Metabolic Disorders In Dairy Cows Research Articles

Integrating on-farm and genomic information improves the predictive ability of milk infrared prediction of blood indicators of metabolic disorders in dairy cows

BackgroundBlood metabolic profiles can be used to assess metabolic disorders and to evaluate the health status of dairy cows. Given that these analyses are time-consuming, expensive, and stressful for the cows, there has been increased interest in Fourier transform infrared (FTIR) spectroscopy of milk samples as a rapid, cost-effective alternative for predicting metabolic disturbances. The integration of FTIR data with other layers of information such as genomic and on-farm data (days in milk (DIM) and parity) has been proposed to further enhance the predictive ability of statistical methods. Here, we developed a phenotype prediction approach for a panel of blood metabolites based on a combination of milk FTIR data, on-farm data, and genomic information recorded on 1150 Holstein cows, using BayesB and gradient boosting machine (GBM) models, with tenfold, batch-out and herd-out cross-validation (CV) scenarios.ResultsThe predictive ability of these approaches was measured by the coefficient of determination (R2). The results show that, compared to the model that includes only FTIR data, integration of both on-farm (DIM and parity) and genomic information with FTIR data improves the R2 for blood metabolites across the three CV scenarios, especially with the herd-out CV: R2 values ranged from 5.9 to 17.8% for BayesB, from 8.2 to 16.9% for GBM with the tenfold random CV, from 3.8 to 13.5% for BayesB and from 8.6 to 17.5% for GBM with the batch-out CV, and from 8.4 to 23.0% for BayesB and from 8.1 to 23.8% for GBM with the herd-out CV. Overall, with the model that includes the three sources of data, GBM was more accurate than BayesB with accuracies across the CV scenarios increasing by 7.1% for energy-related metabolites, 10.7% for liver function/hepatic damage, 9.6% for oxidative stress, 6.1% for inflammation/innate immunity, and 11.4% for mineral indicators.ConclusionsOur results show that, compared to using only milk FTIR data, a model integrating milk FTIR spectra with on-farm and genomic information improves the prediction of blood metabolic traits in Holstein cattle and that GBM is more accurate in predicting blood metabolites than BayesB, especially for the batch-out CV and herd-out CV scenarios.

Elevated thyroid hormones caused by high concentrate diets participate in hepatic metabolic disorders in dairy cows.

ObjectiveHigh concentrate diets are widely used to satisfy high-yielding dairy cows; however, long-term feeding of high concentrate diets can cause subacute ruminal acidosis (SARA). The endocrine disturbance is one of the important reasons for metabolic disorders caused by SARA. However, there is no current report about thyroid hormones involved in liver metabolic disorders induced by a high concentrate diet.MethodsIn this study, 12 mid-lactating dairy cows were randomly assigned to HC (high concentrate) group (60% concentrate of dry matter, n = 6) and LC (low concentrate) group (40% concentrate of dry matter, n = 6). All cows were slaughtered on the 21st day, and the samples of blood and liver were collected to analyze the blood biochemistry, histological changes, thyroid hormones, and the expression of genes and proteins.ResultsCompared with LC group, HC group showed decreased serum triglyceride, free fatty acid, total cholesterol, low-density lipoprotein cholesterol, increased hepatic glycogen, and glucose. For glucose metabolism, the gene and protein expression of glucose-6-phosphatase and phosphoenolpyruvate carboxykinase 1 in the liver were significantly up-regulated in HC group. For lipid metabolism, the expression of sterol regulatory element-binding protein 1, long-chain acyl-CoA synthetase 1, and fatty acid synthase in the liver was decreased in HC group, whereas carnitine palmitoyltransferase 1α and peroxisome proliferator activated receptor α were increased. Serum triiodothyronine, thyroxin, free triiodothyronine (FT3), and hepatic FT3 increased in HC group, accompanied by increased expression of thyroid hormone receptor (THR) in the liver.ConclusionTaken together, thyroid hormones may increase hepatic gluconeogenesis, β-oxidation and reduce fatty acid synthesis through the THR pathway to participate in the metabolic disorders caused by a high concentrate diet.

