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Controlling the properties of mid- and far-infrared radiation can provide a means to transiently alter the properties of materials for novel applications. However, a limited number of optical elements are available to control its polarization state. Here we show that a 15-µm thick liquid crystal cell containing 8CB (4-octyl-4′-cyanobiphenyl) in the ordered, smectic A phase can be used as a phase retarder or wave plate. This was tested using the bright, short-pulsed (∼1 ps) radiation centered at 16.5 µm (18.15 THz) that is emitted by a free electron laser at high repetition rate (13 MHz). These results demonstrate a possible tool for the exploration of the mid- and far-infrared range and could be used to develop novel metamaterials or extend multidimensional spectroscopy to this portion of the electromagnetic spectrum.

Dairy goat's lactation persistence forces farmers at limiting nutrient supply to reduce yield at dry-off. Omitting dry period could be a solution, but metabolic effects of this practice have never been tested. Eight Alpine (AL) and 12 Saanen (SA) goats approaching their second kidding blocked by breed and number of kids carried (single - SIN - or double - DOU) were allocated to one out of two groups (4 AL and 6 SA; 5 SIN and 5 DOU in each group). At -42 +/- 7 days from kidding (DFK), they were either dried off (DR) or milked continuously until kidding (CL). Body condition score (BCS) was assessed, and blood samples were collected at -10, -3, 5, 12, and 29 DFK to determine metabolic profile. Milk yield and composition were assessed at -56, 7, 31, 62, and 97 DFK. Compared with DR, CL had higher plasma reactive oxygen metabolites and liver enzymes. Compared with DR counterparts, AL-CL had higher nonesterified fatty acids (NEFA) at -10, whereas SA-CL had lower NEFA at -3 DFK. CL goats had lower BCS, higher plasma beta-hydroxybutyrate (BHB) and urea before kidding, but higher glucose at -3 and 5, lower NEFA at 5 and 12, and higher BCS at 29 DFK. CL goats had lower haptoglobin and myeloperoxidase at -3 and 5 DFK, paired with higher albumin, cholesterol, and paraoxonase at 12 DFK. Omitting dry period mitigated the inflammatory condition around kidding in dairy goats, possibly accounting for an improved energy balance in early lactation, despite body reserve mobilisation prepartum was greater under continuous lactation.Omitting dry period accrued prepartum energy deficit in dairy goats but improved their postpartum energy balance.Omitting dry period mitigated acute phase response and inflammation in dairy goats during the late gestation and early lactation phases.Omitting dry period in high-yielding goats could allow for a smoother transition to the new lactation coping with the limitations hindering the dry-off procedures.

The aim of this study was to investigate the associations between subclinical intramammary infection (IMI) from different pathogens combined with inflammation status and a set of blood biochemical traits including energy-related metabolites, indicators of liver function or hepatic damage, oxidative stress, inflammation, innate immunity, and mineral status in 349 lactating Holstein cows. Data were analyzed with a linear model including the following fixed class effects: days in milk, parity, herd, somatic cell count (SCC), bacteriological status (positive and negative), and the SCC x bacteriological status interaction. Several metabolites had significant associations with subclinical IMI or SCC. Increased SCC was associated with a linear decrease in cholesterol concentrations which ranged from -2% for the class >= 50,000 and < 200,000 cells/mL to -11% for the SCC class >= 400,000 cells/mL compared with the SCC class < 50,000 cells/mL. A positive bacteriological result was associated with an increase in bilirubin (+24%), paraoxonase (+11%), the ratio paraoxonase/ cholesterol (+9%), and advanced oxidation protein product concentration (+23%). Increased SCC were associated with a linear decrease in ferric reducing antioxidant power concentrations ranging from -3% for the class >= 50,000 and < 200,000 cells/mL to -9% for the SCC class >= 400,000 cells/mL (respect to the SCC class < 50,000 cells/mL). A positive bacteriological result was associated with an increase in haptoglobin concentrations (+19%). Increased SCC were also associated with a linear increase in haptoglobin concentrations, which ranged from +24% for the class >= 50,000 and < 200,000 cells/mL (0.31 g/L) to +82% for the SCC class >= 400,000 cells/mL (0.45 g/L), with respect to the SCC class < 50,000 cells/mL (0.25 g/L). Increased SCC were associated with a linear increase in ceruloplasmin concentrations (+15% for SCC >= 50,000 cells/mL). The observed changes in blood b

