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Mastitis is an inflammation of the mammary gland initiated by pathogenic bacteria. In fact, mastitis is the second most important reason for the culling of cows from dairy herds, after infertility. In this review we focus on various forms of mastitis, including subclinical and clinical mastitis. We also stress the importance of the dry-off period as an important time when pathogenic bacteria might start their insult to the mammary gland. An important part of the review is the negative effects of mastitis on milk production and composition, as well as economic consequences for dairy farms. The two most important groups of bacteria that are involved in infection of the udder, Gram-negative and Gram-positive bacteria, are also discussed. Although all cows have both innate and adaptive immunity against most pathogens, some are more susceptible to the disease than others. That is why we summarize the most important components of innate and adaptive immunity so that the reader understands the specific immune responses of the udder to pathogenic bacteria. One of the most important sections of this review is interrelationship of mastitis with other diseases, especially retained placenta, metritis and endometritis, ketosis, and laminitis. Is mastitis the cause or the consequence of this disease? Finally, the review concludes with treatment and preventive approaches to mastitis.

Targeted direct injection/liquid chromatography coupled to tandem mass spectrometry-based metabolomics was employed to identify metabolite alterations that could differentiate subclinical mastitis (SCM) from control (CON) dairy cows at -8, -4, disease diagnosis, +4 and +8 wks relative to parturition. We identified and measured 128 metabolites in the serum. Univariate analysis revealed significant alterations of serum metabolites at all five time points studied. By applying multivariate analyses including principle component analysis and partial least squares-discriminant analysis, some of the metabolites were found to have the strongest power for discriminating the SCM from CON cows. The top five metabolites with the greatest variable importance in projection values were selected as potential biomarkers for SCM. A set of five serum metabolites including lysine, ornithine, isoleucine, LysoPC a C17:0, and leucine at -8 wks and five other metabolites including lysine, leucine, isoleucine, kynurenine, and sphingomyelin (SM) C26:0 at -4 wks prepartum were determined as predictive biomarkers for SCM, which provided highly predictive capabilities with AUC (area under the curve) at 1.00. Five metabolites including lysine, leucine, isoleucine, kynurenine, and SM C26:1 in the serum were identified as diagnostic biomarkers for SCM with the AUC of 1.00. Moreover, we observed that distinct metabolic pathways were affected in SCM cows including lysine degradation, biotin, cysteine, methionine, and glutathione metabolism, valine, leucine, and isoleucine biosynthesis and degradation, and aminoacyl-tRNA biosynthesis prior to and during the occurrence of the disease. Results of this study showed that metabolomics analyses can be used to identify susceptible cows to SCM starting from -8 and -4 wks prepartum and that blood can be used to diagnose cows with SCM.

Subclinical mastitis (SCM) is a very common disease of dairy cows. Currently, somatic cell count (SCC) is used for SCM diagnoses. There are no prognostic tests to detect which cows may develop SCM during the dry-off period. Therefore, the objectives of this study were to identify metabolic alterations in the serum of pre-SCM cows during the dry-off period, at −8 and −4 weeks before calving, through a targeted mass spectrometry (MS) assay. Fifteen cows, free of any disease, and 10 cows affected only by SCM postpartum served as controls (CON) and the SCM group, respectively. Results showed 59 and 47 metabolites that differentiated (p ≤ 0.05) CON and pre-SCM cows at –8 and −4 weeks prior to the expected date of parturition, respectively. Regression analysis indicated that a panel of four serum metabolites (AUC = 0.92, p < 0.001) at −8 weeks and another four metabolites (AUC = 0.92, p < 0.01) at −4 weeks prior to parturition might serve as predictive biomarkers for SCM. Early identification of susceptible cows can enable development of better preventive measurements ahead of disease occurrence.

Intramammary infections (mastitis) of dairy cows, along with other periparturient diseases, have become problematic within the dairy industry as they lead to loss of milk production. The main objective of this study was to determine whether elevated somatic cell counts (SCC) in cows prior to drying off are related to the incidence of other periparturient diseases. Additionally, we de-termined whether milk composition and milk yield are affected by a high SCC prior to drying off. Somatic cell counts of milk samples were determined prior to dry off (n = 140) and were used to classify cows in the study as high (>200,000 cells/mL) or low (

Postpartum uterine diseases are common in dairy cows and are a great concern for the dairy industry as they are associated with various consequences, including lower fertility, lower milk yield, and an overall negative impact on the host health. An infected uterus is a source of bacterial compounds and cytokines that spill into the systemic circulation, spreading inflammation to other organs. In this review article, we discuss a short overview of the anatomy of the reproductive tract of dairy cows and several infectious diseases of the uterus including metritis, endometritis, and pyometra. Additionally, we discuss the microbiome of the reproductive tract in health and during uterine diseases. As well, diagnostic criteria for metritis and endometritis and contributing factors for increased susceptibility to metritis infection are important topics of this review. To better understand how the uterus and reproductive tract respond to bacterial pathogens, a section of this review is dedicated to immunity of the reproductive tract. Both the innate and adaptive immunity systems are also discussed. We conclude the review with a factual discussion about the current treatments of uterine diseases and the new developments in the area of application of probiotics for uterine health. Mechanisms of actions of probiotics are discussed in detail and also some applications to prevent uterine infections in dairy cows are discussed.

During the periparturient period there is a significant increase in the incidence of multiple metabolic and infectious diseases in dairy cows. Dairy cows are fed high-grain diets immediately after calving to support production of large amounts of milk. Mounting evidence indicates these types of diets are associated with the release of high amounts of endotoxins in the rumen fluid. If infected, the udder and uterus additionally become important sources of endotoxins during the postpartum period. There is increasing evidence that endotoxins translocate from rumen, uterus, or udder into the systemic circulation and trigger chronic low-grade inflammatory conditions associated with multiple diseases including fatty liver, mastitis, retained placenta, metritis, laminitis, displaced abomasum, milk fever, and downer cow syndrome. Interestingly, endotoxin-related diseases are triggered by a bacterial component and not by a specific bacterium. This makes prevention of these type of diseases different from classical infectious diseases. Prevention of translocation of endotoxins into the host systemic circulation needs to take priority and this could be achieved with a new approach: mucosal vaccination. In this review article, we discuss all the aforementioned issues in detail and also report some of our trials with regards to mucosal vaccination of periparturient dairy cows.

Ketosis, characterized by high concentrations of ketone bodies in the blood, urine, and milk, affects a considerable number of cows immediately after calving. Although much is known about ketosis, dairy cows continue to be affected in every herd world-wide. Cows affected by ketosis are treated with palliative treatments after the disease is diagnosed. This is a very expensive approach and costs the dairy industry extra expenses, contributing to lower profitability of dairy herds. In this review article, we summarize the mainstream view on ketosis, classification of ketosis into three types, current diagnostic approaches to ketosis, and the economic impact of ketosis on dairy farms. Additionally, we discuss the most recent applications of the new ‘omics’ science of metabolomics in studying the etiopathology of ketosis as well as its contribution in identification of novel screening or diagnostic biomarkers of ketosis.