Full model selection using regression trees for numeric predictions of biomarkers for metabolic challenges in dairy cows

Dairy cows suffer poor metabolic adaptation syndrome (PMAS)11PMAS: Poor metabolic adaptation syndrome. during early post-calving periods caused by negative energy balance. Measurement of blood beta-hydroxy butyric acid (BHBA)22BHBA: beta-hydroxy butyric acid. and blood non-esterified fatty acids (NEFA)33NEFA: non-esterified fatty acids. allow early and accurate detection of negative energy balance. Machine learning prediction of blood BHBA and blood NEFA using milk testing samples represents an opportunity to identify at-risk animals, using less labor than direct blood testing methods. Routine milk testing on modern dairies and computer record keeping provide an immense amount of data which can then be used in machine learning models. Previous research for predicting blood metabolites using Fourier-transform infrared spectroscopy (FTIR)44FTIR: Fourier-transform infrared spectroscopy. milk data has focused mainly on individual models rather than a comparison among the models. Full model selection is the process of comparing different combinations of pre-processing methods, variable selection, and statistical learning algorithms to determine which model results in the lowest prediction error for a given dataset. For this project we used a full model selection approach with regression trees (rtFMS)55rtFMS: full model selection approach with regression trees. . rtFMS uses the cross-validated performance of different model configurations to feed a regression tree for selecting a final model. A total of 384 possible model configurations (algorithms, predictors and data preprocessing options) for each outcome (blood BHBA and blood NEFA) were considered in the rtFMS technique. rtFMS allows direct comparison of multiple modeling approaches reducing bias due to empirical knowledge, modeling habits, or preferences, identifying the model with minimal root mean squared prediction error (RMSE)66RMSE: root mean squared prediction error. . An elastic net regression model was selected as the best performing model for both biomarkers. The input data for blood BHBA predictions were FTIR milk spectra, with a second derivative pre-processing, and a filter with 212 wave numbers, obtaining RMSE = 0.354 (0.328−0.392). The best performing model for blood NEFA had input data of FTIR milk spectra, with a second derivative pre-processing, and a filter with 212 wave numbers filter along with the time of milking, obtaining RMSE = 0.601 (0.564−0.654). The comparison of multiple modeling strategies, conducted by rtFMS, present an option for improved FTIR prediction models of blood BHBA and blood NEFA by reducing error due to human bias. The implementation of rtFMS to design future prediction models can guide model inputs and features. Our prediction models have the potential to increase early detection of metabolic disorders in dairy cows during the transition period.

\u03b2-hydroxybutyrate and hydroxycarboxylic acid receptor 2 agonists activate the AKT, ERK and AMPK pathways, which are involved in bovine neutrophil chemotaxis

Elevated plasma concentrations of the ketone body β-hydroxybutyrate (BHB), an endogenous agonist of the hydroxycarboxylic acid receptor 2 (HCA2), is associated with an increased incidence of inflammatory diseases during lactation in dairy cows. In the early stages of this pathology, an increase in neutrophil recruitment is observed; however, the role of BHB remains elusive. This study characterized the effect of BHB and synthetic agonists of the HCA2 receptor on bovine neutrophil chemotaxis and the signaling pathways involved in this process. We demonstrated that treatment with BHB concentrations between 1.2 and 10 mM and two full selective agonists of the HCA2 receptor, MK-1903 and nicotinic acid, increased bovine neutrophil chemotaxis. We also observed that BHB and HCA2 agonists induced calcium release and phosphorylation of AKT, ERK 1/2 and AMPKα. To evaluate the role of these pathways in bovine neutrophil chemotaxis, we used the pharmacological inhibitors BAPTA-AM, pertussis toxin, U73122, LY294002, U0126 and compound C. Our results suggest that these pathways are required for HCA2 agonist-induced bovine neutrophil chemotaxis in non-physiological condition. Concentrations around 1.4 mM of BHB after calving may exert a chemoattractant effect that is key during the onset of the inflammatory process associated with metabolic disorders in dairy cows.

