Effect on liver function of acetonaemia and the fat cow syndrome in cattle

Bile acid profiles and mRNA abundance of bile acid-related genes in adipose tissue of dairy cows with high versus normal body condition

Besides their lipid-digestive role, bile acids (BA) influence overall energy homeostasis, such as glucose and lipid metabolism. We hypothesized that BA along with their receptors, regulatory enzymes, and transporters are present in subcutaneous adipose tissue (scAT). In addition, we hypothesized that their mRNA abundance varies with the body condition of dairy cows around calving. Therefore, we analyzed BA in serum and scAT as well as the mRNA abundance of BA-related enzymes, transporters, and receptors in scAT during the transition period in cows with different body conditions around calving. In a previously established animal model, 38 German Holstein cows were divided into either a high (HBCS; n = 19) or normal BCS (NBCS; n = 19) group based on their BCS and back-fat thickness (BFT). Cows were fed different diets to achieve the targeted differences in BCS and BFT (NBCS: BCS <3.5, BFT <1.2 cm; HBCS: BCS >3.75, BFT >1.4 cm) until dry-off at 7 wk antepartum. During the dry period and subsequent lactation, both groups were fed the same diets according to their energy demands. Using a targeted metabolomics approach via liquid chromatography-electrospray ionization-MS /MS, BA were analyzed in serum and scAT at wk -7, 1, 3, and 12 relative to parturition. In serum, 15 BA were observed: cholic acid (CA), chenodeoxycholic acid (CDCA), glycocholic acid (GCA), taurocholic acid (TCA), glycochenodeoxycholic acid (GCDCA), taurochenodeoxycholic acid, deoxycholic acid (DCA), lithocholic acid, glycodeoxycholic acid (GDCA), glycolithocholic acid, taurodeoxycholic acid, taurolithocholic acid, β-muricholic acid, tauromuricholic acid (sum of α and β), and glycoursodeoxycholic acid, whereas in scAT 7 BA were detected: CA, GCA, TCA, GCDCA, taurochenodeoxycholic acid, GDCA, and taurodeoxycholic acid. In serum and scAT samples, the primary BA CA and its conjugate GCA were predominantly detected. Increasing serum concentrations of CA, CDCA, TCA, GCA, GCDCA, DCA, and β-muricholic acid with the onset of lactation might be related to the increasing DMI after parturition. Furthermore, serum concentrations of CA, CDCA, GCA, DCA, GCDCA, TCA, lithocholic acid, and GDCA were lower in HBCS cows compared with NBCS cows, concomitant with increased lipolysis in HBCS cows. The correlation between CA in serum and scAT may point to the transport of CA across cell membranes. Overall, the findings of the present study suggest a potential role of BA in lipid metabolism depending on the body condition of periparturient dairy cows.

Effects of abomasal infusion of branched-chain amino acids or branched-chain keto-acids on liver function, inflammation, and oxidative stress in multiparous fresh cows

Reduced liver function, increased oxidative stress, and inflammation in early lactation negatively impact lactation performance and health of fresh cows. Previous findings from our group demonstrated that branched-chain amino acids (BCAA) infusion improved lactation performance and branched-chain ketoacids (BCKA) infusion decreased liver triglyceride (TG) in fresh cows. The objectives of this study were to determine the effect of BCAA and BCKA on blood and liver biomarkers of liver function, oxidative stress, and inflammation as well as expression of genes regulating inflammation and antioxidant metabolism in the liver. Thirty multiparous Holstein cows were used in a randomized block design receiving continuous abomasal infusion for 21 d after parturition. Treatments (10 cows each) were control (CON), cows abomasally infused with 0.9% saline; BCA, cows abomasally infused with BCAA (67 g valine, 50 g leucine, and 34 g isoleucine); and BCK, cows abomasally infused with BCKA (77 g ketovaline, 57 g ketoleucine, and 39 g ketoisoleucine). All cows were randomly assigned to treatments after parturition and received the same diet throughout the experimental period. Blood was collected at 3, 7, 14, and 21 d postpartum for liver function, oxidative stress, and inflammation biomarker profiling. Liver was also harvested on 7, 14, and 21 d postpartum for quantification of glutathione, protein carbonylation, and expression of genes. ANOVA was conducted for all data using PROC GLIMMIX in SAS. No treatment differences were observed for liver function biomarkers (bilirubin, gamma-glutamyl transferase, and aspartate aminotransferase). Cows receiving BCAA had lower blood NO2- and NO3- concentrations compared with CON. A tendency for lower advanced oxidized protein products was also observed in BCA cows compared with CON. Additionally, on d 7, BCA cows had lower protein carbonylation in the liver compared with CON. In contrast, BCK cows had higher plasma thiol and albumin, as well as liver reduced and total glutathione compared with CON cows. Compared with CON, BCK cows had higher expression glutathione reductase in the liver. Overall, these results suggest favorable alterations in oxidative stress and inflammation status in fresh cows receiving BCAA or BCKA infusion during the first 3 weeks of lactation, which likely contributed to previously-observed changes in lactation performance and liver TG concentrations. Future work is required to evaluate the interrelated metabolism of BCAA and BCKA to better understand their effects on oxidative and immune metabolism.

Bile acid profiles and mRNA expression of bile acid-related genes in the liver of dairy cows with high versus normal body condition

Bile acids (BA) play a crucial role not only in lipid digestion but also in the regulation of overall energy homeostasis, including glucose and lipid metabolism. The aim of this study was to investigate BA profiles and mRNA expression of BA-related genes in the liver of high versus normal body condition in dairy cows. We hypothesized that body condition and the transition from gestation to lactation affect hepatic BA concentrations as well as the mRNA abundance of BA-related receptors, regulatory enzymes, and transporters. Therefore, we analyzed BA in the liver as well as the mRNA abundance of BA-related synthesizing enzymes, transporters, and receptors in the liver during the transition period in cows with different body conditions around calving. In a previously established animal model, 38 German Holstein cows were divided into groups with high body condition score (BCS) (HBCS; n = 19) or normal BCS (NBCS; n = 19) based on BCS and backfat thickness (BFT). Cows were fed diets aimed at achieving the targeted differences in BCS and BFT (NBCS: BCS <3.5, BFT <1.2 cm; HBCS: BCS >3.75, BFT >1.4 cm) until they were dried off at wk 7 before parturition. Both groups were fed identical diets during the dry period and subsequent lactation. Liver biopsies were taken at wk -7, 1, 3, and 12 relative to parturition. For BA measurement, a targeted metabolomics approach with LC-ESI-MS/MS was used to analyze BA in the liver. The mRNA abundance of targeted genes related to BA-synthesizing enzymes, transporters, and receptors in the liver was analyzed using microfluidic quantitative PCR. In total, we could detect 14 BA in the liver: 6 primary and 8 secondary BA, with glycocholic acid (GCA) being the most abundant one. The increase of glycine-conjugated BA after parturition, in parallel to increasing serum glycine concentrations may originate from an enhanced mobilization of muscle protein to meet the high nutritional requirements in early lactating cows. Higher DMI in NBCS cows compared with HBCS cows was associated with higher liver BA concentrations such as GCA, deoxycholic acid (DCA), and cholic acid (CA). The mRNA abundance of BA-related enzymes measured herein suggests the dominance of the alternative signaling pathway in the liver of HBCS cows. Overall, BA profiles and BA metabolism in the liver depend on both, the body condition and lactation-induced effects in periparturient dairy cows.

