Puerarin Alleviates H2O2-Induced Oxidative Stress and Blood-Milk Barrier Impairment in Dairy Cows

During the perinatal period, the bovine mammary epithelial cells of dairy cows exhibit vigorous metabolism and produce large amounts of reactive oxygen species (ROS). The resulting redox balance disruption leads to oxidative stress, one of the main causes of mastitis. Puerarin (PUE) is a natural flavonoid in the root of PUE that has attracted extensive attention as a potential antioxidant. This study first investigated whether PUE could reduce oxidative damage and mastitis induced by hydrogen peroxide (H₂O₂) in bovine mammary epithelial cells in vitro and elucidated the molecular mechanism. In vitro, BMECs (Bovine mammary epithelial cells) were divided into four treatment groups: Control group (no treatment), H₂O₂ group (H₂O₂ stimulation), PUE + H₂O₂ group (H₂O₂ stimulation before PUE rescue) and PUE group (positive control). The growth of BMECs in each group was observed, and oxidative stress-related indices were detected. Fluorescence quantitative PCR (qRT-PCR) was used to detect the expression of tightly linked genes, antioxidant genes, and inflammatory factors. The expression of p65 protein was detected by Western blot. In vivo, twenty cows with an average age of 5 years having given birth three times were divided into the normal dairy cow group, normal dairy cow group fed PUE, mastitis dairy cow group fed PUE, and mastitis dairy cow group fed PUE (n = 5). The contents of TNF-α, IL-6, and IL-1β in milk and serum were detected. In BMECs, the results showed that the PUE treatment increased the activities of glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), and total antioxidant capacity (T-AOC); ROS and malondialdehyde (MDA) levels were reduced. Thus, PUE alleviated H₂O₂-induced oxidative stress in vitro. In addition, the PUE treatment eliminated the inhibition of H₂O₂ on the expression of oxidation genes and tight junction genes, and the enrichment degree of NRF-2, HO-1, xCT, and tight junctions (claudin4, occludin, ZO-1 and symplekin) increased. The PUE treatment also inhibited the expression of NF-κB-associated inflammatory factors (IL-6 and IL-8) and the chemokine CCL5 in H₂O₂-induced BMECs. In vivo experiments also confirmed that feeding PUE can reduce the expression of inflammatory factors in the milk and serum of lactating dairy cows. In conclusion, PUE can effectively reduce the oxidative stress of bovine mammary epithelial cells, enhance the tight junctions between cells, and play an anti-inflammatory role. This study provides a theoretical basis for PUE prevention and treatment of mastitis and oxidative stress. The use of PUE should be considered as a feed additive in future dairy farming.

Maladaptation to the transition period and consequences on fertility of dairy cows

After parturition, dairy cows undergo a plethora of metabolic, inflammatory, and immunologic changes to adapt to the onset of lactation. These changes are mainly due to the homeorhetic shift to support milk production when nutrient demand exceeds dietary intake, resulting in a state of negative energy balance. Negative energy balance in postpartum dairy cows is characterized by upregulated adipose tissue modelling, insulin resistance, and systemic inflammation. However, half of the postpartum cows fail to adapt to these changes and develop one or more types of clinical and subclinical disease within 5 weeks after calving, and this is escorted by impaired reproductive performance in the same lactation. Maladaptation to the transition period exerts molecular and structural changes in the follicular and reproductive tract fluids, the microenvironment in which oocyte maturation, fertilization, and embryo development occur. Although the negative effects of transition diseases on fertility are well-known, the involved pathways are only partially understood. This review reconstructs the mechanism of maladaptation to lactation in the transition period, explores their key (patho)physiological effects on reproductive organs, and briefly describes potential carryover effects on fertility in the same lactation.

