Impact of nutrient restriction at dry-off on performance and metabolism

Thanks to improvements in genetics, nutrition, and management, modern dairy cows can still produce large amounts of milk at the end of lactation, with possible negative effects on health and welfare, particularly when milking is stopped abruptly. To limit yield at dry-off, strategies involving different types of dietary restriction have been used worldwide. Thus, we aimed to investigate the effects of a reduced nutrient density at dry-off on milk production, metabolism, the pattern of rumen fermentation, and milk fatty acid profile around dry-off and in the ensuing periparturient period. During the last week before dry-off, 26 Holstein cows were enrolled in pairs according to the expected calving date and either fed ad libitum ryegrass hay (nutrient restricted, NR; 13 cows) or continued to receive lactation diet (control group, CTR, 13 cows). After dry-off, both groups received only grass hay for 7 d, and free access to water was always provided. Blood, milk, and rumen fluid samples were collected from 7 d before dry-off to 28 d in milk. Milk production, DMI (during the periparturient period), and rumination times were recorded daily. At dry-off, compared with CTR, NR decreased milk yield (- 62%) and milk lactose but had higher fat and protein contents. In the subsequent lactation, no significant differences were observed in milk yield and composition. The BCS did not differ between groups during the transition period, but it decreased in NR after dry-off. Before dry-off, NR had decreased glucose, urea, and insulin, but higher creatinine, β-hydroxybutyrate, and nonesterified fatty acids (NEFA). The day after dry-off, NEFA were lower in NR, but they were higher 7 d after calving. At dry-off, NR had higher rumen pH, lower lactate, urea, and total volatile fatty acid concentrations. Considering volatile fatty acid molar proportions, NR had increased acetate but decreased propionate and butyrate at dry-off. Rumination time dropped 6 d before dry-off in NR and after dry-off in CTR, but no differences were observed in the periparturient period. Milk fatty acid profile revealed a remarkably lower proportion of short-chain fatty acids in NR at dry-off and a higher proportion of medium- and long-chain ones. These results confirmed that decreasing nutrient density reduce milk yield before dry-off. However, metabolism around dry-off was significantly impacted, as suggested by plasma, rumen fluid, and milk analyses. Further research is required to investigate the impact of the metabolic effects on the inflammatory response, liver function, and immune system, particularly concerning the mammary gland.

Effect of supplementing live Saccharomyces cerevisiae yeast on performance, rumen function, and metabolism during the transition period in Holstein dairy cows

Dairy cows have to face several nutritional challenges during the transition period, and live yeast supplementation appears to be beneficial in modulating rumen activity. In this study, we evaluated the effects of live yeast supplementation on rumen function, milk production, and metabolic and inflammatory conditions. Ten Holstein multiparous cows received either live Saccharomyces cerevisiae (strain Sc47; SCY) supplementation from -21 to 21 d from calving (DFC) or a control diet without yeast supplementation. Feed intake, milk yield, and rumination time were monitored until 35 DFC, and rumen fluid, feces, milk, and blood samples were collected at different time points. Compared with the control diet, SCY had increased dry matter intake (16.7 vs. 19.1 ± 0.8 kg/d in wk 2 and 3) and rumination time postpartum (449 vs. 504 ± 19.9 min/d in wk 5). Milk yield tended to be greater in SCY (40.1 vs. 45.2 ± 1.7 kg/d in wk 5), protein content tended to be higher, and somatic cell count was lower. In rumen fluid, acetate molar proportion was higher and that of propionate lower at 21 DFC, resulting in increased acetate:propionate and (acetate + butyrate):propionate ratios. Cows in the SCY group had lower fecal dry matter but higher acetate and lower propionate proportions on total volatile fatty acids at 3 DFC. Plasma analysis revealed a lower degree of inflammation after calving in SCY (i.e., lower haptoglobin concentration at 1 and 3 DFC) and a likely better liver function, as suggested by the lower γ-glutamyl transferase, even though paraoxonase was lower at 28 DFC. Plasma IL-1β concentration tended to be higher in SCY, as well as Mg and P. Overall, SCY supplementation improved rumen and hindgut fermentation profiles, also resulting in higher dry matter intake and rumination time postpartum. Moreover, the postcalving inflammatory response was milder and liver function appeared to be better. Altogether, these effects also led to greater milk yield and reduced the risk of metabolic diseases.

Effect of stage of lactation and dietary starch content on endocrine-metabolic status, blood amino acid concentrations, milk yield, and composition in Holstein dairy cows

Milk yield and composition are modified by level and chemical characteristics of dietary energy and protein. Those factors determine nutrient availability from a given diet, and once absorbed, they interact with the endocrine system and together determine availability of metabolites to the mammary gland. Four multiparous dairy cows in early lactation and subsequently in late lactation were fed 2 diets for 28 d in a changeover design that provided, within the same stage of lactation, similar amounts of rumen fermentable feed with either high (HS) or low starch (LS). All diets had similar dietary crude protein (15.5% dry matter) and rumen-undegradable protein (∼40% of crude protein) content. Profiles of AA were calculated to be similar to that of casein. On d 28, [1-¹³C] Leu was infused into one jugular vein with blood samples taken at 0, 2, 4, 6, and 8 h, and cows milked at 0, 2, 4, 5, 6, 7, and 8 h from start of infusion. Isotopic enrichments of plasma Leu, keto-isocaproic acid, and milk casein were determined for calculation of Leu kinetics. Data were subjected to ANOVA using the MIXED procedure of SAS (SAS Institute Inc.), with time as repeated factor and cow as the random effect. Dry matter intake within each stage of lactation was similar between groups. Feeding LS resulted in lower blood glucose and greater ratio of bovine somatotropin to insulin. This response was associated with greater blood concentrations of nonesterified fatty acids and β-hydroxybutyrate, which might have contributed to greater milk fat content in LS-fed cows. Except for His, average concentrations of all AA in blood were higher in late than early lactation. Diet did not alter average plasma concentrations of AA. However, for most of the essential AA (particularly branched-chain), the HS diet led to a marked decrease in concentrations after the forage meal, resulting in significant differences between dietary groups in early lactation. In early-lactating cows fed HS, a greater reduction in plasma concentrations at 8 h relative to pre-feeding values (time zero) was observed for Met, Lys, and His, resulting in decreases of 27.9%, 33.6%, and 38.5%, respectively. A higher bovine somatotropin/insulin ratio in early lactation and in cows fed LS could possibly have led to greater breakdown and, consequently, higher AA flux from peripheral tissues. In LS-fed cows, higher mobilization of body fat and protein was confirmed by the greater body weight loss in both stages of lactation. Higher irreversible loss of [1-¹³C] Leu in early lactation suggested lower protein retention in peripheral tissues during early compared with late lactation. Milk yield, protein output, and composition were similar between groups at both stages of lactation, whereas milk coagulation was faster (lower curd firming rate) and with higher curd firmness in response to feeding HS in late lactation. Overall, data indicated that rate of carbohydrate fermentability in the rumen can modify the availability of metabolites to the mammary gland and consequently modify milk protein coagulation.