Effects of oral β-cryptoxanthin administration on the transcriptomes of peripheral neutrophil and liver tissue using microarray analysis in post-weaned Holstein calves

We investigated the effects of oral administration of β-cryptoxanthin (β-CRX), a precursor of vitamin A synthesis, on the transcriptomes of peripheral neutrophils and liver tissue in post-weaned Holstein calves with immature immunity. A single oral administration of β-CRX (0.2 mg/kg body weight) was performed in eight Holstein calves (4.0 ± 0.8 months of age; 117 ± 10 kg) on Day 0. Peripheral neutrophils (n = 4) and liver tissue (n = 4) were collected on Days 0 and 7. Neutrophils were isolated by density gradient centrifugation and treated with the TRIzol reagent. mRNA expression profiles were examined by microarray and differentially expressed genes were investigated using the Ingenuity Pathway Analysis software. The differentially expressed candidate genes identified in neutrophils (COL3A1, DCN, and CCL2) and liver tissue (ACTA1) were involved in enhanced bacterial killing and maintenance of cellular homoeostasis respectively. The changes in the expression of six of the eight common genes encoding enzymes (ADH5 and SQLE) and transcription regulators (RARRES1, COBLL1, RTKN, and HES1) were in the same direction in neutrophils and liver tissue. ADH5 and SQLE are involved in the maintenance of cellular homoeostasis by increasing the availability of substrates, and RARRES1, COBLL1, RTKN, and HES1 are associated with the suppression of apoptosis and carcinogenesis. An in silico analysis revealed that MYC, which is related to the regulation of cellular differentiation and apoptosis, was the most significant upstream regulator in neutrophils and liver tissue. Transcription regulators such as CDKN2A (cell growth suppressor) and SP1 (cell apoptosis enhancer) were significantly inhibited and activated, respectively, in neutrophils and liver tissue. These results suggest that oral administration of β-CRX promotes the expression of candidate genes related to bactericidal ability and regulation of cellular processes in peripheral neutrophils and liver cells in response to the immune-enhancing function of β-CRX in post-weaned Holstein calves.

Pre-calving energy density and rumen protected lysine impacted blood metabolites and biomarkers of liver functions in dairy cows during the transition period

Dairy cows usually face negative energy balance and disorders of normal organ function due to a mismatch between energy intake and energy demand. Negative energy balance directly affects liver function and blood metabolites because the liver is used as source of energy supply and a center of metabolic activity. This study was aimed to determine the effect of pre-calving energy density and rumen-protected lysine on blood metabolites and biomarkers of liver functions in the dairy cows during the transition period. Forty 3rd lactation Holstein cows going to enter their 4th lactation were randomly allocated to one of the four dietary treatments (high energy with rumen-protected lysine (HERPL) = 1.53NEL plus 40 g Lys, high energy without lysine (HECK) = 1.53NEL, low energy with rumen-protected lysine (LERPL) = 1.37NEL plus 40 g Lys, and low energy without lysine (LECK) = 1.37NEL arranged in a 2 × 2 factorial design. Blood samples were collected during the transition period, and concentrations of blood metabolites and biomarkers of liver function were measured. Interaction between pre-calving high-energy diet and rumen-protected lysine tended to increase plasma albumin, numerically increased glucose, decreased triglyceride, total bilirubin, and aspartate aminotransferase concentrations. The result revealed that pre-calving high-energy density increased insulin, albumin and decreased blood urea nitrogen and total bilirubin concentrations and substantial favor liver functions during the transition period.

Hepatic Lipidosis in Ruminants

Hepatic lipidosis (ie, fatty liver) occurs primarily during the first weeks of lactation in dairy cows because of excessive lipolysis overwhelming the concomitant capacity for beta-oxidation and hepatic export of triglycerides. Besides economic losses due to reduced lactational and reproductive performance, close associations with concomitantly occurring infectious and metabolic health disorders, in particular ketosis, exist. Hepatic lipidosis is not only a consequence from the postpartal negative energy balance but also acts as a disease component for further health disorders.

Effects of Parity and Stage of Lactation on Trend and Variability of Metabolic Markers in Dairy Cows

Simple Summary

The rise in milk yield per cow, herd size, and the percentage of primiparous cows in dairy herds increasingly requires optimized health management in order to ensure the health of the cows. The transition period (three weeks before to three weeks after calving) has a key role in health problems, because dairy cows undergo tremendous metabolic changes. Metabolic monitoring provides an in-depth insight into how the cows cope with these challenges. A remarkable variability in the metabolic parameters reflects the adaptation of dairy cows during the transition from pregnancy to lactation. In addition, primiparous cows undergo physical adaptations because of growth, first gestation, the maturation of the mammary glands, the onset of lactation, and fighting for social dominance. Previous studies have rarely considered these specific demands due to the influences of parity and the lactation stage. Thus, the objective of our study was to describe the variation in metabolic parameters due to parity and the stage of lactation based on a huge number of primiparous and multiparous cows, observed at all stages of lactation, in a retrospective analysis of laboratory data. The remarkable impact of both parity and lactation was elucidated for most parameters. This should be taken into account for a correct interpretation of the laboratory diagnostics in the framework of metabolic monitoring.

Abstract

Metabolic monitoring is a tool that is helpful with the increasing requirements regarding feeding and health management in dairy herds. This study aimed at describing the trend and variability of different biochemical parameters in blood and urine in relation to the stages of lactation and parity, in a retrospective analysis of laboratory data from clinically healthy German Holstein cows. The results were derived from metabolic monitoring in Thuringia (Germany), during 2009–2019. A total of 361,584 measured values, of 13 different metabolic variables, were assigned to parity (primiparous and multiparous) and stage of lactation (10 classes from −30 to 300 days in milk). The Kruskal–Wallis test was applied for the evaluation of differences regarding parity or the stage of lactation. Non-esterified fatty acids, beta hydroxybutyrate, and the activity of aspartate aminotransferase in serum were clearly affected by parity and lactation. Serum concentrations of cholesterol, bilirubin, and phosphorus, as well as the serum activity of glutamate dehydrogenase, were affected by the stage of lactation, while parity impacted urea concentration. The serum activity of creatine kinase, serum concentrations of calcium, and urine concentrations of net acid base excretion, potassium, and sodium were not affected by parity or lactation. In conclusion, specific reference limits, with respect to parity and the stage of lactation, are necessary.