Adaptive Responses of Thyroid Hormones, Insulin, and Glucose during Pregnancy and Lactation in Dairy Cows

The study examined the effects of different stages of pregnancy and lactation on thyroid, insulin, and glucose responses in dairy cows. In the present study, 30 dairy cows (10 Holstein, 10 Simmental, and 10 Brown) at 30 ± 20 d of lactation were randomly selected and blood samples were collected once every 60 d for one year to measure circulating thyroid stimulating hormone (TSH), total and free triiodothyronines (T3, fT3) and thyroxines (T4, fT4), insulin, and glucose. Pregnant cows showed higher T4 (p = 0.010) and insulin (p = 0.046) concentrations at >180 d than at >60−120 d of pregnancy and in nonpregnant cows. Along the lactation phase, circulating T4 concentrations showed a biphasic trend, decreasing from 0−60 d to >60−120 d phase, which showed the lowest values, and then increasing until the end of lactation (>300 d) (p = 0.016). Glucose showed the highest concentrations at the start of lactation (0−120 days) and the lowest values at the end (p = 0.008). The monitoring of thyroid hormones, insulin, and glucose changes represents an important tool to evaluate the anabolic and/or catabolic adaptation in response to functional periods in dairy cows, which can potentially predispose the cows to an excessive negative energy balance and related metabolic issues.

Aspects of transition cow metabolomics-Part II: Histomorphologic changes in the liver parenchyma throughout the transition period, in cows with different liver metabotypes and effects of a metaphylactic butaphosphan and cyanocobalamin treatment

The aims of this study were to evaluate histopathologic changes during the transition period, describe the histopathological features of the metabotypes identified in Part I (Schären et al., 2021b), and investigate effects of a metaphylactic treatment with butaphosphan and cyanocobalamin (BCC) on the liver parenchyma. Eighty German Holstein cows (mean 305-d production: 10,957 kg, range: 6,480-15,193 kg; mean lactation number: 3.9, range: 2-9) from a commercial dairy farm in Saxony, Germany, were enrolled in a randomized, prospective, triple-blinded study. Two groups received a treatment with BCC (5 or 10 mL/100 kg of body weight 10% butaphosphan and 0.005% cyanocobalamin, Catosal, Bayer Animal Health, n = 20 each) and one group a placebo treatment (NaCl 0.9%, n = 40). Liver biopsy specimens were collected 14 d antepartum (AP) and 7, 28, and 42 d postpartum (PP), routinely processed for histologic examination, and stained with hematoxylin and eosin, Sudan III, periodic acid-Schiff, and picrosirius red stains. The sections were assessed for fat and glycogen content and degenerative, inflammatory, fibrotic, and proliferative changes. The statistical analysis included the effects of the sampling day, the lactation number, the treatment, and the metabotype (A = medium, B = minor, C = large alterations in the liver metabolome profile between AP and PP status). There was mild to moderate fat infiltration in the liver of 37% of cows in the last 2 wk AP, and moderate to severe fat infiltration in 66% of cows in the first days PP. The degree of fat infiltration increased from 2 wk AP until the end of the first week PP, and then decreased until the end of the study period, at which time about 25% of cows had moderate to severe fatty infiltration. Lipidosis was positively correlated with the severity of liver cell degeneration, and negatively correlated with the degree of glycogen deposits. Complete glycogen depletion of hepatocytes was not observed in cows, even in the presence of severe hepatic lipidosis. Moderate to severe lymphocytic hepatitis was seen in 39% of cows throughout the study period, and cows with lactation numbers 5 or greater had perisinusoidal fibrosis more often than younger cows. Severe fibrosis and cirrhosis of the liver did not occur. Metabotype B animals exhibited a higher chance of fatty infiltration, lower glycogen storage, and perisinusoidal fibrosis and for this metabotype positive correlations were calculated between increased fat deposition in the liver and marked glycogen depletion, and increased degenerative, inflammatory, fibrotic, and proliferative changes of hepatic tissue. For the treatment with BCC, no significant effect was observed. In summary, during the transition period, the liver of dairy cows is characterized by fat accumulation and glycogen depletion and histologic signs of hepatitis and hepatocyte degeneration. These histomorphologic changes were accentuated in animals exhibiting little alterations in their liver metabolome profile across the transition period (metabotype B) and support the assumption of a decreased grass silage quality as a causative factor.