Maternal supplementation with cobalt sources, folic acid, and rumen-protected methionine and its effects on molecular and functional correlates of the immune system in neonatal Holstein calves

Calves born to multiparous Holstein cows fed during the last 30 d of pregnancy 2 different cobalt sources [cobalt glucoheptonate (CoPro) or cobalt pectin (CoPectin)], folic acid (FOA), and rumen-protected methionine (RPM) were used to study neonatal immune responses after ex vivo lipopolysaccharide (LPS) challenge. Groups were (n = 12 calves/group) CoPro, FOA+CoPro, FOA+CoPectin, and FOA+CoPectin+RPM. Calves were weighed at birth and blood collected at birth (before colostrum), 21 d of age, and 42 d of age (at weaning). Growth performance was recorded once a week during the first 6 wk of age. Energy metabolism, inflammation, and antioxidant status were assessed at birth through various plasma biomarkers. Whole blood was challenged with 3 µg/mL of LPS or used for phagocytosis and oxidative burst assays. Target genes evaluated by real-time quantitative PCR in whole blood samples were associated with immune response, antioxidant function, and 1-carbon metabolism. The response in mRNA abundance in LPS challenged versus nonchallenged samples was assessed via Δ = LPS challenged - LPS nonchallenged samples. Phagocytosis capacity and oxidative burst activity were measured in neutrophils and monocytes, with data reported as ratio (percentage) of CD14 to CH138A-positive cells. Data including all time points were subjected to ANOVA using PROC MIXED in SAS 9.4 (SAS Institute Inc.), with Treatment, Sex, Age, and Treatment × Age as fixed effects. A 1-way ANOVA was used to determine differences at birth, with Treatment and Sex as fixed effects. Calf birth body weight and other growth parameters did not differ between groups. At birth, plasma haptoglobin concentration was lower in FOA+CoPro compared with CoPro calves. We detected no effect for other plasma biomarkers or immune function due to maternal treatments at birth. Compared with CoPro, in response to LPS challenge, whole blood from FOA+CoPectin and FOA+CoPectin+RPM calves had greater mRNA abundance of intercellular adhesion molecule 1 (ICAM1). No effect for other genes was detectable. Regardless of maternal treatments, sex-specific responses were observed due to greater plasma concentrations of haptoglobin, paraoxonase, total reactive oxygen metabolites, nitrite, and β-carotene in female versus male calves at birth. In contrast, whole blood from male calves had greater mRNA abundance of IRAK1, CADM1, and ITGAM in response to LPS challenge at birth. The longitudinal analysis of d 0, 21, and 42 data revealed greater bactericidal permeability-increasing protein (BPI) mRNA abundance in whole blood from FOA+CoPectin versus FOA+CoPro calves, coupled with greater abundance in FOA+CoPro compared with CoPro calves. Regardless of maternal treatments, most genes related to cytokines and cytokine receptors (IL1B, IL10, TNF, IRAK1, CXCR1), toll-like receptor pathway (TLR4, NFKB1), adhesion and migration (ICAM1, ITGAM), antimicrobial function (MPO), and antioxidant function (GPX1) were downregulated over time. Phagocytosis capacity and oxidative burst activity in both neutrophils and monocytes did not differ due to maternal treatment. Regardless of maternal treatments, we observed an increase in the percentage of neutrophils capable of phagocytosis and oxidative burst activity over time. Overall, these preliminary assessments suggested that maternal supplementation with FOA and Co combined with RPM had effects on a few plasma biomarkers of inflammation at birth and molecular responses associated with inflammatory mechanisms during the neonatal period.

Plasma albumin-to-globulin ratio before dry-off as a possible index of inflammatory status and performance in the subsequent lactation in dairy cows

The dry-off of dairy cows represents an important phase of the lactation cycle, influencing the outcome of the next lactation. Among the physiological changes, the severity of the inflammatory response can vary after the dry-off, and this response might have consequences on cow adaptation in the transition period. The plasma protein profile is a diagnostic tool widely used in humans and animals to assess the inflammatory status and predict the outcome of severe diseases. The albumin-to-globulin ratio (AG) can represent a simple and useful proxy for the inflammatory condition. In this study, we investigated the relationship between AG before dry-off and inflammation, metabolic profile, and performance of 75 Holstein dairy cows. Blood samples were collected from -62 (7 d before dry-off) to 28 d relative to calving (DFC) to measure metabolic profile biomarkers, inflammatory variables, and liver function. Daily milk yield in the first month of lactation was recorded. Milk composition, body condition score, fertility, and health status were also assessed. The AG calculated 1 wk before dry-off (-62 DFC) was used to retrospectively group cows into tertiles (1.06 ± 0.09 for HI, 0.88 ± 0.04 for IN, and 0.72 ± 0.08 for LO). Data were subjected to ANOVA using the PROC MIXED program in SAS software. Differences among groups observed at -62 DFC were almost maintained throughout the period of interest, but AG peaked before calving. According to the level of acute-phase proteins (haptoglobin, ceruloplasmin, albumin, cholesterol, retinol-binding protein), bilirubin, and paraoxonase, a generally overall lower inflammatory condition was found in HI and IN than in the LO group immediately after the dry-off but also after calving. The HI cows had greater milk yield than LO cows, but no differences were observed in milk composition. The somatic cell count reflected the AG ratio trend, with higher values in LO than IN and HI either before dry-off or after calving. Fertility was better in HI cows, with fewer days open and services per pregnancy than IN and LO cows. Overall, cows with high AG before dry-off showed an improved adaptation to the new lactation, as demonstrated by a reduced systemic inflammatory response and increased milk yield than cows with low AG. In conclusion, the AG ratio before dry-off might represent a rapid and useful proxy to evaluate the innate immune status and likely the ability to adapt while switching from the late lactation to the nonlactating phase and during the transition period with emphasis on early lactation.

