Supplementation of antioxidant micronutrients reduces stress and improves immune function/response in periparturient dairy cows and their calves

Prepartum supplementation of dairy cows with inorganic selenium, organic selenium or rumen-protected choline does not affect carotenoid composition or colour characteristics of bovine colostrum or transition milk

Minerals are supplemented routinely to dairy cows during the dry period to prevent metabolic issues postpartum. However, limited information exists on the impacts of mineral supplementation on colostrum carotenoids. This study aimed to determine the effects of prepartum supplementation with three micro-nutrients; inorganic selenium (INORG), organic selenium (ORG) or rumen-protected choline (RPC) on the carotenoid content of bovine colostrum and transition milk (TM) from pasture-based dairy cows. A total of 57 (12 primiparous and 45 multiparous) Holstein-Friesian (HF) and HF × Jersey (JEX) cows were supplemented daily for 49 ± 12.9 d before calving. Colostrum samples were collected from all cows immediately postpartum and TM one to five (TM1-TM5) were collected from a sub-set of 15 cows (five per treatment group) at each consecutive milking postpartum. Carotenoid concentration was determined using ultra-high performance liquid chromatography - diode array detection (UHPLC-DAD). With the use of transmittance, the colour index and colour parameters a*, b* and L* were used to determine colour variations over this period. Prepartum supplementation did not have a significant effect on colostrum β-carotene concentration or colour. Positive correlations between β-carotene and colour parameter b* (R2 = 0.671; P < 0.001) and β-carotene and colour index (R2 = 0.560; P < 0.001) were observed. Concentrations of β-carotene were highest in colostrum (1.34 μg/g) and decreased significantly with each milking postpartum (TM5 0.31 μg/g). Breed had a significant effect on colostrum colour with JEX animals producing a greater b* colostrum than HF animals (P = 0.030). Primiparous animals produced colostrum with the weakest colour compared to second or ≥third parity animals (P = 0.042). Despite statistical increases in the b* parameter in colostrum from JEX cows and multiparous cows, β-carotene concentrations did not significantly increase suggesting that other factors may influence colostrum colour. The b* parameter may be used as an indicator for estimating carotenoid concentrations in colostrum and TM, particularly when assessed via transmittance spectroscopy.

Injection of antioxidant trace minerals/vitamins into peripartum crossbred cows improves the nutritional and immunological properties of colostrum/milk and the health of their calves under heat stress conditions

Multimineral and vitamin injections can provide better nutrient availability at the cellular level, which is essential for mitigating transition period stress and improving the wellbeing and productivity of dairy cows. The present study was conducted to assess the colostrum quality and calf health after intramuscular injection of multi-minerals (MM) and multi-vitamins (MV) to peripartum cows during winter (THI = 58 to 66) and summer (THI = 78 to 82) months. In each season, twenty-four pregnant crossbred Karan Fries cows were grouped into four, each consisting of six cows. Group I, referred to as the Control, received solely the basal diet, without any additional supplements. Groups II, III, and IV were administered additional MM (T1), MV (T2), and a combined MM and MV (T3) along with their basal diet, starting 30 days before calving and continuing for 30 days after calving. Blood samples were collected from the calves, while colostrum/milk samples were obtained from the cows on days 1, 3, 7, and 15 after calving. The somatic cell counts (SCC) in the milk were determined using a cell counter. Cortisol, IgG, IGF1 and total immunoglobulins (TIG) in whey and plasma from cow colostrum/milk or calf blood samples were estimated by ELISA. Cows that calved in the summer exhibited notably reduced levels (P < 0.05) of IgG, milk, and plasma IGF1, along with lower calf body weights, in comparison to those calving in the winter season. Furthermore, the summer months saw significant increases (P < 0.05) in plasma and milk cortisol levels, as well as total somatic cell counts (SCC) in both colostrum and milk samples. Maximum beneficial effect was observed in T3 group. Results indicate that injections to peripartum cows could be an important strategy for improving colostrum quality and calf health during the summer seasons.

