Professor Ametaj of the University of Alberta wrote that periparturient hypocalcemia can be reinterpreted as an adaptive, protective response (Ametaj, 2025). However, it should be noted that this idea is far from universally accepted. Cows with clinical milk fever usually will die unless treated with Ca and in that case, hypocalcemia is not protective. A plethora of epidemiological studies show links between low blood Ca and a host of health problems which suggest low blood Ca is not protective (Martinez, 2021) (Neves R. L., 2020). It may be that a mild, transient hypocalcemia could be protective.  However, describing hypocalcemia without qualification as protective is inconsistent with the weight of evidence accumulated over many years. Regardless, Ametaj’s proposed new framework suggested that reduced circulating calcium levels may help temper systemic inflammation by limiting lipopolysaccharide (LPS) aggregation and curbing excessive macrophage activation. The review discussed how calcium signaling, the calcium-sensing receptor (CaSR), and immune cell functions adapt under hypocalcemic conditions to modulate inflammatory processes. This integrated perspective not only redefines the role of hypocalcemia but also proposes the Calci-Inflammatory Network as a novel concept, through which, we can understand how changes in calcium homeostasis mitigate inflammatory cascades, potentially lowering the incidence of periparturient diseases and enhance overall cow health and farm productivity.

Given the substantial impact of these subclinical conditions on dairy herd productivity, proactive monitoring and management strategies are essential. Routine health assessments, nutritional optimization, and targeted interventions can mitigate their effects, ensuring improved herd performance and overall economic sustainability in dairy operations. Clearly, inflammation is a critical physiological response in dairy cows, playing a central role in their health and productivity. It is the body’s natural defense mechanism against infections, injuries, and harmful stimuli.

However, when inflammation becomes chronic or excessive, it can lead to significant health issues, impacting milk production, fertility, and overall well-being. Understanding the causes, symptoms, and effects of inflammation in dairy cows is essential for maintaining herd health and optimizing milk production.

Proper management strategies including nutrition, hygiene, and veterinary interventions can help mitigate inflammation and improve both animal welfare and farm profitability. By exploring the mechanisms and impacts of inflammation in dairy cows, farmers and veterinarians can develop better preventive and treatment approaches to ensure healthier and more productive livestock. (Mezzetti, Carpenter, Bradford, & Trevisi, 2024). This multifaceted issue, shaped by both homeostatic and homeorhetic processes, presents a complex landscape of potential sources and potential intervention strategies that are discussed below.

Inflammation is often triggered by a pathogenic invasion, abiotic stress and/or a concomitant metabolic shifts as discussed above (Lange, 2025) (Horst, Mayorga, & Baumgard, 2024) (Qiao, et al., 2024). Lange performed enteric pathogen measurements in the field and found that enteric pathogens like E.coli, C. perfringens and others peaked in fresh cows. Given that the transition period involves multiple concurrent changes, most notably a marked and abrupt alteration in diet, it is plausible that the findings in Lange’s post?calving samples were diet?related and not necessarily indicative of inflammatory processes.  However, the possibility of higher levels of GI pathogens at this time may reflect the effect of inflammation and immunosuppression in the rumen, which may be a indirect evidence of Amatej’s adaptive protective response framework.

In the case of a direct insult, like enteric pathogens measured by Lange, the biochemistry of the dairy cow undergoes a cascade of defensive and adaptive changes. The cow’s immune system recognizes pathogen-associated molecular patterns (PAMPs) via toll-like receptors (TLRs), triggering a rapid inflammatory response. Pro-inflammatory cytokines like TNF-?, IL-1, and IL-6 are released, initiating systemic inflammation and recruiting immune cells to the site of infection. (Vlasova & Saif, 2021) The liver ramps up production of proteins like haptoglobin and serum amyloid A, which help neutralize pathogens and modulate inflammation. (Mezzetti, Carpenter, Bradford, & Trevisi, 2024) White blood cells flood the infected tissue, especially in cases like mastitis, where somatic cell count in milk spikes dramatically. Reactive oxygen species (ROS) are produced during immune activation, which can damage tissues if not properly regulated. (Mezzetti, Carpenter, Bradford,, & Trevisi, 2024) Stress hormones like cortisol rise, which can suppress adaptive immunity and exacerbate metabolic strain. Typically, a direct insult is concomitant with a metabolic shift.

In the case of severe abiotic stress, like heat, cold, humidity, solar radiation, or poor air quality, a dairy cow shifts dramatically to maintain homeostasis and protect vital functions.