Effects of rumen-protected glutamate supplementation during the periparturient period on digestibility, inflammation, metabolic responses, and performance in dairy cows

The objective of this study was to evaluate the effects of feeding rumen-protected glutamate during the periparturient period (d -21 ± 3 to d 21 ± 3 relative to calving) on apparent total-tract digestibility (ATTD), inflammation, metabolic responses, and production performance of dairy cows. Fifty-two multiparous Holstein cows were blocked by parity, body condition score, and expected calving date, and randomly assigned to one of the experimental diets with rumen-protected monosodium glutamate (RP-Glu; intestinally available Glu = 8.8%) or without RP-Glu (control) at d -21 ± 3 relative to expected calving date. The RP-Glu was fed at 4% and 3% of dietary dry matter, before and after calving, respectively. Prepartum diets contained 17.1% and 16.5% crude protein, and 13.1% and 13.3% starch, and postpartum diets contained 18.8% and 18.3% crude protein, and 22.5% and 22.7% starch on a dry matter basis, respectively for RP-Glu and control treatments. A subset of 19 cows was used to measure ATTD. Cows fed the RP-Glu had greater ATTD of dry matter (70.6 vs. 69.1%), crude protein (75.1 vs. 72.6%), and ether extract (66.0 vs 61.2%) on d 5 ± 1 after calving. Cows fed the RP-Glu also had greater dry matter intake (15.7 vs. 13.7 kg/d) on d 1 after calving. Cows fed the RP-Glu had greater plasma concentrations of Glu (4.60 vs. 3.89 µmol/dL) and insulin-like growth factor-1 (44.2 vs. 30.1 mg/mL), lower serum concentrations of free fatty acids (670 vs. 981 μEq/L) and total bilirubin (0.22 vs. 0.34 mg/dL), and lower plasma 3-methylhistidine concentration (1.28 vs. 1.50 μmol/dL) on d 4 after calving. However, these treatment effects observed between d 1 and d 5 ± 1 immediately after calving did not continue until d 21 after calving. Concentrations of serum amyloid A, serum haptoglobin, and plasma lipopolysaccharide binding protein were not affected by the treatment. In addition, no differences were observed for serum β-hydroxybutyrate concentration and milk yield during the postpartum period between the 2 groups, and cows fed the RP-Glu had a decreased lactose yield. These findings suggest that feeding RP-Glu during the periparturient period can increase digestive capacity and feed intake, and decrease mobilization of body fat and protein immediately after calving without increasing milk production.

Associations between ultrasound measurements and hematochemical parameters for the assessment of liver metabolic status in Holstein-Friesian cows

Metabolic disorders, including hepatic lipidosis and ketosis, severely affect animal health status and welfare with a large economic burden in dairy herds. The gold standard for diagnosing hepatic lipidosis is the liver biopsy, which is impractical and invasive for the screening at farm level. Ultrasound (US) imaging is a promising technique for identifying liver dysfunction, but standardized specifications in physiological conditions are needed. Herein, we described the features of four US measurements, namely the liver predicted triacylglycerol (pTAG) content, liver depth (LD), and portal vein area (PVA) and depth (PVD) and we investigated their associations with a set of hematochemical (HC) indicators in 342 clinically healthy Holstein Friesian dairy cows. Liver pTAG content was negatively associated with hematocrit and positively with globulin, whereas PVA was negatively associated with thiol group levels, and LD positively with ceruloplasmin. We found significant interactions between some HC parameters and parity: in particular, creatinine, thiol groups and globulin for PVA, and aspartate aminotransferase, paraoxonase and ceruloplasmin for PVD. This study offers new insights on variations in liver function occurring after calving and pave the way for the potential use of minimally invasive techniques for prompt detection of metabolic disorders in dairy herds.

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.

Effects of pre-transport diet, transport duration and transport condition on immune cell subsets, haptoglobin, cortisol and bilirubin in young veal calves

The aim of this study was to investigate effects of pre-transport diets, transport durations and transport conditions on immune cell subsets, haptoglobin, cortisol and bilirubin of young calves upon arrival at the veal farm. An experiment was conducted with a 2 × 2 × 2 factorial arrangement with 3 factors: 1) provision of rearing milk or electrolytes at the collection center (CC); 2) transport duration (6 or 18 hours) and 3) transport condition (open truck or conditioned truck). Holstein-Friesian and cross-bred calves were used (N = 368; 18 ± 4 days; 45.3 ± 3.3 kg). Blood samples were collected from calves (N = 128) at the collection center, immediately post-transport (T0) and 4, 24, 48 hours, week 1, 3 and 5 post-transport. Blood was analyzed for cortisol, bilirubin, haptoglobin, IgG and IgM. Moreover, cell counts of neutrophils, lymphocytes, monocytes, basophils and eosinophils were measured in blood samples taken at the collection center and T0. In these same blood samples, different lymphocyte populations were characterized by flow cytometry, including CD14+ cells, NK cells, δγ+ T cells, CD8+ cells, CD4+ cells and CD21+ cells. Calves transported in the conditioned truck had higher amounts of white blood cell count (WBC) (Δ = 1.39 × 10⁹/l; P = 0.01), monocytes (Δ = 0.21 × 10⁹/l; P = 0.04), neutrophils (Δ = 0.93 × 10⁹/l; P = 0.003), than calves transported in the open truck regardless, of pre-transport diet or transport duration. The study showed that transport condition and duration influenced parts of the innate immune system of young veal calves. Cortisol, bilirubin and WBC seemed to be connected by similar underlying mechanisms in relation to transport conditions. However, it is unclear which specific pathways in the immune system of young calves are affected by different transport conditions (e.g. temperature, humidity, draught).

Influence of feeding methods on blood biochemical parameters of Japanese Black breeding herd

The aim of this study was to investigate the effect of different feeding methods on blood biochemical parameters by using a total of 32 Japanese Black breeding cows. The diet (silage) was distributed at a rough estimate for 18 days (FN period), and stanchions were not used in this period. After the FN period, the cows were separated in stanchions for feeding and were fed specified amount of silage by using scales on a feeder wagon, which was determined according to the diet formulation and average body weight of cows, for 30 days (FW period). On the last day of the two experiment periods, the body weight of all cows was recorded and blood samples were collected from 10 randomly selected cows. β-hydroxybutyric acid and albumin (Alb) levels were significantly higher after the FW period than after FN period. The variation of glucose, Alb, calcium and lactic acid was significantly smaller after the FW period. Several blood parameters of the FW period were approximately the appropriate range of a Japanese Black breeding herd in the dry period. Our results suggest that the feeding method by use of a stanchion and proper diet formulation affects blood biochemical parameters and improves nutritional conditions for breeding cows.