Feeding a Saccharomyces cerevisiae fermentation product improves udder health and immune response to a Streptococcus uberis mastitis challenge in mid-lactation dairy cows

Background

We aimed to characterize the protective effects and the molecular mechanisms of action of a Saccharomyces cerevisiae fermentation product (NTK) in response to a mastitis challenge. Eighteen mid-lactation multiparous Holstein cows (n = 9/group) were fed the control diet (CON) or CON supplemented with 19 g/d NTK for 45 d (phase 1, P1) and then infected in the right rear quarter with 2500 CFU of Streptococcus uberis (phase 2, P2). After 36-h, mammary gland and liver biopsies were collected and antibiotic treatment started until the end of P2 (9 d post challenge). Cows were then followed until day 75 (phase 3, P3). Milk yield (MY) and dry matter intake (DMI) were recorded daily. Milk samples for somatic cell score were collected, and rectal and udder temperature, heart and respiration rate were recorded during the challenge period (P2) together with blood samples for metabolite and immune function analyses. Data were analyzed by phase using the PROC MIXED procedure in SAS. Biopsies were used for transcriptomic analysis via RNA-sequencing, followed by pathway analysis.

Results

DMI and MY were not affected by diet in P1, but an interaction with time was recorded in P2 indicating a better recovery from the challenge in NTK compared with CON. NTK reduced rectal temperature, somatic cell score, and temperature of the infected quarter during the challenge. Transcriptome data supported these findings, as NTK supplementation upregulated mammary genes related to immune cell antibacterial function (e.g., CATHL4, NOS2), epithelial tissue protection (e.g. IL17C), and anti-inflammatory activity (e.g., ATF3, BAG3, IER3, G-CSF, GRO1, ZFAND2A). Pathway analysis indicated upregulation of tumor necrosis factor α, heat shock protein response, and p21 related pathways in the response to mastitis in NTK cows. Other pathways for detoxification and cytoprotection functions along with the tight junction pathway were also upregulated in NTK-fed cows.

Conclusions

Overall, results highlighted molecular networks involved in the protective effect of NTK prophylactic supplementation on udder health during a subclinical mastitic event.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40104-021-00560-8.

One-carbon, carnitine, and glutathione metabolism-related biomarkers in peripartal Holstein cows are altered by prepartal body condition

We investigated how prepartal body condition score (BCS) alters key hepatic enzymes associated with 1-carbon, carnitine, and glutathione metabolism and the related biomarkers in liver tissue and plasma of periparturient dairy cows. Twenty-six multiparous Holstein dairy cows were retrospectively selected according to BCS at 4 wk prepartum and divided into high (HighBCS, BCS ≥ 3.50) and normal (NormBCS, BCS ≤ 3.25) BCS groups (n = 13 each). Blood plasma samples were obtained at -30, -10, 7, 15, and 30 d relative to calving. Liver tissue biopsies were performed at -15, 7, and 30 d relative to calving, and samples were used to assess protein abundance via Western blot assay. Cows in the HighBCS group lost ∼1 unit of BCS between -4 and 4 wk around calving, while NormBCS cows lost ∼0.5 unit in the same period. Prepartal dry matter intake (DMI, kg/d) did not differ between groups. Compared with NormBCS cows, HighBCS cows had higher postpartal DMI and milk yield (+5.34 kg/d). In addition, greater overall plasma concentrations of fatty acids and activity of the neutrophil-enriched enzyme myeloperoxidase were observed in HighBCS compared with NormBCS cows. Despite similar reactive oxygen metabolite concentrations in both groups at 30 d, HighBCS cows had lower overall concentrations of β-carotene and tocopherol, explaining the lower (BCS × Time) antioxidant capacity (ferric reducing ability of plasma). The HighBCS cows also had greater liver malondialdehyde concentrations and superoxide dismutase activity at 30 d. Overall, compared with NormBCS cows, HighBCS cows had lower hepatic protein abundance of the 1-carbon metabolism enzymes cystathionine-β-synthase, betaine-homocysteine methyltransferase, and methionine adenosyltransferase 1 A (MAT1A), as well as the glutathione metabolism-related enzymes glutathione S-transferase α 4 and glutathione peroxidase 3 (GPX3). A lower protein abundance of glutathione S-transferase mu 1 (GSTM1) at -15 and 7 d was also observed. Regardless of BCS, cows had increased abundance of GSTM1 and GPX3 between -15 and 7 d around calving. A marked decrease of gamma-butyrobetaine dioxygenase 1 from -10 to 7 d in HighBCS compared with NormBCS cows suggested a decrease in de novo carnitine synthesis that was partly explained by the lower abundance of MAT1A. Overall, data suggest biologic links between BCS before calving, milk yield, immune response, and hepatic reactions encompassing 1-carbon metabolism, carnitine, and antioxidant synthesis.

Maternal body condition influences neonatal calf whole-blood innate immune molecular responses to ex vivo lipopolysaccharide challenge