Comparison between two preventive treatments for hyperketonaemia carried out pre-partum: effects on non-esterified fatty acids, β-hydroxybutyrate and some biochemical parameters during peripartum and early lactation

The objective of this study was to compare the effect of two different preventive protocols, on serum β-hydroxybutyrate (BHB) concentration and liver health indices pre-partum and during early-lactation in high-yielding Holstein dairy cows. One hundred cows were randomly divided into three groups: control group (CTRL, n = 20, without preventive treatment), second group (SUPP, n = 40 animals treated with a compound based on acetyl-methionine, inositol, cyanocobalamin, l-alanine, l-arginine, l-threonine, l-glutamic acid supplementation and α-lipoic acid) and third group (MON, n = 40 animals treated with monensin). Blood samples were collected from all cows at on 3 occasions pre-partum and 3 occasions post-partum. Body condition (BCS) score was evaluated and glucose, non-esterified fatty acids (NEFA), BHB, triglycerides, total cholesterol, alanine aminotransferase (ALT), aspartate aminotransferase (AST), γ-glutamyltransferase (GGT), total bilirubin, total proteins, globulins, albumin and urea concentrations were assessed. Two-way repeated measures analysis of variance was applied. Statistically significant differences among the three experimental groups were found in the values of all studied parameters (P < 0.05). Our results confirm the established beneficial effect of MON treatment in decreasing BHB levels and increasing glucose availability after calving. Serum biochemical analysis revealed the expected post-partum alterations attributable to adaptations that influenced the metabolism and liver function in CTRL, whereas these alterations were reduced or absent in SUPP and MON. Results from the present study suggest that both preventive protocols, but in particular SUPP, could positively affect selected indicators of energy metabolism reducing the risk of hyperketonaemia and increase of liver function in Holstein dairy cows, both pre- and post-partum.

Prognostic value of serum potassium level predicting the duration of recumbency in downer cows due to metabolic disorders

Downer cows and variations in the treatment response are of great interest to farmers. Positively responded animals get up at different extended periods after receiving the same treatment protocol. The objective of this study is to determine if there is any association between the duration of recumbency and the level of serum biomarkers. Serum samples from 165 crossbred Holstein dairy cows (105 downer cows of metabolic causes only and 50 healthy) and from 65 cured cows after treatment were used for analysis of calcium (Ca), inorganic phosphorus (P), potassium (K), magnesium (Mg), creatine phosphokinase (CPK), aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma-glutamyl transferase (GGT), beta-hydroxybutyric acid (BHBA), non-esterified fatty acid (NEFA), and triglycerides (TG). Assessment of diagnostic performance of these biomarkers was performed using analysis of the receiver operating characteristic (ROC). Serum levels of Ca, P, K, and TG decreased significantly (P < 0.001), while CPK, AST, ALT, BHBA, and NEFA increased significantly (P < 0.001) in those downers compared with controls. They achieved high diagnostic performance in ROC curve analysis. Interestingly, 65 cows responded after treatment and stood up (cured cases) after a period of recumbency varying from 4 to 15 days and statistics revealed a significant association (P < 0.05) between those days of recumbency and only serum K levels. We concluded that only the serum potassium (K) level is a significant predictor of post-treatment recumbency period and that the serum P, CPK, and NEFA levels have the highest diagnostic performance.

Effects of Propylene Glycol on Negative Energy Balance of Postpartum Dairy Cows

Simple Summary

After calving, the milk production of dairy cows increases rapidly, but the nutrient intake cannot meet the demand for milk production, forming a negative energy balance. Dairy cows in a negative energy balance have an increased risk of developing clinical or subclinical ketosis. The ketosis in dairy cows has a negative impact on milk production, dry matter intake, health, immunity, and reproductive performance. Propylene glycol can be used as an important gluconeogenesis in ruminants and can effectively inhibit the formation of ketones. Supplementary propylene glycol to dairy cows during perinatal is an effective method to alleviate the negative energy balance. This review summarizes the reasons and consequences of negative energy balance as well as the mechanism and effects of propylene glycol in inhibiting a negative energy balance in dairy cows. In addition, the feeding levels and methods of using propylene glycol to alleviate negative energy balance are also discussed.