Blood metabolic profile tests at dairy cattle farms as useful tools for animal health management

Blood metabolic profile tests are simple cost-effective biochemical tests which are mostly used to identi-fy nutritional and/or management challenges in dairy cattle herds, but they also can be simply used to find animals which are clinically healthy, but really have some hidden problems like low production performance, reproductive diseases and/or long calving intervals and other sub-clinical diseases. Rou-tine metabolic profile tests commonly consist of blood glucose, urea, albumin, cholesterol, beta-hydroxybutyric acid and non-esterified fatty acids values, as well as sodium, potassium, chloride, calci-um, magnesium and inorganic phosphate levels. Briefly, the current review discusses blood metabolic profile tests, their importance, introduces an easy method for it, emphasises on the relation between blood metabolic profile parameters and many important sub-clinical diseases including ketosis, milk fever, mastitis, cystic ovaries, displaced abomasum and etc., and indicates that because of its simplicity, low cost and easy for analysis results, it can be considered as a good method for diagnosis of important diseases at dairy cattle farms.

Evaluation of some blood liver parameters in cows with subclinical and clinical ketosis

The purpose of the present study was to establish the changes in some blood liver parameters in cows in different physiological conditions with subclinical (SCK) and clinical ketosis (CK). The study was performed on 157 Holstein cows with annual milk yield of 9,000–11,000 L. The animals were divided into 3 groups: I group – pregnant cows (from day 15 to day 0 pre-calving); II group – recently calved (from day 0 to day 15 postpartum) and III group – lactating (from day 30 to 45 postpartum). Blood concentrations of β-hydroxybutyric acid (ВНВА) (mmol/L), glucose (mmol/L), total protein (g/L), albumin (g/L) and total bilirubin (μmol/L) were assayed in all cows. The animals were divided in groups with SCK and CK according to their blood BHBA levels. It was established, that the con-centrations of total bilirubin were statistically significantly elevated vs control groups, while blood glucose, total protein and albumin values decreased, reflecting the impaired liver function in cows with SCK and CK.

Field evidence of metabolic stress in dairy cows?

The authors review their experiences of metabolic profiles in dairy herds, with a view to assessing whether metabolic stress is a problem in Great Britain at present. Many cows show elevated blood beta-hydroxybutyrate concentration, indicating energy deficit, or elevated urea levels, indicating an imbalance between energy and protein in the rumen but at present there is no evidence that high-yielding cows in commercial herds show more metabolic stress than low-yielding cows. The authors suggest that more cows could suffer metabolic stress in the future, unless farmers’ ability to feed and manage dairy cows develops as rapidly as genetic selection for high milk yield.

Effects of monensin and essential oils on immunological, haematological and biochemical parameters of cows during the transition period

Using a model to generate experimental groups with different manifestations of post-partum (p.p.) fat mobilization and ketogenesis, the effects of a dietary and a medical intervention on biochemical and haematological parameters, antibody titre, leucocytes subsets and function of transition cows were examined. In total, 60 German Holstein cows were allocated 6 weeks antepartum (a.p.) to 3 high-body condition score (BCS) groups (BCS 3.95) and 1 low-BCS group (LC, BCS 2.77). High-BCS cows received a monensin controlled-release capsule (HC/MO) or a blend of essential oils (HC/EO) or formed a control group (HC). Parameters were evaluated in 3 periods (day (d) -42 until calving, 1 until 14 days in milk (DIM), 15 until 56 DIM). Over the course of trial, various parameters were influenced by period with greatest variability next to calving. White blood cell count was higher in the HC (8.42 × 10³ /μl) and HC/EO (8.38 × 10³ /μl) groups than in the HC/MO group (6.81 × 10³ /μl) considering the whole trial. Supplementation of monensin decreased aspartate aminotransferase in comparison with the HC group similar to LC treatment. Bilirubin concentration was nearly doubled in all high-BCS cows in period 2. In period 3, essential oils increased γ-glutamyltransferase (80.4 Units/l) in comparison with all other groups and glutamine dehydrogenase (61 Units/l) in comparison with the LC (19 Units/l) and the HC/MO group (18 Units/l). Results suggest that parameters were generally characterized by a high variability around calving. Based on biochemical characteristics, it appeared that the HC cows seemed to have compromised hepatocyte integrity when compared to the LC cows. From the immune parameters investigated, the BVDV antibody response was more pronounced in HC/MO compared to HC/EO.

Metabolic indicators for retention of fetal membranes in Zebu and crossbred dairy cattle

The present study assessed the peripartum metabolic profile of Karan Fries crossbred (Holstein Friesian × Tharparkar) and Zebu (Sahiwal) cows in relation to expulsion of fetal membranes. Peripheral blood concentrations of glucose, total protein, total cholesterol, blood urea nitrogen, non-esterified fatty acid (NEFA) and β-hydroxy butyric acid (BHBA) were determined (from 30 days before and 2 days after calving) in cows that expelled fetal membranes normally (n = 13; 7 crossbred and 6 Zebu cows) and in cows that developed retention of fetal membranes (RFM; n = 13; 7 crossbred and 6 Zebu cows). In both breeds, the cows that developed RFM had significantly lower concentrations of cholesterol, glucose and total protein, while the concentrations of NEFA, BHBA and blood urea nitrogen were significantly (P < 0.05) higher than those in cows that normally expelled the fetal membranes. In crossbred cows affected with RFM, the concentrations of NEFA increased significantly (P < 0.05) from Day 14 prepartum to Day 2 postpartum and the concentrations of BHBA increased from Day 7 prepartum to Day 2 after calving. Similarly, in Zebu cows, NEFA and BHBA concentrations increased significantly (P < 0.05) between Day 5 prepartum and Day 2 postpartum in RFM cows. Using receiver operator characteristic analysis, we observed that the concentrations of NEFA and BHBA before calving were highly related to the RFM. It may be inferred that monitoring the levels of NEFA and BHBA during prepartum period would help in identifying the cows at the risk of developing RFM.

Sex of offspring influences metabolism during early transition period in dairy cows

Abstract. A study using 20 Holstein Friesian cows was conducted to investigate the influence of calf gender on metabolism during the transition period in dairy cattle. Blood samples were collected at three time points: 2–4 days prepartum (time 1), and 1 week and 2 weeks postpartum (time 2 and time 3 respectively). Serum samples obtained were analysed for total proteins, albumin, urea, glucose, non-esterified fatty acids (NEFA) and β-hydroxybutyrate (BHB). Depending on the sex of the offspring, cows were divided into two groups: Group 1 consisted of cows with heifer offspring (n = 12) and Group 2 consisted of cows with bull offspring (n = 8). A two-way repeated measures ANOVA and t tests for unpaired data were used to analyse the pattern of studied parameters and differences between the two groups. The results indicate differences in metabolic parameters between the two groups. These results highlight the importance of considering fetal sex as a factor that influences maternal metabolism during the early transition period in dairy cows.

