Influence of parturition and diets enriched in n-3 or n-6 polyunsaturated fatty acids on immune response of dairy cows during the transition period

Effects of parity and week after calving on the metabolic, redox and immune status of dairy cows

At the onset of lactation in dairy cows, inflammation and oxidative stress may occur and result in a risk of pathologies and lower milk yield. To propose an innovative management strategy for cows during this period, it is essential to better understand these physiological variations. Our objective was to evaluate the metabolic, redox and immune status of 7 primiparous and 8 multiparous Holstein cows during late gestation and the first months of lactation. Blood samples were collected between 3 weeks before calving until 12 weeks postpartum. Milk samples were also collected, but only at the time points after calving. The metabolic (nonesterified fatty acids (NEFA), BHB, glucose, urea, calcium) and redox (reactive oxygen metabolites (ROM), oxidative stress index (OSI), glutathione peroxidase activity, vitamin E) statuses were analyzed in plasma or erythrocytes. The expression of genes related to antioxidant functions was determined in leukocytes collected from milk. For immune status, plasma cytokine levels and the production of reactive oxygen species (ROS) in classical and regulatory neutrophils were measured in 2 whole blood ex vivo challenges. The data were analyzed using a mixed model that included the fixed effects of parity and week and their interaction. Milk yield, plasma NEFA and BHB in wk 2 and 4 after calving were higher in multiparous cows than in primiparous cows, whereas glucose and calcium tended to be lower. Plasma ROM and OSI levels in wk 8 were higher in multiparous than in primiparous cows. Multiparous cows also displayed higher glutathione peroxidase activity in erythrocytes, and antioxidant transcription factor and superoxide dismutase-1 expression levels in milk leukocytes. Moreover, multiparous cows had higher plasma concentrations of vitamin E but lower plasma levels of cytokines CXCL10, CCL2, IL1Rα and IFNγ. Following ex vivo whole blood stimulation with Escherichia coli, lower IL1α and TNFα levels were measured in multiparous than in primiparous cows. Intracellular ROS production by neutrophils was lower in multiparous than in primiparous cows. These results thus indicated marked physiological changes in wk 8 compared with wk 2 and 4 of lactation. These differences in the physiological status of primiparous and multiparous cows offer interesting perspectives for potential dietary strategies to prevent pathologies which take account of parity and week relative to calving.

Maternal supplementation with n-3 fatty acids affects placental lipid metabolism, inflammation, oxidative stress, the endocannabinoid system, and the neonate cytokine concentrations in dairy cows

BACKGROUND

The placenta plays a crucial role in supporting and influencing fetal development. We compared the effects of prepartum supplementation with omega-3 (n-3) fatty acid (FA) sources, flaxseed oil (FLX) and fish oil (FO), on the expression of genes and proteins related to lipid metabolism, inflammation, oxidative stress, and the endocannabinoid system (ECS) in the expelled placenta, as well as on FA profile and inflammatory response of neonates. Late-pregnant Holstein dairy cows were supplemented with saturated fat (CTL), FLX, or FO. Placental cotyledons (n = 5) were collected immediately after expulsion, and extracted RNA and proteins were analyzed by RT-PCR and proteomic analysis. Neonatal blood was assessed for FA composition and concentrations of inflammatory markers.

RESULTS

FO increased the gene expression of fatty acid binding protein 4 (FABP4), interleukin 10 (IL-10), catalase (CAT), cannabinoid receptor 1 (CNR1), and cannabinoid receptor 2 (CNR2) compared with CTL placenta. Gene expression of ECS-enzyme FA-amide hydrolase (FAAH) was lower in FLX and FO than in CTL. Proteomic analysis identified 3,974 proteins; of these, 51-59 were differentially abundant between treatments (P ≤ 0.05, |fold change| ≥ 1.5). Top canonical pathways enriched in FLX vs. CTL and in FO vs. CTL were triglyceride metabolism and inflammatory processes. Both n-3 FA increased the placental abundance of FA binding proteins (FABPs) 3 and 7. The abundance of CNR1 cannabinoid-receptor-interacting-protein-1 (CNRIP1) was reduced in FO vs. FLX. In silico modeling affirmed that bovine FABPs bind to endocannabinoids. The FLX increased the abundance of inflammatory CD44-antigen and secreted-phosphoprotein-1, whereas prostaglandin-endoperoxide synthase 2 was decreased in FO vs. CTL placenta. Maternal FO enriched neonatal plasma with n-3 FAs, and both FLX and FO reduced interleukin-6 concentrations compared with CTL.

CONCLUSION

Maternal n-3 FA from FLX and FO differentially affected the bovine placenta; both enhanced lipid metabolism and modulated oxidative stress, however, FO increased some transcriptional ECS components, possibly related to the increased FABPs. Maternal FO induced a unique balance of pro- and anti-inflammatory components in the placenta. Taken together, different sources of n-3 FA during late pregnancy enhanced placental immune and metabolic processes, which may affect the neonatal immune system.

Testing the Induction of Metritis in Healthy Postpartum Primiparous Cows Challenged with a Cocktail of Bacteria

Metritis is a postpartum uterine disease with greater incidence in primiparous than in multiparous cows. In primiparous cows, the impact on production and health is lessened, presumably due to a superior immune response. Here, we tested whether an in vivo model of clinical metritis induction developed for postpartum multiparous Holstein cows would produce similar results in primiparous cows. Thirty-six cows were randomly assigned to one of three groups and received intrauterine infusion within 24 h of parturition. The controls were infused with sterile saline; the low-dose group received a bacterial cocktail containing 103 cfu of Escherichia coli, Trueperella pyogenes, and Fusobacterium necrophorum; and the high-dose group were infused with 106 cfu of the same cocktail. Production, health traits, and the vaginal discharge culture were assessed daily, from enrollment until 14 d in milk. Clinical metritis occurred in 64% of high-dose cows, 33% of the controls, and 42% of low-dose cows, with no significant difference of incidence between groups. However, when accounting by time, high-dose cows had a 2.7 times greater hazard of metritis compared with the controls. The bacterial challenge affected milk production and dry matter intake tended to decrease. In the high-dose group, a greater growth of F. necrophorum in the selective medium was also observed, suggesting an association with metritis. Therefore, this study suggests intrauterine inoculation with 106 cfu of this bacterial cocktail elicits physical and clinical outcomes consistent with clinical metritis.

