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Dairy cows at dry-off undergo several management and physiological changes, resulting in alterations in plasma biomarkers of inflammation, oxidative stress, and immune system. High milk yield at the end of lactation exacerbates these responses. The underlying mechanism of these changes has yet to be elucidated. We hypothesized altered leukocyte gene expression after dry-off and different responses in cows with different milk yield. Thirteen Holstein dairy cows were sampled at the turn of dry-off to investigated whole blood leukocyte gene expression and were grouped according to the average milk yield during the last week of lactation: low (< 15 kg/d) and high milk yield (> 15 kg/d). Blood samples were collected in PAXgene tubes (Preanalytix, Hombrechtikon, Switzerland) at -7, 7, and 34 days from dry-off (DFD) to measure mRNA abundance of 37 genes. Normalized gene abundance data were subjected to MIXED model ANOVA (SAS Institute Inc., Cary, NC). Compared with -7 DFD, at 7 DFD RNA abundance of lipoxygenase genes (ALOX5, ALOX15) and myeloperoxidase (MPO) increased, and that of the antioxidant gene (SOD2) decreased. Meanwhile, genes related to recognition and immune mediation (CD16, MYD88, TLR2), migration and cell adhesion (CX3CR1, ITGAL, ITGB2, TLN1), and the antimicrobial gene MMP9 were downregulated at 7 or 34 DFD, whereas the antimicrobial IDO1 gene was upregulated. Compared with low-producing cows, cows with high milk yield at dry-off cows had upregulated expression of the pro-inflammatory cytokines IL8 and IL18 and a greater reduction in transcript abundance of the toll-like receptor (TLR) recognition-related gene TLR2. Overall, the dry-off confirmed to be a phase of intense changes, triggering an inflammatory response and somewhat suppressing leukocyte immune function. In cows with high milk yield during the week before dry-off, the inflammatory response was exacerbated. [ABSTRACT FROM AUTHOR]

Our study investigates metabolic changes occurring at dry-off and the contribution of milk yield (MY) in such alterations. Thirteen Holsteins were dried off at 55 days from expected calving day (assumed as 0 days from dry-off, DFD) and divided in two groups according to their average daily MY in the last week of lactation, assuming a cut-off of 15 kg·d−1: low MY (7 cows) and high MY (6 cows). From −7 to 34 DFD dry matter intake (DMI) and rumination time were measured. Blood samples were collected at −7, 2, 7, 27 and 34 DFD to assess an haematological and metabolic profile and at −7, 7 and 34 DFD to test functions of circulating white blood cell (WBC) through ex vivo challenges. Data were included in a mixed model for repeated measures assuming MY at dry-off, time and their interaction as fixed effects. After dry-off, DMI was reduced and rumination time was increased in all the animals. High MY cows had greater DMI and rumination time than low MY cows. In blood, WBC counts decreased at 7 DFD and increased the production of pro-inflammatory cytokines at 7 and 34 DFD. Plasmatic concentrations of liver enzymes indicators, positive acute phase proteins (APPs); and nitrogen species increased after dry-off. Conversely, negative APPs and antioxidant species decreased. Those alterations were more marked in high MY animals. This study suggests that dry-off decreased liver function, triggered a systemic inflammation and depleted antioxidant systems, especially in the group of cows with high MY at dry-off. Inflammation, liver dysfunctions and altered redox balance has been detected after dry-off in all the animals. Cows with highest milk yield before halting of milk removal faced the most severe metabolic challenges. Such founding indicates the management of dry-off as a key point for dairy cows health. [ABSTRACT FROM AUTHOR]