Clinical Ketosis-Associated Alteration of Gene Expression in Holstein Cows.

Ketosis is one of the most prevalent transition metabolic disorders in dairy cows, and has been intrinsically influenced by both genetic and nutritional factors. However, altered gene expression with respective to dairy cow ketosis has not been addressed yet, especially at the genome-wide level. In this study, we recruited nine Holsteins diagnosed with clinical ketosis and ten healthy controls, for which whole blood samples were collected at both prepartum and postpartum. Four groups of blood samples were defined: from cows with ketosis at prepartum (PCK, N = 9) and postpartum (CK, N = 9), respectively, and controls at prepartum (PHC, N = 10) and postpartum (HC, N = 10). RNA-Seq approach was used for investigating gene expression, by which a total of 27,233 genes were quantified with four billion high-quality reads. Subsequently, we revealed 75 and four differentially expressed genes (DEGs) between sick and control cows at postpartum and prepartum, respectively, which indicated that sick and control cows had similar gene expression patterns at prepartum. Meanwhile, there were 95 DEGs between postpartum and prepartum for sick cows, which showed depressed changes of gene expression during this transition period in comparison with healthy cows (428 DEGs). Functional analyses revealed the associated DEGs with ketosis were mainly involved in biological stress response, ion homeostasis, AA metabolism, energy signaling, and disease related pathways. Finally, we proposed that the expression level of STX1A would be potentially used as a new biomarker because it was the only gene that was highly expressed in sick cows at both prepartum and postpartum. These results could significantly help us to understand the underlying molecular mechanisms for incidence and progression of ketosis in dairy cows.

Relation between Liver Lipid Content and Plasma Biochemical Indicators in Dairy Cows

Background: The incidence of metabolic disorders in dairy cows has increased as a result of intensive production practices and genetic selection for milk yield. Among such disorders, liver lipidosis is very frequently observed and has significant negative effects on cow health and milk yield. Severe energy supply deficit causes high fat mobilization, resulting in rapid body condition loss and liver lipid infiltration, which cannot always be detected by known blood biochemical indicators. The main objective of the study was to determine possible associations of blood biochemical parameters with liver lipid infiltration severity in high-yield multiparous Holstein cows along prepartum and postpartum periods.Materials, Methods & Results: Fifty-four high-yield Holstein cows from a herd managed in a free-stall system in the northwest region of the state of Rio Grande do Sul, Brazil were evaluated. Cows were divided in two groups according to their physiological status. Group 1 included 19 prepartum cows, with an average milk yield of 44.7 L/d in the previous lactation, and 2.8 average parity, and Group 2 included 35 postpartum cows, with an average milk yield of 46.8 L/d in the previous lactation, and 2.5 average parity. The farm produced 10,000 kg milk per year, containing 3.5% of fat, 3.2% of protein and 4.7% of lactose. Total cholesterol (CH), plasma triglycerides (TGp), beta-hydroxybutyrate (BHB), albumin (ALB), non-esterified free fatty acids (NEFA) levels, and aspartate aminotransferase (AST) and creatine kinase (CK) activities were analyzed in the plasma and liver triglycerides (TGl) levels were determined in liver tissue samples.The SPSS statistical software was used for the statistical analyses. The obtained data were analyzed for normality by the Shapiro-Wilk test and for homoscedasticity by Bartlett test. Data were submitted to analysis of variance, and means were compared by the t-test (PROC TTEST). Pearson correlation test (PROC CORR) was used to compare the results between prepartum and postpartum cows, and between those with and without lipidosis.An overall incidence of 20% severe hepatic lipidosis was determined both in prepartum and postpartum cows. Positive significant correlations were obtained between days in milk (DIM) and AST (r= 0.43; P < 0.01), CH and TGp (r= 0.44; P < 0.01), TGl and AST (r=0.32; P < 0.05), NEFA and AST (r= 0.45; P < 0.01) and CK and AST (r= 0.447; P < 0.01). Negative significant correlations were detected between TGp and DIM (r= -0.45; P < 0.01), and between TGl and TGp (r= -0.30; P < 0.05).Discussion: Prepartum cows showed moderate fat infiltration in the liver, while 25.7% of postpartum cows presented severe lipidosis. AST values increased as lactation progressed, suggesting a greater tendency of liver damage, in early postpartum. The obtained CK values were within the reference range, except for the cows with hepatic lipidosis, indicating that the measured AST activity was originated from the liver and not from the muscle tissues. TGp, NEFA and AST values indicate the degree of fat mobilization and, possibly, liver infiltration, while TGl indicates fat infiltration in the liver. Although negative energy balance (NEB) may trigger lipolysis and some degree of hepatic lipidosis, plasma BHB values did not significantly increase. The obtained results show that the evaluated plasma parameters may be useful to establish guidelines for the identification of changes in the metabolic profile of dairy cows during different production stages, as well as measures for the prevention and control of metabolic disorders.