Impact of Parenteral Maternal Supplementation with Trace Minerals and Vitamins on Neonatal Calf Antioxidant System and Growth in a Dairy Herd

Oxidative stress may affect new born calves due to high stress suffered around birth. We hypothesized that maternal supplementation with micronutrients and vitamins in late gestation enhance the neonatal calf's antioxidant system, decreasing the occurrence and duration of diarrhea, and improving growth from birth through weaning. To test this hypothesis, 80 multiparous cows were cluster-assigned to treatment groups. Treated group (TG) cows received mineral and vitamin supplementation while control group (CG) cows received saline solution. Feed intake and fecal score were measured daily until the ninth week. Weight and body measurements were registered weekly, and blood samples were collected from postpartum cows and calves after birth and at 7, 14, and 63 days of life. Although CG calves had greater fecal scores (p = 0.01), diarrhea characteristics did not differ. Calves in the TG showed greater starter intake (p = 0.04). Feed efficiency showed a trend with treatment-age interaction (p = 0.06). Calves in the CG had wider hips in the first week (p = 0.03), but not by the ninth week. Total antioxidant status, thiobarbituric acid reactive substances, and haptoglobin did not differ between treatment groups. Serum metabolites showed no differences. Supplementation did not impact calf antioxidant system or growth in the first two months.

Strategic administration of antioxidant multiminerals and vitamins to transitional buffaloes augments antioxidant and udder defense mechanisms in early lactation

The aim of the study was to examine the effects of repeated administrations of antioxidant multiminerals and vitamins in transition buffaloes on udder defense mechanism, antioxidant activity and occurrence of intramammary infection (IMI) in early lactation period. Forty clinically healthy pregnant buffaloes were enrolled 45 days before expected date of calving and randomly allocated into five different supplementation groups (n = 8): only basal ration (control), vitamin E and selenium (VES), multiminerals (MM), ascorbic acid (AA) and chromium (Cr) picolinate in basal diet. The udder defense mechanism was monitored by measuring phagocytic activity (PA), myeloperoxidase (MPO) and nitric oxide (NO) productions in milk leukocytes, antioxidant activity was evaluated by measuring total antioxidant capacity (TAC) in plasma and occurrence of IMI was assessed by milk cytology, bacterial count in milk and visible clinical signs of udder until day 28 post-calving. The results showed that the VES and MM supplementations exhibited significantly higher PA, MPO and NO productions of milk leukocytes till first week of lactation whereas, elevated mean TAC in plasma was maintained from day -7 to 1 of calving in MM supplementation group as compared to control group. Statistically, no significant difference in occurrences of subclinical or clinical IMI was noted across the groups until four weeks of lactation. Taken together, it is concluded that repeated administrations of VES and MM to transition buffaloes could be an effective strategy to maintain good udder health by augmenting milk leukocyte functions and antioxidant status and preventing incidence of IMI in early lactation.

Supplementation with Combined Additive Improved the Production of Dairy Cows and Their Offspring with Maintenance of Antioxidative Stability

Oxidative stress damage in periparturient cows decreases both production and their health; supplementation with complex additives during the periparturient period has been used as an important strategy to enhance the antioxidant status and production of dairy cows. The periparturient cows not only risk a negative energy balance due to reduced dry matter intake but also represent a sensitive period for oxidative stress. Therefore, we have developed an immunomodulatory and nutritional regulation combined additive (INC) that hopefully can improve the immune status and production of cows during the periparturient period and their offspring health and growth by improving their antioxidant stress status. The INC comprised a diverse array of additives, including water-soluble and fat-soluble vitamins, Selenomethionine, and active dry Saccharomyces cerevisiae. Forty-five multiparous Holstein cows were randomly assigned to three treatments: CON (no INC supplementation, n = 15), INC30 (30 g/d INC supplementation, n = 15), and INC60 (60 g/d INC supplementation, n = 15) based on last lactation milk yield, body condition score, and parity. Newborn calves were administered 4 L of maternal colostrum originating from the corresponding treatment and categorized based on the treatment received by their respective dams. The INC not only served to maintain the antioxidative stress system of dairy cows during the periparturient period but also showed a tendency to improve the immune response (lower tumor necrosis factor and interleukin-6) during the perinatal period. A linear decrease in concentrations of alkaline phosphatase postpartum and β-hydroxybutyrate was observed with INC supplementation. Milk fat yield, milk protein yield, and energy-corrected milk yield were also increased linearly with increasing additive supplementation. Calves in the INC30 group exhibited greater wither height and chest girth but no significant effect on average daily gain or body weight. The diarrhea frequency was linearly decreased with the incremental level of INC. Results indicate that supplementation with INC in peripartum dairy cows could be a major strategy to improve immune response, decrease inflammation, maintain antioxidant stress status in transition dairy cows, and have merit in their calves. In conclusion, this study underlines the benefits of INC supplementation during the transition period, as it improved anti-inflammatory capacity, could positively impact antioxidative stress capacity, and eventually enhanced the production performance of dairy cows and the health and growth of calves.