Managing body condition in dairy cows during the close-up period could alter the availability of nutrients to the fetus during the final growth stages in utero. We investigated how maternal body condition score (BCS) in late pregnancy affected calf whole-blood mRNA abundance and IL-1β concentrations after ex vivo lipopolysaccharide (LPS) challenge. Thirty-eight multiparous Holstein cows and their calves from a larger cohort were retrospectively grouped by prepartal BCS as normal BCS (≤3.25; n = 22; NormBCS) and high BCS (≥3.75; n = 16; HighBCS). Calf blood samples collected at birth (before receiving colostrum, d 0) and at ages 21 and 42 d (at weaning) were used for ex vivo whole-blood challenge with 3 µg/mL of LPS before mRNA isolation. Target genes evaluated by real-time quantitative PCR were associated with immune response, antioxidant function, and 1-carbon metabolism. Plasma IL-1β concentrations were also measured. Responses in plasma IL-1β and mRNA abundance were compared between LPS-challenged and nonchallenged samples. Statistical analyses were performed at all time points using a MIXED model in SAS 9.4. Neither birth body weight (NormBCS = 43.8 ± 1.01 kg; HighBCS = 43.9 ± 1.2 kg) nor colostrum IgG concentration (NormBCS = 70 ± 5.4 mg/mL; HighBCS = 62 ± 6.5 mg/mL) differed between groups. At birth, whole blood from calves born to HighBCS cows had greater mRNA abundance of IL1B, NFKB1, and GSR and lower GPX1 and CBS abundance after LPS challenge. The longitudinal analysis of d 0, 21, and 42 data revealed a BCS × age effect for SOD2 and NOS2 due to lower mRNA abundance at 42 d in the HighBCS calves. Regardless of maternal BCS, mRNA abundance decreased over time for genes encoding cytokines (IL1B, IL6, IL10, TNF), cytokine receptors (IRAK1, CXCR1), toll-like receptor pathway (TLR4, NFKB1), adhesion and migration (CADM1, ICAM1, ITGAM), and antimicrobial function (MPO). Concentration of IL-1β after LPS challenge was also markedly lower at 21 d regardless of maternal BCS. Overall, results suggested that maternal BCS in late prepartum influences the calf immune system response to an inflammation challenge after birth. Although few genes among those studied were altered due to maternal BCS, the fact that genes related to oxidative stress and 1-carbon metabolism responded to LPS challenge in HighBCS calves underscores the potential role of methyl donors (e.g., methionine, choline, and folic acid) in the early-life innate immune response.

Methyl donor supply to heat stress-challenged polymorphonuclear leukocytes from lactating Holstein cows enhances 1-carbon metabolism, immune response, and cytoprotective gene network abundance

Mechanisms controlling immune function of dairy cows are dysregulated during heat stress (HS). Methyl donor supply-methionine (Met) and choline (Chol)-positively modulates innate immune function, particularly antioxidant systems of polymorphonuclear leukocytes (PMN). The objective of this study was to investigate the effect of Met and Chol supply in vitro on mRNA abundance of genes related to 1-carbon metabolism, inflammation, and immune function in short-term cultures of PMN isolated from mid-lactating Holstein cows in response to heat challenge. Blood PMN were isolated from 5 Holstein cows (153 ± 5 d postpartum, 34.63 ± 2.73 kg/d of milk production; mean ± SD). The PMN were incubated for 2 h at thermal-neutral (37°C; TN) or heat stress (42°C; HS) temperatures with 3 levels of Chol (0, 400, or 800 μg/mL) or 3 ratios of Lys:Met (Met; 3.6:1, 2.9:1, or 2.4:1). Supernatant concentrations of IL-1β, IL-6, and tumor necrosis factor-α were measured via bovine-specific ELISA. Fold-changes in mRNA abundance were calculated separately for Chol and Met treatments to obtain the fold-change response at 42°C (HS) relative to 37°C (TN). Data were subjected to ANOVA using PROC MIXED in SAS (SAS Institute Inc., Cary, NC). Orthogonal contrasts were used to determine the linear or quadratic effect of Met and Chol for mRNA fold-change and supernatant cytokine concentrations. Compared with PMN receiving 0 μg of Chol/mL, heat-stressed PMN supplemented with Chol at 400 or 800 μg/mL had greater fold-change in abundance of CBS, CSAD, GSS, GSR, and GPX1. Among genes associated with inflammation and immune function, fold-change in abundance of TLR2, TLR4, IRAK1, IL1B, and IL10 increased with 400 and 800 μg of Chol/mL compared with PMN receiving 0 μg of Chol/mL. Fold-change in abundance of SAHH decreased linearly at increasing levels of Met supply. A linear effect was detected for MPO, NFKB1, and SOD1 due to greater fold-change in abundance when Met was increased to reach Lys:Met ratios of 2.9:1 and 2.4:1. Although increasing Chol supply upregulated BAX, BCL2, and HSP70, increased Met supply only upregulated BAX. Under HS conditions, enhancing PMN supply of Chol to 400 μg/mL effectively increased fold-change in abundance of genes involved in antioxidant production (conferring cellular processes protection from free radicals and reactive oxygen species), inflammatory signaling, and innate immunity. Although similar outcomes were obtained with Met supply at Lys:Met ratios of 2.9:1 and 2.4:1, the response was less pronounced. Both Chol and Met supply enhanced the cytoprotective characteristics of PMN through upregulation of heat shock proteins. Overall, the modulatory effects detected in the present experiment highlight an opportunity to use Met and particularly Chol supplementation during thermal stress.

Molecular networks of insulin signaling and amino acid metabolism in subcutaneous adipose tissue are altered by body condition in periparturient Holstein cows

Peripartal cows mobilize not only body fat but also body protein to satisfy their energy requirements. The objective of this study was to determine the effect of prepartum BCS on blood biomarkers related to energy and nitrogen metabolism, and mRNA and protein abundance associated with AA metabolism and insulin signaling in subcutaneous adipose tissue (SAT) in peripartal cows. Twenty-two multiparous Holstein cows were retrospectively classified into a high BCS (HBCS; n = 11, BCS ≥ 3.5) or normal BCS (NBCS; n = 11, BCS ≤ 3.17) group at d 28 before expected parturition. Cows were fed the same diet as a total mixed ration before parturition and were fed the same lactation diet postpartum. Blood samples collected at -10, 7, 15, and 30 d relative to parturition were used for analyses of biomarkers associated with energy and nitrogen metabolism. Biopsies of SAT harvested at -15, 7, and 30 d relative to parturition were used for mRNA (real time-PCR) and protein abundance (Western blotting) assays. Data were subjected to ANOVA using the MIXED procedure of SAS (v. 9.4; SAS Institute Inc., Cary, NC), with P ≤ 0.05 being the threshold for significance. Cows in HBCS had greater overall plasma nonesterified fatty acid concentrations, due to marked increases at 7 and 15 d postpartum. This response was similar (BCS × Day effect) to protein abundance of phosphorylated (p) protein kinase B (p-AKT), the insulin-induced glucose transporter (SLC2A4), and the sodium-coupled neutral AA transporter (SLC38A1). Abundance of these proteins was lower at -15 d compared with NBCS cows, and either increased (SLC2A4, SLC38A1) or did not change (p-AKT) at 7 d postpartum in HBCS. Unlike protein abundance, however, overall mRNA abundances of the high-affinity cationic (SLC7A1), proton-coupled (SLC36A1), and sodium-coupled amino acid transporters (SLC38A2) were greater in HBCS than NBCS cows, due to upregulation in the postpartum phase. Those responses were similar to protein abundance of p-mTOR, which increased (BCS × Day effect) at 7 d in HBCS compared with NBCS cows. mRNA abundance of argininosuccinate lyase (ASL) and arginase 1 (ARG1) also was greater overall in HBCS cows. Together, these responses suggested impaired insulin signaling, coupled with greater postpartum AA transport rate and urea cycle activity in SAT of HBCS cows. An in vitro study using adipocyte and macrophage cocultures stimulated with various concentrations of fatty acids could provide some insights into the role of immune cells in modulating adipose tissue immunometabolic status, including insulin resistance and AA metabolism.