Abstract

With the improvement in the intense genetic selection of dairy cows, advanced management strategies, and improved feed quality and disease control, milk production level has been greatly improved. However, the negative energy balance (NEB) is increasingly serious at the postpartum stage because the intake of nutrients cannot meet the demand of quickly improved milk production. The NEB leads to a large amount of body fat mobilization and consequently the elevated production of ketones, which causes metabolic diseases such as ketosis and fatty liver. The high milk production of dairy cows in early lactation aggravates NEB. The metabolic diseases lead to metabolic disorders, a decrease in reproductive performance, and lactation performance decline, seriously affecting the health and production of cows. Propylene glycol (PG) can alleviate NEB through gluconeogenesis and inhibit the synthesis of ketone bodies. In addition, PG improves milk yield, reproduction, and immune performance by improving plasma glucose and liver function in ketosis cows, and reduces milk fat percentage. However, a large dose of PG (above 500 g/d) has toxic and side effects in cows. The feeding method used was an oral drench. The combination of PG with some other additives can improve the effects in preventing ketosis. Overall, the present review summarizes the recent research progress in the impacts of NEB in dairy cows and the properties of PG in alleviating NEB and reducing the risk of ketosis.

Changes of milk fatty acid composition in four lipid classes as biomarkers for the diagnosis of bovine ketosis using bioanalytical Thin Layer Chromatography and Gas Chromatographic techniques (TLC-GC)

The aim of this study was to extend the limited research available on the association between the concentration of milk fatty acids and the elevated plasmatic value of β-hydroxybutyrate (BHB) in early lactation of dairy cows. Fifty-four Holstein Friesian dairy cows were enrolled in the study. All animals were classified on the basis of their blood BHB concentration: BHB ≥ 1.0 mmol/L (BHB-1, sick group) and BHB ≤ 0.99 mmol/L (BHB-0, healthy group). Using Thin Layer Chromatography (TLC), four lipid classes (cholesterol esters -CE-, phospholipids -PL-, free fatty acids -FFA- and triacylglycerols -TAG-) were separated, and then the fatty acid (FA) composition was determined by High Resolution Gas Chromatography coupled with Flame Ionization Detector/Mass Spectrometer (HRGC-FID/MS). The FA profiles were used to investigate the diagnostic potential value of milk fatty acids for the correct classification of cows with BHB concentration above the established threshold (BHB < 1.0 mmol/L). Boruta Test and Receiver Operating Characteristic curves (ROC) were used to identify which FA and their thresholds of concentration could be used when animals presented hyperketonemia. The research has identified fourteen FA, belonging to CE, FFA, and TAG classes, useful for an association with BHB-1. These compounds, with predictive value for the development of hyperketonemia, could be considered valuable biomarkers. Further studies on a wider sampling, based on clinical and therapeutic approach, will be necessary to confirm, by bioanalytical chromatographic approaches, if these predictive FA will change between healthy and sick animals. New approaches in relation on the administration of different diets or supplements, and administration of drugs might improve the prevention of hyperketonemia.

Identification of Plasma Fatty Acids in Four Lipid Classes to Understand Energy Metabolism at Different Levels of Ketonemia in Dairy Cows Using Thin Layer Chromatography and Gas Chromatographic Techniques (TLC-GC)

Excessive mobilization of adipose tissue in high milk producing dairy cows predisposes to metabolic diseases. The aim of this research was to identify the plasma fatty acids in four lipid classes as biomarkers for the diagnosis of hyperketonemia in bovines using thin layer chromatography and gas chromatographic techniques (TLC-GC). Sixty multiparous Holstein-Friesian dairy cows were enrolled in the study. Blood samples from the coccygeal vein were collected and β-hydroxybutyrate (BHB) was evaluated. All animals were divided into three groups on the basis of ketonemia: BHB < 0.50 mmol/L, 0.50 < BHB < 1.0 mmol/L, and BHB > 1.0 mmol/L. Plasma fatty acid concentrations were evaluated in four lipid classes: Free Fatty Acids (FFA), Triglycerides (TG), Cholesterol Esters (CE) And Phospholipids (PL). The concentration of fatty acids was analyzed using TLC-GC. The results showed the following significance in the lipid classes: 19 fatty acids were significant (p < 0.053) in FFA, nine fatty acids were significant (p < 0.050) in TG, eight fatty acids were significant (p < 0.050) in CE and three fatty acids were significant (p < 0.049) in PL. Eleven parameters were considered as predictive fatty acids related to animals in hyperketonemia. The FFA increased simultaneously with blood BHB levels, although the identified predictive fatty acids related to the TG and CE lipid classes decreased, meanwhile the BHB values increased. In the PL lipid class, no fatty acids were predictive.