A Comprehensive Review of Bovine Colostrum Components and Selected Aspects Regarding Their Impact on Neonatal Calf Physiology

Colostrum contains macro- and micronutrients necessary to meet the nutritional and energy requirements of the neonatal calf, bioactive components that intervene in several physiological aspects, and cells and microorganisms that modulate the calf's immune system and gut microbiome. Colostrum is sometimes mistaken as transition milk, which, although more nutritive than whole milk, has a distinct biochemical composition. Furthermore, most research about colostrum quality and colostrum management focuses on the transfer of maternal IgG to the newborn calf. The remaining components of colostrum and transition milk have not received the same attention, despite their importance to the newborn animal. In this narrative review, a large body of literature on the components of bovine colostrum was reviewed. The variability of these components was summarized, emphasizing specific components that warrant deeper exploration. In addition, the effects of each component present in colostrum and transition milk on several key physiological aspects of the newborn calf are discussed.

Enhancing bovine immune, antioxidant and anti-inflammatory responses with vitamins, rumen-protected amino acids, and trace minerals to prevent periparturient mastitis

Mastitis, the inflammatory condition of mammary glands, has been closely associated with immune suppression and imbalances between antioxidants and free radicals in cattle. During the periparturient period, dairy cows experience negative energy balance (NEB) due to metabolic stress, leading to elevated oxidative stress and compromised immunity. The resulting abnormal regulation of reactive oxygen species (ROS) and reactive nitrogen species (RNS), along with increased non-esterified fatty acids (NEFA) and β-hydroxybutyric acid (BHBA) are the key factors associated with suppressed immunity thereby increases susceptibility of dairy cattle to infections, including mastitis. Metabolic diseases such as ketosis and hypocalcemia indirectly contribute to mastitis vulnerability, exacerbated by compromised immune function and exposure to physical injuries. Oxidative stress, arising from disrupted balance between ROS generation and antioxidant availability during pregnancy and calving, further contributes to mastitis susceptibility. Metabolic stress, marked by excessive lipid mobilization, exacerbates immune depression and oxidative stress. These factors collectively compromise animal health, productive efficiency, and udder health during periparturient phases. Numerous studies have investigated nutrition-based strategies to counter these challenges. Specifically, amino acids, trace minerals, and vitamins have emerged as crucial contributors to udder health. This review comprehensively examines their roles in promoting udder health during the periparturient phase. Trace minerals like copper, selenium, and calcium, as well as vitamins; have demonstrated significant impacts on immune regulation and antioxidant defense. Vitamin B12 and vitamin E have shown promise in improving metabolic function and reducing oxidative stress followed by enhanced immunity. Additionally, amino acids play a pivotal role in maintaining cellular oxidative balance through their involvement in vital biosynthesis pathways. In conclusion, addressing periparturient mastitis requires a holistic understanding of the interplay between metabolic stress, immune regulation, and oxidative balance. The supplementation of essential amino acids, trace minerals, and vitamins emerges as a promising avenue to enhance udder health and overall productivity during this critical phase. This comprehensive review underscores the potential of nutritional interventions in mitigating periparturient bovine mastitis and lays the foundation for future research in this domain.