Feeding Flaxseed and Lupins during the Transition Period in Dairy Cows: Effects on Production Performance, Fertility and Biochemical Blood Indices

Flaxseed and lupin seed were offered as an alternative dietary approach in dairy cows, through the partial substitution of soybean meal. Milk production and fertility traits were investigated. A total of 330 animals were allocated into two groups, treated (n = 176) and control (n = 154). From each group, 30 animals were selected for hematological and cytological studies. The experimental feeding period lasted for 81 days (25 days prepartum and 56 days postpartum). The control ration (group C) contained corn, barley, soybean meal, rapeseed cake, corn silage and lucerne hay; whereas, in the treatment group (group T), 50% of the soybean meal was replaced by an equal mixture of flaxseed and lupins. The two rations were formulated to be isonitrogenous and isoenergetic. Milk samples were analyzed for chemical composition, somatic cell count (SCC) content and total colony forming units (CFU). Blood samples were collected, and serum was analyzed for non-esterified fatty acids (NEFA), acute phase proteins (haptoglobin and serum amyloid) and lipid oxidation indices, namely thiobarbituric-acid-reactive substances (TBARS) and catalase activity. To assess polymorphonuclear neutrophils (PMN) numbers, endometrial samples from each cow were collected on days 21 and 42. No difference was recorded between groups in milk yield (p > 0.05). In multiparous cows, NEFA (mMol/L) concentrations were significantly lower in group T than in group C on day 14 (p > 0.009) and on day 42 (p = 0.05), while no difference was detected in the group of primiparous cows. At all time points, serum TBARS and catalase values were similar in both groups (p > 0.05). Multiparous cows in group T expressed the first postpartum estrus and conceived earlier than cows in group C (p ≤ 0.05). Between days 21 to 42 postpartum, the PMN reduction rate was higher in group T animals (p ≤ 0.05). Acute phase protein levels were in general lower in group T animals, and at specific time points differed significantly from group C (p ≤ 0.05). It was concluded that the partial replacement of soybean meal by flaxseed and lupins had no negative effect on milk yield or milk composition, and improved cow fertility; which, along with the lower cost of flaxseed and lupins mixture, may increase milk production profitability.

Alpha-linolenic acid modulates systemic and adipose tissue-specific insulin sensitivity, inflammation, and the endocannabinoid system in dairy cows

Metabolic disorders are often linked to alterations in insulin signaling. Omega-3 (n-3) fatty acids modulate immunometabolic responses; thus, we examined the effects of peripartum n-3 on systemic and adipose tissue (AT)-specific insulin sensitivity, immune function, and the endocannabinoid system (ECS) in dairy cows. Cows were supplemented peripartum with saturated fat (CTL) or flaxseed supplement rich in alpha-linolenic acid (ALA). Blood immunometabolic biomarkers were examined, and at 5-8 d postpartum (PP), an intravenous glucose-tolerance-test (GTT) and AT biopsies were performed. Insulin sensitivity in AT was assessed by phosphoproteomics and proteomics. Peripartum n-3 reduced the plasma concentrations of Interleukin-6 (IL-6) and IL-17α, lowered the percentage of white blood cells PP, and reduced inflammatory proteins in AT. Systemic insulin sensitivity was higher in ALA than in CTL. In AT, the top canonical pathways, according to the differential phosphoproteome in ALA, were protein-kinase-A signaling and insulin-receptor signaling; network analysis and immunoblots validated the lower phosphorylation of protein kinase B (Akt), and lower abundance of insulin receptor, together suggesting reduced insulin sensitivity in ALA AT. The n-3 reduced the plasma concentrations of ECS-associated ligands, and lowered the abundances of cannabinoid-1-receptor and monoglycerol-lipase in peripheral blood mononuclear cells PP. Peripartum ALA supplementation in dairy cows improved systemic insulin sensitivity and immune function, reduced ECS components, and had tissue-specific effects on insulin-sensitivity in AT, possibly counter-balancing the systemic responses.

Nutrigenomic Interventions to Address Metabolic Stress and Related Disorders in Transition Cows

For dairy cattle, the period involving a shift from late pregnancy to early lactation termed transition or periparturient is an excruciating phase. Health-related disorders are likely to happen in this time frame. Timely postpartum and metabolic adjustments to this new physical state demands correct management strategies to fulfill the cow's needs for a successful transition to this phase. Among the management strategies, one of the most researched methods for managing transition-related stress is nutritional supplementation. Dietary components directly or indirectly affect the expression of various genes that are believed to be involved in various stress-related responses during this phase. Nutrigenomics, an interdisciplinary approach that combines nutritional science with omics technologies, opens new avenues for studying the genome's complicated interactions with food. This revolutionary technique emphasizes the importance of food-gene interactions on various physiological and metabolic mechanisms. In animal sciences, nutrigenomics aims to promote the welfare of livestock animals and enhance their commercially important qualities through nutritional interventions. To this end, an increasing volume of research shows that nutritional supplementation can be effectively used to manage the metabolic stress dairy cows undergo during the transition period. These nutritional supplements, including polyunsaturated fatty acids, vitamins, dietary amino acids, and phytochemicals, have been shown to modulate energy homeostasis through different pathways, leading to addressing metabolic issues in transition cows.

Proteome dataset of peripheral blood mononuclear cells in postpartum dairy cows supplemented with different sources of omega-3 fatty acids

This article contains raw and processed data related to research published by Kra et al. [1]. There is a scarce knowledge on the proteome of peripheral blood mononuclear cells (PBMC) during the transition period in dairy cows. In human research, proteomics PBMC is used in order to gain insight into inflammatory diseases and syndromes. Dietary fats, and specifically omega-3 (n-3) FA, can moderate the immune fluctuation caused by parturition through improvements of the immune function [2]. Therefore, this study aim was to characterize the changes that may occur in proteome of PBMC during transition, as influenced by different n-3 FA supplementation. Proteomics data of PBMC was obtained from postpartum dairy cows supplemented peripartum with either encapsulated saturated fat (CTL), encapsulated flaxseed oil that is enriched with ALA (α-linolenic acid; FLX) or encapsulated fish oil that is enriched with EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid; FO).The analysis was done by liquid chromatography-mass spectrometry from PBMCs protein extraction. The cells were collected from six cows per treatment during the 1^st week postpartum. Quantification of differential abundance between groups was done using MS1 intensity based label-free. Label-free quantitative shotgun proteomics was used for characterization. This novel dataset of proteomics data from PBMC contains 3807 proteins; 44, 42 and 65 were differently abundant (P ≤ 0.05 and FC ± 1.5), in FLX vs. CTL, FO vs. CTL and FLX vs. FO, respectively; these findings are discussed in our recent research article (Kra et al., 2021). The present dataset of PBMC proteome adds new information regarding the effects of n-3 FA on the immune system, while providing reference for PBMC proteome in postpartum dairy cows.