Heat Shock Proteins (HSPs): Proteins like HSP70 and HSP90 are upregulated to protect cells from thermal damage and help refold denatured proteins. (Kim, et al., March, 2024) Stress triggers the hypothalamic-pituitary-adrenal (HPA) axis, increasing cortisol levels, which suppress immune function and alter metabolism. (Mezzetti, Carpenter, Bradford,, & Trevisi, 2024) Heat stress elevates pro-inflammatory markers like TNF-? and IL-6, contributing to systemic inflammation. Once again, NEB from reduced feed intake and increased energy demands lead to mobilization of fat stores, raising NEFA and ketone bodies. Glucose is diverted from milk production to support vital organs and immune responses, often reducing milk yield. Insulin signaling is disrupted which impairs glucose uptake and exacerbates energy deficits. (Horst, Mayorga, & Baumgard, International Symposium on Ruminant Physiology: Integrating our understanding of stress physiology, 2024) Reactive oxygen species (ROS) accumulate which damage lipids, proteins, and DNA. Moreover, antioxidant defenses like that of glutathione are often overwhelmed.

Non-infectious inflammation has roots in metabolic stress especially during the transition period when cows experience NEB which is common to both direct insult and abiotic stress biochemistry. Mobilization of adipose tissue increases circulating free fatty acids, which, when present in excess, can exceed hepatic metabolic capacity, leading to lipid accumulation, oxidative stress, and activation of inflammatory pathways.. Meanwhile, chronic physical or psychological stress can modulate endocrine pathways, such as cortisol secretion, which dampens immune function and skews the balance between pro- and anti-inflammatory mediators.

Altogether, the historical rise in  the study of inflammation reflects a growing need to understand the interplay between microbial challenges and metabolic dysregulation, intensified by the physiological demands of high-yield milk production. Glucose is diverted from milk production to fuel immune cells and inflammatory processes, often leading to reduced milk yield. The cow may experience decreased feed intake and increased energy demands, resulting in mobilization of fat stores and elevated NEFA and ketone bodies. Inflammatory stress may impair calcium metabolism, contributing to hypocalcemia and further weakening immune function. A common thread connecting direct insult, abiotic stress and metabolic shifts is the control of reactive oxygen species sometimes known as oxidative stress discussed below.

Oxidative stress has emerged as a key research focus in animal science, given its involvement in the development of a wide array of pathological conditions. It contributes to the onset and progression of diseases such as the clinical and subclinical conditions discussed above. Beyond its pathological role, oxidative stress is increasingly recognized for its regulatory influence on metabolic activity and its impact on impact on livestock productivity.. In response to elevated oxidative pressure, cells often reprogram energy metabolism, diverting glucose utilization from glycolysis to the pentose phosphate pathway (PPP). This adaptation enhances the supply of NADPH, which supports the function of major intracellular redox systems such as glutathione and thioredoxin pathways. (Kim, et al., March, 2024) Notably, physiological events like pregnancy and lactation are understood to impose  metabolic stress. These transitions heighten vulnerability to oxidative imbalance, making them critical periods for veterinary monitoring. Metabolic disorders have been the subject of investigation for several decades. Although the association with oxidative stress has gained prominence more recently, discussions of this relationship have appeared in the literature since at least the 1990s. However, relatively recent research has spotlighted metabolic disorders in dairy ruminants during the peripartum period, emphasizing the need for targeted nutritional strategies. (Vlasova & Saif, 2021) Recently, Professor Abuelo published, Shakin? off the Rust, Oxidative stress and redox status which summarized decades of research that demonstrated that oxidative stress is related to immune dysfunction at calving.. (Abuelo, 2025) In this paper he essentially reframes oxidative stress (OS) not merely as a biochemical imbalance but as a central driver of immune dysfunction in dairy cattle during the periparturient period and the preweaning phase.

Abuelo differentiates between physiological shifts in the redox balance and those imbalances whose magnitude is such that oxidative damage results.

Quantifying oxidative stress requires reliable biomarkers that reflect molecular damage and disruptions in redox homeostasis. Abuelo’s research highlights several key indicators commonly used in veterinary and biomedical contexts. As a terminal product of lipid peroxidation, elevated Malondialdehyde (MDA) concentrations serve as a robust indicator of oxidative degradation of cellular membranes. Its presence in biological matrices is widely accepted as a proxy for systemic oxidative stress. Oxidized nucleoside results from DNA damage induced by reactive oxygen species. Increased levels of 8-Hydroxy-2′-deoxyguanosine (8-OHdG) are frequently observed in immunocompromised or physiologically stressed animals, reflecting genotoxic stress and impaired cellular repair mechanisms. Disruptions in the activity of endogenous antioxidant enzymes, including superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase, are indicative of redox imbalance.