The protective role of maternal genetic immunization on maternal-fetal health and welfare

Pregnancy is a critical period associated with alterations in physiologic, biologic, and immunologic processes, which can affect maternal-fetal health through development of several infectious diseases. At birth, neonates have an immature immune system that makes them more susceptible to severe viral infections and diseases. For this reason, different maternal nutritional and immunization interventions have been used to improve the immune and health status of the mother and her neonate through passive immunity. Here, we reviewed the protective role of maternal immunization with different types of vaccines, especially genetic vaccines, during pregnancy in maternal-fetal health, immune response, colostrum quality, immune response, and anti-oxidative status. For this purpose, we have used different scientific databases (PubMed and Google Scholar) and other official web pages. We customized the search period range from the year 2000 to 2023 using the key words "maternal immunization" OR "gestation period/pregnancy" OR "genetic vaccination" OR "maternal-fetal health" OR "micronutrients" OR "neonatal immunity" "oxidative stress" OR "colostrum quality". The evidence demonstrated that inactivated or killed vaccines produced significant immune protection in the mother and fetus. Furthermore, most recent studies have suggested that the use of genetic vaccines (mRNA and DNA) during pregnancy is efficient at triggering the immune response in mother and neonate without the risk of undesired pregnancy outcomes. However, factors such as maternal redox balance, nutritional status, and the timing of immunization play essential roles in regulating immune response inflammatory status, antioxidant capacity, and the welfare of both the pregnant mother and her newborn.

Effects of replacing inorganic salts of trace minerals with organic trace minerals in the diet of prepartum cows on quality of colostrum and immunity of newborn calves

Our objectives were to evaluate the impact of supplementary trace mineral (TM) form-inorganic salts (STM; Co, Cu, Mn, Zn sulfates, and Na selenite) or organic (OTM; Co, Cu, Mn, Zn proteinates, and selenized yeast)-in the prepartum diet on quantity and quality of colostrum, passive immunity, antioxidant biomarkers, cytokine responses to lipopolysaccharide (LPS), health, and growth of newborn calves. Pregnant heifers (n = 100) and cows (n = 173) were enrolled at 45 d before calving, blocked by parity and body condition score, and allocated randomly to STM (50 heifers; 86 cows) or OTM (50 heifers; 87 cows) supplementation. Cows in both treatments were fed the same diet, except for the source of supplementary TM. Within 2 h of calving, dams and calves were separated, colostrum was harvested, the yield was measured, and a sample was saved for posterior analyses of colostrum quality. A subgroup of calves (n = 68) had a blood sample collected before colostrum feeding. After colostrum feeding, all samples and data collection were limited to 163 calves (STM = 82; OTM = 81) fed 3 L of good quality (Brix% >22) maternal colostrum via nipple bottle minutes after harvesting. Concentration of IgG in colostrum and serum was determined 24 h after colostrum feeding using radial immunodiffusion. Concentration of TM in colostrum and serum were performed by inductively coupled plasma mass spectrometry. Activity of glutathione peroxidase, ferric reducing ability of plasma, and concentration of superoxide dismutase were evaluated in plasma by colorimetric assays. Ex vivo whole blood stimulation with LPS was performed on d 7 of life to evaluate cytokine responses in a subgroup of 66 calves. Health events were recorded from birth to weaning, and body weight was recorded at birth (all calves) and on d 30 and 60 (heifers only). Continuous variables were analyzed by ANOVA and binary responses were analyzed by logistic regression. Complete replacement of STM by OTM in prepartum diet resulted in greater concentration of Se (461 vs. 543 ± 7 μg/g; ± SEM) but did not alter the concentration or total mass of other TM and IgG in colostrum. Female calves of the OTM group had greater concentration of Se in serum at birth (0.23 vs. 0.37 ± 0.05 μg/mL), were lighter in weight at birth (40.9 vs. 38.8 ± 0.6 kg) and weaning (93.2 vs. 89.7 ± 1.6 kg) than those of the STM group. Maternal treatments did not affect passive immunity or antioxidant biomarkers. On d 7, basal concentrations (log₁₀ of concentration in pg/mL) of IFNγ (0.70 vs. 0.95 ± 0.083) and LPS-stimulated concentrations of CC chemokine ligand 2 (CCL2; 2.45 vs. 2.54 ± 0.026), CC chemokine ligand 3 (CCL3; 2.63 vs. 2.76 ± 0.038), IL-1α (2.32 vs. 2.49 ± 0.054), and IL-1β (3.62 vs. 3.86 ± 0.067) were greater in OTM than in STM. Supplementation with OTM in pregnant heifers, but not in pregnant cows, reduced the incidence of preweaning health problems in their calves (36.4 vs. 11.5%). Complete replacement of STM by OTM in the prepartum diet did not cause major changes in colostrum quality, passive immunity, and antioxidant capacity, but increased cytokine and chemokine responses to LPS on d 7 of life and benefited preweaning health of calves born to primiparous cows.