Diagnostics of metabolic disorders in the cows’ organism by basic biochemical blood markers: Evidence from FP ‘Mriia’ (Rivne District, Rivne Region, Ukraine)

The purpose of the research was to determine the characteristics of metabolic disorders in dairy cows in the dry periods, calving, and after calving periods in FG ‘Mriia’ in Rivne district of Rivne region. Researches were conducted in FG ‘Mriia’ v. Velyka Omeliana of Rivne district, Rivne region on cows of Ukrainian black-rumped dairy breed. The presence of metabolic changes in the cows in dry period (n = 6), post-partum cows (n = 8), and cows 10 days after calving (n = 8) were determined by biochemical parameters (markers) in blood serum samples, which were tested by conventional biochemical methods using the ‘Cobas c 311’ analyzer, and the content of inorganic elements was determined using the ‘C-115M1’ atomic absorption spectrophotometer. According to the results of obstetric examination of sick animals, carried out in the dry season, such diseases as ketosis (8.9%), fatty liver syndrome (6.7%), and udder edema (5.6%) were determined. In cows, the level of ketone bodies was 2.0 ± 0.04 mmol/l. 75.0% of animals diagnosed with ketosis in the dry period were prone to develop other diseases such as ovarian cysts and postpartum endometritis. Idiopathic diseases averaged 12.2%. Among the concomitant pathologies, the detention of litter was detected — 32.2%. 25 cases (27.8%) of post-partum paresis were recorded out of 90 cows examined. The following metabolic disorders have been established by biochemical markers in animals of the respective groups, namely: in cows in the dry period — a decrease of the total protein level along with its globulin fraction, the decrease of glucose content relative to the reference values of these indicators; in cows in the calving group on the background of changes in the proteinogram — a decrease in total cholesterol was determined; and in cows 10 days after calving — a decrease in the content of albumin relative to the reference values of these indicators was determined. As a result of determining the content of inorganic elements, it has been established: in the cows in dry period group — lack of zinc, copper, manganese, selenium, iodine, and cobalt and excess of iron and nickel; in the group of calving cows — there is a lack of zinc, copper, selenium, and iodine and excess of iron; in the group of cows 10 days after calving — lack of zinc, manganese, selenium, and cobalt. The data obtained can be interpreted to diagnose metabolic disorders in other farms and to perform corrective measures

Association between feed sorting and the prevalence of metabolic disorders in Hungarian large-scale dairy herds.

This research communication describes the possible association between feed sorting and the risk of metabolic disorders in dairy cows. Feed sorting, that is selecting smaller size TMR particles over longer length fibers, can lead to imbalanced energy input. In addition, sorting can lead to lower nutritive value of leftover TMR. To detect a possible relationship between TMR sorting and the occurrence of metabolic disorders in large-scale herds, TMR separation and metabolic profile tests were performed in 22 Hungarian dairies. Feed sorting was defined as >5% alteration in the mass proportion of any of the TMR fractions between the time of feed distribution and 5-6 h later. The prevalence of ketosis and subclinical acidosis differed between feed sorting and non-sorting groups. Inhomogeneous TMR seems to be a predisposing factor for imbalanced energy status. TMR homogeneity measurements should be routinely included in herd health monitoring.