The term redox balance, aka oxidant status, denotes the dynamic equilibrium between the generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS), primarily by mitochondria and immune cells, and the counteracting capacity of endogenous and exogenous antioxidants. This balance is critical for maintaining cellular integrity, modulating immune responses, and preventing oxidative damage to biomolecules. The term OS is reserved for situations when the magnitude of the imbalance leads to excessive accumulation of ROS/RNS. OS is both a consequence and a catalyst of inflammation, metabolic stress, and disease susceptibility, as reviewed by Abuelo. He proposed a refined framework for measuring redox status and calls for targeted antioxidant strategies that go beyond traditional supplementation.

In transition cows, OS contributes to neutrophil dysfunction, impaired macrophage activity, and dysregulated inflammatory signaling. In calves, OS skews T-helper cell differentiation toward Th2-biased responses, undermining immunologic memory and vaccine efficacy. These disruptions increase susceptibility to metabolic and infectious diseases, including mastitis, metritis, diarrhea, and respiratory illness as mentioned above. OS is a mechanistic contributor to immune failure. Mitigating OS should be a core component of herd health protocols.

Whether you subscribe to the traditional causation model in which a NEB results in a metabolic shift to a high non-esterified fatty acid metabolism mobilized from adipose tissue or an alternative model in which an immune activation with concomitant inflammation following an imposed stressor results in an abnormal or diseased condition, the body’s chemistry and biochemistry adapts or attempts to adapt. Understanding the cascade of biochemical reactions while connecting the dots between immune function and nutrient strategies is a compelling pursuit that continues to inspire scientific innovation.

Nutritional modulation of the immune system represents a pivotal opportunity to reduce the incidence and severity of inflammation-related disorders. Extensive research has identified specific nutrients and feed interventions that influence inflammatory pathways, oxidative stress responses, and energy metabolism.

Antioxidant supplementation is critical for counteracting ROS generated in the biochemical cascade in defense of pathogens, abiotic stress and/or metabolic shifts. This strategy can enhance immune resilience and protect cellular functions. A variety of dietary antioxidants can be incorporated into dairy nutrition to enhance the animal’s antioxidant defense system. Vitamin E and Selenium in particular are known to improve leukocyte function and reduce acute-phase protein levels associated with lower prevalence of mastitis and uterine infections. (Smith, Hogan, & Weiss, 1997) Due to its close chemical resemblance to methionine (Met), L-SeMet is indistinguishable to the body’s transport mechanisms. In the main storage forms of plants and yeast, Se predominantly exists in the organic form of L-SeMet, accounting for over 50% of total selenium content. This prevalence suggests that, through evolutionary adaptation, the digestive systems of animals have become optimized for the assimilation of methionine (Met) and both the sulfur and selenium structures are transported   using the same pathwaysAs a result, SeMet is efficiently absorbed from the diet and utilized in metabolic pathways. It should be noted that L-SeMet can readily be used in any pathway that uses Met but must be degraded. Degraded L-SeMet will release Se but because Met or L-SeMet is in high demand for protein synthesis, Met degradation is limited which means a lot of the L-SeMet is stored (Weiss, 2025). The organic form of selenium, L-Selenomethionine  therefore holds a distinctive role as the precursor to selenoproteins, the active form of which is seleno-cysteine, which are integral to numerous biological processes. (Surai, Kochish, Fisinin, & Juniper, 2019) These selenoproteins are distributed throughout cellular compartments and contribute to key physiological functions, including peroxidase and reductase activity, hormone metabolism, protein folding, redox signaling, selenocysteine biosynthesis, and selenium transport. Notably, over half of these selenoproteins are directly involved in maintaining redox homeostasis and mitigating oxidative stress through their enzymatic and signaling roles. Organic L-SeMet supplementation results in an endogenous selenium reserve, which can be mobilized during periods of physiological stress.  If conditions cause increased protein breakdown or enzyme turnover then animals fed Se-met will release more Se into the central pool than if they were fed selenite which has very limited body stores (Weiss, 2025)

 Innovative solutions such as Nutrilock® SelenoSure™ are more bioavailable and consistent than traditional sources and yield a superior response.