The cessation of lactation (i.e., dry-off) in dairy cattle is an area of research that has received much focus in recent years. The dry period is necessary to optimize tissue remodeling of the mammary gland, but repre-sents a stressful event, incorporating several changes in daily routine, diet, and metabolism. Moreover, the high milk yields achieved by modern cows in late gestation exacerbate the need for relevant manipulations in the days around dry-off, as excessive accumulation of milk might jeopardize the success of the dry period, with potential negative effects on future lactation. Produc-tion levels over 15 kg/d are an additional risk factor for udder health, delay mammary involution, and worsen metabolic stress and inflammatory responses. Furthermore, the pressure to reduce antibiotic usage in farm animals has resulted in increased attention on the dry period, given that historically most dairy cattle were provided prophylactic intramammary antibiotic treatment at dry-off as a means to reduce the risk of intramammary infections in the subsequent lactation. Several strategies have been proposed over the years to cope with these challenges, aiming to gradually reduce milk yield before dry-off, promoting at the same time the start of mammary involution. Among them, the most common are based on feed or nutrient restric-tion, a decrease in milking frequency, or administration of prolactin inhibitors. These practices have differ-ent capacities to reduce milk yield through different mechanisms and entail several implications for udder health, animal welfare, behavior, endocrine status, metabolism, and inflammatory conditions. The present review aims to provide a comprehensive overview of the dry-off phase in high-yielding cows and of the impact of high milk production at dry-off, and to describe pos-sible strategies that might be implemented by farmers and veterinarians to optimize this critical phase in an integrated way.

Positive effects have been observed as a result of Aloe arborescens supplementation in the dry-off phase in dairy cows. Metabolomic approaches can provide additional information about animal physiology. Thus, we characterized plasma metabolome around dry-off in 12 cows supplemented (AL) or not (CTR) with 10 g/d of lyophilized A. arborescens with an untargeted metabolomic approach. Overall, 1658 mass features were annotated. Regardless of treatment, multivariate statistics discriminated samples taken before and after dry-off. Overall, 490 metabolites were different between late lactation and early dry period, of which 237 were shared between AL and CTR. The most discriminant compounds (pentosidine and luteolin 7-O-glucoside) were related to the more fibrous diet. Pathway analysis indicated that pyrimidine and glycerophospholipid metabolisms were down-accumulated, suggesting reduced rumen microbial activity and liver load. Samples from AL were discriminated from CTR either the day of dry-off or 7 days after. At dry-off, aloin and emodin were the most discriminant metabolites, indicating that Aloe's bioactive compounds were absorbed. Seven days later, 534 compounds were different between groups, and emodin was among the most impacted. Pathway analysis highlighted that glycerophospholipid, pyrimidine, and folate metabolisms were affected. These results might indicate that Aloe has positive effects on liver function and a modulatory effect on rumen fermentation.

Twelve Holstein (HOL), 9 Brown Swiss (BRO), and 9 Simmental (SIM) dairy cows raised in the same barn and managed identically were enrolled to characterise the responses to the transition period. From -21 to 28 d from calving (DFC), body condition score (BCS) and milk yield were measured, and blood samples were collected to assess plasma biomarkers of metabolism, minerals, liver function, inflammation, and oxidative status. Compared with SIM, HOL and BRO had higher milk yield during the first week of lactation. HOL had the highest milk yield from the second to the fourth week and the lowest BCS at 28 DFC. SIM had the highest BCS and the highest plasma creatinine and P, reflecting a greater attitude to gain muscle mass. Compared with SIM, BRO and HOL had lower plasma fructosamine, indicating reduced glucose availability driven by lactose synthesis. SIM had the mildest acute phase response at the onset of lactation, as suggested by the lowest ceruloplasmin concentration. HOL had the highest cholesterol and paraoxonase concentrations, and the greatest interleukin-1 beta production by leukocytes following ex-vivo stimulation, suggesting that they had the quickest resolution of the acute phase response due to the fastest immune cell activation. BRO had the highest concentration of reactive oxygen metabolites, ceruloplasmin, bilirubin, glutamate-oxaloacetate transaminase, gamma-glutamyl transferase, and beta-hydroxybutyrate, and the lowest concentration of paraoxonase, reflecting the strongest activation of leukocytes and the most severe acute phase response. Together, these results highlight different metabolic and inflammatory conditions around calving in the three explored breeds.