Dairy cows during the transition period are faced with important physiological changes which include a dysfunctional immune system and an increased inflammatory state. New data are necessary to understand the key factors involved in the immune system regulation. Six dairy cows were sampled during transition period to investigate the leukocyte transcriptome changes and its relationship with blood biomarkers. Blood samples were collected at − 20 ± 2, − 3 ± 1, 3, and 7 days from parturition (DFP). Leukocyte transcriptome was analyzed by deep sequencing technology (Hiseq1000 Illumina, USA). Plasma was analyzed for metabolic biomarkers. Differentially expressed genes (DEG) were used to run an enrichment analysis through the Dynamic Impact Approach (DIA). Considering − 20 DFP as references time, the main KEGG impacted pathways were activated before calving (− 3 DFP) and were connected to lipid metabolism, lipid transport in plasma, and phagosome. The greatest differences were found after parturition with 281 DEG (179 upregulated and 102 downregulated). The activated pathways were mainly related to immunity and endocrine aspects, while metabolic pathways related to lipid and amino acid metabolism were inhibited. Plasma BHBA had a substantial inhibitory impact on KEGG pathways related to DNA replication and cell cycle, while plasma IL-1β had an inhibitory impact on fatty acid elongation in mitochondria and an activated impact in several pathways related to cellular energy metabolism. Overall, this study confirmed that many changes in lipid metabolism and immune competence of the circulating leukocytes occurred in dairy cow around calving. Interestingly, BHBA and IL-1β connected with the transcriptome. [ABSTRACT FROM AUTHOR]

Simple Summary: During the transition period (TP), the innate and adaptive immune system of dairy cows is impaired, contributing to an increase in susceptibility to infectious disease. Pegbovigrastim is a recombinant form of the granulocyte colony-stimulating factor, that stimulates differentiation of hemopoietic stem cells to granulocyte and shortens maturation time within the bone marrow and their release in circulation. For the first time, this study investigated the effect of pegbovigrastim on the hematologic profile, including red cells and platelets during the TP in dual-purpose Simmental dairy cows. Results confirm the efficacy of pegbovigrastim administration in promoting the numbers of total with cells, mainly neutrophils. Nevertheless, this study highlighted the presence of an anemia condition in treated cows most likely caused by an inflammatory process involving the endothelium. Overall, this study confirms the safety of pegbovigrastim administration, but further studies need to check its ability to reduce infection even in Simmental breed. Pegbovigrastim is a long-acting analog of recombinant bovine granulocyte colony-stimulating factor, that promotes and increases the count and functionality of polymorphonuclear cells in dairy cows. The present study aimed to explore, for the first time in Simmental cows, the clinical and hematological effect of pegbovigrastim during the transition period (TP). Cows were randomly assigned into two groups: treated group (PEG; n = 16) received pegbovigrastim at approximately 7 days before expected parturition and within 6 h after calving, and control group (CTR; n = 16) received saline solution. Blood samples were obtained at −7, 0, 1, 3, 7, 14, 21, and 30 days relative to calving. PEG group showed white blood cells (WBC) count consistently higher compared with CTR group (p < 0.001) until to 3 weeks after calving. Neutrophils remained higher in PEG group (p < 0.001) up to three weeks after calving, compared with CTR group, with slight increment of band cells. Moreover, PEG group displayed a lower index of myeloperoxidase at 1, 3, and 7 days after calving (p < 0.01) compared with CTR. Basophils and lymphocytes showed a similar trend to those observed for neutrophils at 1 day after calving in PEG group. Finally, monocytes remained markedly elevated until 3 days after calving in PEG compared to CTR group (p < 0.001), whereas in PEG group, eosinophils population showed lower percentage values at 1 and 3 days after calving but higher values at 30 days compared with CTR group. PEG group was characterized by lower red blood cells (RBCs) count compared with CTR group (p < 0.05) and higher % of red cell volume distribution width (RDW) from week 2 and mean corpuscular volume (MCV) at 30 days after calving. In addition, the mean platelet volume (MPV) was significantly higher in PEG group at calving, 1, 3, and 7 days after calving compared with CTR group (p < 0.05). For the first time, we described the effect of pegbovigrastim in a breed not specialized exclusively in milk production as Holstein, but with dual purpose (meat and milk), evaluating the complete hematological profile in cows during the transition period. These results provide evidence on the proliferative effect of pegbovigrastim on WBC in Simmental breed highlighting its possible side effect on RBCs. [ABSTRACT FROM AUTHOR]