Association of postpartum uterine diseases with lying time and metabolic profiles of multiparous Holstein dairy cows in the transition period

The objective of this study was to assess how uterine disorders alter the lying behaviour and plasma biomarkers in dairy cows. 34 multiparous cows were retrospectively classified into three groups according to the first uterine disorder that cows were diagnosed with: retained placenta (RP), metritis (MET), or healthy (H; cows without any clinical disease). Lying time (LT) and duration of lying bouts (LB) were monitored between 6 weeks prior to and 8 weeks after calving via the AfiAct II pedometer. Blood samples were collected routinely between 14 days before and 28 days after calving. Data was analysed using Proc MIXED of SAS ver. 9.4. Regardless of grouping, both LT and LB were longer (P < 0.01) in the prepartum period (774 ± 16.6 min/day and 89.9 ± 2.1 min/bout) than in the first 28 days after calving (DFC; 653 ± 16.7 min/day and 63.7 ± 2.1 min/bout). Cows with RP had longer LT than healthy cows during the last 3 weeks before calving (837 ± 30.9 vs. 735 ± 27.1 min/day; P < 0.05). LT in cows with MET and healthy cows were not significantly different. The LB was similar among groups, averaging 76.1 ± 3.4 min/bout in healthy cows, 73.2 ± 3.8 min/bout in cows with RP, and 75.2 ± 3.7 min/bout in cows with MET (P > 0.05). Compared with healthy cows, cows with RP laid down longer and stood up for shorter times (P < 0.05), particularly before calving. In addition, cows with RP had increased mobilization of body stores and more pronounced inflammatory status, as demonstrated by plasma haptoglobin (P = 0.04) and albumin (P < 0.01) concentrations. Our data suggest that automatic monitoring of lying behaviour could help identify cows at increased risk of developing certain disorders, such as RP.

The effect of parity number on the metabolism, inflammation, and oxidative status of dairy sheep during the transition period

The objective of this study was to evaluate whether dairy sheep during the transition period are affected by their parity numbers with regard to (1) body weight (BW), body condition score (BCS), and production performance (milk yield and composition) and (2) metabolic, inflammation, and stress biomarkers. For this purpose, 30 Sarda dairy ewes [15 primiparous (PRP) and 15 multiparous (MUP) ewes] were recruited on d 90 of gestation. Each group was homogeneous according to age, BW, and BCS. Sampling was carried out at -60, -30, -7, 0, +30, and +60 d from lambing. The MUP ewes showed a higher BW (46.32 vs. 38.71 kg) and larger litter size (1.45 vs. 1.06 kg) but a lower BCS (2.47 vs. 2.70) than the PRP ewes. Furthermore, the MUP ewes had lower concentrations of glucose (3.49 vs. 4.27 mol/L), cholesterol (1.63 vs. 1.81 mmol/L), free fatty acids (0.47 vs. 0.62 mmol/L), and triglycerides (0.22 vs. 0.25 mmol/L) compared with PRP ewes. With regard to inflammation and oxidative stress parameters, the PRP group had higher haptoglobin (0.48 vs. 0.18 g/L) and paraoxonase (187.90 vs. 152.11 U/L) activity than the MUP group. Overall, the MUP ewes were characterized by greater milk production performance and greater feed intake, resulting in a better energy balance, than the PRP ewes. Interestingly, these findings highlighted a different metabolic and inflammatory response over the transition period between PRP and MUP ewes, with the latter displaying lower concentrations of inflammatory-related biomarkers.

Body condition alters glutathione and nuclear factor erythroid 2-like 2 (NFE2L2)-related antioxidant network abundance in subcutaneous adipose tissue of periparturient Holstein cows

Dairy cows with high body condition score (BCS) in late prepartum are more susceptible to oxidative stress (OS). Nuclear factor erythroid 2-like 2 (NFE2L2) is a major antioxidant transcription factor. We investigated the effect of precalving BCS on blood biomarkers associated with OS, inflammation, and liver function, along with mRNA and protein abundance of targets related to NFE2L2 and glutathione (GSH) metabolism in s.c. adipose tissue (SAT) of periparturient dairy cows. Twenty-two multiparous Holstein cows were retrospectively classified into a high BCS (HBCS; n = 11, BCS ≥3.5) or normal BCS (NBCS; n = 11, BCS ≤3.17) on d 28 before parturition. Cows were fed a corn silage- and wheat straw-based total mixed ration during late prepartum, and a corn silage- and alfalfa hay-based total mixed ration postpartum. Blood samples obtained at -10, 7, 15, and 30 d relative to parturition were used for analyses of biomarkers associated with inflammation, including albumin, ceruloplasmin, haptoglobin, and myeloperoxidase, as well as OS, including ferric reducing ability of plasma (FRAP), reactive oxygen species (ROS), and β-carotene. Adipose biopsies harvested at -15, 7, and 30 d relative to parturition were analyzed for mRNA (real-time quantitative PCR) and protein abundance (Western blotting) of targets associated with the antioxidant transcription regulator nuclear factor, NFE2L2, and GSH metabolism pathway. In addition, concentrations of GSH, ROS and malondialdehyde were measured. High BCS cows had lower prepartum dry matter intake expressed as a percentage of body weight along with greater BCS loss between -4 and 4 wk relative to parturition. Plasma concentrations of ROS and FRAP increased after parturition regardless of treatment. Compared with NBCS, HBCS cows had greater concentrations of FRAP at d 7 postpartum, which coincided with peak values in those cows. In addition, NBCS cows experienced a marked decrease in plasma ROS after d 7 postpartum, while HBCS cows maintained a constant concentration by d 30 postpartum. Overall, ROS concentrations in SAT were greater in HBCS cows. However, overall mRNA abundance of NFE2L2 was lower and cullin 3 (CUL3), a negative regulator of NFE2L2, was greater in HBCS cows. Although HBCS cows had greater overall total protein abundance of NFE2L2 in SAT, ratio of phosphorylated NFE2L2 to total NFE2L2 was lower, suggesting a decrease in the activity of this antioxidant system. Overall, mRNA abundance of the GSH metabolism-related genes glutathione reductase (GSR), glutathione peroxidase 1 (GPX1), and transaldolase 1 (TALDO1), along with protein abundance of glutathione S-transferase mu 1 (GSTM1), were greater in HBCS cows. Data suggest that HBCS cows might experience greater systemic OS after parturition, while increased abundance of mRNA and protein components of the GSH metabolism pathway in SAT might help alleviate tissue oxidant status. Data underscored the importance of antioxidant mechanisms at the tissue level. Thus, targeting these pathways in SAT during the periparturient period via nutrition might help control tissue remodeling while allowing optimal performance.