Effect of the flavonoid baicalin on the proliferative capacity of bovine mammary cells and their ability to regulate oxidative stress

BackgroundHigh-yielding dairy cows are prone to oxidative stress due to the high metabolic needs of homeostasis and milk production. Oxidative stress and inflammation are tightly linked; therefore, anti-inflammatory and/or natural antioxidant compounds may help improve mammary cell health. Baicalin, one of the major flavonoids in Scutellaria baicalensis, has natural antioxidant and anti-inflammatory properties in various cell types, but its effects on bovine mammary epithelial cells (BMECs) have not been investigated.MethodsExplants from bovine mammary glands were collected by biopsy at the peak of lactation (approximately 60 days after the start of lactation) (n = three animals) to isolate BMECs corresponding to mature secretory cells. Cell viability, apoptosis, proliferative capacity and reactive oxygen species (ROS) production by BMECs were measured after increasing doses of baicalin were added to the culture media in the absence or presence of H2O2, which was used as an in vitro model of oxidative stress.ResultsLow doses of baicalin (1–10 µg/mL) had no or only slightly positive effects on the proliferation and viability of BMECs, whereas higher doses (100 or 200 µg/mL) markedly decreased BMEC proliferation. Baicalin decreased apoptosis rate at low concentrations (10 µg/mL) but increased apoptosis at higher doses. ROS production was decreased in BMECs treated with increasing doses of baicalin compared with untreated cells, and this decreased production was associated with increased intracellular concentrations of catalase and NRF-2. Irrespective of the dose, baicalin pretreatment attenuated H2O2-induced ROS production.DiscussionThese results indicate that baicalin exerts protective antioxidant effects on bovine mammary cells. This finding suggests that baicalin could be used to prevent oxidative metabolic disorders in dairy cows.

Occurrence of subclinical metabolic disorders in dairy cows from western Santa Catarina state, Brazil

ABSTRACT: The management of dairy herds during the transition period has been studied in several studies due to the severe adjustments to which cows are submitted in the metabolism of carbohydrates, lipids and minerals at early lactation. This is a period when occurs most of the metabolic disorders in dairy cows, especially in their subclinical form. Hitherto a lack of information exists on the occurrence of subclinical metabolic disorders in Brazil. The aim of this study was to determine the occurrence of subclinical metabolic disorders, including ketosis, liver lipidosis, hypocalcemia, lactacidemia and hypomagnesemia, as well as phosphorous, copper and zinc deficiency in dairy cattle from the western region of Santa Catarina state, southern Brazil, during the first 30 days of lactation. Blood samples from 15 dairy herds managed in intensive production (free-stall) and semi-confined systems were collected. Milk yield, reproduction and health data of the herd were recorded in a questionnaire, based on the records of the farm and on the observations during samples collection. Blood samples were collected for the measurement of beta-hydroxybutyrate (BHB) and lactate using portable monitors at the farm and for obtaining serum to perform the following biochemical determinations: total calcium, phosphorus, magnesium, albumin, aspartate transaminase (AST) and creatine kinase (CK) by UV-visible spectrophotometry, and copper and zinc by atomic absorption spectrophotometry. In this study, the cutoff points considered were as follows: serum BHB concentrations >1.2mmol/L for subclinical ketosis, AST >140U/L and CK <94U/L for subclinical liver lipidosis, serum lactate concentrations >2.2mmol/L for lactacidemia, serum total calcium concentrations <7.5mg/dL for subclinical hypocalcemia, serum magnesium concentration <1.7mg/dL for hypomagnesemia, serum phosphorus concentration <2.5mg/dL for phosphorus deficiency, serum copper concentrations <32.8μg/dL for copper deficiency, and serum zinc concentrations <60μg/dL for zinc deficiency. The results showed an occurrence of 9% for subclinical ketosis, 11% for subclinical liver lipidosis, 44.5% for lactacidemia, 11% for subclinical hypocalcemia, 7.4% for subclinical hypomagnesemia, 10.7% for copper deficiency and 8.7% for zinc deficiency. According to the survey results, the occurrence of subclinical ketosis, lipidosis and hypocalcemia in western Santa Catarina differ from data found in the literature