Palmitic acid-enriched fat supplementation alleviates negative production responses during early lactation of Holstein dairy cows

Effects of rumen-protected fat (RPF) on suppressing the negative performance responses in early lactation period of Holstein dairy cows were investigated. Three hundred multiparous Holstein cows (647 ± 16 kg bodyweight and 90 days in milk (DIM)) were randomly housed into three free-stall barns (100 cows per barn) and assigned to the treatments for 90 days, as follows: (1) control (CTL) diet without RPF; (2) calcium salt of palm fatty acids (CaFA) 30 g/kg DM, and (3) fractionated fatty acids of palm oil (FFA) 25 g/kg DM. Cows were fed total mixed ration containing 580 g of concentrate and 420 g of roughage per kilogram DM. Cows fed FFA exhibited a higher (P &lt; 0.05) DM intake and body condition score than did those fed CaFA or CTL diets respectively. Moreover, cows fed the FFA diet showed decreased (P &lt; 0.05) changes to bodyweight at 30 DIM and to body condition score at 60 DIM and increased digestibility of ether extract and neutral detergent fibre. Blood concentrations of triglycerides, cholesterol and glucose were higher (P &lt; 0.05) for cows fed FFA diet than for those fed the other diets, between 4 and 30 DIM, whereas concentrations of non-esterified fatty acids, β-hydroxybutyric acid and urine ketones were lower for cows fed RPF sources (P &lt; 0.05). Relative to CTL diet, CaFA and FFA diets increased (P &lt; 0.05) milk yield and milk fat content at 4–30 DIM. Feeding FFA improved feed efficiency by 8.9% (P = 0.006), between 31 and 60 DIM, compared with CaFA. Inclusion of a palmitic acid-enriched fat supplement in Holstein cow diet increased milk yield and fat content and mitigated the deleterious effects of metabolic disorders during the early lactation period.

Effect of zinc and vitamin E supplementation on hormones and blood biochemicals in peri-partum Sahiwal cows

Thirty-two advanced pregnant multiparous Sahiwal cows were used to study the effect of additional zinc (Zn) and vitamin E (VE) supplementation on hormonal and biochemical changes. Cows were randomly assigned to four groups and fed a basal diet of compounded concentrate, berseem fodder, and wheat straw in a ratio of 60:20:20. The groups were: (1) the basal diet with no supplement (control treatment); (2) the basal diet supplemented with 60 mg/kg DM/cow daily of Zn (Zn treatment); (3) the basal diet supplemented with 1000 IU/cow daily of vitamin E (VE treatment); and (4) the basal diet supplemented with a combination of 60 mg Zn/kg DM/cow and 1000 IU vitamin E/cow/d (Zn + VE treatment). Blood samples were collected on -60, -45, -30, -15, -7, -3, 0, 3, 7, 15, 30, 45, 60, 90, and 120 d in relation to expected date of calving and were analyzed for endocrine variables and biochemical changes. Plasma concentrations of leptin, insulin, insulin like growth factor-1 (IGF-1), triidothyronine (T3), and tetraiodothyronine (T4) were decreased toward calving and observed lowest (P < 0.05) on 3 d post-partum. However, plasma levels of growth hormone (GH) and cortisol increased toward calving and were found highest (P < 0.05) on 3 d post-partum. Pre-partum concentrations of leptin and IGF-1 were higher (P < 0.05) than its respective concentration observed during post-partum. Post-partum concentrations of GH and cortisol were higher (P < 0.05) than its respective pre-partum concentration. Pre-partum concentrations of urea, triglycerides, Zn, and VE were higher (P < 0.05) and total cholesterol and HDL cholesterol were lower than its values observed in post-partum among all the groups. Treatments had significant (P < 0.05) effect on plasma hormonal levels and levels of Zn and VE but no effect on biochemical attributes. Cows fed on diet supplemented with Zn + VE had highest (P < 0.05) pre as well as post-calving concentrations of leptin (6.38 vs 5.01 ng/ml), insulin (1.39 vs 1.33 ng/ml), GH (9.29 vs 13.72 ng/ml), IGF-1 (14.55 vs 12.59 nmol/l), T3 (1.45 vs 1.40 ng/ml), T4 (32.44 vs 31.79 ng/ml) whereas as lowest concentration of cortisol hormone (3.05 vs 3.44 ng/ml). Cows supplemented with combination of Zn and VE showed minimum decline in plasma concentration of leptin, insulin, GH, IGF-1, T3, and T4, and minimum increase in cortisol concentration. In conclusion, dairy cows around parturition faces various endocrine and biochemical alterations and supplementation of Zn in combination with VE can ameliorate adverse effect of calving stress by maintaining circulatory concentration of hormone and biochemicals towards the basal levels.