Technical note: Capillary electrophoresis as a rapid test for the quantification of immunoglobulin G in serum of newborn lambs

Finding a rapid and simple method of serum IgG determination in lambs is essential for monitoring failure of passive transfer of immunity. The aim of this study was to assess the ability of capillary electrophoresis (CE), an instrument mainly used in blood serum protein analysis, to estimate IgG content in serum of newborn lambs through determination of only total Ig percentage by comparing the results with those obtained with radial immunodiffusion (RID), the reference method for serum IgG quantification. Serum samples were collected at 24 h after birth from 40 Sarda lambs. The IgG concentration measured by RID and serum total Ig concentration measured by CE were (mean ± standard deviation) 29.8 ± 16.1 g/L and 37.8 ± 15.0%, respectively. Data provided by RID and CE analysis showed a polynomial trend (RID = 0.02CE² - 0.04CE + 4.13; coefficient of determination, R² = 0.96), displaying a strong relationship between these 2 methods. Applying the polynomial equation, the IgG values were predicted. Predicted IgG values were highly correlated (r = 0.98) and related (R² = 0.96) to IgG values obtained by RID assay. These data were subjected to Bland-Altman analysis, revealing a high level of agreement between CE and RID methods with a bias that was not different from 0 (-0.04 g/L) and agreement limits of -6.38 g/L (low) and +6.30 g/L (high). In addition, the linear regression analysis between differences (dependent variable) and average of IgG concentration by CE and RID (independent variable) did not show proportional bias (R² = 0.01). In conclusion, CE is a reliable instrument for a lamb health monitoring program, where Bland-Altman analysis also confirmed that the CE method can be a suitable alternative to RID.

Short communication: Inflammation, migration, and cell-cell interaction-related gene network expression in leukocytes is enhanced in Simmental compared with Holstein dairy cows after calving

The aim of this study was to investigate changes in the abundance of genes involved in leukocyte function between cows highly specialized for milk production (Holstein, n = 12) and cows selected for meat and milk (Simmental, n = 13). Blood was collected on d 3 after calving in PAXgene tubes (Preanalytix, Hombrechtikon, Switzerland) to measure mRNA abundance of 33 genes. Normalized gene abundance data were subjected to MIXED model ANOVA using SAS (SAS Institute Inc. Cary, NC). Simmental cows had greater transcript abundance of proinflammatory cytokines and receptor genes (IL1B, TNF, IL1R, TNFRSF1A), cell migration- and adhesion-related genes (CX3CR1, ITGB2, CD44, LGALS8), and the antimicrobial IDO1 gene. In contrast, compared with Holstein cows, Simmental cows had lower abundance of the toll-like receptor (TLR) recognition-related gene TLR2, the antimicrobial-related gene LTF, and S100A8, which is involved in cell maturation, regulation of inflammatory processes, and immune response. These results revealed that breed plays an important role in the modulation of genes involved in immune adaptation and inflammatory response, and the immune system of Simmental cows could potentially have a more acute response in early lactation. In turn, this might be beneficial for mounting a more efficient response after calving and allow for a smoother homeorhetic adaptation to lactation.

Feeding synthetic zeolite to transition dairy cows alters neutrophil gene expression

Synthetic zeolites are used to control the availability of dietary minerals (e.g., Ca, Mg, and P) in dairy cows. Due to calcium demand increasing with lactation onset, most cows become hypocalcemic immediately postpartum, which likely contributes to poorer immune function because calcium is important for immune cell signaling. To overcome postpartum hypocalcemia, we fed transition cows synthetic zeolite A (sodium aluminosilicate) precalving and hypothesized that it would alter calcium and thus neutrophil function during the transition period. Multiparous Holstein-Friesian cows in late gestation were randomly allocated to an untreated control group (n = 10) or a treatment group in which each cow received 500 g of zeolite A daily (n = 10) for 14 d prior to the expected calving date (actual duration = 17 ± 3 d prepartum). The cows grazed pasture, and each was supplemented with 2 kg/d of maize silage (dry matter basis), with or without zeolite, until calving. Blood samples for neutrophil isolation and analysis of plasma indicators of mineral status, energy status, liver function, and inflammation were collected pretreatment (covariate; d -19); on d -14 and -7 precalving; on the day of calving (d 0); and on d 1, 4, 7, and 28 postcalving. Neutrophils were isolated and gene expression was analyzed using microfluidic gene expression arrays. Neutrophil respiratory burst was assessed using stimulation with phorbol 12-myristate 13-acetate and flow cytometry. Plasma calcium and phosphorus revealed a treatment by time interaction; cows offered zeolite had greater plasma calcium concentrations at d 0, 1, and 4 postcalving and plasma phosphorus concentrations were lower in zeolite-treated cows during the precalving period until d 1 postcalving compared with control animals. Zeolite treatment downregulated neutrophil gene expression of CXCR4 and S100A8 and tended to lower gene expression for other immune mediators (CXCR1, IFNG, S100A12, and S100A9) compared with the control. Zeolite treatment did not affect neutrophil respiratory burst or expression of the other genes investigated. Plasma concentrations of cytokine IL-6 were reduced with zeolite treatment, which was most evident immediately postcalving (d 0, 1, and 7). Overall, feeding zeolite precalving had few effects on neutrophil gene expression and function; however, the lower gene expression of neutrophil inflammatory mediators may be due to altered availability of dietary minerals prepartum and indicates that zeolite A may control inflammation during the transition period.