Proteomic analysis of peripheral blood mononuclear cells and inflammatory status in postpartum dairy cows supplemented with different sources of omega-3 fatty acids

We examined the effects of dietary n-3 fatty acids on the proteome of peripheral blood mononuclear cells (PBMC) in transition dairy cows. Forty-two dry cows were divided into three groups supplemented with: saturated fat (CTL); flaxseed oil (FLX); or fish oil (FO). PBMC were collected from five cows per group at week 1 postpartum for proteomic analysis. The n-3 fatty acid content in plasma and PBMC was higher in FLX and FO than in CTL cows. In PBMC, 3807 proteins were quantified and 44, 42 and 65 were differently abundant in FLX vs. CTL, FO vs. CTL and FLX vs. FO, respectively. In FLX vs. CTL, the abundance of the p65-subunit-of-transcription-factor NF-κB was higher, whereas albumin, C4b-binding protein and complement factor H levels were lower. In FLX vs. FO, complement factors B and H and hemopexin were higher. The top canonical pathway enriched in FLX compared to other groups was acute-phase-response signaling. The percentage of CD25+ blood cells was lower in FLX and FO at 1 week postpartum, and gene expression of NF-κB in white blood cells was lower in FLX than in CTL. Dietary sources of n-3 fatty acids differentially affected the proteome of PBMC, possibly altering the inflammatory status. SIGNIFICANCE: The transition dairy cow experiences a variable degree of systemic subacute inflammation, and proteomics of peripheral blood mononuclear cells (PBMC) may contribute to obtain insight into this process. Omega-3 fatty acids can moderate the immunological effect, and therefore we examined the effects of these fatty acids from flaxseed (FLX) or fish oils (FO) on the proteome of PBMC at week 1 postpartum. More than 3800 proteins were quantified, and in cows supplemented with FLX, enrichment of the acute-phase-signaling and complement systems were apparent in the PBMC compared to CTL and FO PBMC. This information may be useful to further explore the mechanism by which dietary omega-3 fatty acids affect the immune system in postpartum dairy cows.

NETosis of Peripheral Neutrophils Isolated From Dairy Cows Fed Olive Pomace

Neutrophils represent primary mobile phagocytes recruited to the site of infection, and their functions are essential to enhance animals' health performance. Neutrophils have an essential role in innate immunity and are able to kill the pathogens via the synthesis of neutrophil extracellular traps (NETs). The objective of the present work was the study of the in vitro NETosis of peripheral neutrophils isolated from dairy cows supplemented with olive pomace. Dairy cows (n = 16) balanced for parity (3.67 ± 1.5 for CON, 3.67 ± 1.9 for OP), milk yield (24.3 ± 4.5 kg d⁻¹for CON and 24.9 ± 1.7 kg d⁻¹ for OP), the number of days in milk (109 ± 83.5 for CON and 196 ± 51 for OP), and body weight (647 ± 44.3 kg for CON and 675 ± 70.7 kg for OP) were divided into two experimental groups fed with a control diet (CON) and supplemented with 6% of olive pomace (OP). Peripheral blood neutrophils were isolated and stimulated in vitro with phorbol-myristate-acetate (PMA) as a marker for activation and reactivity of the neutrophils. After isolation, both the viability and CD11b expression were analyzed by flow cytometry. Both NETosis by neutrophil elastase-DNA complex system and myeloperoxidase (MPO) activity were evaluated by ELISA. The specific antibodies against MPO and citrullination of Histone-H1 were used for investigating NETosis by immunofluorescence microscopy. The neutrophil elastase-DNA complexes produced during NETosis and MPO activity of neutrophil extracts were affected by OP supplementation. Furthermore, results from immunofluorescence analysis of NETosis depicted a similar result found by ELISA showing a higher expression of MPO and citrullination of Histone-H1 in OP than the CON neutrophils. In addition, all data showed that the OP diet resulted in a better response of neutrophils to PMA stimulation than the CON diet, which did not support the neutrophils' responses to PMA stimulation. Our results demonstrated that OP supplementation can enhance the neutrophil function in dairy cows leading to udder defense and inflammation response especially when an immunosuppression state can occur.

Advances in fatty acids nutrition in dairy cows: from gut to cells and effects on performance

High producing dairy cows generally receive in the diet up to 5-6% of fat. This is a relatively low amount of fat in the diet compared to diets in monogastrics; however, dietary fat is important for dairy cows as demonstrated by the benefits of supplementing cows with various fatty acids (FA). Several FA are highly bioactive, especially by affecting the transcriptome; thus, they have nutrigenomic effects. In the present review, we provide an up-to-date understanding of the utilization of FA by dairy cows including the main processes affecting FA in the rumen, molecular aspects of the absorption of FA by the gut, synthesis, secretion, and utilization of chylomicrons; uptake and metabolism of FA by peripheral tissues, with a main emphasis on the liver, and main transcription factors regulated by FA. Most of the advances in FA utilization by rumen microorganisms and intestinal absorption of FA in dairy cows were made before the end of the last century with little information generated afterwards. However, large advances on the molecular aspects of intestinal absorption and cellular uptake of FA were made on monogastric species in the last 20 years. We provide a model of FA utilization in dairy cows by using information generated in monogastrics and enriching it with data produced in dairy cows. We also reviewed the latest studies on the effects of dietary FA on milk yield, milk fatty acid composition, reproduction, and health in dairy cows. The reviewed data revealed a complex picture with the FA being active in each step of the way, starting from influencing rumen microbiota, regulating intestinal absorption, and affecting cellular uptake and utilization by peripheral tissues, making prediction on in vivo nutrigenomic effects of FA challenging.

Effect of supplementing palmitic acid and altering the dietary ratio of n-6:n-3 fatty acids in low-fibre diets on production responses of dairy cows

Supplementing palmitic acid (C16 : 0) in combination with modifying the dietary n-6:n-3 fatty acid (FA) ratio may benefit energy metabolism and milk responses of dairy cows. Twelve Holstein cows (70 (sd 11) days in milk) were used in a replicated 4 × 4 Latin square and allocated to four low-fibre diets (18·5 % forage neutral-detergent fibre) supplemented with no FA (CON), or 2·4 % C16 : 0-enriched supplement (PAL), 2·4 % mixture (2:1) of C16 : 0 and n-6 FA (PW6), and mixture (2:1) of C16 : 0 and n-3 FA (PW3). The dietary ratio of n-6:n-3 was increased with PW6 (10:1) and decreased with PW3 (2·8:1), whereas PAL alone made no change in the ratio (about 7:1). Compared with CON, all FA-supplemented treatments increased milk yield. However, feed and energy intakes were higher in PAL than PW3 or PW6, resulting in greater feed efficiency for PW3 and PW6 than PAL. Dietary FA supplements decreased milk protein concentration but tended to increase protein yield. Compared with CON and FA mixtures, PAL increased milk fat content and tended to increase milk SFA and atherosclerotic index. The concentration of milk n-3 FA was similar between CON and PW3. Feeding PAL increased milk energy output and decreased energy partitioning towards body reserves (-4·2 %), while this measure was positive for other treatments. Blood TAG and NEFA concentrations, but not β-hydroxybutyrate, were increased by FA-supplemented treatments. Feeding C16 : 0 combined with either n-6 or n-3 FA enhanced feed efficiency, alleviated the negative impacts on body energy reserves, but lowering the dietary n-6:n-3 ratio improved the FA profile of milk.