Associations of dietary antioxidant micronutrients with the prevalence of obesity in adults

Background

Antioxidant micronutrients have a therapeutic potential for clinical treatment of obesity. NO research, however, has examined the connection between the complex level of dietary antioxidants and obesity.

Materials and methods

We mainly aimed to investigate the relationship between a combination of antioxidants and obesity using the database of the national health and nutrition examination survey (NHANES). This cross-sectional study contains a survey of 41,021 people (≥18 years) in total ranging from 2005 to 2018. Multivariate logistic and weighted quantile sum (WQS) regression were performed to investigate the associations between these antioxidants, both individually and collectively, and the prevalence of obesity. The restricted cubic spline (RCS) regression was also utilized to analyze the linearity of these associations.

Results

According to multivariate logistic models, we found that the levels of most antioxidants in the highest quartile were independently related to a lower prevalence of obesity, while a reverse result was observed in selenium (p for trend &lt;0.05). The WQS index revealed that a total of the 11 antioxidants is negatively related to the prevalence of obesity and abdominal obesity (all p&lt;0.001), and iron/vitamin C have the greatest weight in the negative associations between antioxidant complex and obesity, as well as abdominal obesity. In addition, the RCS regression showed that retinol, vitamin A, α-carotene, β-carotene, β-cryptoxanthin, vitamin C, iron, and copper all had a non-linear association with obesity. Threshold effect analysis demonstrated that the inflection points of retinol, vitamin A, α-carotene, β-carotene, β-cryptoxanthin, vitamin C, iron, and cooper were 235.57, 374.81, 58.89, 891.44, 30.70, 43,410.00, 11,240.00, and 990.00 μg/day, respectively.

Conclusion

Our study found that a high level of a complex of 11 dietary antioxidants is related to a lower prevalence of obesity and abdominal obesity, among this inverse associations iron and vitamin C have the greatest weight.

Maternal treatment with pegbovigrastim influences growth performance and immune-metabolic status of calves during the pre-weaning period

This study aimed to investigate the immune-metabolic status and growth performance of Simmental calves born from cows subjected to pegbovigrastim administration 7 days before calving. Eight calves born from cows subjected to pegbovigrastim administration (PEG group) and 9 calves born from untreated cows (CTR group) were used. Growth measurements and blood samples were collected from birth to 60 d of age. The PEG group had lower body weight from 28 up to 60 d of age (P < 0.01), lower heart girth (P < 0.05), lower weekly and total average daily gain values (P < 0.05) than the CTR group throughout the monitoring period. A decrease in milk replacer (MR) intake was observed in the PEG group compared with the CTR group around 20-28 d of age (P < 0.01). The PEG group had lower values of γ-glutamyl transferase (GGT) at d 1 of age (P < 0.05), Zn at 21 and 28 d of age (P < 0.05), hemoglobin, MCH and MCHC at 54 and 60 d of age (P < 0.01), and higher urea concentration at 21 and 28 d of age (P < 0.05) compared with the CTR group. Lower values of retinol (P < 0.05), tocopherol (P < 0.01), mean myeloperoxidase index (P < 0.05) and higher total reactive oxygen metabolites (P < 0.05) and myeloperoxidase (P < 0.05) were also detected in the PEG group. In light of the results gathered in the current study, it can be speculated that activation of the cow's immune system by pegbovigrastim could have influenced the immune competence, growth performance as well as the balance between oxidant and antioxidant indices of the newborn calf.

Repeated injection of multivitamins and multiminerals during the transition period enhances immune response by suppressing inflammation and oxidative stress in cows and their calves