Short communication: Supply of methionine during late pregnancy enhances whole-blood innate immune response of Holstein calves partly through changes in mRNA abundance in polymorphonuclear leukocytes

The supply of methionine (Met) in late pregnancy can alter mRNA abundance of genes associated with metabolism and immune response in liver and polymorphonuclear leukocytes (PMN) of the neonatal calf. Whether prenatal supply of Met elicits postnatal effects on systemic inflammation and innate immune response of the calf is not well known. We investigated whether enhancing the maternal supply of Met via feeding ethyl-cellulose rumen-protected Met (RPM) was associated with differences in calf innate immune response mRNA abundance in PMN and systemic indicators of inflammation during the first 50 d of life. Calves (n = 14 per maternal diet) born to cows fed RPM at 0.09% of diet dry matter per day (MET) for the last 28 ± 2 d before calving or fed a control diet with no added Met (CON) were used. Blood for biomarker analysis and isolation of PMN for innate immune function assays and mRNA abundance was harvested at birth (before colostrum feeding) and at 7, 21 and 50 d of age. Whole blood was challenged with enteropathogenic bacteria (Escherichia coli 0118:H8) and phagocytosis and oxidative burst of neutrophils and monocytes were quantified via flow cytometry. Although concentration of haptoglobin and activity of myeloperoxidase among calves from both maternal groups increased markedly between 0 and 7 d of age followed by a decrease to baseline at d 21 the responses were lower in MET compared with CON calves. Nitric oxide concentration decreased markedly between 0 and 7 d regardless of maternal group but MET calves tended to have lower overall concentrations during the study. In vitro phagocytosis in stimulated neutrophils increased markedly over time in both CON and MET calves but responses were overall greater in MET calves. Oxidative burst in both neutrophils and monocytes increased over time regardless of maternal treatment. The mRNA abundance of lactate dehydrogenase (LDHA) signal transducer and activator of transcription 3 (STAT3) and S100 calcium binding protein A8 (S100A8) in PMN was overall greater in MET calves. Overall data suggest that increasing the maternal supply of Met during late pregnancy could affect the neonatal calf inflammatory status and innate immune response. Although changes in mRNA abundance could play a role in coordinating the immune response the exact mechanisms merit further study.

Immunometabolic status and productive performance differences between periparturient Simmental and Holstein dairy cows in response to pegbovigrastim

In the present study, we aimed to investigate the side effects of pegbovigrastim, injected approximately 7 d before parturition and on the day of calving, on a panel of plasma biomarkers to evaluate energy, inflammatory, oxidative, and liver function status. We also addressed treatment responses in different breeds during the transition period. Holstein and Simmental cows were randomly assigned into 2 groups based on expected calving date and according to parity: the treated group (PEG; 14 Holstein and 12 Simmental cows) received pegylated recombinant bovine granulocyte colony stimulating factor (pegbovigrastim, Imrestor; Elanco Animal Health, Greenfield, IN), and the control group (CTR; 14 Holstein and 14 Simmental cows) received saline solution. The PEG or CTR treatments were administered via subcutaneous injection in the scapular region at approximately 7 d (mean 7.80 ± 5.50 d) before expected parturition and within 24 h after calving. Blood samples were collected at -21, -7 (before injection), 1, 3, and 28 d relative to calving. Milk production was recorded at 7, 15, 21, 30, and 42 d. A mixed model with repeated measures was fitted to the normalized data using Proc MIXED of SAS (SAS Institute Inc., Cary, NC). Simmental PEG cows showed higher plasma protein concentrations at 1 and 3 d after calving compared with Simmental CTR and Holstein PEG cows, whereas no differences were detected between Holstein PEG and CTR cows. Albumin was greater at 1 d in Simmental PEG compared with Simmental CTR cows. In contrast, γ-glutamyl transferase was higher overall (across breed) in PEG than in CTR. The PEG group had higher values throughout the postcalving period compared with CTR. Cows treated with pegbovigrastim had also higher alkaline phosphatase (ALP) activity at 1 and 3 d after calving. The Holstein PEG group had higher ALP activity at 3 d compared with the Holstein CTR and Simmental PEG groups, and higher ALP at 1 d compared with the Simmental CTR group. The PEG group had higher levels of IL-6 at 3 and 28 d but higher IL-1β only at 28 d after calving compared with the CTR group. Overall, Holstein cows were characterized by a greater response in the production of inflammation biomarkers (cytokines, haptoglobin, and ceruloplasmin). In addition, PEG cows had higher values of zinc at 1 and 3 d after calving compared with CTR cows. The response observed in plasma biomarkers for energy metabolism and liver functionality after pegbovigrastim treatment in Simmental and Holstein cows was not different from that in control cows. However, our data shed light on the different metabolic adaptations during the transition period between Simmental and Holstein cows, characterized by different energy, inflammatory, and oxidative pattern responses. For the first time, we have highlighted the effect of pegbovigrastim in maintaining stable cytokine levels during the first month after parturition, reflecting greater regulation of neutrophil recruitment, trafficking, and maturation during the inflammatory response. These results provide evidence of the immunomodulatory action of pegbovigrastim around parturition, when dairy cows are highly immunosuppressed. At the same time, these data demonstrate that increasing release of cytokines after parturition is not linked to exacerbation of a systemic inflammation evaluated based on haptoglobin and ceruloplasmin levels.