Role of nutraceuticals during the transition period of dairy cows: a review

The transition period of dairy cattle is characterized by a number of metabolic, endocrine, physiologic, and immune adaptations, including the occurrence of negative energy balance, hypocalcemia, liver dysfunction, overt systemic inflammatory response, and oxidative stress status. The degree and length of time during which these systems remain out of balance could render cows more susceptible to disease, poor reproductive outcomes, and less efficient for milk production and quality. Studies on both monogastrics and ruminants have reported the health benefits of nutraceuticals (e.g. probiotics, prebiotics, dietary lipids, functional peptides, phytoextracts) beyond nutritional value, interacting at different levels of the animal’s physiology. From a physiological standpoint, it seems unrealistic to disregard any systemic inflammatory processes. However, an alternate approach is to modulate the inflammatory process per se and to resolve the systemic response as quickly as possible.

To this aim, a growing body of literature underscores the efficacy of nutraceuticals (active compounds) during the critical phase of the transition period. Supplementation of essential fatty acids throughout a 2-month period (i.e. a month before and a month after calving) successfully attenuates the inflammatory status with a quicker resolution of phenomenon. In this context, the inflammatory and immune response scenario has been recognized to be targeted by the beneficial effect of methyl donors, such as methionine and choline, directly and indirectly modulating such response with the increase of antioxidants GSH and taurine. Indirectly by the establishment of a healthy gastrointestinal tract, yeast and yeast-based products showed to modulate the immune response, mitigating negative effects associated with parturition stress and consequent disorders.

The use of phytoproducts has garnered high interest because of their wide range of actions on multiple tissue targets encompassing a series of antimicrobial, antiviral, antioxidant, immune-stimulating, rumen fermentation, and microbial modulation effects. In this review, we provide perspectives on investigations of regulating the immune responses and metabolism using several nutraceuticals in the periparturient cow.

Effect of stearic or oleic acid on milk performance and energy partitioning when fed in diets with low and high rumen-active unsaturated fatty acids in early lactation

This experiment was conducted to determine the effects of stearic acid (SA; C18:0) or rumen-protected oleic acid (OA; C18:1 cis-9) on milk performance and energy partitioning of early lactation cows when supplemented in diets with low and high level of rumen unsaturated fatty acids (RUFA). In low RUFA experiment (LRUFA), FA supplement rich in either SA or calcium salts OA was added to a basal diet with a low concentration of RUFA (0.75% vs. 1.4%, LRUFA-SA vs. LRUFA-OA). In high RUFA experiment (HRUFA), 2% soybean oil was added to the diet fed in the LRUFA experiment. In each experiment, 30 multiparous cows were blocked by parity and predicted transmitting ability for milk yield and were randomly fed 1 of 2 treatment diets from 2 to 13 wk postpartum. In the LRUFA experiment, LRUFA-SA had 2.4 kg/d more dry matter intake (DMI) (P < 0.01), 3.8 kg/d more energy-corrected milk (P < 0.01), and 0.3% units more milk fat percentage (P < 0.01) and 0.2 kg/d more milk fat yield (P < 0.01). Dietary treatments did not affect body weight, energy balance, and energy intake partitioning into milk, maintenance, and body tissues (P > 0.1). In the HRUFA experiment, HRUFA-SA had 1.4 kg/d more DMI (P = 0.03) but similar milk and milk components yields (P > 0.1). HRUFA-SA had a tendency to gain more body weight (P = 0.07) and had more positive energy balance (P = 0.01) and decreased gross feed efficiency (milk yield/DMI) (P = 0.01). Consistently, HRUFA-SA increased intake energy partitioning into body tissues (P = 0.02) and decreased energy partitioning into milk (P = 0.01). In summary, SA supplementation had more DMI relative to OA, but the effects on milk and milk fat production were different and affected by the level of RUFA in the basal diet. In application, SA supplementation was more effective to improve milk production when included in the basal diet with the low RUFA.

Far-off and close-up feeding levels affect immunological performance in grazing dairy cows during the transition period

During the peripartum period, dairy cows often have signs of inflammation. Various stresses, including infectious and metabolic diseases, have been discussed as causative for this inflammation. In this study, expression profiles for 17 immune markers were measured in whole blood preparations from 78 dairy cows over a time frame starting 1 wk before calving to 4 wk after calving. Additionally, the effects of far-off and close-up feeding on immune function of dairy cows during the peripartum period were investigated. Cows were assigned to 1 of 2 feeding levels in late lactation to achieve a low and high BCS at the time of dry-off (approximately 4.25 and 5.0 on a 10-point scale). Following dry-off, both herds were managed to achieve a BCS of 5.0 one month before calving; this involved controlled feeding (i.e., maintenance) and over-feeding of ME during the far-off dry period. Within each far-off feeding-level treatment, cows were offered 65, 90, or 120% of their precalving ME requirements for 3 wk precalving in a 2 × 3 factorial arrangement. Analysis of gene expression profiles from blood cells revealed effects of time indicating that the transition cow's immune system counteracts the peripartum inflammation, whereas later postcalving it becomes activated to provide protection against postpartum infections. Far-off feeding affected (P < 0.05) the expression of 2 of the investigated genes at calving. Interleukin-6 (IL-6) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) expression in unstimulated, peripheral leukocytes were lower (P < 0.05) in animals from the Far-Off_Over-fed group compared with the Far-Off_Control-fed group. Close-up feeding had several effects on gene expression, indicating that immune function in Feed120 animals was distinct from the Feed90 and Feed65. In conclusion, feeding management precalving becomes an important intervention to ensure immunocompetence at and after calving.

Comparison of total-mixed-ration and feed-to-yield strategies on blood profiles and dairy cow health

Seventy-two Holstein-Friesian dairy cows were offered the same amount of concentrates over the first 140 days of lactation, by either a 'total-mixed-ration' or a 'feed-to-yield' strategy. The effects on blood profiles and cow health were examined. Cows on total-mixed-ration were offered a mixed ration comprising grass silage and concentrates (50:50 dry matter basis). Cows on feed-to-yield were offered a basal mixed ration (grass silage plus 6 kg concentrates/cow/day) plus additional concentrates via an out-of-parlour feeding system, calculated according to each individual cow's milk yield during the previous week. Cows on total-mixed-ration had a higher mean haemoglobin, packed cell volume and lymphocyte percentage. Concentrate allocation strategy had no effect on serum haptoglobin concentrations, interferon-gamma production of pokeweed mitogen-stimulated whole blood culture, the incidence of clinical or subclinical mastitis, lameness, respiratory or digestive problems and no strong relationships were identified between production parameters with serum metabolites, inflammatory and immune measures. This study demonstrates small physiological differences in metabolic parameters, and no differences in inflammatory or immune parameters, when allocating concentrates by total-mixed-ration or feed-to-yield.