Evaluation of fructosamine as a new biomarker for diagnosis of hepatic lipidosis in dairy cows

An abattoir-based cohort study using liver and serum specimens from Holstein dairy cows (452 healthy and 54 fatty liver cases) was conducted. Serum fructosamine and other biochemical parameters and fat content of liver specimens were measured. There were significant negative correlations of fructosamine with hepatic lipid content (P = 0.001), and serum total bilirubin (P = 003) and significant positive correlation with glucose (P < 0.02), albumin (P < 0.0001) and cholesterol (P < 0.0001) within normal cows. In fatty liver-affected cows significant positive correlations were seen between fructosamine and cholesterol (P < 0.0001) and albumin (P < 0.0001). In addition fructosamine had a significant negative correlation with the ratio of non-esterified fatty acids to cholesterol in both normal (P < 0.0001) and fatty liver-affected cows (P = 0.006). We found that serum fructosamine concentration was lower (P < 0.001) in cows suffering from fatty liver. The area under the receiver operating characteristic curve of fructosamine for diagnosis of fatty liver was 67.6. Optimum fructosamine cut-point based on the maximum total of sensitivity (SE) and specificity (SP) was <213 µmol/L (SE = 71%; SP = 65). Cows with serum fructosamine concentrations below 213 µmol/L were 4.5 times more likely to have hepatic lipidosis (odds ratio = 4.5; 95% CI = 2.4–8.6; P < 0.0001). We found that fructosamine showed a combination of high SE, SP, which was greater than aspartate aminotransferase, non-esterified fatty acids, β-hydroxybutyrate, total cholesterol, bile acids and bilirubin. In addition, fructosamine showed a positive likelihood ratio of 2.0, and negative likelihood ratio of 0.45. In conclusion, the present results indicate that fructosamine measurement could improve the diagnosis of fatty liver in dairy cows.

Relationship among blood indicators of lipomobilization and hepatic function during early lactation in high-yielding dairy cows

Blood indicators are used as a tool to diagnose metabolic disorders. The present work was conducted to study the relationships among blood indicators of lipomobilization and hepatic function in high-yielding dairy cows. Two groups of Holstein cows were studied: 27 early lactation cows and 14 mid lactation cows from four different herds with similar husbandry characteristics in Galicia, Spain. Blood samples were obtained to measure beta-hydroxybutyrate (BHB), non-esterified fatty acids (NEFA), triglycerides (TG), and the activity of aspartate transaminase (AST) and gamma-glutamyl transferase. Cows in early lactation had higher levels of BHB and NEFA than mid lactation cows. High lipomobilization (NEFA > 400 µmol/L) was detected in 67% and 7% of early lactation and mid lactation cows, respectively, while subclinical ketosis (BHB > 1.2 mmol/L) was detected in 41% and 28% of the early lactation and lactation cows, respectively. TG concentrations were low in all cows suffering subclinical ketosis and in 61% of the cows with high lipomobilization. During early lactation, 30% of cows suffered hepatic lipidosis as detected by levels of AST. Compromised hepatic function was observed in early lactation cows as shown by lower concentrations of glucose, total protein, and urea.

Ketosis in buffalo (Bubalus bubalis): clinical findings and the associated oxidative stress level

As little is known about the oxidant/antioxidant status in buffalo with ketosis, the present study was delineated to assess the oxidative stress level associated with clinical ketosis in water buffalo. A total of 91 parturient buffalo at smallholder farms were studied (61 suspected to be ketotic and 30 healthy). Clinical and biochemical investigations were carried out for each buffalo. Based on clinical findings and the level of beta-hydroxybutyrate (BHB), buffalo were allocated into ketotic (42), subclinical cases (19). Clinically, there was an association between clinical ketosis and anorexia (p<0.001), constipation (p<0.001), decreased milk yield (p<0.001), ruminal stasis (p<0.001), and loss of body condition (p<0.01). Biochemically, in clinical ketosis compared with subclinical and control cases, there was a significant increase (p<0.05) of BHB, malondialdehyde (MDA), nitric oxide (NO), aspartate aminotransferase (AST), L-alanine aminotransferase (ALT). However, there was a significant decrease of glucose, phosphorus, magnesium,total cholesterol and HDL-cholesterol. There was a positive correlation between BHB and MDA (r=0.433), BHB and NO (r=0.37), MDA and NO (r=0.515), and Glucose and phosphorus(r=0.521). However, there was a negative correlation between BHB and glucose (r= -0.341) and HDL and NO (r= -0.379). The result of the present study indicates that hyperketonemia in buffalo is associated with an increase of oxidative stress levels. Further studies need to be done on the efficacy of antioxidants as an ancillary treatment to relief the oxidative stress caused by ketosis.

Lecithin cholesterol acyltransferase (LCAT) activity as a predictor for ketosis and parturient haemoglobinuria in Egyptian water buffaloes

Lecithin cholesterol acyltransferase (LCAT) activity was measured in 48 Egyptian water buffaloes four weeks pre-parturient. The activity was significantly low in 37 buffaloes (77.1%). Four weeks post-partum, clinical examination revealed that 23 buffaloes had the clinical signs of ketosis (K) while 14 had the clinical signs of parturient-haemoglobinuria (PHU). Serum samples were collected from 5 buffaloes of each group (K and PHU) besides 5 clinically healthy buffaloes with normal LCAT (control). Glucose level was significantly reduced in K and PHU groups while the phosphorous (P) level was significantly reduced in PHU group compared to control. There were significant reductions in the total cholesterol, free cholesterol, triglycerides, total protein and albumin in K and PHU groups; whereas, significant increases in AST, GGT, non-esterified fatty acids (NEFA) and beta-hydroxybutyric acid (BHBA) in K and PHU groups were detected. Therefore, LCAT could be a predictor for metabolic disorders in Egyptian water buffaloes.

Hepatic triacylglycerols and plasma non-esterified fatty acids and albumin levels in cross breed cows in Ahvaz city of Khuzestan Province of Iran: an abattoir study

The aim of the present study was to compare the hepatic triacylglycerols (TAG) and total lipid and plasma Non-Esterified Fatty Acids (NEFA) and albumin in cows in different stages of productivity slaughtered at Ahvaz abattoir. So, a total of 203 blood and liver samples were collected from the indigenous hybrid cows immediately after being slaughtered at the abattoir. The cows were divided into 4 groups according to their pregnancy statuses: 1-8 months pregnant, 8-9 months pregnant, less and more than 1 month of parturition. Percentage of TAG and Total Lipids (TL) were measured in the liver and NEFA and albumin were measured in the blood circulation. All the liver samples in this study showed some degrees of fatty infiltration. The accumulation of fat in the liver rose significantly (p < 0.001) during the first month after parturition and returned to the same level of pregnancy after one month. We also noticed that plasma NEFA concentration was significantly higher (p < 0.05) during the first month of parturition and serum albumin level relegated to its lowest level (p < 0.05) in the last month of pregnancy. These results reveal that fatty liver is quite common in all the animals in the region especially in their early lactation. These findings indicate the necessity of reconsideration in the animal's food policies in the area and some especial approaches during the early phase of lactation.