Huge differences exist between cow yields and body sizes during their first and second lactations. The tran-sition period is the most critical and investigated phase of the lactation cycle. We compared metabolic and endocrine responses between cows at different parities during the transition period and early lactation. Eight Holstein dairy cows were monitored at their first and second calving during which they were reared under the same conditions. Milk yield, dry matter intake (DMI), and body weight (BW) were regularly measured, and energy balance, efficiency, and lactation curves were calculated. Blood samples were collected on scheduled days from -21 d relative to calving (DRC) to 120 DRC for the assessment of metabolic and hormonal profiles (biomarkers of metabolism, mineral status, inflamma-tion, and liver function). Large variations in the period in question for almost all variables investigated were observed. Compared with their first lactation, cows during their second lactation had higher DMI (+15%) and BW (+13%), their milk yield was greater (+26%), lactation peak was higher and earlier (36.6 kg/d at 48.8 DRC vs. 45.0 kg/d at 62.9 DRC), but persistency was reduced. Milk fat, protein, and lactose contents were higher during the first lactation and coagulation prop-erties were better (higher titratable acidity, faster and firmer curd formation). Postpartum negative energy balance was more severe the during the second lacta-tion (1.4-fold at 7 DRC) and plasma glucose was lower. Circulating insulin and insulin-like growth factor-1 were lower in second-calving cows during the transi-tion period. At the same time, markers of body reserve mobilization (beta-hydroxybutyrate and urea) increased. Moreover, albumin, cholesterol, and gamma-glutamyl trans-ferase were higher during second lactation, whereas bilirubin and alkaline phosphatase were lower. The inflammatory response after calving was not different, as suggested by the similar haptoglobin concentrations and

Anticoagulants, such as ethylenediaminetetraacetic acid (EDTA), sodium citrate (Na-citrate), or heparin are normally used in hematological clinical tests to prevent coagulation. Although anticoagulants are fundamental for the correct application of clinical tests, they produce adverse effects in different fields, such as those involving specific molecular techniques; for instance, quantitative real time polymerase chain reactions (qPCR) and gene expression evaluation. For this reason, the aim of this study was to evaluate the expression of 14 genes in leukocytes that were isolated from the blood of Holstein cows, and which were collected in Li-heparin, K-EDTA, or Na-citrate tubes; then, they were analyzed using qPCR. Only the SDHA gene showed a significant dependence (p ≤ 0.05) on the anticoagulant that was used with the lowest expression; this was observed in Na-Citrate after being compared with Li-heparin and K-EDTA (p < 0.05). Although a variation in transcript abundance with the three anticoagulants was observed in almost all the investigated genes, the relative abundance levels were not statistically significant. In conclusion, the qPCR results were not influenced by the presence of the anticoagulant; thus, we had the opportunity to choose the test tube that was used in the experiment without interfering effects impacting the gene expression levels caused by the anticoagulant.

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

The final weeks of gestation represent a critical period for dairy cows that can determine the success of the subsequent lactation. Many physiological changes take place and additional exogenous stressors can alter the success of the transition into lactation. Moreover, this phase is pivotal for the final stage of intrauterine development of the fetus, which can have negative long-lasting postnatal effects. Heat stress is widely recognised as a threat to dairy cattle welfare, health, and productivity. Specifically, late gestation heat stress impairs the dam's productivity by undermining mammary gland remodelling during the dry period and altering metabolic and immune responses in early lactation. Heat stress also affects placental development and function, with relevant consequences on fetal development and programming. In utero heat stressed newborns have reduced birth weight, growth, and compromised passive immune transfer. Moreover, the liver and mammary DNA of in utero heat stressed calves show a clear divergence in the pattern of methylation relative to that of in utero cooled calves. These alterations in gene regulation might result in depressed immune function, as well as altered thermoregulation, hepatic metabolism, and mammary development jeopardising their survival in the herd and productivity. Furthermore, late gestation heat stress appears to exert multigenerational effects, influencing milk yield and survival up to the third generation.