Effects of dietary CLA supplementation, parity and different concentrate levels before calving on immunoglobulin G1, G2 and M concentrations in dairy cows

Peripartal dairy cows exhibit a higher susceptibility for infectious diseases, which might be linked to the negative energy balance occurring at the onset of lactation. A dietary supplementation of conjugated linoleic acids (CLA) may reduce milk fat yield and subsequently lower the energy deficit. The utilization of immunoglobulins (Ig) for colostrogenesis might impair humoral immunity in peripartal dairy cows; therefore this study investigated the effects of a CLA supplement, parity and different dietary energy levels on plasma and colostrum IgG1, IgG2 and IgM levels in dairy cows and their calves. Blood samples were collected from 64 cows from 21days before until 56days after parturition and colostrum samples for the first 3days of lactation. Plasma immunoglobulin concentrations of 19 calves were determined before colostrum uptake. Neither plasma IgG1, nor IgG2 levels were affected by CLA or dietary energy level. However, immunoglobulin levels were affected by parity. Heifers possessed the lowest IgG1 concentrations. IgG2 concentrations were highest in cows with 2 lactations prior to parturition and in heifers after parturition. Plasma IgM levels were characterized by a sharp decrease 3days prior to parturition and were scarcely affected by the feeding regimen or parity. Generally, immunoglobulin levels appear to be mostly independent from the peripartal energy balance of the cows and are not influenced by dietary CLA. However, pronounced differences among parities for IgG1 and IgG2 were revealed which should be further evaluated.

Concentrate supplementation of a diet based on medium-quality grass silage for 4 weeks prepartum: Effects on cow performance, health, metabolic status, and immune function

Because negative energy balance (EB) contributes to transition-period immune dysfunction in dairy cows, dietary management strategies should aim to minimize negative EB during this time. Prepartum diets that oversupply energy may exacerbate negative EB in early lactation, with detrimental effects on immune function. However, with lower body condition score (BCS) cows, it has been shown that offering concentrates in addition to a grass silage-based diet when confined during an 8-wk dry period resulted in increased neutrophil function in early lactation. The aim of this study was to examine if similar benefits occur when concentrate feeding was restricted to a 4-wk period prepartum. Twenty-six multiparous and 22 primiparous Holstein-Friesian cows were offered ad libitum access to medium-quality grass silage until 28 d before their predicted calving dates (actual mean of 32 d prepartum; standard deviation = 6.4). At this time multiparous cows had a mean BCS of 2.9 (standard deviation = 0.12) and primiparous cows a mean BCS of 3.0 (standard deviation = 0.14) on a 1 to 5 scale. Cows were then allocated in a balanced manner to 1 of 2 treatments (13 multiparous cows and 11 primiparous cows on each treatment): silage only (SO) or silage plus concentrates (S+C) until calving. Cows on SO were offered the same grass silage ad libitum. Cows on S+C were offered an ad libitum mixed ration of the same grass silage and additional concentrates in a 60:40 dry matter (DM) ratio, which provided a mean concentrate DM intake (DMI) of 4.5 kg/cow per d. After calving, all cows were offered a common mixed ration (grass silage and concentrates, 40:60 DM ratio) for 70 d postpartum. Offering concentrates in addition to grass silage during the 4 wk prepartum increased prepartum DMI (12.0 versus 10.1 kg/cow per d), EB (+40.0 versus +10.6 MJ/cow per d), and body weight (BW; 640 versus 628 kg), and tended to increase BCS (3.02 versus 2.97). However, postpartum DMI, milk yield, milk composition, BW change, BCS change, serum nonesterified fatty acid, and β-hydroxybutryrate concentrations, health, and corpus luteum measures were unaffected by treatment. The in vitro assays of neutrophil phagocytosis, neutrophil oxidative burst, and interferon gamma production, conducted on blood samples obtained at d 14 prepartum and d 3, 7, 14, and 21 postpartum, were unaffected by treatment. Primiparous cows had higher phagocytic fluorescence intensity at d 14 prepartum and d 3 and 7 postpartum; a higher percentage of neutrophils undergoing oxidative burst at d 3, 7, and 21 postpartum; and a higher oxidative burst fluorescence intensity at d 14 prepartum and d 7, 14, and 21 postpartum compared with multiparous cows. This suggests that neutrophil function of primiparous cows was less sensitive to the changes occurring during the transition period than that of multiparous cows. In conclusion, offering concentrates during the 4-wk period prepartum had no effect on postpartum DMI, milk yield, body tissue mobilization, EB, measures of neutrophil or lymphocyte function, health, or corpus luteum activity.

The effect of supplementing rumen undegradable unsaturated fatty acids on marbling in early-weaned steers

The objective of this study was to determine if supplementation with a rumen undegradable unsaturated fatty acids (FA) source improved marbling deposition in early-weaned steers. All steers (Angus, = 23; Angus × Hereford, = 24) were weaned at 150 ± 5 d of age. Steers were blocked by BW and breed and then randomly assigned to either control (CON; average 1.5 kg of corn gluten feed [CGF], = 23) or isocaloric supplementation containing a rumen undegradable fat source (RUF; 200 g of Megalac-R added to an average of 1.06 kg of CGF, = 24) offered 5 d/wk for 110 d. All steers had ad libitum access to pastures throughout treatment and received supplements individually. Steer BW and blood samples were collected at 0, 55, and 110 d of supplementation, and real-time ultrasound measurements were collected at d 110. Following treatment, steers were transported to Oklahoma State University for finishing and subsequent harvesting at a commercial plant. All data were analyzed using the PROC MIXED procedure of SAS either as repeated measures or ANOVA depending on parameters. There were no significant changes in BW from the beginning of treatment to harvest due to treatment. Ultrasound data showed that RUF steers tended ( = 0.08) to have more i.m. fat than CON at d 110. Serum concentrations of FA showed a treatment × day interaction ( < 0.02) for 16:0, 18:0, 18:1-9, 18:2, 20:4, and total FA. These specific FA concentrations slightly increased in CON steers, but there was a more pronounced increase in the concentration of these FA across the supplementation period in RUF steers. Serum triglyceride and cholesterol concentrations were increased ( < 0.01) on d 55 and 110 in RUF steers compared with those in CON steers. Serum leptin concentration in RUF steers was greater ( < 0.01) than CON steers at d 110. After harvest, RUF carcasses had greater ( = 0.01) marbling scores than those of CON carcasses. All other carcass measures were similar between treatments. The percentage of total lipids was increased ( = 0.011) in steaks from RUF compared to CON. There was a decrease ( < 0.05) in adipocyte diameter in i.m. fat depot of RUF steers compared to CON. There was also a tendency ( = 0.06) for RUF steers to have a greater percentage of 20 to 30 μm adipocytes in their i.m. depot than CON steers. This study indicates that supplementation of unsaturated FA can positively impact marbling deposition in early-weaned steers without impacting other carcass measures.