Evaluation of classification modes potentially suitable to identify metabolic stress in healthy dairy cows during the peripartal period1

The transition of pregnancy to lactation, with the concomitant negative energy balance during early lactation, requires substantial adaptive performance of the cow. Apart from clinical disease problems, the identification of cows with suboptimal adaptation is relevant to be able to adequately treat these animals or modify the ration. Effective approaches are necessary to provide maximal information at the earliest time possible. We therefore aimed to identify a measurement that, when applied at a defined point in time relative to calving, was relevant as much as possible to other information on metabolic and health status during early lactation. Blood samples were collected weekly from 4 wk antepartum to 12 wk postpartum from 38 high-yielding Holstein-Friesian cows. Nonesterified fatty acids, beta-hydroxybutyrate, IGF-I, and leptin were measured in serum, and BCS was recorded. Health status was characterized using the concentrations of haptoglobin, the number of leukocytes and neutrophils, as well as the activity of glutamate dehydrogenase (GLDH) in blood to evaluate liver status. Using the factors related to fat mobilization, the animals were classified according to their values recorded at one defined point in time or time interval as being above or below certain thresholds. For each criterion, the groups classified were compared with regard to the time-course yielded from all recordings. From 7 criteria of classification, the most closely related to the variables of fat mobilization was obtained when using NEFA and IGF-I (thresholds of 0.5 mM and 39 ng/mL in wk 1 postpartum, respectively). Both items were then combined into to the criterion NEFA + IGF-I. Applying these criteria, the relations to indices of health and liver status were detectable on the basis of NEFA- and NEFA + IGF-I-classes, which yielded differences in both GLDH and leukocyte numbers. Animals with NEFA > 0.5 mM showed increased GLDH activity but decreased leukocyte numbers. The time and effort required for measuring the IGF-I-concentration in addition to NEFA is not justified for evaluating the metabolic status. Nonesterified fatty acid values > or = 0.5 mM during the first week of lactation were considered as the most suitable criterion for identifying limited adaptive performance.

Evaluation of ornithine carbamoyl transferase and other serum and liver-derived analytes in diagnosis of fatty liver and postsurgical outcome of left-displaced abomasum in dairy cows

OBJECTIVE

To evaluate postsurgical outcome in dairy cows with left-displaced abomasum (LDA) with regard to severity of fatty liver and assess the usefulness of preoperative determination of serum ornithine carbamoyl transferase (OCT) activity, bile acids concentration, and other variables for evaluating liver function during the postsurgical convalescence period.

DESIGN

Prospective study.

ANIMALS

68 Holstein cows.

PROCEDURES

Blood and liver biopsy specimens were obtained during standing LDA surgery. Liver tissue was examined histologically and classified by severity of fatty change. Serum activities of liver-derived enzymes and concentrations of total lipids, triglycerides, bile acids, glucose, beta-hydroxybutyric acid, bilirubin, and nonesterified fatty acids were determined.

RESULTS

Most cows with LDA and cows with severe fatty liver were detected within the first month after calving. Postsurgical outcome was related to severity of fatty liver. All cows that died had severe fatty liver. Serum activities of OCT, aspartate aminotransferase, and glutamate dehydrogenase and serum total bilirubin concentration were sensitive indicators of fatty liver. Serum bile acids concentration was not an accurate indicator of fatty liver.

CONCLUSIONS AND CLINICAL RELEVANCE

Postsurgical outcome of cows undergoing surgery to correct LDA was related to fatty liver severity. Assessment of serum activities of OCT, aspartate aminotransferase, and glutamate dehydrogenase and serum total bilirubin concentration is recommended for diagnosis of fatty liver in dairy cows with LDA, whereas determination of bile acids concentration is not. The strong correlation between OCT activity and degree of hepatocellular damage supports use of this enzyme for assessing severity of fatty liver and predicting postsurgical outcome in cows with LDA.

Invited review: pathology, etiology, prevention, and treatment of fatty liver in dairy cows

Fatty liver (i.e., hepatic lipidosis) is a major metabolic disorder of many dairy cows in early lactation and is associated with decreased health status and reproductive performance. In severe cases, milk production and feed intake are decreased. Therefore, a practical preventative or an efficacious treatment of fatty liver could save millions of dollars yearly in treatment, replacement, and production losses for dairy farmers. Fatty liver develops when the hepatic uptake of lipids exceeds the oxidation and secretion of lipids by the liver, which usually is preceded by high concentrations of plasma NEFA mobilized from adipose tissue. Excess lipids are stored as triacylglycerol in the liver and are associated with decreased metabolic functions of the liver. Liver can be categorized into normal liver or mild, moderate, or severe fatty liver; the latter can be subdivided further into nonencephalopathic severe fatty liver and hepatic encephalopathy. Insufficient or unbalanced dietary intake, obesity, and elevated estrogen concentrations are involved in the etiology of fatty liver, which is associated with greater incidence of dystocia, diseases, infections, and inflammations. Because even mild fatty liver is associated with decreased health status and reproductive performance of dairy cows, prevention of fatty liver by supplying cows with sufficient nutrients and a clean and health-promoting environment in the peripartal period would reduce production losses of cows more than would any treatment of fatty liver. This, however, might not be enough for cows that are obese or do not eat well, had calving difficulties or twins, have metabolic or infectious diseases, or are in severe negative energy balance because of high milk production immediately after calving. Potential and commonly used preventatives, as well as treatments, are discussed in the review. Currently, detection of fatty liver is possible only by minor surgery. Ultrasonic techniques offer a potential tool to noninvasively detect fatty liver. Future gene-array and proteomic studies may provide means to detect early molecular events in the etiology of fatty liver plus their connection with immune function and reproductive performance so that more effective treatments and preventatives of fatty liver can be developed. Such advances hopefully will make fatty liver a problem of the past.