The objective of this study was to determine urinary metabotypes of dairy cows prior to, during, and after diagnosis of subclinical mastitis (SCM). Twenty controls (CON) and 6 cows with SCM were included in the study. DI/LC-MS/MS was used to measure 186 metabolites in the urine at −8 and − 4 wks prepartum, disease diagnosis, and at +4 and + 8 wks postpartum. Results showed a total of 24 and 27 metabolites that differentiated SCM and CON cows at −8 and − 4 wks, respectively, with 5 top metabolites having an accuracy to predict SCM of 1.0, for both time point. Altered metabolites included several acylcarnitines (ACs), phosphatidylcholines (PCs), amino acids (AAs), and biogenic amines (BAs). During SCM diagnosis week there were a total of 22 metabolites that differentiated the SCM and CON cows including 13 ACs, 5 AAs, hexose, and phosphatidylethanolamine ae C44:3. The top 5 metabolites Symmetric dimethylarginine (SDMA), methylglutarylcarnitine, dodecanoylcarnitine, phosphatidylethanolamine ae C42:1, and phosphatidylethanolamine ae C42:0 showed an AUC of 1.0. Metabolite alterations continued at +4 and + 8 wks postpartum with 13 (9 ACs, 3 glycerophospholipids, and 1 BA) and 28 metabolites (14 ACs, 2 glycerophospholipids, hexose, 8 AAs, and 2 BAs) that differentiated the two groups, respectively. The top 5 most important metabolites, for both time points, showed AUCs of 1.0. Results of this study showed that typical urinary metabotypes preceded SCM event starting from −8 and − 4 wks prepartum. Metabotypes typical of SCM continued to be present during the week of SCM and at +4 and + 8 wks postpartum. These data show that the urine of dairy cows can be used with very high accuracy for screening dairy cows for susceptibility to SCM prior to entering into the dry off period and a potential new pen-side test can help dairy producers and veterinarians to make selective treatments.

The objective of this study was to evaluate whether whole raw milk originating from Holstein dairy cows affected by lameness alters its composition. A total of 20 healthy control cows and 6 cows diagnosed with lameness were selected out of 100 sampled cows in a nested case control study at 2 weeks postpartum, and whole raw milk samples were collected and analyzed with direct inject/liquid chromatography-tandem mass spectrometry and nuclear magnetic resonance. In total, 168 metabolites were identified and quantified using an in-house mass spectrometry library. A total of 35 of the identified metabolites decreased versus control cows. Only two metabolites (i.e., sn-glycero-3-phosphocholine and phosphatidylethanolamine ae C42:1) were increased in the milk of lame cows. In conclusion, milk metabotyping of lame cows revealed significant changes in multiple milk components, including amino acids, lipids, and biogenic amines. Most of the milk compounds identified as altered were lowered, suggesting deflection of nutrients from the mammary gland to the host needs for healing lameness-associated pathological processes.

Previously we observed that bacterial lipopolysaccharide (LPS) was able to instantly convert recombinant murine prion protein (moPrP) from an alpha-helical to a beta-sheet enriched state. The objectives of this study were to evaluate the effects of a single in vitro administration of recombinant moPrP alone or combined with detoxified lipopolysaccharide (D-LPS) on innate immunity and antibacterial gene expression in the colon of male FVB/N mice, under an Ussing chamber system. Results showed that moPrP alone affected the expression of genes related to both toll-like receptor (TLR)- and nod-like receptor (NLR)-signaling as well as pro- and anti-inflammatory responses. moPrP induced a strong antibacterial response with Slpi mRNA over expression (9-fold). Combination of moPrP with D-LPS on the mucosal side of the colon induced genes associated with TLR-signaling, apoptosis, and a very strong antibacterial response (35-fold Slpi expression). Administration of moPrP on the mucosal side and D-LPS on the serosal side triggered expression of 12 genes related to TLR signaling, apoptosis, and antibacterial responses, as illustrated by overexpression of Slpi by30-fold. The over expression of Slpi mRNA was further reaffirmed by ELISA and when moPrP was added to the mucosal side and D-LPS on the serosal side, an increased Slpi protein was observed. Application of combined moPrP and D-LPS on the mucosal side significantly increased the Slpi protein. Results of this study demonstrated that moPrP alone or combined with D-LPS affected the expression of various genes related to inflammation, antibacterial, and apoptotic responses.

Previously, we showed that bacterial lipopolysaccharide (LPS) converts mouse PrPC protein to a beta-rich isoform (moPrPres) resistant to proteinase K. In this study, we aimed to test if the LPS-converted PrPres is infectious and alters the expression of genes related to prion pathology in brains of terminally sick mice. Ninety female FVB/N mice at 5 weeks of age were randomly assigned to 6 groups treated subcutaneously (sc) for 6 weeks either with: (1) Saline (CTR); (2) LPS from Escherichia coli 0111:B4 (LPS), (3) one-time sc administration of de novo generated mouse recombinant prion protein (moPrP; 29-232) rich in beta-sheet by incubation with LPS (moPrPres), (4) LPS plus one-time sc injection of moPrPres, (5) one-time sc injection of brain homogenate from Rocky Mountain Lab (RLM) scrapie strain, and (6) LPS plus one-time sc injection of RML. Results showed that all treatments altered the expression of various genes related to prion disease and neuroinflammation starting at 11 weeks post-infection and more profoundly at the terminal stage. In conclusion, sc administration of de novo generated moPrPres, LPS, and a combination of moPrPres with LPS were able to alter the expression of multiple genes typical of prion pathology and inflammation.

Red osier dogwood (ROD; Cornus sericea) is an abundant native shrub plant across North America and it is rich in bioactive compounds with total phenolic concentration up to 220 g/kg dry matter (DM) depending on the season. The phenolics include anthocyanins, gallic acid, ellagic acid, quercetin, and cyanin, which have both antioxidant and antimicrobial properties. The objective of this study was to determine the effect of increasing substitution of ROD for barley silage in a high-grain diet on DM intake, ruminal pH and fermentation, digestibility in the total digestive tract, blood metabolites and acute phase response in beef heifers. Five ruminally cannulated Angus heifers (averaged body weight of 660 ± 40.8 kg; initial age of 18 months) were used in a 5 × 5 Latin square design with 21-d periods including 14 d for adaptation to new diets and 7 d for data collection. Treatments were a control diet containing 150 g/kg barley silage and 850 g/kg barley concentrate mix (DM basis), the control diet substituted with 30, 70 or 100 g/kg of ROD for equal proportions of barley silage, respectively, and the control diet supplemented with antibiotics (330 mg monensin + 110 mg tylosin/heifer/d). Apparent digestibility was determined using Cr2O3 as external marker by sampling feces from the rectum. Intake of DM quadratically (P

In this study, we aimed to identify metabolite signatures that characterize metritis prior to, during, and after the disease incidence. Blood samples were collected from 100 Holstein cows at five time points before and after parturition. Six cows that developed metritis and 20 controls were selected for metabolomics analysis in a nested case-control study. Twenty nine serum metabolites were quantified using gas chromatography–mass spectroscopy. Results showed that similar panels of metabolites differentiated pre-metritic and control cows at 8 and 4 wk prepartum. The top most important metabolites that differentiated the two groups of cows at 8 wk prepartum were oxalate, ornithine, pyroglutamic acid, d-mannose, and glutamic acid, and at 4 wk prepartum were ornithine, pyroglutamic acid, d-mannose, glutamic acid, and phosphoric acid, suggesting their potential use as risk biomarkers for metritis. Area under the curve with values of 1.0 and 0.969 at 8 and 4 wk, respectively, indicated that those panels of metabolites have a very high sensitivity and specificity to be used as risk biomarkers for metritis. Overall, results showed that specific serum metabolite signatures can be used to screen cows for susceptibility to metritis during the dry off period, and to better understand the etiopathobiology of the disease.

The objective of this meta-analytical study was to investigate selected macrominerals, microminerals, and toxic heavy metals in the bovine whole-raw-milk (WRM) samples of published data. An analytical data set was constructed from 72 different studies from 37 countries with two types of production systems: a conventional production system (CPS) and an organic production system (OPS) compared with commercially available or retail-store-available milk (COM). Results of the meta-analytical study showed differences in the concentrations of macrominerals. Concentrations of Ca, Mg, K, and P were greater in the CPS samples, whereas Na was greater in the COM samples ( P0.05). Data also demonstrated that concentrations of microminerals like Cu, I, Fe, Mn, Se, and Zn in the organic WRM were lower ( P0.05) compared with the milk from CPS. The highest concentration of Ni was reported for COM ( P0.05); however, this value was below the minimum-risk level (MRL). Concentrations of heavy metals like As and Ni were greater in CPS milk than those in organic milk ( P0.05). In addition, there were greater concentrations of Cd and Pb in the WRM from CPS versus that from the organic farms. Concentration of Al was lowest in the OPS milk versus Al in the CPS which was 6.5-fold greater than in organic milk. The amount of Hg was below the MRL of 0.01 μmol/L for all production systems. A high variability was observed in the published data regarding the country of origin. Raw milk originating from Europe and North America was characterized by concentrations of macro- and microminerals below the MRLs as compared with that from specific countries, which had some minerals above the MRLs. For example, concentrations of Pb were above the MRL in the milk samples from Brazil, Croatia, Egypt, Mexico, Nigeria, Palestine, Romania, Serbia, and Turkey. Moreover, data from this study indicate that organic dairy farms are characterized by lower concentrations of toxic heavy metals in the WRM compared with those from CPS dairy farms.