Effects of monensin and essential oils on immunological, haematological and biochemical parameters of cows during the transition period

Using a model to generate experimental groups with different manifestations of post-partum (p.p.) fat mobilization and ketogenesis, the effects of a dietary and a medical intervention on biochemical and haematological parameters, antibody titre, leucocytes subsets and function of transition cows were examined. In total, 60 German Holstein cows were allocated 6 weeks antepartum (a.p.) to 3 high-body condition score (BCS) groups (BCS 3.95) and 1 low-BCS group (LC, BCS 2.77). High-BCS cows received a monensin controlled-release capsule (HC/MO) or a blend of essential oils (HC/EO) or formed a control group (HC). Parameters were evaluated in 3 periods (day (d) -42 until calving, 1 until 14 days in milk (DIM), 15 until 56 DIM). Over the course of trial, various parameters were influenced by period with greatest variability next to calving. White blood cell count was higher in the HC (8.42 × 10³ /μl) and HC/EO (8.38 × 10³ /μl) groups than in the HC/MO group (6.81 × 10³ /μl) considering the whole trial. Supplementation of monensin decreased aspartate aminotransferase in comparison with the HC group similar to LC treatment. Bilirubin concentration was nearly doubled in all high-BCS cows in period 2. In period 3, essential oils increased γ-glutamyltransferase (80.4 Units/l) in comparison with all other groups and glutamine dehydrogenase (61 Units/l) in comparison with the LC (19 Units/l) and the HC/MO group (18 Units/l). Results suggest that parameters were generally characterized by a high variability around calving. Based on biochemical characteristics, it appeared that the HC cows seemed to have compromised hepatocyte integrity when compared to the LC cows. From the immune parameters investigated, the BVDV antibody response was more pronounced in HC/MO compared to HC/EO.

Nutritional strategies to optimize dairy cattle immunity

Dairy cattle are susceptible to increased incidence and severity of both metabolic and infectious diseases during the periparturient period. A major contributing factor to increased health disorders is alterations in bovine immune mechanisms. Indeed, uncontrolled inflammation is a major contributing factor and a common link among several economically important infectious and metabolic diseases including mastitis, retained placenta, metritis, displaced abomasum, and ketosis. The nutritional status of dairy cows and the metabolism of specific nutrients are critical regulators of immune cell function. There is now a greater appreciation that certain mediators of the immune system can have a reciprocal effect on the metabolism of nutrients. Thus, any disturbances in nutritional or immunological homeostasis can provide deleterious feedback loops that can further enhance health disorders, increase production losses, and decrease the availability of safe and nutritious dairy foods for a growing global population. This review will discuss the complex interactions between nutrient metabolism and immune functions in periparturient dairy cattle. Details of how either deficiencies or overexposure to macro- and micronutrients can contribute to immune dysfunction and the subsequent development of health disorders will be presented. Specifically, the ways in which altered nutrient metabolism and oxidative stress can interact to compromise the immune system in transition cows will be discussed. A better understanding of the linkages between nutrition and immunity may facilitate the design of nutritional regimens that will reduce disease susceptibility in early lactation cows.

Prepartum feeding level and body condition score affect immunological performance in grazing dairy cows during the transition period

Precalving feeding level affects dry matter intake, postcalving energy balance, the risk of hepatic lipidosis and metabolic disease, and gene expression in liver and adipose tissue. These coincide with a higher risk of disease postpartum and, very likely, a failure to reach optimum production as well as reproductive targets. Current interpretation of the available evidence suggest that metabolic stressors affect the immune system of transition dairy cows and lead to reduced immunocompetence. The objective of the current study was to investigate the effect of precalving body condition score (BCS) and level of feeding on immunocompetence during the peripartum period. Twenty-three weeks before calving, 78 cows were allocated randomly to 1 of 6 treatment groups (n=13) in a 2 × 3 factorial arrangement: 2 precalving BCS categories (4.0 and 5.0, based on a 10-point scale) and 3 levels of energy intake during the 3 wk preceding calving (75, 100, and 125% of estimated requirements). Blood was sampled precalving and at 1, 2 and 4 wk after calving. Cells were analyzed by flow cytometry and quantitative real-time PCR. The numbers of T helper lymphocytes (CD4+), cytotoxic T lymphocytes (CD8+), natural killer cells (CD335+), and γδ T lymphocytes (WC1+) as well as their activation status [IL-2 receptor (CD25)+ cells] were highly variable between animals, but there was no evident effect of BCS, feeding level, or time. All groups presented with an increase in expression of cytokines in unstimulated blood cells in the week after calving, although this was significant only for IFNG in the BCS 4.0 group. Analysis of in vitro-stimulated cells allowed 2 general observations: (1) cows with high energy intake precalving (125%) had increased cytokine expression precalving, and (2) all cows had increased cytokine expression in the week after calving. The present study provides evidence that prepartum feed management can affect immunocompetence during the transition period. Considering the current results, optimally conditioned animals might benefit from a restricted precalving diet, whereas underconditioned cows can be fed to requirements.

Dietary polyunsaturated fatty acids from flaxseed affect immune responses of dairy sheep around parturition

The objective of the study was to characterize the immune profile of dairy ewes fed flaxseed, rich in polyunsaturated fatty acids (PUFA), around parturition. The hypothesis to be verified was that a physiological stressor, such as parturition, could be overcome with a nutritional manipulation in the diet of the animal in order to guarantee welfare of animals and to sustain their immune responses. Twenty Comisana ewes were divided in two groups (10 ewes/group), and fed a supplementation of whole flaxseed in the diet (FS group) or no supplementation (CON group). Blood samples were collected at parturition and then 7, 14, 21, 28, and 42 day post partum. Plasma samples were used to assess the humoral immune response after ovalbumin (OVA) immunization. At parturition, at 14 day, and 42 day post partum the level of plasma cytokines was assessed. The sheep showed a reduced responsiveness to OVA immunization. In FS ewes the IL-6 level remained unchanged until 14 day post partum and then significantly decreased from 14 day to 42 day post partum. IL-10 level was significantly higher in FS ewes than in CON ewes at 14 day. At parturition IL-1β level was significantly lower in FS ewes than in CON ewes and significantly decreased in both groups from parturition to 42 day. In conclusion, PUFA from flaxseed, as supplement in the diet of ewes around parturition can modulate sheep immune reactivity by influencing cytokine production.

Postpartum uterine diseases and their impacts on conception and days open in dairy herds in Italy

The objective of this study was to describe the incidence and the impact of postpartum uterine diseases in postpartum cows on future uterine status and reproductive performance in large Italian dairy herds. This study provides an important quantitative estimate of uterine and postpartum diseases incidence that afflict high-producing Italian dairy cows. The total number of cows included in the study was 1498 on three farms; all cows were followed from the dry period until 300 days postpartum. All farms used high-quality data collection systems and standard operating procedures: weekly herd health visits, monthly Dairy Herd Improvement Association visits, and, due to cheese-making milk quality requirements, a supplementary milk sample collected at 7 ± 3 days postpartum evaluated for milk components. Clinical metritis in primiparous cows did not change the time to the first artificial insemination (AI) or days open; conversely, clinical metritis in multiparous cows had impact on the time to first AI (hazard ratio: 0.66, P < 0.01) and resulted in a lower conception rate at first insemination and a increase in days open (odds ratio: 0.64, P < 0.05). Clinical endometritis had a strong deleterious effect on first AI conception rate (odds ratio: 0.34, P < 0.05) and days open across all lactations (hazard ratio: 0.68, P < 0.05). Persistent metritis, defined as the presence of both clinical metritis and clinical endometritis in the same animal in the same lactation, caused low conception rate both in the first-lactation and in older cows and had a strong negative effect on the proportion of pregnant cows at 300 days (P < 0.05). In conclusion, the impact of endometritis on fertility was true across lactation groups. A good management and precocious diagnosis of the pathologies is not resolutive to restore good fertility parameters, and understanding the immune response in first-lactation cows may be of value for developing alternative intervention protocols for older-lactation cows.