Ultrasonographic measurement of liver, portal vein, hepatic vein and perivisceral adipose tissue in high-yielding dairy cows with fatty liver during the transition period

The aim of the present study was to evaluate the potential for diagnosis of fatty liver by means of ultrasonographic measurement of liver and perivisceral adipose tissue as an alternative to blood indicators of lipomobilization and liver biopsy in periparturient high-yielding dairy cows. Thirty cows were enrolled and divided into two groups. The evaluation of body condition score (BCS), non-esterified fatty acids (NEFA), β-hydroxybutyrate (BHB), liver and perivisceral adipose tissue ultrasonographic measurement and histological liver lipid content (GdL) was performed at 15 ± 5 d prepartum (T0), 10 ± 2 d postpartum (T1), 30 ± 2 d postpartum (T2) and 50 ± 2 d postpartum (T3). Mesenteric fat thickness (the thickness of the perivascular adipose tissue) measured on ultrasound was shown to be an independent determinant of fatty liver. The cut-off of the ultrasonographic evaluation of the liver may be useful as a first and practical approach in identifying fatty liver. In conclusion, a non-invasive and reliable diagnostic method for predicting the risk of fatty liver in high yielding dairy cows has been demonstrated.

Metabolic and hormonal adaptation in Bubalus bubalis around calving and early lactation

Pregnancy and lactation are physiological periods that result in an increased metabolic demand that, if not satisfied, could provoke a threat to homeostasis. In this study changes in the values of Non-Esterified Fatty Acids (NEFA) and β-hydroxybutyrate (BHB), glucose, insulin, thyroid hormones, milk composition and yield were investigated in buffaloes during the late pregnancy and early lactation. From a total of 50 buffaloes, blood samples were collected -7±5 days before expected calving; +7±5; +30±5 and +50±5 days post-partum; milk samples were collected at the same post-partum time points. On serum samples, the values of Non-Esterified Fatty Acids (NEFA), β-hydroxybutyrate (BHB), glucose, insulin, Triiodothyronine (T3), Thyroxine (T4) and Thyroid-stimulating hormone (TSH) were evaluated. On milk, fat %, protein %, lactose %, somatic cells score (SCS), milk yield and daily milk production (DMP) were assessed. Peripartum period significantly influenced all studied parameters (P<0.05). Milk constituents and productivity statistically changed throughout monitoring period (P<0.005). Milk yield resulted positively correlated with insulin and TSH values, negatively correlated with NEFA and BHB. Insulin was negatively correlated with lactose % and positively correlated with SCS. The obtained results showed that the peripartum period and lactation are accompanied by marked changes in some biochemical variables and in the thyroid hormones values in Italian Mediterranean Buffaloes. Moreover, the relationship found between TSH values and milk yield seems to suggest a possible role of thyroid gland on the maintenance of lactogenesis. This study underlines the importance of monitoring the hormonal status of buffalo during the transition period in order to understand when adjustments of regulatory mechanisms break through physiological limits predisposing the buffalo to metabolic problems.