Relationship between daily rumination time, physical activity, estrus and metabolic changes in dairy cows

The present study attempted to ascertain whether there is any connection between reduced daily rumination time and increased physical activity of the animals, on the one hand, and the presence of estrus or metabolic disorders in dairy cows, on the other hand. It has been observed that of the total of 168 cows, 55 (32.73%) showed decreased daily rumination time, 57 cows (33.92%) had specific manifestations for estrous period, while 25 cows (14.88%) showed both decreased daily rumination time and the presence of estrus. Statistical assessment of the data demonstrated a highly significant correlation between these two factors, with a p-value <0.05 (p = 0.0369). Regarding the correlation between increased physical activity, found in 40 cows (23.80%) and the presence of estrus, observed in 57 cows (33.92%) this one is extremely statistically significant with a p-value <0.001 (p = 0.0005), the combination of increased physical activity and estrus being detected in a total of 23 cows (13.69%). Thus, of 168 dairy cows taken into the study, 37 (22.02%) showed an association between decreased daily rumination time and increased physical activity, resulting in a extremely statistically significant correlation between the combination of the two events and the presence of estrus in cows, with a p-value <0.001 (p = 0.0003). Metabolic disorders were found in a total of 12 dairy cows (7.14 %), the association between decreased daily rumination time and increased physical activity being not statistically correlated with the development of metabolic disorders, p = 0.4676 . It remains to be observed if a correlation between the association of decreased daily rumination time and increased physical activity with the presence of metabolic disorders exists.

β-Hydroxybutyrate induces bovine hepatocyte apoptosis via an ROS-p38 signaling pathway.

β-Hydroxybutyrate (BHB) is an important indicator for metabolic disorders in dairy cows, such as ketosis and fatty liver. Dairy cows with ketosis display oxidative stress that may be associated with high levels of BHB. The purpose of this study was to demonstrate a correlation between the high levels of BHB and oxidative stress in dairy cows with ketosis, and to investigate the molecular mechanisms underlying oxidative damage in bovine hepatocytes. The results showed that dairy cows with ketosis exhibited oxidative stress and liver damage, which was significantly correlated with plasma BHB. Similarly, high concentrations of BHB increased the oxidative stress of cow hepatocytes in vitro, resulting in the phosphorylation and activation of p38 mitogen-activated protein kinase (MAPK), which led to increased expression, nuclear localization, and transcriptional activity of p53 and decreased Nrf2 in bovine hepatocytes. High concentrations of BHB significantly increased the expression of proapoptotic genes and significantly inhibited the expression of antiapoptotic genes. Finally, high concentrations of BHB promoted apoptosis in bovine hepatocytes. N-Acetyl-l-cysteine, glucose, and SB203580 (p38 inhibitor) significantly attenuated BHB-induced apoptotic damage in hepatocytes. These results indicate that BHB induces bovine hepatocyte apoptosis through the ROS-p38-p53/Nrf2 signaling pathway.