Polyphenols and flavonoids which are plant-derived compounds (e.g. grapeseed, green tea extracts) are known to inhibit nuclear factor kappa B (NF-?B) signaling, modulate cytokine expression, and reduce oxidative burden. (Yahfoufi, Alsadi , Jambi, & Matar , 2018) Examples such as Quercetin, Catechins from green tea, Resveratrol from grapes inhibit NF-?B activation by interfering with IKK phosphorylation and DNA binding. These compounds modulate cytokine profiles, suppressing pro-inflammatory mediators like TNF-? and IL-1? while enhancing anti-inflammatory IL-10. They also reduce oxidative stress by scavenging reactive oxygen species (ROS), chelating metal ions, and upregulating endogenous antioxidant enzymes like superoxide dismutase.

Another nutritional strategy for regulating inflammation is to modulate essential fatty acids content. Most notably omega-3 and omega-6 polyunsaturated fatty acids (PUFAs), serve as biochemical precursors to oxylipins which are bioactive lipid mediators derived via enzymatic oxidation. Oxylipins play a critical role in modulating inflammatory responses, immunological signaling pathways, and reproductive physiology. Moreover, long-chain omega-3 fatty acids, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), competitively inhibit the cyclooxygenase (COX) and lipoxygenase (LOX) pathways responsible for the synthesis of pro-inflammatory eicosanoids from arachidonic acid. This results in reduced levels of prostaglandins and leukotrienes associated with inflammation. (Calder, 2015) Omega-6 fatty acids, predominantly linoleic acid and arachidonic acid, contribute to immune competence and tissue remodeling through their conversion into signaling molecules such as prostaglandins (e.g., PGE2) and thromboxanes. (Kaviani, Hajibabaie, Abedpoor, & Safavi, 2025) While excessive omega-6 intake may exacerbate inflammatory cascades, a physiologically balanced ratio with omega-3 PUFAs promotes resolution-phase immune activity and supports regenerative mechanisms essential to reproductive tissue integrity.

In addition to selenium, trace elements such as zinc (Zn), copper (Cu), iron (Fe) and manganese (Mn) are essential micronutrients that serve as cofactors for numerous antioxidant enzymes and play pivotal roles in modulating innate and acquired  immune responses. (Alghamdi, Gutierrez, & Komarnytsky, 2023) (Weyh, Krüger, Peeling, & Castell, 2022).  Trace minerals that function as essential cofactors in antioxidant enzymes can also exert pro?oxidant effects when present in unbound or free forms. Consequently, cellular homeostatic mechanisms tightly regulate their absorption, transport, and storage to prevent oxidative damage and cytotoxicity.

Trace mineral bioavailability and functional efficacy are influenced by chemical form, with hydroxy trace minerals (i.e. TBCC, TBMC, TBZC) demonstrating superior absorption and cellular uptake compared to inorganic salts.

Zinc is integral to the structural and catalytic activity of over 300 enzymes, including superoxide dismutase (SOD), and regulates immune cell signaling, proliferation, and apoptosis. It modulates neutrophil chemotaxis, enhances macrophage phagocytic capacity, and influences cytokine production by promoting anti-inflammatory mediators such as IL-10 while suppressing pro-inflammatory cytokines like TNF-? and IL-1?. Zinc deficiency impairs both innate and adaptive immunity, increasing susceptibility to infection and oxidative stress. (Rodriguez-Jimenez, et al., 2025)

Copper is a cofactor for enzymes such as cytochrome c oxidase and Cu/Zn-SOD, contributing to redox balance and mitochondrial function. It supports macrophage activation and neutrophil generated reactive oxygen species used to kill pathogens (i.e. oxidative burst), and its homeostasis is tightly regulated to prevent cytotoxicity. (Galloway, McMillan, & Sattar, 2000) Elevated ceruloplasmin levels during inflammation reflect copper’s role in acute-phase responses and antioxidant defense.

Manganese is required for Mn-SOD activity within mitochondria, protecting cells from superoxide radicals. (Alghamdi, Gutierrez, & Komarnytsky, 2023) It also influences macrophage responsiveness and cytokine signaling pathways, including NF-?B and Mitogen-Activated Protein Kinase (MAPK) cascades, thereby shaping inflammatory outcomes. Mn-dependent enzymes are involved in cellular metabolism and immune cell differentiation, particularly under oxidative stress conditions. Nutrilock® Hydroxy Trace Minerals, which are superior forms of the trace minerals for bioavailability and value, are available from Chemlock Nutrition.