The objective of this study was to search for potential alterations in innate immunity reactants and carbohydrate and lipid metabolism in the blood of transition dairy cows before, during, and after clinical occurrence of milk fever (MF) and identify potential predictive biomarkers of disease. One hundred pregnant multiparous Holstein dairy cows were involved in the study starting from -8wks before the expected day of parturition until +8wks postpartum as part of a large retrospective longitudinal study. Health status, DMI, milk yield, and milk composition were monitored during the whole experimental period. Six healthy cows (CON) and 6 cows that showed clinical signs of MF were selected for blood analyses. Serum concentrations of lactate, non-esterified fatty acids (NEFA), β-hydroxybutyric acid (BHBA), interleukin-1 (IL-1), interleukin-6 (IL-6), tumor necrosis factor (TNF), haptoglobin (Hp), and serum amyloid A (SAA) were determined. Results indicated that concentrations of serum lactate, IL-6, TNF, SAA, and Hp were greater in cows with MF than those in the CON group at different time points. Moreover, serum lactate, TNF, SAA, and Hp were greater in cows with MF starting at -8 and -4wks prior to parturition. Both principal component analysis (PCA) and partial least squares - discriminant analysis (PLS-DA) showed separated clusters between MF and CON cows at -8, -4, and disease diagnosis weeks. Overall DMI and milk production were lower in MF-affected cows. Additionally milk fat and fat:protein ratio were greater in MF. In conclusion, cows affected by MF showed alterations in some of the innate immunity reactants and metabolites related to carbohydrate metabolism several weeks prior to appearance of clinical signs of MF. Variable importance in projection plots demonstrated that TNF and SAA in the serum were the strongest discriminators between MF cows and CON ones, which might be useful as predictive biomarkers of the disease.

Previously, we showed that bacterial lipopolysaccharide (LPS) converts mouse PrPC protein to a beta-rich isoform (moPrPres) resistant to proteinase K. In this study, we aimed to test if the LPS-converted PrPres is infectious and alters the expression of genes related to prion pathology in brains of terminally sick mice. Ninety female FVB/N mice at 5 weeks of age were randomly assigned to 6 groups treated subcutaneously (sc) for 6 weeks either with: (1) Saline (CTR); (2) LPS from Escherichia coli 0111:B4 (LPS), (3) one-time sc administration of de novo generated mouse recombinant prion protein (moPrP; 29-232) rich in beta-sheet by incubation with LPS (moPrPres), (4) LPS plus one-time sc injection of moPrPres, (5) one-time sc injection of brain homogenate from Rocky Mountain Lab (RLM) scrapie strain, and (6) LPS plus one-time sc injection of RML. Results showed that all treatments altered the expression of various genes related to prion disease and neuroinflammation starting at 11 weeks post-infection and more profoundly at the terminal stage. In conclusion, sc administration of de novo generated moPrPres, LPS, and a combination of moPrPres with LPS were able to alter the expression of multiple genes typical of prion pathology and inflammation.

Bovine milk is a nutritionally rich, chemically complex biofluid consisting of hundreds of different components. While the chemical composition of cow's milk has been studied for decades, much of this information is fragmentary and very dated. In an effort to consolidate and update this information, we have applied modern, quantitative metabolomics techniques along with computer-aided literature mining to obtain the most comprehensive and up-to-date characterization of the chemical constituents in commercial cow's milk. Using nuclear magnetic resonance (NMR) spectroscopy, liquid chromatography-mass spectrometry (LC-MS), and inductively coupled plasma-mass spectrometry (ICP-MS), we were able to identify and quantify 296 bovine milk metabolites or metabolite species (corresponding to 1447 unique structures) from a variety of commercial milk samples. Through our literature analysis, we also found another 676 metabolites or metabolite species (corresponding to 908 unique structures). Detailed information regarding all 2355 of the identified chemicals in bovine milk have been made freely available through a Web-accessible database called the Milk Composition Database or MCDB ( http://www.mcdb.ca/ ).

The dairy industry continues to suffer severe economic losses due to the increased disease incidence cows experience during the transition period. It has long been the classical view that the major contributing factor to the development of these periparturient diseases is the considerable increase in nutritional demands for milk production. This classical view, however, fails to account for the substantial correlation between both metabolic and infectious diseases and the detrimental effects that can occur with the provision of high-energy diets to support these nutritional demands. Currently, increasing evidence implicates bacterial endotoxins in the etiopathology of most periparturient diseases. Bacterial endotoxins are components of the outer cell wall of gram-negative and gram-positive bacteria that are highly immunostimulatory and can trigger proinflammatory immune responses. The ability of endotoxins to translocate from the mucosal tissues, including the gastrointestinal tract, mammary gland, and uterus, into the systemic circulation has been observed. Once they have entered the circulation, endotoxins potentially contribute to disease either directly, through eliciting an inflammatory response, or indirectly through other factors such as the overreaction of the natural protective mechanisms of the host. Although the evidence implicating a role of endotoxins in the pathogenesis of transition diseases continues to grow, our current knowledge of the host response to mucosal endotoxin exposure and pathogenic mechanisms remain largely unknown. Developing our understanding of the connection between endotoxemia and dairy cattle disease holds significant potential for the future development of preventative measures that could benefit the productivity of the dairy industry as well as animal welfare.

The objective of this investigation was to evaluate whether intravaginal infusion of probiotics (a lactic acid bacteria cocktail) around parturition would influence metabolic status and increase milk production of transition dairy cows. One hundred pregnant Holstein dairy cows were assigned to 1 of the 3 experimental groups receiving intravaginal infusion of probiotics or carrier (i.e., sterile skim milk) once a week at wk -2, -1, and +1 relative to calving as follows: 2 consecutive probiotics before parturition and 1 carrier dose after parturition (TRT1), 3 consecutive probiotics doses around parturition (TRT2), and 3 consecutive carrier doses around parturition (CTR). The probiotics were a lyophilized culture mixture composed of FUA3089 and FUA3138 and FUA3140 with a cell count of 10 to 10 cfu/dose. Blood was sampled from wk -2 to +3 and milk was sampled on the third day in milk (DIM) and from wk +1 to +5 on a weekly basis. Feed intake and milk production was monitored until wk +8. Results showed that the TRT2 group (366.12 ± 49.77 μmol/L) had a lower ( = 0.01) concentration of NEFA in the serum than the CTR group (550.85 ± 47.16 μmol/L). The concentrations of IgG in the milk were 32.71 ± 3.00 mg/mL in the TRT1 group, 17.47 ± 4.54 mg/mL in the TRT2 group, and 6.73 ± 3.43 mg/mL in the CTR group at 3 DIM ( < 0.01). Meanwhile, both the TRT1 and the TRT2 group had lower haptoglobin in the milk compared with the CTR group at 3 DIM ( < 0.01). The TRT1 group had greater milk protein content than the CTR group (2.99 ± 0.04 vs. 2.82 ± 0.04%; = 0.02), whereas the TRT2 group tended to have greater lactose content compared with the CTR group (4.53 ± 0.03 vs. 4.44 ± 0.03%; = 0.05). The effect of treatment interacted with parity with regards to milk production and feed efficiency. Multiparous cows in the TRT1 and TRT2 groups had greater milk production and feed efficiency than those in the CTR group ( < 0.01 and = 0.02, respectively). Among primiparous cows, those in the TRT2 group had greater milk production ( = 0.04) whereas those in the TRT1 group had lower feed intake ( < 0.01) than those in the CTR group. Both the TRT1 and the TRT2 groups had enhanced feed efficiency compared with the CTR group ( < 0.01). In conclusion, intravaginal infusion of lactic acid bacteria modulated concentrations of selected serum metabolites and milk components and increased milk efficiency of transition dairy cows.