Effects of elevated parameters of subclinical ketosis on the immune system of dairy cows: in vivo and in vitro results

Using an established model in which subclinical ketosis is induced, the response of differential blood counts and levels of various haematological variables, including the inflammatory marker haptoglobin (Hp), were tested over the last six weeks of parturition until the 56th day post-partum in cows with lower or higher body condition scores (LBC and HBC, respectively; n = 9/group). Animals in the HBC group evidenced subclinical ketosis whereas LBC animals were metabolically healthy. For in vitro examination with ß-hydroxybutyrate (BHB) as a further stimulus, peripheral blood mononuclear cell (PBMC) counts of cows with and without subclinical ketosis (n = 5/group) were observed. Counts of leucocytes, granulocytes and lymphocytes (LY) peaked at day 1 post-partum in HBC cows, with a more marked increase in heifers. In subclinical ketosis LY count increased again, with significantly higher values in the HBC group. The red blood cell (RBC) profile was affected by parity (counts were higher in heifers). Hp showed a positive linear correlation with BHB and non-esterified fatty acids (NEFA; R(2) = 0.41). PBMC from cows that were not pre-stressed with subclinical ketosis were more sensitive to increasing levels of BHB in vitro, as evidenced by both their higher proliferative capability and increased release of nitric oxide (NO). In summary, cows with subclinical ketosis showed a heightened immune response compared with metabolically healthy individuals, based on increased LY counts, increasing stimulative properties of PBMC and a relationship between Hp and typically increased values of BHB and NEFA. Concentrations of BHB in vivo during subclinical ketosis did not alter the proliferative capability of bovine PBMC in vitro, which was first significantly decreased at a dosage of 5 mM BHB.

Managing the grazing dairy cow through the transition period: a review

The transition period of the dairy cow generally refers to the last three weeks of gestation and the first three weeks of lactation. During this period, the dairy cow faces numerous physiological challenges, requiring both homeostatic and homeorhetic changes to support the demands of lactation. Management strategies to achieve a successful transition have developed over many decades. Historically, these strategies focussed on achieving high energy intakes pre-calving in an attempt to improve post-calving metabolism; however, more recent research has indicated that this approach may not be appropriate. Physiological and molecular data have indicated that imposing a slight negative energy balance (EBAL) pre-calving can improve post-calving EBAL, metabolic health indices and milk production. It was hypothesised that the challenges of the transition period would be less in a grazing system than in an intensive confinement system, due to the lower milk production and the difference in population density and, therefore, pathogen exposure. However, the molecular and immunological responses to the change of state are similar in magnitude in a moderate-yielding pasture-fed cow and in a high-yielding cow fed a total mixed ration. The collective data point to a peripartum immunosuppression, which is affected by body condition score and feeding level. This review will outline the literature and provide an assessment of the most recent transition cow management for grazing dairy cows.

Supplementation of herbal plants differently modulated metabolic profile, insulin sensitivity, and oxidative stress in transition dairy cows fed various extruded oil seeds

The study investigated the effects of a mixture of herbal plants (HM) and two sources of unsaturated fatty acids (FA), extruded linseed (LS) and soybean (SB), on metabolic profile, insulin sensitivity, and oxidative status of transition dairy cows. Thirty-two prepartum Holstein cows, blocked by parity and calving day, were randomly assigned to 1 of 4 treatments, in a 2×2 factorial design, starting from 25 days before the expected calving date to 26 days postpartum. The supplementation rates of HM were 150 and 170 g/animal/day at pre- and postpartum, respectively. Blood samples were analyzed for metabolites on day 7.15±1.70 prepartum and on days 1 and 21 postpartum. An intravenous glucose tolerance test (IV-GTT) was conducted on day 25 postpartum. Data showed that cows supplemented with HM had lower serum concentration of NEFA (0.395 vs. 0.602±0.044 mmol/L; P<0.01) and NEFA to insulin ratio (P<0.01) postpartum. Compared to animals fed SB-based diets, cows fed the LS-based diet had greater serum glucose concentration during prepartum (80.7 vs. 71.3±3.32 mg/dL; P=0.06) and postpartum period (86.3 vs. 73.5±3.35 mg/dL; P=0.01), as well as lower NEFA (0.425 vs. 0.572±0.044 mmol/L; P=0.03) and insulin to glucose ratio (P<0.01) postpartum. Revised quantitative insulin-sensitivity check index revealed that supplementing HM in LS-based diet improved insulin sensitivity (0.45 vs. 0.41±0.013; P=0.03) prepartum, whereas after parturition, the HM addition was effective for both oil seeds (0.40 vs. 0.37±0.008; P=0.06) in enhancing insulin sensitivity. Result of IV-GTT indicated that cows fed LS-based diets had higher basal glucose concentration (63.7 vs. 55.7±2.37; mg/dL; P=0.02) and lower glucose area under the curve (995.8 vs. 1529.5±100.7; mg/dL×45 min; P<0.01). Supplementing HM resulted in greater total antioxidant capacity prepartum (0.55 vs. 0.48±0.017 nmol/L; P=0.01) and lower malondialdehyde concentration at prepartum (1.03 vs. 1.96±0.140 μmol/L; P<0.01) and postpartum (1.32 vs. 1.88±0.178 μmol/L; P=0.04). Although feeding LS ameliorated insulin resistance, this feeding strategy lowered total antioxidant capacity prepartum (0. 48 vs. 0.55±0.017 nmol/L; P<0.01) and increased malondialdehyde concentration postpartum more than the SB diet (1.91 vs. 1.28±0.172 μmol/L; P=0.02). Overall, both HM supplementation and LS feeding improved metabolic profile and insulin response following glucose infusion, although feeding of LS-based diets induced an increased oxidative stress.

Effect of parenteral administration of glutamine on autophagy of liver cell and immune responses in weaned calves

The objectives of this study were to determine the effects of an increased jugular supply of L-Gln on post-weaning growth, immune responses, intestinal morphology and autophagy of weaned calves. At 35 days of age, 24 Holstein calves (initial 50 ± 1.5 kg; 35 ± 2 day of age) were randomly allocated to four treatments, and each treatment included five male and one female calves. Holstein calves were assigned to treatments of (i) i.v. infusion of 2 l of 0.85% NaCl, Control group [C]; (ii) i.v. infusion of 8 g/day of L-Gln mixed with 2 l of 0.85% NaCl solution [L]; (iii) i.v. infusion of 16 g/day of L-Gln mixed with 2 l of 0.85% NaCl solution [M]; and (iv) i.v. infusion of 32 g/day of L-Gln mixed with 2 l of 0.85% NaCl [H]; The infusion was 2 h/day for each of 14 consecutive days starting on day 1 after weaning. Feed and water were freely available to all calves. All calves were killed on the 14th day post-weaning for measurements of autophagy of liver cell and intestinal morphology. Gln has no effect on dry matter intake (DMI) and average daily gain (ADG). Gln infusion increased quadratically the abundance of CD4+, monocyte and the ratio of CD4+/CD8+. The urea N, Gln and Glucose in plasma increased linearly with increasing Gln loads. Gln infusion increased quadratically villus height and crypt depth of intestine. The autophagy level of liver cell was improved with the Gln infusion dose increased.