Periparturient dairy cows undergo major physiological and metabolic changes as well as immunosuppression, associated with decrease in plasma concentrations of various minerals and vitamins. The present study was conducted to investigate effects of repeated injections of vitamins and minerals on oxidative stress, innate and adaptive immune response in periparturient dairy cows and their offspring. Experiment was carried out on 24 peripartum Karan-Fries cows, randomly divided into four groups (n=6): control, Multi-mineral (MM), Multi-vitamin (MV) and Multi-minerals and Multi-vitamin (MMMV). Five ml of MM (Zinc 40 mg/ml, Manganese 10 mg/ml, Copper 15 mg/ml, Selenium 5 mg/ml) and five ml of MV (Vitamin E 5 mg/ml, Vitamin A 1000 IU/ml, B-Complex 5 mg/ml, and Vitamin D₃ 500 IU/ml) were injected intramuscularly (IM) to the MM and MV groups. MMMV group cows were injected with both. In all treatment groups, injections and blood sampling were carried out on 30^th, 15^th, 7^th days before and after expected date of parturition and at calving. In calves, blood was collected at calving and on 1, 2, 3, 4, 7, 8, 15, 30 and 45 days post-calving. Colostrum/milk were collected at calving and at days 2, 4, and 8 post-calving. A lower percentage of total neutrophils and immature neutrophils, higher percentage of lymphocytes together with increased phagocytic activity of neutrophils and proliferative capacity of lymphocytes found in blood of MMMV cows/calves. Lower relative mRNA expression of TLRs and CXCRs and higher mRNA expression of GR-α, CD62L, CD11b, CD25 and CD44 found in blood neutrophils of MMMV groups. Total antioxidant capacity was higher, activity of antioxidant enzymes (SOD and CAT), TBARS levels were lower in the blood plasma of treated cows/calves. In both cows/calves, plasma pro-inflammatory cytokines (IL-1α, IL-1β, IL-6, IL-8, IL-17A, IFN-γ and TNF-α) increased, whereas anti-inflammatory cytokines (IL-4 and IL-10) decreased in MMMV groups. Total immunoglobulins increased in colostrum/milk of MMMV injected cows and plasma of their calves. Results indicate that repeated injections of multivitamins and multiminerals to peripartum dairy cows could be a major strategy to improve immune response and decrease in inflammation and oxidative stress in transition dairy cows and their calves.

Nutrition and Immunity in Perinatal Hypoxic-Ischemic Injury

Perinatal hypoxia ischaemia (PHI), acute and chronic, may be associated with considerable adverse outcomes in the foetus and neonate. The molecular and cellular mechanisms of injury and repair associated with PHI in the perinate are not completely understood. Increasing evidence is mounting for the role of nutrients and bioactive food components in immune development, function and repair in PHI. In this review, we explore current concepts around the neonatal immune response to PHI with a specific emphasis on the impact of nutrition in the mother, foetus and neonate.

Supplementation With Zinc Proteinate Increases the Growth Performance by Reducing the Incidence of Diarrhea and Improving the Immune Function of Dairy Calves During the First Month of Life

Two experiments were conducted to identify the optimal dose of zinc proteinate (ZP) in the diet for dairy calves and then to compare early supplementation with the ZP or zinc methionine (ZM) on the growth performance, incidence of diarrhea, antioxidant status, and immune function of dairy calves during their first month of life. In Experiment 1, forty newborn female Holstein dairy calves were randomly divided into four groups (n = 10): a control group (without ZP supplementation, ZP0) or groups that received ZP supplementation at 40, 80, and 120 mg zinc/day, respectively (ZP40, ZP80, and ZP120). The experiment lasted 14 days, and the growth performance, incidence of diarrhea, and serum zinc concentration were analyzed. In Experiment 2, thirty-six newborn female Holstein dairy calves were randomly allocated to three groups (n = 12): a negative control group (without zinc supplementation, CON), a positive control group (supplemented with 80 mg zinc/day in the form of zinc methionine, ZM), and a ZP group (supplemented with 80 mg zinc/day in the form of ZP). The experiment lasted 28 days, and the growth performance, incidence of diarrhea, serum zinc concentration, serum antioxidant indicators, and concentrations of plasma immunoglobulins and cytokines were determined on days 7, 14, 21, and 28. Results showed that in Experiment 1, supplementation with ZP to yield 80 mg zinc/day increased the ADG (P &lt; 0.01) and serum zinc concentration (P &lt; 0.01), and decreased the F/G (P &lt; 0.01) and the incidence of diarrhea (P &lt; 0.05) during days 1–14. In Experiment 2, compared with the CON group, ZP increased the ADG (P &lt; 0.01), serum zinc concentration (P &lt; 0.01), and plasma immunoglobulin G (IgG; P &lt; 0.01) and IgM (P &lt; 0.01) concentrations, but reduced the incidence of diarrhea (P &lt; 0.01), serum malondialdehyde (P &lt; 0.01), and plasma interleukin-1β (P &lt; 0.01) concentrations during days 1–28. Overall, ZP supplementation to yield 80 mg zinc/day improves the growth performance and immune function, and decrease the incidence of diarrhea of dairy calves, which was comparable to the same dose of zinc in the form of ZM.