(1) Background: The objective of this study was to evaluate the urine of dairy cows for presence of metabolites with the potential to be used as screening biomarkers for lameness as well as to characterize pre-lame, lame, and post-lame cows from the metabolic prospective. (2) Methods: Six lame and 20 control healthy cows were used in this nested case-control study. Urinary 1H-NMR analysis was used to identify and measure metabolites at five time points including &minus, 8 and &minus, 4 weeks prepartum, lameness diagnosis week (1&ndash, 3 weeks postpartum) as well as at +4 and +8 weeks after calving. (3) Results: A total of 90 metabolites were identified and measured in the urine. At &minus, 4 weeks, 27 prepartum metabolites were identified as altered, at both timepoints, with 19 and 5 metabolites excreted at a lower concentration, respectively. Additionally, a total of 8 and 22 metabolites were found at greater concentration in pre-lame cows at &minus, 4 weeks, respectively. Lame cows were identified to excrete, at lower concentrations, seven metabolites during a lameness event with the top five most important metabolites being Tyr, adipate, glycerate, 3-hydroxy-3-methylglutarate, and uracil. Alterations in urinary metabolites also were present at +4 and +8 weeks after calving with N-acetylaspartate, glutamine, imidazole, pantothenate, beta-alanine and trimethylamine, with the greatest VIP (variable importance in projection) score at +4 weeks, and hipurate, pantothenate 1,3-dihydroxyacetone, galactose, and Tyr, with the greatest VIP score at +8 weeks postpartum. (4) Conclusions: Overall, results showed that urine metabotyping can be used to identify cows at risk of lameness and to better characterize lameness from the metabolic prospective. However, caution should be taken in interpretation of the data presented because of the low number of replicates.

The objectives of this study were to identify metabolite fingerprints in the serum related to amino acid (AA), carbohydrate, and lipid metabolism in transition dairy cows at −8 and −4 wks prior to parturition, at +2 wks postpartum during lameness diagnosis as well as at +4 and +8 wks after parturition. All cases of lameness occurred at around +2 wks after parturition. Out of 100 dairy cows included in this nested case-control study only 6 pregnant multiparous (parity: 3.0 ± 0.6, Mean ± SEM) Holstein dairy cows with lameness only and 20 healthy control cows (CON) were selected for serum GC–MS metabolomics analysis. All cows selected were not injured mechanically and had similar parity (3.3 ± 0.6) and body condition score (BCS). A total of 29 metabolites were identified and quantified in the serum. Results showed that 18 and 15 metabolites differentiated pre-lame cows from CON ones at −8 and −4 wks prior to parturition. Ten metabolites were found altered at the week of lameness diagnosis. Of note: pre-lame cows were characterized by greater concentrations of several amino acids including Gly, Leu, Phe, Ser, Val, D-mannose, Myo-inositol, and phosphoric acid (PA) at −8 and −4 wks prior to lameness and at the week of lameness diagnosis. At +4 wks after parturition 11 metabolites were altered in lameness cows, and at +8 wks there were 13 metabolites that differentiated the two groups. The high accuracy of the top 6 metabolites at −8 wks prior to parturition or approximately 9–11 wks before lameness diagnosis (Glu, Orn, Phe, Ser, Val, and PA) and another 5 metabolites at −4 wks before parturition, or approximately 5–7 wks before lameness diagnosis (Leu, Orn, Phe, Ser, and D-mannose) suggest that those metabolites may serve as potential monitoring biomarkers of lameness prior to lameness diagnosis. Data also showed multiple alterations during the week of lameness as well as at +4 and +8 wks postpartum suggesting lame cows are not metabolically healthy several weeks after the incidence of lameness. Significance Lameness is one of the top three health issues of dairy cows in Canada that influences early culling of dairy cows. Despite a few efforts, there is scarcity of data regarding metabolic alterations that precede, associate, and follow lameness. We investigated whether alterations in the metabolite signatures prior, during, and after development of lameness can be used to screen cows for susceptibility to lameness, characterize lameness from the metabolic prospective, and predict the outcome of this economically important health issue of dairy cows. The results demonstrate typical metabotypes as shown by increased serum concentrations of Val, Gly, Ser, Leu, Phe, D-mannose, myo-inositol, and phosphoric acid at −8 and −4 wks prior to parturition (or −6 to −10 wks prior to occurrence of lameness) and at the week of lameness diagnosis.

Metritis is an uterine pathology that causes economic losses for the dairy industry. It is associated with lower reproductive efficiency, increased culling rates, decreased milk production and increased veterinary costs. To gain a more detailed view of the urine metabolome and to detect metabolite signature in cows with metritis. In addition, we aimed to identify early metabolites which can help to detect cows at risk to develop metritis in the future. We used nuclear magnetic resonance spectroscopy starting at 8 and 4 weeks prior to the expected day of parturition, during the week of diagnosis of metritis, and at 4 and 8 weeks after diagnosis of metritis in Holstein dairy cows. At 8 weeks before parturition, pre-metritic cows had a total of 30 altered metabolites. Interestingly, 28 of them increased in urine when compared with control cows (P

The objectives of this study were to test whether recombinant mouse (mo)PrP alone or in combination with LPS or under simulated endotoxemia would affect expression of genes related to host inflammatory and antimicrobial responses. To test our hypotheses colon tissues were collected from 16 male mice (FVB/N strain) and mounted in an Ussing chamber. Application of moPrP to the mucosal side of the colon affected genes related to TLR- and NLR- signaling and antimicrobial responses. When LPS was added on the mucosal side of the colon, genes related to TLR, Nlrp3 inflammasome, and iron transport proteins were over-expressed. Addition of LPS to the serosal side of the colon up-regulated genes related to TLR- and NLR-signaling, Nlrp3 inflammasome, and a chemokine. Treatment with both moPrP and LPS to the mucosal side of the colon upregulated genes associated with TLR, downstream signal transduction (DST), inflammatory response, attraction of dendritic cells to the site of inflammation, and the JNK-apoptosis pathway. Administration of moPrP to the mucosal side and LPS to the serosal side of the colon affected genes related to TLR- and NLR-signaling, DST, apoptosis, inflammatory response, cytokines, chemokines, and antimicrobial peptides. Overall this study suggests a potential role for moPrP as an endogenous 'danger signal' associated with activation of colon genes related to innate immunity and antibacterial responses.

The objectives of this study were to evaluate alterations of metabolites in the blood of dairy cows before, during, and after diagnosis of metritis and identify predictive serum metabolite biomarkers for metritis. DI/LC-MS/MS was used to analyze serum samples collected from both healthy and metritic cows during −8, −4, disease diagnosis, +4, and +8 wks relative to parturition. Results indicated that cows with metritis experienced altered concentrations of serum amino acids, glycerophospholipids, sphingolipids, acylcarnitines, and biogenic amines during the entire experimental period. Moreover, two sets of predictive biomarker models and one set of diagnostic biomarker models for metritis were developed, and all of them showed high sensitivity and specificity (e.g., high AUC values by the ROC curve evaluation), which indicate that serum metabolites identified have pretty accurate predictive, diagnostic, and prognostic abilities for metritis in transition dairy cows.

