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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 DIM. Milk production, DMI (during the periparturient period), and rumination times were recorded daily. At dry-off, NR cows had decreased milk yield (-62%) and milk lactose compared with CTR 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, BHB, 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, b

Dairy cow longevity is an important economic trait for producers. In modern dairy farming, longevity of dairy cows is the result of culling decisions, which are determined by several risk factors, including diseases, and reproductive and productive performance. Previous studies have documented that seasonal changes affect health, behavior, and performance of dairy cows throughout their life cycle. Increasing cow comfort by making management adjustments to decrease exposure to high temperatures during the hot months gives farmers the opportunity to decrease culling risk factors and possibly increase cow productive life. In the present study, we obtained the records of primiparous and multiparous Holstein cows from Florida (n = 10,812) and California (n = 8,197) during a 10-yr period (2012–2022). We analyzed the relationship between birth season and longevity (i.e., cows that remained in the herd for 5 or more lactations) in Florida (n = 1,567) and in California (n = 1,669). The number of cows dead, sold, the reasons why they were sold, and their relationship with birth season were also analyzed in the Florida dataset. The hypothesis was that birth in a cool season will increase the length of herd productive life and decrease the number of cows sold or dead during all lactations. The birth seasons were cool (CL; cows born in December, January, February, or March) and hot (HS; cows born in June, July, August, or September). Results showed that in Florida, most cows that remained in the herd for more than 5 lactations (i.e., 14.5% of total cow records) were born during CL compared with cows born during HS (1,129, 72% vs. 438, 28%). The same observations were made in California, where greater longevity (i.e., 5 or more lactations, representing 20.4% of total cow records) was attributed to cows born in CL compared with HS cows (939, 56.3% vs. 730, 43.7%). In Florida, a greater number of HS were sold compared with CL cows (765, 52.6% vs. 689, 47.4%). More HS cows were sold

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.