Measurement of serum haptoglobin in neonatal farm-raised and bob veal calves using two immunoassay methods

Two immunoassays using an anti-bovine haptoglobin monoclonal antibody, Hap 1, were used to measure serum haptoglobin levels in neonatal farm-raised and bob veal calves. Bob veal calves were grouped into condemned, normal, and icteric groups based on the appearance of the carcass and viscera at postmortem examination. The competitive inhibition assay was more sensitive than the direct hemoglobin binding assay in detecting low levels of haptoglobin in all groups of calves. A significant number of bob veal calves with gross postmortem lesions other than icterus had detectable haptoglobin levels. The low levels of haptoglobin that were detected were not useful in distinguishing the relative severity of the inflammatory or degenerative process; however, the predictive values of a positive and negative test suggest haptoglobin measurement may be useful as a supplemental tool in evaluating the health status of the neonatal calf.

Altered functional and immunophenotypical properties of neutrophilic granulocytes in postpartum cows associated with fatty liver

The intention of the study was to analyze the relationship between liver triacyl glycerol content (liver TAG content) and immunophenotypical and functional properties of polymorphonuclear neutrophilic granulocytes (PMN) of dairy cows in the peripartum period. We investigated characteristics of bovine PMN from the blood and uterus of clinically healthy cows in the periparturient period. The numbers of circulating leukocytes and segmented granulocytes continuously increased until parturition and declined afterwards to starting values. This was independent of the liver TAG content and mainly affected neutrophils. The liver TAG content exceeded 40 mg/g liver, the reference value, in 12 of 19 cows in the first two weeks postpartum. Increased liver TAG content, > 40 mg/g, went in parallel with a reduced expression of function-associated surface molecules on blood neutrophils (e.g. CD11b/CD18 = CR3 and CD11c/CD18 = CR4). Moreover, in cows with high liver TAG levels the antibody-independent and -dependent cellular cytotoxicity (AICC, ADCC) of blood PMN was markedly reduced. PMN also were less capable of ROS generation after stimulation with Phorbol Myristate Acetate (PMA). In comparison with contemporarily harvested blood PMN, neutrophils recovered from the uterine lumen showed a decreased expression of 4/6 examined surface structures. Only the expression densities of CR3 molecules and those detected by mAb IL-A110 were enhanced on uterine PMN. The cytotoxic capacity and the ROS generation were significantly lower for uterine PMN than for blood PMN. The results suggest that increased liver TAG content in the first and second week after calving is associated with decreased functional capacities of PMN derived from blood and uterus. This may help to explain why cows who are too fat at calving (who therefore have an increased liver TAG content) have a higher incidence of infectious diseases such as endometritis

ADSA Foundation Scholar Award. Biology of dairy cows during the transition period: the final frontier?

The transition period, from 3 wk before to 3 wk after parturition, is critically important to health, production, and profitability of dairy cows. Most health disorders occur during this time. Compared with other stages of the lactation cycle, relatively little is known about fundamental biological processes during the transition period. The regulation and coordination of lipid metabolism among adipose tissue, liver, gut, and mammary gland are key components of the adaptations to lactation. Lipid accumulation in liver may contribute to health disorders and decreased milk production. Knowledge of key control points in hepatic metabolism of long-chain fatty acids is lacking, as is an understanding of the metabolic effects of hormones, growth factors, and cytokines that mediate stress. Recent evidence indicates that supplemental fats or restricted intakes before parturition can induce a coordinated set of metabolic changes in metabolism of long-chain fatty acids, including peroxisomal beta-oxidation, perhaps mediated by peroxisome proliferator-activated receptors. Estimates of the mixture of fuels constituting metabolizable energy in cows during the early postpartum period suggest that supply of amino acids and glucogenic compounds may be under proposed optima, whereas ketogenic and lipogenic compounds and long-chain fatty acids may be in excess. Because dietary fat does not suppress body lipid mobilization, during the early postpartum period supplemental fat may further imbalance the mixture of fuels and lead to decreased dry matter intake. Increased understanding of the biology of the transition period should decrease health problems and increase profitability of dairy cows.

Relationship between overfeeding and overconditioning in the dry period and the problems of high producing dairy cows during the postparturient period

In dairy cows, overfeeding during the dry period leads to overcondition at calving and to depression of appetite after calving. As a consequence, at calving overconditioned high-producing dairy cows inevitably go into a more severe negative energy balance (NEB) postpartum than cows that have a normal appetite. During the period of NEB, the energy requirements of the cow are satisfied by lipolysis and proteolysis. Lipolysis results in an increased concentration of non esterified fatty acids (NEFA) in the blood. In the liver, these NEFA are predominantly esterified to triacylglycerols (TAG) that are secreted in very low density lipoproteins (VLDL). In early lactation in cows with a severe NEB, the capacity of the liver to maintain the export of the TAG in the form of VLDL in balance with the hepatic TAG production is not always adequate. As a result, the excess amount of TAG accumulates in the liver, leading to fatty infiltration of the liver (hepatic lipidosis or fatty liver). The NEB and/or fatty liver postpartum are frequently associated with postparturient problems. In general, a severe NEB induces changes in biochemical, endocrinological, and metabolic pathways that are responsible for production, maintenance of health, and reproduction of the postparturient dairy cow. These changes include a decrease in blood glucose and insulin concentrations, and an increase in blood NEFA concentrations. High NEFA concentrations caused by intensive lipolysis are accompanied by impairment of the immune system, making the cows more vulnerable to infections. Metabolic diseases such as ketosis, milk fever, and displaced abomasum are related to overcondition at calving. The changes in biochemical, endocrinological, and metabolic pathways are associated with delay of the first visible signs of oestrus, an increase in the interval from calving to first ovulation, a decrease in conception rate, and a prolonged calving interval. It is possible that the increased blood NEFA concentration directly impairs ovarian function.

Effect of prepartum administration of monensin in a controlled-release capsule on postpartum energy indicators in lactating dairy cows

The effects of monensin on the energy metabolism of dairy cows in early lactation were investigated in a large clinical trial that was randomized and double-blinded. A total of 1010 Holstein cows and first lactation heifers were allocated to receive a controlled-release capsule of monensin or a placebo at 3 wk prior to expected calving date. Treatments were randomized across 25 dairy farms located near Guelph, Ontario, Canada. Serum samples obtained at the time of treatment administration and at wk 1, 2, 3, 6, and 9 postcalving were analyzed for beta-hydroxybutyrate, glucose, aspartate aminotransferase, urea, total protein, calcium, and phosphorus. Cows were also assigned a body condition score at the time each sample was obtained. Monensin treatment significantly reduced serum beta-hydroxy-butyrate concentrations at wk 1, 2, and 3 postpartum and significantly raised serum glucose concentrations during wk 1 and 2 of lactation. In addition, monensin treatment significantly reduced the loss of body condition score and decreased serum activity of aspartate aminotransferase during the postpartum period. Concentrations of serum urea were significantly higher during wk 2 and 3 postpartum for the cows that were treated with monensin. Monensin treatment had no effect on the concentrations of calcium, phosphorus, or total protein.