Ketosis is a prevalent metabolic disease of transition dairy cows that affects milk yield and the development of other periparturient diseases. The objective of this study was to retrospectively metabotype the serum of dairy cows affected by ketosis before clinical signs of disease, during the diagnosis of ketosis, and after the diagnosis of disease and identify potential predictive and diagnostic serum metabolite biomarkers for the risk of ketosis. Targeted metabolomics was used to identify and quantify 128 serum metabolites in healthy (CON, n = 20) and ketotic (n = 6) cows by DI/LC-MS/MS at −8 and −4 weeks prepartum, during the disease week, and at +4 and +8 weeks after parturition. Significant changes were detected in the levels of several metabolite groups including amino acids, glycerophospholipids, sphingolipids, acylcarnitines, and biogenic amines in the serum of ketotic cows during all time points studied. Results of this study support the idea that ketosis is preceded and associated and followed by alterations in multiple metabolite groups. Moreover, two sets of predictive biomarker models and one set of diagnostic biomarker model with very high sensitivity and specificity were identified. Overall, these findings throw light on the pathobiology of ketosis and some of the metabolites identified might serve as predictive biomarkers for the risk of ketosis. The data must be considered as preliminary given the lower number of ketotic cows in this study and more research with a larger cohort of cows is warranted to validate the results.

The objectives of this study were to determine alterations in the serum metabolites related to amino acid (AA), carbohydrate, and lipid metabolism in transition dairy cows before diagnosis of subclinical mastitis (SCM), during, and after diagnosis of disease. A subclinical mastitis case was determined as a cow having somatic cell count (SCC)200 000/mL of milk for two or more consecutive reports. Blood samples were collected from 100 Holstein dairy cows at five time points at -8 and -4 weeks before parturition, at the week of SCM diagnosis, and +4 and +8 weeks after parturition. Twenty healthy control cows (CON) and six cows that were diagnosed with SCM were selected for serum analysis with GC-MS. At -8 weeks a total of 13 metabolites were significantly altered in SCM cows. In addition, at the week of SCM diagnosis 17 metabolites were altered in these cows. Four weeks after parturition 10 metabolites were altered in SCM cows and at +8 weeks 11 metabolites were found to be different between the two groups. Valine (Val), serine (Ser), tyrosine (Tyr), and phenylalanine (Phe) had very good predictive abilities for SCM and could be used at -8 weeks and -4 weeks before calving. Combination of Val, isoleucine (Ile), Ser, and proline (Pro) can be used as diagnostic biomarkers of SCM during early stages of lactation at +4 to +8 weeks after parturition. In conclusion, SCM is preceded and followed by alteration in AA metabolism.

In dairy cows, periparturient disease states, such as metritis, mastitis, and laminitis, are leading to increasingly significant economic losses for the dairy industry. Treatments for these pathologies are often expensive, ineffective, or not cost-efficient, leading to production losses, high veterinary bills, or early culling of the cows. Early diagnosis or detection of these conditions before they manifest themselves could lower their incidence, level of morbidity, and the associated economic losses. In an effort to identify predictive biomarkers for postpartum or periparturient disease states in dairy cows, we undertook a cross-sectional and longitudinal metabolomics study to look at plasma metabolite levels of dairy cows during the transition period, before and after becoming ill with postpartum diseases. Specifically we employed a targeted quantitative metabolomics approach that uses direct flow injection mass spectrometry to track the metabolite changes in 120 different plasma metabolites. Blood plasma samples were collected from 12 dairy cows at 4 time points during the transition period (-4 and -1 wk before and 1 and 4 wk after parturition). Out of the 12 cows studied, 6 developed multiple periparturient disorders in the postcalving period, whereas the other 6 remained healthy during the entire experimental period. Multivariate data analysis (principal component analysis and partial least squares discriminant analysis) revealed a clear separation between healthy controls and diseased cows at all 4 time points. This analysis allowed us to identify several metabolites most responsible for separating the 2 groups, especially before parturition and the start of any postpartum disease. Three metabolites, carnitine, propionyl carnitine, and lysophosphatidylcholine acyl C14:0, were significantly elevated in diseased cows as compared with healthy controls as early as 4 wk before parturition, whereas 2 metabolites, phosphatidylcholine acyl-alkyl C42:4 and phosphatidylcholine diacyl C42:6, could be used to discriminate healthy controls from diseased cows 1 wk before parturition. A 3-metabolite plasma biomarker profile was developed that could predict which cows would develop periparturient diseases, up to 4 wk before clinical symptoms appearing, with a sensitivity of 87% and a specificity of 85%. This is the first report showing that periparturient diseases can be predicted in dairy cattle before their development using a multimetabolite biomarker model. Further research is warranted to validate these potential predictive biomarkers.

The objective of this study was to identify urinary metabolite signatures that can be used for monitoring and diagnosing of subclinical mastitis in Holstein dairy cows. Six multiparous pregnant Holstein cows with subclinical mastitis (SCM) and 20 healthy controls (CON) were selected out of 100 cows in the study. DI/LC-MS/MS-based urinary analyses were conducted on samples collected at -8, -4, SCM diagnosis, and at +4 and +8 wks around the expected day of calving. Data indicated that 14 amino acids and derivatives were found in the urine with Gln and SDMA consistently increased (P

The objective of this study was to determine the concentrations of 20 minerals in the whole raw milk from Holstein dairy cows in the province of Alberta, Canada. A total of 156 milk samples were collected from 26 dairy farms (n = 6 per farm) and analyzed with inductively coupled plasma mass spectrometry (ICP-MS) for five macrominerals (Ca, Mg, P, K, and Na), ten microminerals (Bo, Co, Cu, Fe, Mn, Mo, Ru, Se, St, and Zn), and five heavy metals (Al, As, Cd, Cr, and Pb). Calculated means were compared with their recommended daily intakes (RDIs) or minimal risk levels (MRLs) obtained from several food safety agencies and with data obtained from a world meta-analytical study we conducted previously. Results of the present study showed differences in the concentrations of multiple minerals between the Alberta farms involved and world averages (WA) and within Alberta farms. Concentrations of macrominerals, including Ca, Mg, P, K, and Na, in the raw milk were greater in Alberta dairy farms than the WA (p &lt, 00.5, except Ca). Of note, concentrations of Ca showed the highest variability among Alberta farms, with 11 farms having lower milk Ca than WA. The other macrominerals were higher than WA in more than 88% of Alberta farms. Data demonstrated that concentrations of microminerals, including Co, Cu, Fe, Mn, and Mo, in Alberta raw milk were lower compared with WA (p &lt, 0.05). Selenium was the only element in raw milk that was found to have higher concentrations in all farms in Alberta vs. WA. High variability was observed for B, Sr, and Zn, which were lower in multiple locations around the province. Concentrations of heavy metals in the Alberta raw milk, including Al, As, Cd, and Pb, were lower than WA, whereas concentrations of Cr were higher. Most importantly, all heavy metals were below their respective MRLs in all analyzed samples. Overall, data from this study showed that raw milk from Holstein dairy cows in Alberta has concentrations of most mineral elements below their MRLs and some of them different from WA. Of note, although concentrations of Se and Zn in the raw milk were higher in Alberta compared with WA, their concentrations were still below their respective MRLs.

The study evaluated the effects of repeated oral exposure to LPS and lipoteichoic acid (LTA) on immune responses of dairy cows. Thirty pregnant Holstein cows were randomly assigned to two treatment groups. Cows received orally either 2 ml of 0.85% sterile saline solution (control group), or 2 ml of sterile saline solution containing three doses of LPS from Escherichia coli 0111 : B4 along with a flat dose of LTA from Bacillus subtilis. Blood and saliva samples were collected and analyzed for serum amyloid A (SAA); LPS-binding protein (LBP); anti-LPS plasma IgA, IgG and IgM; TNF-α; and IL-1. Results showed greater concentrations of IgA in the saliva of treated cows compared with the controls ( P 0.10). Overall, the results of this study indicate that repeated oral administration with LPS and LTA stimulates innate and humoral immune responses in periparturient dairy cows.