Oxidative Stress in Dairy Cows: Insights into the Mechanistic Mode of Actions and Mitigating Strategies

This review examines several molecular mechanisms underpinning oxidative stress in ruminants and their effects on blood and milk oxidative traits. We also investigate strategies to alleviate or repair oxidative damages by improving animal immune functions using novel feed additives. Microbial pathogenic cells, feeding management, and body condition score were some of the studied factors, inducing oxidative stress in ruminants. The predominance of Streptococcus spp. (24.22%), Acinetobacter spp. (21.37%), Romboutsia spp. (4.99%), Turicibacter spp., (2.64%), Stenotrophomonas spp. (2.33%), and Enterococcus spp. (1.86%) was found in the microbiome of mastitis cows with a decrease of d-mannose and increase of xanthine:guanine ratio when Streptococcus increased. Diversity of energy sources favoring the growth of Fusobacterium make it a keystone taxon contributing to metritis. Ruminal volatile fatty acids rose with high-concentrate diets that decreased the ruminal pH, causing a lysis of rumen microbes and release of endotoxins. Moreover, lipopolysaccharide (LPS) concentration, malondialdehyde (MDA), and superoxide dismutase (SOD) activities increased in high concentrate cows accompanied by a reduction of total antioxidant capacity (T-AOC), glutathione peroxidase (GPx), and catalase (CAT) activity. In addition, albumin and paraoxonase concentrations were inversely related to oxidative stress and contributed to the protection of low-density and high-density lipoproteins against lipid peroxidation, protein carbonyl, and lactoperoxidase. High concentrate diets increased the expression of MAPK pro-inflammatory genes and decreased the expression of antioxidant genes and proteins in mammary epithelial tissues. The expression levels of NrF2, NQO1, MT1E, UGT1A1, MGST3, and MT1A were downregulated, whereas NF-kB was upregulated with a high-grain or high concentrate diet. Amino-acids, vitamins, trace elements, and plant extracts have shown promising results through enhancing immune functions and repairing damaged cells exposed to oxidative stress. Further studies comparing the long-term effect of synthetic feed additives and natural plant additives on animal health and physiology remain to be investigated.

Nutritional management of dairy animals for sustained production under heat stress scenario

Dairy industry plays a significant role in the agriculture sector for sustainable growth. Heat stress, on the other hand, has been proven to have a detrimental impact on dairy output in terms of growth, reproductive performance and milk production in dairy animals, especially in tropical areas. Heat stress is one of the most significant issues facing the dairy industry, as rising temperatures and humidity limit animal productivity throughout the summer, resulting in devastating economic repercussions. The purpose of this review is to gather knowledge on the effects of heat stress on dairy output and how to ameliorate them. The diversion of energy resources from the production to the adaptation pathway may be responsible for the loss in productive capacity of dairy animals, when they are exposed to heat stress. There are different approaches pertaining to relieving the adverse effects of heat stress on dairy production system. These approaches may be classified into three major categories viz. genetic, management and nutritional interventions. These approaches might help dairy animals to perform better by reducing the harmful impacts of heat stress. Appropriate shelter design, giving shade, employing sprinklers, installing cooling devices, and using fans and ventilation systems are among the management strategies. The nutritional interventions comprise ration balancing and providing essential micronutrients to improve the productive and reproductive performance. Some of the most widely used dietary measures to ensure optimal production are inclusion of protein or fat (prill fat), micronutrients antioxidants (vitamins and minerals) and some feed additives (Astaxanthin, betaine, melatonin, Chlorophytum borivilianum) in the diet. These antioxidants and feed additives can be used to attenuate the negative effects of environmental stress. Furthermore, providing adequate energy and antioxidants help to ensure optimum growth, milk production and reproduction efficiency during heat stress. This review provides an overview of the consequences of heat stress on dairy animals, emphasizes essential nutritional strategies for heat stress reduction in dairy animals, and evaluates the influence of various feed supplements on growth, productivity and physiology.