Milk yield and composition, body condition, rumen characteristics, and blood metabolites of dairy cows fed diet supplemented with palm oil

An addition of rumen-protected fat to the diet of cows may limit negative energy balance and/or shorten its duration, leading to increased milk production with reduced risk of metabolic disorders in dairy cows. The aim of the study was to test the effect of rumen-inert fat supplement of palm oil on milk production, milk composition, rumen characteristics, and metabolic variables of early lactating dairy cows. For this purpose, 24 Holstein-Friesian cows were divided into two equal groups and fed a corn silage-based diet, without palm oil supplementation (control) or with 300 g palm oil (Palm Fat 99, Noack & Co. GmbH, Vienna, Austria) per cow for 8 weeks starting from day 30 after parturition. Milk, rumen, and blood samples were taken three times during experiment at days 30, 58, and 86 of lactation. Body condition scores of cows were determined in the same time periods. Milk yields were measured at the morning and evening milking (600 and 1800). Milk samples were analyzed for milk fat and milk protein content. Rumen content was tested for electrochemical reaction. A native slide was prepared for microscopical examination of the rumen protozoa motility that was numerically estimated. Protozoa were counted in whole rumen contents by light microscopy. Blood samples were tested for total protein, albumin, urea, tryglicerides, cholesterol, total bilirubin, beta-hydroxybutyrate, Ca, and P. Compared with the control, palm oil supplementation resulted in an increase of the average milk yield and milk fat content. The loss in body condition was significantly lower in the group fed palm oil than in the control group. Rumen pH, total number, and motility of protozoa in the group fed palm oil were significantly higher than those in the control group. Palm oil supplementation did not influence blood metabolite concentrations except for urea and glucose which were significantly lower and Ca and cholesterol which were significantly higher in the palm oil-supplemented group. Our results indicate that supplementation with palm oil in weeks 4 to 12 postpartum spared postpartum body weight loss, increased milk yield and milk fat content, and had positive effects on rumen characteristics.

Short communication: Circulating serotonin (5-HT) concentrations on day 1 of lactation as a potential predictor of transition-related disorders

The monoamine serotonin (5-hydroxytryptamine; 5-HT) has been described as a homeostatic regulator of lactation. Recently, our laboratory determined that 5-HT is involved in the regulation of calcium and glucose homeostasis during the transition period in rodents. More specifically, we demonstrate that 5-HT is responsible for calcium mobilization from bone and upregulation of hepatic gluconeogenic enzymes and mammary gland glucose transporters. Our objective was to investigate the correlation between circulating 5-HT concentrations and circulating ionized calcium, parathyroid hormone-related protein (PTHrP), and glucose concentrations on d 1 postpartum. We also investigated the correlation between circulating 5-HT and milk fever and ketosis incidence and severity in multiparous Holstein cows at the onset of lactation. Blood samples were collected from 42 multiparous cows on d 1 of lactation and analyzed for 5-HT, calcium, glucose, and PTHrP. Milk fever (determined subjectively for each cow on d 1 postpartum) and ketosis incidence and severity (scale 1 to 4, determined objectively for each cow during the first 10 d postpartum) were recorded for all animals. Serum 5-HT was positively correlated with serum calcium and with plasma PTHrP (r>0.37). Serum 5-HT was negatively correlated with milk fever incidence and with ketosis severity (most severe ketosis incidence recorded during the first 10 d postpartum; r<-0.33). Serum calcium and plasma glucose concentrations were negatively correlated with milk fever and ketosis severity, respectively (r<-0.39). These data indicate that 5-HT potentially plays a role in the regulation of calcium and glucose homeostasis during the transition period in cattle, which we previously demonstrated in rodents. Increased circulating concentrations of 5-HT might decrease milk fever at the onset of lactation and ketosis severity during the first 10 d postpartum in dairy cows. Understanding this physiological axis could help describe the underlying mechanisms associated with these periparturient metabolic disorders in dairy cows.