Milk fever, a metabolic disease of dairy cattle, is associated with perturbations of calcium homeostasis, the pathogenesis of which is not yet completely understood.The aim of this study was to investigate plasma concentrations of calcitonin gene-related peptide and selected minerals and metabolites in periparturient cows with and without milk fever.Plasma concentrations of calcitonin gene-related peptide, as well as calcium, phosphate, magnesium, iron, glucose, lactate, and cortisol, were determined in multiple plasma samples from Jersey cows with and without spontaneous milk fever.Cows affected by milk fever (n = 5) had lower concentrations of calcitonin gene-related peptide (P = .038) and inorganic phosphate (P.001) in plasma than did the controls (n = 5). Also, these cows tended to have lower calcium concentrations (P = .071). Magnesium, iron, lactate, glucose, and cortisol concentrations were comparable between both groups of cows (P.10). Around the day of calving, plasma concentrations of lactate, glucose, and cortisol increased and the concentration of iron decreased in all cows (P ≤ .01).Despite the limited number of cows evaluated, this report is the first to indicate lowered concentrations of calcitonin gene-related peptide as part of the metabolic changes during milk fever in cows. Further work with a larger cohort of animals is warranted to understand the precise role of calcitonin gene-related peptide and the potential associations with disturbances in plasma minerals typically observed during milk fever.

Ketosis (hyperketonemia) is a prevalent metabolic disease of transition dairy cows that affects ~30–40% of the cows during early lactation. Cows with ketosis have lower milk yield and reproductive performance, greater risk of other periparturient diseases, and higher culling rates. Ketosis is characterized by an excess level of circulating ketone bodies with blood concentration of beta-hydroxybutyrate (BHBA) been recognized as a golden standard for diagnosis of the disease. However, the cutoff value for serum BHBA for diagnosis of ketosis appears to be somewhat arbitrary. Negative energy balance at early lactation is the primary hypothesis for the explanation of the pathobiology of ketosis. Treatment strategies are focused on maintenance of glucose and ketone body homeostasis. The exact causes and the etiopathology of ketosis remain incompletely understood. In some recent metabolomics studies, data show that the number of metabolites altered in the plasma/serum or milk and metabolic pathways perturbed during ketosis are numerous. It is obvious that ketone bodies and glucose metabolism are not the only perturbed metabolites during ketosis. Mounting evidence indicates that multiple alterations also occur at proteome, transcriptome, and genome levels and other component networks. Integration of all the knowledge generated by genomics, transcriptomics, proteomics, metabolomics, and lipidomics can help detect perturbations of biological information on distinct tiers and give insight on the causes and pathobiology of ketosis in dairy cows.

Milk fever affects mostly multiparous and high-performance dairy cows that are close to calving and at the beginning of lactation. While much is known about milk fever, the real cause of failure in the Ca homeostatic mechanism remains unanswered, and, despite the considerable number of hypotheses presented over the years, milk fever still remains a complex and not very well understood disease of dairy cattle. From the recent “omics” studies, it is obvious that Ca is not the only perturbed variable in the organism of a cow affected by milk fever. Therefore, the complexity of the pathobiology of this disease makes it necessary to consider it from a systems veterinary perspective instead of the reductionist view only. A new approach is necessary in order to clarify and better understand the pathobiology of milk fever. Systems biology sciences have modestly contributed to the identification of multiple unknown alterations in cows with milk fever including unidentified QTL, a number of genes and proteins with altered expressions as well as a number of metabolic changes. A combination of the omics sciences will offer great possibilities for animal health scientists to incorporate all the information generated and study component-to-component interactions and the dynamic communications that result from them.

Animal scientists have made tremendous progress and put their best efforts, during the last 50 years, in regard to selecting dairy cows for high milk yield and in designing the best rations for high milk production. Moreover, dairy cow health scientists have persistently studied health issues and offered the best solutions to numerous transition cow diseases. Indeed, one dairy cow today produces an amount of milk that is equal to six cows 50 years ago. This is an accomplishment of both geneticists and animal nutritionist that deserve to be credited. However, there is still one grey area that both animal and health scientists have not been able to solve, the reason for high incidence of periparturient diseases and the high cull rates. Indeed, despite much research work and progress made with regard to cow health there are still various health concerns that continue to affect dairy cows, which cost dairy industry billions of dollars in economic losses on a yearly basis. The number of cull cows is increasing and so has the incidence of several diseases including uterine infections and infertility, mastitis, laminitis, ketosis, and retained placenta. This has raised questions whether the approach, the philosophy, or the scientific methodology that we have been using to address diagnosis, treatment, and prevention of transition cow diseases is appropriate. There is broad discussion among scientists in biological and medical sciences that suggests that the reductionist philosophy that has led biological sciences and medicine for centuries has failed to find optimal solutions to the many unresolved health issues of humans and animals. A new philosophy, known as systems biology approach, is emerging that has been embraced by various leading groups in the world that seems very promising and that proposes to look at the animal as a whole and the disease as a complex interaction among genotype, phenotype, and environment. This discussion, recently, has involved animal and veterinary scientists and we are bringing those debates to the readers of this book. In this chapter, we examine some of the concepts that have dominated the animal and veterinary sciences during the last century and have become myths and suggest that it is time to revisit and redefine those concepts in order to improve cows’ health, their welfare and well-being as well as the profitability of dairy industry. In the last section of the chapter a comparison between the reductionist approach and the systems biology or veterinary approach is made and a discussion of the advantages and the drawbacks are presented so that the readers better understand the philosophy of veterinary medicine and adopt the best approach in their research activities.

Laminitis and lameness-associated diseases in dairy cattle have plagued the dairy industry for decades. It is a costly illness with significant impact on dairy production and the animal’s health and welfare. Laminitis in dairy cattle is complex and the initiation, progression, and severity of disease is affected by multiple factors including the individual animal’s health, heritable traits, and its environment. As such, understanding the pathophysiology of bovine laminitis in dairy cattle requires research that explores both local events (i.e., histopathology alterations and mechanical injury) directly affecting the hoof and indirect pathophysiology perturbations (i.e., hyperinsulinemia) distant from the hoof. This provides a more generalized understanding of multiple physiologic systems—a systems veterinary approach. Presently, there is a relative paucity of information investigating the induction and progression of this disease in dairy cattle. Incorporating new omics technologies into the study of laminitis in cattle should shed light on the disease processes. Indeed, omics sciences, namely genomics, transcriptomics, proteomics, and metabolomics demonstrate that laminitis is a collection of complex changes in gene expression, protein translation, and the metabolism of components involved in the inflammatory process. Most certainly bovine laminitis is associated with increased production of pro-inflammatory cytokines, matrix metalloproteinases, and the metabolism of amino acids, carbohydrates, lipids, and energy producing molecules. As research advances, a comprehensive understanding of the pathophysiology of laminitis in dairy cattle will ensue and this could translate into better animal husbandry practices for the dairy industry and treatment modalities for mitigating the disease.

Retained placenta (RP) or retention of fetal membranes (RFM) is a common condition with high incidence in cattle that is typically defined as failure to expel the placenta within 24 h after parturition. Retained placenta is financially important to dairy industry because of treatment related costs, reduced milk production, milk withdrawal, labor, and veterinary services. Although RP has been a permanent issue of dairy industry, the real reason for failure to expel the fetal membranes and the pathogenesis still remain unknown. Mounting information suggest that retained placenta is a multifactorial health issue which involves cellular aspects of immune system, gene expression as well as protein and metabolite alterations. Recent pioneering research work utilizing omics sciences is bringing forth new findings that deserve to be discussed further. Utilization of systems biology in researching the pathobiology of the disease and causative agents promises to throw light on the etiopathology of RP.

Traditionally, research of transition cow immunity has focused on a reductionist approach trying to pinpoint a single factor that causes periparturient immunosuppression. Both previous and recent research has revealed that this phenomenon has a multifactorial etiology and that our current understanding remains insufficient to properly manage the high disease incidence at this time. In taking a systems biology approach through omics technologies we will be able to develop a fundamental understanding of the causal agents and the mechanisms underlying immunosuppression where preceding technologies have failed. Moreover, these new technologies have the potential to help us develop management techniques to restore the normality of immune response during transition period and lower the increased disease incidence that follows immunosuppression. It should be noted that currently application of omics approaches to transition cow immunity are at their pioneering level and further research is warranted to realize the importance of these sciences in the field of cow health and immunity.