Glucose and insulin responses to glucagon injection in dairy cows with ketosis and fatty liver

The purpose of this investigation was to study the metabolic situation in clinical cases of bovine ketosis and to diagnose additional diseases. Extensive clinical examination, clinical biochemistry, haematology and fine-needle aspiration biopsy of liver was performed on 17 ketotic and eight control dairy cows in the field, and on seven hospitalized hyperketonaemic fatty liver patients. Additional findings in the ketotic group were heat (n = 7), indigestion (n = 5), endometritis (n = 2), cystic ovaries (n = 1), and mastitis (n = 1), and in the fatty liver group displaced abomasum (n = 4), abomasal ulcers (n = 3), mastitis (n = 2), laminitis (n = 1), bronchopneumonia (n = 1), and hypomagnesaemia (n = 2). There were no additional findings in the control group. Aspartate aminotransferase (AST) and creatine kinase (CK) were elevated in the ketosis and fatty liver groups. Total bilirubin, gamma-glutamyl transferase (GGT) and glutamate dehydrogenase (GD) were elevated in the fatty liver group and in some animals in the ketosis group. Total bile acid was not different between the groups. The free fatty acid/cholesterol ratio was higher in the fatty liver group compared with the control and ketosis groups. There was no or only slight fatty degeneration of the liver cells in the control and ketosis groups. Glucose and insulin preinjection concentrations and changes from basal values after glucagon injection were significantly lower in the ketosis group if compared with the control group. The responses in the fatty liver animals after glucagon injection were more heterogeneous than in the control and ketosis animals, a sign of disturbance in the metabolic adaptation, which together with high free fatty acid (FFA) levels can lead to fatty liver in cows with concurrent diseases.

Hepatic lipidosis in anorectic, lactating holstein cattle: a retrospective study of serum biochemical abnormalities

The association between hepatic lipidosis (HL) and disease in 59 anorectic, ketotic, lactating Holstein heifers and cows was investigated. Severe HL, as determined by histologic evaluation of liver tissue, was present in 46 animals; only half of these animals required intensive treatment for ketosis, and only half had serum biochemical evidence of liver disease, as determined by the presence of a last value of 2-fold or greater than the upper limit of the reference ranges for at least 2 of the 4 serum tests: gamma-glutamyl transferase, aspartate aminotransferase, and sorbitol dehydrogenase activities and bile acid concentrations. Most cattle with biochemical evidence of liver disease and severe HL had been lactating for 14 or more days. Cows that required intensive treatment inconsistently had serum biochemical evidence of liver disease. Although cattle with severe HL had significantly higher serum bilirubin concentrations and aspartate aminotransferase and sorbitol dehydrogenase activities than cattle with less severe lipidosis, the specificity of abnormally high serum sorbitol dehydrogenase activity or bilirubin concentration for severe lipidosis was only 8%. Abnormally high serum aspartate aminotransferase activity was 83% sensitive and 62% specific for severe lipidosis. Serum glucose and total carbon dioxide concentrations were significantly lower in cattle with severe lipidosis than in those with mild or moderate lipidosis, and low serum glucose or total carbon dioxide concentrations were rare in cattle without severe lipidosis. From these data, we conclude that the use of a single biochemical or histopathologic criterion to define severity of disease or degree of liver compromise in anorectic, ketotic cows results in the misidentification of many animals.

Changes in the profile of liver enzymes in newborn calves induced by experimental, subclinical acidosis in pregnant cows and osmotic diarrhoea

Experimental, subclinical acidosis was induced by oral administration of sacharose during the last 2 months of pregnancy in 15 cows. Seven cows and their newborn calves were used as a control group. The liver enzyme activities in the serum and the blood acid-base status were determined in the 15 calves from the cows in the experimental group. Mannitol was administered orally to 8 calves from the experimental group to induce osmotic diarrhoea. It was concluded that subclinical acidosis in pregnant cows alters the biochemical liver profile of their newborn calves, affecting the aspartate aminotransferase, alanine transaminase, beta glucuronidase, glutamate dehydrogenase and bilirubin activities in the serum, which are associated with oedematous changes to the hepatocytes. Diarrhoea was accompanied by an increase in the alkaline phosphatase and gammaglutamyl transferase activities and a decrease in the total protein concentration in the serum. These changes were apparently related to the numerous necrotic foci in the liver and the proliferation of the Kuppfer cells. It would appear from these results that the liver damage in the newborn calves was associated with the subclinical, metabolic acidosis in their dams and that osmotic diarrhoea occurring in the neonatal period additionally impaired the liver function.

Liver triacylglycerol concentrations around parturition in goats with either pre-partum restricted or free access to feed

The hypothesis was tested that goats allowed ad libitum access to feed during the dry period develop higher post partum hepatic triacylglycerol concentrations than do goats given a restricted amount of feed during the dry period. Goats in their second or more pregnancies were either given a restricted amount of hay, maize silage and concentrate (n = 5) or had free access to this feed mixture while the composition was kept constant (n = 11). After parturition both groups were allowed ad libitum access to feed. Post partum liver triacylglycerol concentrations, as measured in liver biopsies, were significantly raised in goats allowed ad libitum access to feed during the dry period. The increase in liver triacylglycerols was associated with slightly higher plasma concentrations of non-esterified fatty acids but lower serum 3-hydroxybutyrate concentrations. The feeding regimen during the dry period did not significantly influence post partum liver glycogen concentrations and serum levels of glucose, cholesterol, and insulin. The increase in post partum liver triacylglycerol concentrations in the goats allowed ad libitum access to feed instead of a restricted ration during the dry period, was associated with a significant rise in serum alkaline phosphatase activities, whereas other liver function and cell damage indicators in serum, i.e. aspartate aminotransferase, lactate dehydrogenase, gamma glutamyl transpeptidase, and bilirubin, were unchanged. Feed intake after parturition tended to be higher in the goats allowed ad libitum access to feed during the dry period but milk production was significantly raised.(ABSTRACT TRUNCATED AT 250 WORDS)

Determination of the fructosamine concentration in bovine serum samples

The study reports on a spectrophotometric assay for the determination of serum fructosamine concentration. The assay was evaluated for use in bovine serum samples by assessment of the precision, accuracy and detectability. A reference interval for the bovine serum fructosamine concentration was also established. Further, the effect of acute changes in blood glucose on serum fructosamine concentration as well as the diurnal variations of the serum fructosamine concentration were investigated. The main conclusions can be summarized as follows: Determination of bovine serum fructosamines may be achieved by a precise and accurate assay with a detection limit well below the serum fructosamine concentration normally found in bovine sera. As a reference interval for the bovine serum fructosamine concentration 213.4 mumol/l to 265.0 mumol/l may be used. Serum fructosamine concentration is not affected by acute changes in blood glucose, and it displays no significant diurnal variation in cows.