Another nutritional strategy that is finally coming into its own is chromium supplementation in its various forms with chromium propionate dominating the immunomodulatory effects and production improvements. Chromium is now recognized as a vital nutrient that influences insulin sensitivity, glucose metabolism, and immune function. Certain physiological stressors from transportation, market transitions, or high production demands can exacerbate chromium loss. These conditions increase glucose turnover, mobilize chromium from tissue stores, and lead to irreversible urinary excretion of minerals. Chromium is known to impact several biological functions, including glucose and fatty acid metabolism, immune responses, and antioxidant activity. (Lashkari, Habibian, & Jensen, 2018) Cr supplementation has been associated with increased dry matter intake, enhanced milk production, and improved milk composition across different stages of lactation. These benefits suggest that chromium may help optimize the nutritional balance required for high-yielding cows, especially when aiming for supra-physiological diets that push beyond standard nutritional recommendations.

With respect to antioxidant effects of chromium, Moghadam et al. studied the effect of chromium and probiotics on biomarkers associated with immune function. (Moghadam, Razavi, Hajimohammadi, Nazifi, & Rowshan?Ghasrodashti, 2023) They found that that calves chromium supplementation group exhibited significantly lower levels of stress-related markers such as cortisol, interleukin-1?, serum amyloid A, adenosine deaminase, and ferritin. Additionally, malondialdehyde levels, which indicate oxidative stress, were slightly lower in the supplemented group. The total antioxidant capacity (TAC) was notably lower in control group calves, suggesting a diminished ability to counteract oxidative damage. Interestingly, the group receiving both probiotics and chromium showed the lowest mean globulin concentration, which may reflect a nuanced interaction between the supplements and immune protein levels.

Overall, the data suggest that dietary supplementation with probiotics and chromium can positively influence immune responses and reduce stress indicators in dairy calves during weaning.

Shan et al. studied a chromium supplementation strategy for mid lactation dairy cows exposed to heat stress (temp humidity index consistently above 72). (Shan, et al., 2020) Chromium increased the activity of key antioxidant enzymes, glutathione peroxidase and superoxide dismutase, as well as total antioxidant capacity. At the same time, levels of malondialdehyde, a marker of oxidative stress, decreased in some but not all studies. Furthermore, chromium supplementation did not affect levels of IL-6, IL-10, IgA, or IgM. However, it significantly reduced concentrations of pro-inflammatory cytokines IL-2, IL-4, and IL-1?, while increasing levels of IgG, an important antibody for immune defense. Interestingly enough, although chromium did not significantly alter overall milk yield or composition, it did lead to a linear increase in dry matter intake and milk lactose content. These changes suggested that chromium may help modulate the immune response, reduce inflammation and enhance immunity. Horst et al. investigated whether supplementing lactating Holstein cows with chromium propionate could influence how their immune systems use glucose and respond to an inflammatory challenge. Activated immune cells are highly insulin sensitive and require large amounts of glucose, the researchers hypothesized that improving insulin sensitivity with chromium might modulate immune dynamics after exposure to bacterial endotoxin (lipopolysaccharide, LPS). (Horst, et al., 2018) In summary, supplementing lactating cows with chromium propionate during an acute endotoxin challenge reduced their insulin surge and accelerated neutrophil recovery but did not change how much glucose their immune systems consumed. These findings point to chromium’s potential for fine-tuning inflammatory and metabolic responses in dairy cows, though its impact on whole-body energy balance during immune stress appears limited. Given its multifaceted benefits including its indirect antioxidant and immunomodulatory effects, chromium supplementation should be considered a strategic nutritional strategy.

Nutrilock® Chromium from Chemlock Nutrition is 100% made in the USA and has OMRI approval for use in organic farming.

 

Other targeted dietary components modulate gut microbiota composition and enhance intestinal barrier function, serving as strategic nutritional supplementation strategies to mitigate systemic inflammatory responses include but are not limited to yeast-based products, beta-glucans, rumen protected choline and methionine as well as pro and prebiotics. They can help to improve epithelial integrity, reduce lipopolysaccharide (LPS) translocation, enhance immune cell activation against pathogens, stabilize rumen fermentation, reduce endotoxemia and enhance gastrointestinal health and immune regulation through host-microbe signaling.

By mapping subclinical disorders such as SCK, SCM, SARA, and SCHto their common threads of immune activation by pathogen or abiotic stress, inflammation and metabolic stress, we reveal how targeted nutritional interventions can restore immuno-metabolic balance in dairy cows.

Strategic inclusion of antioxidants, essential fatty acids, trace minerals and bioactive feed additives not only fortifies barrier integrity and modulates gut microbiota but also dampens pro-inflammatory cascades.

This interconnected framework underscores a holistic approach where nutrient partitioning, immune resilience, and production efficiency converge to drive animal well-being and farm profitability.

The mission of Chemlock Nutrition is to use its deep knowledge and understanding of chemistry to bring multi-generational products to the dairy industry that are inherently useful and are born out of connecting the dots in the 21^st century.

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