Rumen is the most significant organ of the ruminant animal containing trillions of bacteria known also as microbiota. The ruminant host and the microbiota live in a symbiotic relationship where bacteria are provided shelter and nutrients and the host benefits from many essential nutrients released by bacterial fermentation activities, otherwise not available to the ruminant animal because of the lack of specific enzymes to do so. In nature the ruminants usually graze and have almost no grain as part of their daily diet. However, under intensive husbandry dairy cows producing large amounts of milk need very large amounts of energy to support the high demand for milk production. The usual form of energy fed to ruminants in intensive dairy farms is grain whether in the form of corn (maize), barley, wheat, or any other species of cereals. Feeding large amounts of grain in the ration, especially immediately after parturition, has been reported to influence majorly composition of gastrointestinal (GI) tract microbiota and their metabolite composition. Besides releasing large amounts of beneficial and essential nutrients bacterial activity has been reported to be associated with the release of multiple harmful compounds including bacterial endotoxins. Translocation of those compounds into important organs like mammary or uterus or into the systemic circulation is associated with multiple deleterious effects on health status of the postpartum cow. Gastrointestinal microbiota, factors that influence its composition, and harmful effects on the host will be discussed in detail in this chapter.

The objective of this study was to evaluate whether repeated oronasal administration of LPS before parturition showed effects on metabolic and clinical responses in periparturient dairy cows. Hundred Holstein dairy cows were randomly allocated to two treatment groups (n = 50). Thirty cows out of 100 were randomly assigned for intensive sampling (n = 15) started at 28 d before the expected day of parturition. Cows received an oral and a nasal treatment of 2 mL and 1 mL of sterile saline solution (0.15 M of NaCl), respectively, alone (control), or containing 3 increasing doses of LPS from Escherichia coli 0111:B4 as follows: 1) 0.01 μg/kg body weight (BW) on d ﹣28, 2) 0.05 μg/kg BW on d ﹣25, and ﹣21, and 3) 0.1 μg/kg BW on d ﹣18 and ﹣14. Blood samples were collected from coccygeal vein at different time points around parturition and analyzed for glucose, lactate, non-esterified fatty acids (NEFA), cholesterol, and betahydro-xybutyrate (BHBA). Clinical monitoring of animals was done throughout the experiment at different time points for overall health status, udder edema (UE), manure score, and body condition score (BCS). Results showed that oronasal administration of LPS increased concentrations of glucose and cholesterol in the serum compared to the control group (P 0.05). Oronasal LPS did not influence BCS, manure score or the incidence of UE (P > 0.05). Overall, repeated oronasal administration of LPS modulated some serum metabolites related to energy metabolism around parturition in the treated cows. Further research is warranted to elucidate the mechanisms behind greater glucose and cholesterol status in the serum and their potential effects on long-term metabolic health status of dairy cows.

The aim of this study was to evaluate the effects of repeated oronasal administration of lipopolysaccharide (LPS) on milk composition and the overall productive performance of dairy cows. One hundred pregnant Holstein dairy cows were randomly assigned to two treatment groups (n = 50). 30 cows out of 100 were selected for intensive sampling (n = 15) starting at 28 d before parturition. Cows were administered orally and nasally with 2 and 1 mL of saline solution, respectively (control), or saline solution containing 3 doses of LPS from Escherichia coli 0111:B4 as follows: 1) 0.01 μg/kg body weight (BW) on d ﹣28, 2) 0.05 μg/kg BW on d ﹣25 and ﹣21, and 3) 0.1 μg/kg BW on d ﹣18 and ﹣14. Daily feed intake and milk production were recorded for each cow during the first 28 d postpartum. Milk samples were obtained once per week and analyzed for various milk components. Overall, results indicated that treatment did not affect feed intake, milk yield, milk efficiency, fat content, fat yield, protein content, protein yield, lactose content, lactose yield, milk urea nitrogen (MUN), total solid contents, fat-corrected milk (FCM), and energy-corrected milk (ECM; P > 0.05). However, milk somatic cell count (SCC) tended to be lower in the treated cows (P eek interaction for milk energy (P = 0.03), and tendencies for FCM, ECM, lactose content, and milk efficiency (P

Profiles of energy metabolites and haptoglobin (Hp) in dairy cows that are transitioned from conventional to organic management in various Alberta farms were compared with those of dairy cows managed conventionally at the University of Alberta dairy farm. Blood samples were collected during the following periods: Dry, 0 - 30, 30 - 60, and 60 - 90 days in milk (DIM, n = 7 cows). Concentrations of metabolites were evaluated by enzymatic colorimetric methods. Concentrations of Hp were determined by bovine ELISA kits. Data were analyzed by the mixed procedures of SAS. Concentrations of NEFA and BHBA in blood were elevated (P < 0.001) 0 to 30 d, intermediate 30 to 60, and 60 to 90 d, and lower in the dry period. In addition, BHBA was higher (P < 0.0001) at all stages of lactation in conventional than organic cows (e.g. 1289.4 ± 88.6 vs. 883.6 ± 47.5 µmol/L in conventional and organic cows at 0 - 30 d, respectively). Serum concentrations of cholesterol increased with increasing DIM and returned to nadir levels during dry period and was higher (P < 0.0001) in conventional than organic cows. Low glucose concentrations were observed 0 to 30 d, levels were intermediate 30 to 60 and 60 to 90 d, and peaked during the dry period (P < 0.0001). However, glucose concentrations did not differ (P < 0.54) between conventional and organic cows. Lactate did not (P < 0.24) vary with DIM or day × farm type but was higher (P < 0.0001) in organic cows than in conventional cows. Serum concentrations of Hp were elevated during dry period; reached peak levels 0 to 30 d and decreased gradually with increasing days postpartum and were much higher at all periods in conventional than organic cows. Overall, concentrations of Hp were 528.1 ± 45.2 µg/mL in conventional cows vs. 261.1 ± 16.9 µg/mL in organic cows (P < 0.0001). Taken together, these data indicate that metabolic changes associated with initiation of lactation are preceded by an acute phase response in dairy cows, and that cows in organic systems seem to be healthier than cows under conventional systems. These differences might be due to differences in nutritional management in the two systems.

Background Failure to expel fetal membranes within 24 h of calving is a pathological condition defined as retained placenta (RP). The objective of this investigation was to evaluate whether there are alterations in several selected serum variables related to innate immunity and carbohydrate and lipid metabolism that precede occurrence of RP in transition Holstein dairy cows. Methods One hundred multiparous Holstein dairy cows were involved in the study. Blood samples were collected from the coccygeal vein during the −8 to +4 wks around parturition, once per week before the morning feeding. Six healthy control cows (CON) and 6 cows with RP were selected and serum samples at −8, −4, time of diagnosis of disease, and +4 wks relative to parturition were used for analyses. All samples were analyzed for lactate, non-esterified fatty acids (NEFA), β-hydroxybutyrate (BHBA), interleukin-1 (IL-1), interleukin-6 (IL-6), tumor necrosis factor (TNF), haptoglobin (Hp), and serum amyloid A (SAA). Results Cows with RP had greater concentrations of serum lactate, IL-1, IL-6, TNF, and SAA in comparison with CON cows. Intriguingly, elevated concentrations of all five variables were observed at −8 and −4 wks before the occurrence of RP compared to healthy cows. Cows with RP also had lower DMI and milk production vs CON animals; however milk composition was not affected by RP. Conclusions Cows with RP showed an activated innate immunity 8 wks prior to diagnosis of disease. Overall results suggest that serum IL-1, IL- 6, and TNF, and lactate can be used as screening biomarkers to indicate cows that might have health issues during the transition period.