Changes in Thyroid Hormones Levels and Metabolism in Dairy Cows around Calving

The hormonal activity of the thyroid gland has an important role in ruminants for the modulation of metabolic variables. In this study changes in thyroid hormones and biochemical parameters in dairy cows around calving were evaluated and the critical thyroid hormones thresholds for predicting the risk of ketosis were estimated. Blood samples were collected from 82 dairy cows at 5±3 days pre-partum and 5±3 days postpartum. Serum values of triiodothyronine (T3), thyroxine (T4), thyroid-stimulating hormone (TSH), non-esterified fatty acids (NEFA), β-hydroxybutyrate (BHB), insulin, glucose, Ca, Cl, Mg, P, K, Na, aspartate transaminase (AST), alanine transaminase (ALT) and urea were evaluated. Signifi cant decrease in the levels of T3, T4 and TSH was found in the postpartum period. The values of T3 and T4 were negatively correlated with NEFA and BHB levels, and TSH values were negatively correlated with NEFA. A critical T3 threshold was found by means of ROC analysis for predicting the risk of ketosis. T3 values < 1.23 nmol/L were associated with BHB > 1.10 mmol/L in postpartum, which represents the BHB threshold commonly used as the indicator of hyperketonaemia. The results confirm that the peripartum period is accompanied by marked changes in circulating thyroid hormone profile that is correlated with lipomobilization predictors.

Changes in some blood parameters, milk composition and yield of buffaloes (Bubalus bubalis) during the transition period

In this study changes in hematochemical parameters, milk composition and yield were investigated in buffaloes during the transition period. A total of 93 buffaloes 113.9 ± 8.03 months old and 535 ± 50 kg average body weight were used. Parity was recorded, blood samples were collected from 80 days pre-partum until 70 days post-partum; milk samples were collected from 5 days to 70 days post-partum. On serum samples, the values of non-esterified fatty acids, β-hydroxybutyrate, glucose, cholesterol, triglycerides, aspartate aminotransferase, alanine aminotransferase, gamma-glutamyltransferase, urea, total proteins were evaluated. On milk, percentage of fat, protein and lactose, along with the somatic cell count (SCC), milk yield and daily milk production (DMP) were assessed. The peripartum period significantly (P ≤ 0.01) influenced all studied parameters with the exception of glucose. Milk fat percentage showed decreasing trend from 10 until 40 days post-partum; DMP significantly (P ≤ 0.01) increased from 1 day post-partum until 40 days post-partum. Milk yield significantly (P ≤ 0.01) decreased in animals over the sixth lactation. Our results confirmed the importance of transit period in buffaloes. Blood parameters and milk composition alterations are crucial to predict the energy balance status of buffaloes in order to improve their management and feed intake during the transition period.

Milk fatty acid composition as an indicator of energy status in Holstein dairy cows

Abstract. Transition dairy cows often enter a stage of negative energy balance during which the utilization of energy reserves is reflected in the milk fatty acid (FA) composition. In this study, metabolic status was evaluated by measuring milk FA, ruminal short-chain FA (RSCFA), and serum biochemical parameters in Holstein cows. Samples (milk, rumen contents, and blood) were collected around days 30 (early) and 150 (middle) of lactation, and rumen contents and blood samples were collected 30 days before calving (dry). Fatty acids were extracted and FA composition was determined. Glucose, triacylglycerols, total cholesterol, low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C), beta-hydroxybutyric acid (BHB), and non-esterified fatty acid (NEFA) concentrations were determined in serum samples. Lower percentages of saturated FA in milk and higher percentages of monounsaturated FA, polyunsaturated FA, and C18:1n-9 were observed in early lactation compared to mid-lactation. In rumen higher concentrations of propionic acid were determined at mid-lactation compared to early lactation. Acetic and butyric acid concentrations showed no significant differences between sampling intervals. In serum higher glucose concentrations were observed during the dry period and mid-lactation than during early lactation. Lower BHB and higher NEFA concentrations were noted during early lactation compared to mid-lactation and the dry period. Total cholesterol, LDL-C, HDL-C and triacylglycerols showed no significant differences between sampling intervals. The results of the present study suggest that determination of milk FA is a potential indicator of energy status in dairy cows.