Choline supply during negative nutrient balance alters hepatic cystathionine β-synthase, intermediates of the methionine cycle and transsulfuration pathway, and liver function in Holstein cows

Although choline requirements for cows are unknown, enhanced postruminal supply may decrease liver triacylglycerol and increase flux through the Met cycle to improve immunometabolic status during a negative nutrient balance (NNB). Our objectives were to investigate the effects of postruminal choline supply during a feed restriction-induced NNB on (1) hepatic activity cystathionine β-synthase and transcription of enzymes in the transsulfuration pathway and Met cycle; (2) hepatic metabolites in the Met cycle and the transsulfuration pathway, bile acids, and energy metabolism; and 3) plasma biomarkers of liver function, inflammation, and oxidative stress. Ten primiparous rumen-cannulated Holstein cows (158 ± 24 d postpartum) were used in a replicated 5 × 5 Latin square design with 4-d treatment periods and 10 d of recovery (14 d/period). Treatments were unrestricted intake with abomasal infusion of water, restricted intake (R; 60% of net energy for lactation requirements) with abomasal infusion of water, or R plus abomasal infusion of 6.25, 12.5, or 25 g/d choline ion. Liver tissue was collected on d 5 after infusions ended, and blood was collected on d 1, 3, and 5. Statistical contrasts were A0 versus R0 (CONT1), R versus the average of choline doses (CONT2), and tests of linear and quadratic effects of choline dose. Activity of cystathionine β-synthase was lower with R (CONT1) and decreased linearly with choline. Hepatic glutathione was not different with R or choline, but taurine tended to be greater with choline (CONT2). Betaine and carnitine were greater with R (CONT1) and further increased with choline (CONT2). Concentrations of NAD⁺ were greater with choline (CONT2). Cholic and glycol-chenodeoxycholic acids were decreased by R and choline, while taurocholic and tauro-chenodeoxycholic acids were not altered. Plasma aspartate aminotransferase and bilirubin were greater with R (CONT1) but decreased with choline (CONT2). Paraoxonase was lower with R and increased with choline (CONT2). Data suggest that enhanced supply of choline during NNB decreases entry of homocysteine to the transsulfuration pathway, potentially favoring remethylation to Met by acquiring a methyl group from betaine. As such, Met may provide methyl groups for synthesis of carnitine. Along with production data indicating that 12.5 g/d choline ion improved milk yield and liver fatty acid metabolism during NNB, the changes in blood biomarkers also suggest a beneficial effect of choline supply on liver function and oxidative stress.

Dietary energy level affects adipose depot mass but does not impair in vitro subcutaneous adipose tissue response to short-term insulin and tumor necrosis factor-α challenge in nonlactating, nonpregnant Holstein cows

We assessed effects of overfeeding energy to nonlactating and nonpregnant Holstein cows during a length of time similar to a typical dry period on body lipid storage and the abundance of genes related to insulin signaling, inflammation, and ubiquitination in subcutaneous adipose tissue (SAT) in vitro challenged with insulin and recombinant bovine tumor necrosis factor-α. Fourteen cows were randomly assigned to either a high-energy (OVE; net energy for lactation = 1.60 Mcal/kg of dry matter; n = 7) or control (CON; net energy for lactation = 1.30 Mcal/kg of dry matter; n = 7) diet for 6 wk. Immediately after slaughter, liver, kidneys, and mammary gland were separated and weighed. The adipose tissue mass in the omental, mesenteric, and perirenal depots was dissected and weighed. Subcutaneous adipose tissue was collected from the tail-head region and was used as follows: control, bovine insulin (INS) at 1 µmol/L, tumor necrosis factor-α at 5 ng/mL (TNF), and their combination. Despite a lack of difference in final body condition score, OVE cows had greater energy intake and were heavier than CON cows. Furthermore, overfeeding led to greater mass of mesenteric and perirenal adipose, liver, and mammary gland. Overall, SAT incubated with INS had an upregulation of insulin receptor (INSR), interleukin-10 (IL10), small ubiquitin-like modifier 3 (SUMO3), and ubiquitin conjugating enzyme E2I (UBC9), whereas TNF upregulated peroxisome proliferator-activated receptor gamma (PPARG), diacylglycerol O-acyltransferase 2 (DGAT2), interleukin-6 (IL6), nuclear factor kappa B subunit 1 (NFKB1), small ubiquitin-like modifier 2 (SUMO2), and UBC9. Regardless of in vitro treatment, feeding OVE upregulated PPARG, fatty acid synthase (FASN), and insulin induced gene 1 (INSIG1). Abundance of PPARG was greater in SAT of OVE cows cultured individually with INS and TNF. The interaction between diet and in vitro treatment revealed that sterol regulatory element binding transcription factor 1 (SREBF1) had greater abundance in SAT from the CON group in response to culture with INS, whereas SAT from OVE cows had greater SREBF1 abundance in response to culture with TNF. The mRNA abundance of IL6 and NFKB1 was greater in response to TNF treatment and overall in CON cows. Furthermore, SAT from these cows had greater IL10 abundance when cultured with INS and TNF. Overall, data highlighted that overfeeding energy increases adipose tissue mass in part by stimulating transcription of key genes associated with insulin signaling, adipogenesis, and lipogenesis. Because SAT thickness or mass was not measured, the lack of effect of overfeeding on body condition score limits its use to predict overall body lipid storage. An overt inflammatory response in SAT after a 6-wk period of over-consumption of energy could not be discerned.

Estimation of dry matter intake by n-alkanes in dairy cows fed TMR: effect of dosing technique and faecal collection time

Estimation of individual intakes in dairy cows would be beneficial to select animals according to efficiency of milk production. The n-alkanes technique has been used to estimate intake by dairy cows in free stall barns, limiting faecal samples to one or two per day, but diurnal variation in the ratio of dosed to natural alkanes in faeces represents a source of error. We aimed to adapt this technique to estimate feed intake on a large number of lactating dairy cows housed on commercial dairy farms. Using a change-over design, six lactating cows fed a TMR diet were given a dose of 0.5 g/day of C32 n-alkane administered once a day as a drench (DRE) or top fed (TP). Feed offered and refused were weighed daily. After the lead-in phases, faeces were collected at 0700 hours, 1400 hours and 1900 hours on the last 5 days of each dosing period. Dry matter intake (DMI) was estimated from C31, C33 and C32 concentrations in feeds and in faeces for each dosing system and sampling time. DMI estimated from C31 : C32 ratio was better correlated with measured individual DMI than estimates from C33 : C32 ratio. For DRE, the best correlation was for sampling at 1400 hours (R2 = 0.96, P < 0.001), but estimated DMI for the 1400 hours sampling was much higher than the actual DMI. For TP, the best correlation was for sampling at 0700 hours (R2 = 0.83, P < 0.001). Feeding C32 n-alkane and collecting faeces once a day at the same time (0700 hours) represents a valuable protocol to measure individual intake on a large number of animals.