We showed recently that repeated oral exposure to LPS stimulated humoral immune responses in periparturient dairy cows. Here, metabolic and mineral responses to repeated oral administration of LPS were investigated. Sixteen clinically healthy, pregnant Holstein cows were orally administered 3 ml of saline solution (control) or 3 ml of saline solution containing 3 increasing doses of LPS, at 07:00 h, as follows: (i) 0.01 µg/kg body mass (BM) on d −14 and −10, (ii) 0.05 µg/kg BM on d −7 and −3, and (iii) 0.1 µg/kg BM on d 3 and 7 relative to parturition. Blood samples were measured shortly before, and at 8 different time-points after (up to 6 h), the first challenge of each LPS dosage to evaluate the post-challenge plasma profile, as well as weekly up to 4 wk postpartum. Results showed that oral administration of LPS lowered concentrations of non-esterified fatty acids ( P

The rumen is a unique organ that serves as the primary site for microbial fermentation of ingested plant material for domestic livestock such as cattle, sheep and goats. The chemical composition of ruminal fluid is thought to closely reflect the healthy/unhealthy interaction between rumen microflora and diet. Just as diet and feed quality is important for livestock production, rumen health is also critical to the growth and production of high quality milk and meat. Therefore a detailed understanding of the chemical composition of ruminal fluid and the influence of diet on its composition could help improve the efficiency and effectiveness of farming and veterinary practices. Consequently we have undertaken an effort to comprehensively characterize the bovine ruminal fluid metabolome. In doing so, we combined NMR spectroscopy, inductively coupled plasma mass-spectroscopy (ICP-MS), gas chromatography-mass spectrometry (GC-MS), direct flow injection (DFI) mass spectrometry and lipidomics with computer-aided literature mining to identify and quantify essentially all of the metabolites in bovine ruminal fluid that can be routinely detected (with today’s technology). The use of multiple metabolomics platforms and technologies allowed us to substantially enhance the level of metabolome coverage while critically assessing the relative strengths and weaknesses of these techniques. Tables containing the set of 246 ruminal fluid metabolites or metabolite species, their concentrations, related literature reference and links to their known diet associations for the bovine rumen metabolome are freely available at http://www.rumendb.ca .

This study investigated the effects of feeding barley grain treated with lactic acid (LA) and heat on the profile of plasma metabolites related to carbohydrate and lipid metabolism and variables related to rumen health and acute phase response. Eight primiparous rumen-fistulated lactating Holstein cows were randomly assigned, in a crossover design, to 1 of the 2 dietary treatments consisting of 32% (DM basis) rolled barley grain steeped in an equal quantity of either tap water alone (CTR) or a 1.0% LA solution and heated at 55°C for 48 h (LAH). Each experimental period was 21 d, with the last 10 d used for measurements. Blood samples were collected on d 1, 3, 5, 7, 9, and 11 before the morning feeding and on the last day of each period at 0, 2, 4, 6, 8, 10, and 12 h postfeeding to measure glucose, lactate, cholesterol, beta-hydroxybutyrate (BHBA), NEFA, haptoglobin (Hp), serum amyloid A (SAA), and tumor necrosis factor-alpha (TNF-α). Also, rumen samples were collected on d 1, 5, and 11 as well as at 0, 4, 8, and 12 h postfeeding on the last day of each period for measuring the concentration of rumen endotoxin. Results of the day-to-day analysis indicated that cows fed the LAH diet had reduced preprandial concentrations of rumen endotoxin (472 vs. 793 ng/mL; P 0.10). Postprandial responses showed that the LAH diet tended to decrease the concentration of SAA (4.67 vs. 8.50 μg/mL; P = 0.06). Also, there was a treatment by time interaction for rumen endotoxin (P < 0.01), suggesting a role for both the treatment and the time of sampling on this variable. Furthermore, greater concentration of BHBA and a tendency for greater NEFA and reduced concentrations of plasma glucose were observed in cows fed the LAH diet. In conclusion, results indicated that feeding dairy cows barley grain steeped in 1.0% LA and treated with heat modulated the profile of plasma metabolites and acute phase response.

This study examined the extent by which changes in the concentrate level and neutral detergent fiber (NDF) content in the diet as well as the severity of acidotic insult, measured as the duration time of rumen pH below 6.0 and daily mean rumen pH, and the concentration of endotoxin in the rumen fluid are involved in the development of inflammatory conditions in cattle. A meta-analytical approach accounting for inter- and intraexperimental variation was used to generate prediction models, and data from recent studies were used to parameterize these models. A total of 10 recently conducted experiments with 43 different dietary treatments fulfilled the criteria for inclusion in this study. Diets of all of the experiments included in this meta-analysis were based on rapidly degradable grain sources, such as barley and wheat, and the findings of this study apply only to these kinds of diets. Data indicated that greater levels of concentrate in the diet were associated with increased concentrations of rumen endotoxin (R 2 =0.27), plasma haptoglobin (R 2 =0.19), and serum amyloid A (SAA) level (R 2 =0.46). Similar correlations, but in opposite directions, were observed between dietary NDF content and rumen endotoxin (R 2 =0.39) and plasma SAA concentrations (R 2 =0.22). The meta-analysis revealed that the relationships between those variables were not linear. Additionally, the breakpoint model fitted to the data of rumen endotoxin, plasma haptoglobin, and SAA indicated the presence of a threshold level of dietary concentrate and NDF, above which those responses became linear to increasing amounts of concentrate or decreasing contents of NDF in the diet. Also, feeding cattle more than 44.1% concentrate or less than 39.2% NDF in the diet was associated with a linear increase in the risk of systemic inflammation. Low daily mean rumen pH (R 2 =0.38) and duration of rumen pH 2 =0.59) were associated with increased concentrations of endotoxin in the rumen fluid; although those events were not always associated with systemic inflammation. Accordingly, only 15 to 21% of the overall variation in the responses of SAA was explained by variables of rumen pH, whereas the concentrate level in the diet accounted for 46% of this variation. In conclusion, data from this study indicated the presence of thresholds of dietary concentrate and NDF levels in the diets based on rapidly fermentable grains beyond which the risk of systemic inflammation in cattle increases linearly.

The objective of the present study was to investigate whether feeding barley grain steeped in lactic acid (LA) and treated with heat would affect rumen fermentation patterns, milk production and composition in lactating dairy cows. Eight rumen-cannulated Holstein cows were assigned to a 2×2 crossover design and fed once daily a total mixed ration containing rolled barley grain (319.6 g/kg, dry matter basis) steeped for 48 h in equal quantity of tap water (CTR) or in 10 g/L of LA and heat at 55 °C (LAH). Results demonstrated that cows fed the LAH diet had rumen pH values above 5.8 during most intensive fermentation phases (i.e., 8–12 h) post-feeding (P 0.05) postprandial concentrations of volatile fatty acids (VFA) but lowered (P

The objective of this study was to evaluate the effects of repeated oral exposure to LPS on humoral immune responses of periparturient dairy cows. Sixteen Holstein cows were assigned to two treatment groups 2 wk before the expected day of parturition. Cows were administered orally, twice weekly at wk −2, −1 and +1 around parturition, with the following treatments: 3 ml saline; or 3 ml of saline containing LPS from Escherichia coli 0111:B4. The amount of LPS administered during wk −2, −1, and +1 was 0.01, 0.05, or 0.1 µg/kg body weight, respectively. Multiple blood samples were collected by jugular vein and various immune and clinical variables were measured. Results indicated that, on one hand, concentrations of plasma IgG anti-LPS Abs decreased ( P 0.05) in the concentrations of serum amyloid A, LPS-binding protein, haptoglobin, cortisol, IgA anti-LPS Abs in the plasma, feed intake, body temperature and rumen contractions rate between the control and treatment groups. To our knowledge, this study is the first to show that repeated oral administration with LPS from E. coli 0111:B4 has the potential to stimulate humoral immune responses in periparturient dairy cows.