Fatty acid profile and proliferation of bovine blood mononuclear cells after conjugated linoleic acid supplementation

BACKGROUND

Conjugated linoleic acids (CLA) are in focus of dairy cattle research because of its milk fat reducing effects. Little is known about the impact of CLA on immune function in dairy cows. Therefore, in the present study we investigated the effects of a long term supplementation of dairy cows with CLA on the fatty acid profile of peripheral blood mononuclear cells (PBMC) and their proliferation ex vivo.

RESULTS

The supplementation of dairy cows with either 100 g/d of a control fat preparation (CON, n = 15), 50 g/d of the control fat preparation and 50 g/d CLA supplement - containing 12.0% cis-9, trans-11 and 11.9% trans-10, cis-12 CLA of total fatty acid methyl esters - (CLA-50, n = 15) or 100 g/d of the CLA supplement (CLA-100, n = 16) did not influence the major fatty acids (C18:0, C16:0, cis-9 C18:1, cis-9, cis-12 C18:2, cis-5, cis-8, cis-11, cis-14 C20:4) in the lipid fraction of PBMC. The proportion of trans-10, cis-12 CLA of total fatty acids was increased in both CLA supplemented groups, but there was no effect on the cis-9, trans-11 isomer. Furthermore, the proportion of trans-9 C18:1 and cis-12 C24:1 was reduced in the CLA-100 group. The mitogen stimulated cell proliferation was not influenced by CLA feeding.

CONCLUSION

CLA supplementation influenced the FA profile of some minor FA in PBMC, but these changes did not lead to differences in the mitogen induced activation of the cells.

Effects of rumen-protected polyunsaturated fatty acid supplementation on performance and physiological responses of growing cattle after transportation and feedlot entry

Two experiments were conducted to evaluate the effects of rumen-protected PUFA supplementation on performance and inflammation measures in beef calves after truck transportation and feedyard entry. In Exp. 1, 30 weaned Braford steers (BW = 218 ± 4.3 kg) were transported for 1,600 km over a 24-h period in a commercial trailer and delivered to a feedlot (d 0). Upon arrival (d 1), steers were stratified by BW and allocated to receive 1 of 3 treatments (10 steers/treatment), which consisted of grain-based concentrates without supplemental fat (NF), or with the inclusion of a rumen-protected SFA (SF; 2.1% as-fed basis) or PUFA source (PF; 2.5% as-fed basis). Shrunk BW was determined on d 1 and 30 for ADG calculation. Individual DMI was recorded from d 2 to 28. Blood samples were collected on d 0, 1, 4, 8, 15, 22, and 29 for determination of acute-phase protein concentrations. Steers fed PF had decreased (P = 0.04) mean DMI and tended to have reduced ADG (P = 0.07) compared with NF-fed steers (2.32 vs. 2.72% of BW, and 0.78 vs. 1.07 kg/d, respectively). No other treatment effects were detected. In Exp. 2, 48 weaned Brahman-crossbred heifers (BW = 276 ± 4.6 kg) were stratified by initial BW and randomly allocated to 6 pastures (8 heifers/pasture) before transportation (d -30 to 0). Pastures were randomly assigned (3 pastures/treatment) to receive (DM basis) 3.0 kg/heifer daily of NF, or 2.5 kg/heifer daily of a concentrate containing 5.7% (as-fed basis) of a rumen-protected PUFA source (PF). On d 0, heifers were transported as in Exp. 1. Upon arrival (d 1), 24 heifers were randomly selected (12 heifers/treatment), placed into individual feeding pens, and assigned the same pretransport treatment. Shrunk BW was recorded on d -30, 1, and 30 to determine ADG. Individual DMI was recorded daily from d 2 to 28. Blood samples were collected on d 0, 1, 4, 8, 15, 22, and 29 for determination of acute-phase protein concentrations. A treatment × day interaction was detected for haptoglobin (P < 0.01) because PF-fed heifers had decreased haptoglobin concentrations compared with NF-fed heifers on d 1, 4, and 8. No other treatment effects were detected. Data from this study indicate that PUFA reduces haptoglobin concentrations in beef calves after transport and feedlot entry when supplemented before and after transportation. Further, PUFA supplementation during the feedyard only appears to negatively affect cattle performance by decreasing ADG and DMI.

Osteopontin: an early innate immune marker of Escherichia coli mastitis harbors genetic polymorphisms with possible links with resistance to mastitis

Background

Mastitis is the most important disease in dairy cows and it causes significant lost of profit to producers. Identification of the genes, and their variants, involved in innate immune responses is essential for the understanding of this inflammatory disease and to identify potential genetic markers for resistance to mastitis. The progeny of dairy cows would benefit from receiving favourable alleles that support greater resistance to infection, thus reducing antibiotic use. This study aims to identify a key gene in the innate immune response to mastitis, led us to evaluate its genetic association with somatic cell score (SCS), which is an indicator of clinical mastitis, and to evaluate its impact on other traits related to milk production.

Results

The osteopontin transcript (SPP1) was identified in the somatic cells from cows experimentally infected with Escherichia coli. By selecting bulls with extreme estimated breeding values (EBVs) for SCS, which is an indicator of mammary gland health, four DNA polymorphisms in the SPP1 genomic sequence were found. Statistical analysis revealed that the SNP SPP1c.-1301G>A has an impact on EBV for SCS (P < 0.001) Using an allele substitution model, SPP1c.-1251C>T, SPP1c.-430G>A, and SPP1c.*40A>C have an impact on SCS whereas SPP1c.-1301G>A has an effect on the EBVs for milk yield (second and third lactations), fat and protein percentages (all three lactations). Analysis revealed statistically significant differences between haplotype groups at a comparison-wise level with sire EBVS for SCS for the first (P = 0.012), second (P < 0.001), and third (P < 0.001) lactations.

Conclusion

This study reports the link between DNA polymorphisms of SPP1, the number of milk immune cells and, potentially, the susceptibility to mastitis. These SNPs were identified by in silico search to be located in transcription factor recognition sites which factors are presumably involved in the Th1 immune response and in the Th2 regulation pathway. Indeed, one SNP abolished the SP1 recognition site, whereas another SNP affected the transcription binding factor IKAROS. All together, these findings support the genetic potential of these variants in terms of selection for the improvement of mastitis resistance in dairy cows.