Effect of 2-methyl-2-phenoxy propionic acid on serum lipid profile and ovarian activity in dairy cows

Hepatic lipidosis and ketosis are frequent metabolic disorders in dairy cows during the transition period. The 2-methyl-2-phenoxy propionic acid (MFPA) is an activator of energy metabolism. The objective of this study was to evaluate the effect of administration of MFPA 10 days prepartum to day 36&amp;nbsp;postpartum on serum lipid profile, ovarian reactivity, and milk yield. Fifty seven multiparous Holstein cows were divided into four groups. The groups 1 (n = 14) and 2 (n = 14) had body condition score (BCS) above 4; BCS of the groups 3 (n = 15) and 4 (n = 14) was between 3.25 and 3.75 at calving. The solution containing 10 mg/kg MFPA was injected intramuscularly (IM) to cows of groups 1 and 3, 10&amp;ndash;7 days prepartum and 6&amp;nbsp;h postpartum. The groups 2 and 4 received 50 ml of 0.9% NaCl as placebo in the same way. Blood samples for serum lipid profile were collected from all cows 10 days before calving without treatment, 2 days after the first administration of MFPA and postpartum at days 2, 10, and 21 after the second administration of MFPA. At days 21, 24, 27, 30, 33, and 36 postpartum, blood samples were obtained for plasma progesterone determination. Milk yield was registered daily during 60 days postpartum. Prepartum free fatty acids (FFA) were mildly increased without difference among all the groups (P &amp;gt; 0.05). b-hydroxybutyrate (BHB) was increased only at day 10 after calving in cows of group 1 treated with MFPA (P &amp;lt; 0.05) due to higher number of postpartum diseases. In cows from groups 3 and 4 (BCS normal), BHB was mildly increased, not indicating subclinical ketosis. The serum concentrations of triacylgycerols, cholesterol, albumin, activities of aspartate aminotransferase and creatine kinase were within the limits of reference values, indicating adequate liver integrity and function. Cows of normal BCS treated with MFPA presented better milk production but without significant difference among four groups (P &amp;gt; 0.05). Ovarian reactivity was present at day 21 in all groups of cows without difference (P&amp;nbsp;&amp;gt;&amp;nbsp;0.05). The administration of MFPA had no effect on serum lipid profile and ovarian activity in this study. &amp;nbsp;

Risk factors for displaced abomasum or ketosis in Swedish dairy herds

Risk factors associated with high or low long-term incidence of displaced abomasum (DA) or clinical ketosis were studied in 60 Swedish dairy herds, using multivariable logistic regression modelling. Forty high-incidence herds were included as cases and 20 low-incidence herds as controls. Incidence rates were calculated based on veterinary records of clinical diagnoses. During the 3-year period preceding the herd classification, herds with a high incidence had a disease incidence of DA or clinical ketosis above the 3rd quartile in a national database for disease recordings. Control herds had no cows with DA or clinical ketosis. All herds were visited during the housing period and herdsmen were interviewed about management routines, housing, feeding, milk yield, and herd health. Target groups were heifers in late gestation, dry cows, and cows in early lactation. Univariable logistic regression was used to screen for factors associated with being a high-incidence herd. A multivariable logistic regression model was built using stepwise regression. A higher maximum daily milk yield in multiparous cows and a large herd size (p=0.054 and p=0.066, respectively) tended to be associated with being a high-incidence herd. Not cleaning the heifer feeding platform daily increased the odds of having a high-incidence herd twelvefold (p<0.01). Keeping cows in only one group in the dry period increased the odds of having a high incidence herd eightfold (p=0.03). Herd size was confounded with housing system. Housing system was therefore added to the final logistic regression model. In conclusion, a large herd size, a high maximum daily milk yield, keeping dry cows in one group, and not cleaning the feeding platform daily appear to be important risk factors for a high incidence of DA or clinical ketosis in Swedish dairy herds. These results confirm the importance of housing, management and feeding in the prevention of metabolic disorders in dairy cows around parturition and in early lactation.

Effects of chromium supplementation on early lactation performance of Holstein cows

Two experiments were conducted to evaluate the effects of chromium (Cr) supplementation on early lactation performance of Holstein cows. Experiment 1 involved 12 primiparous (PP) and 22 multiparous (MP) cows, while exp. 2 involved 18 PP and 22 MP cows. In each trial, cows were fed total mixed rations (TMR) and assigned to one of two treatments: control or 0.5 mg kg−1 supplemental chelated Cr from week 6 prepartum to week 16 postpartum The cortisol response to synthetic adrenocorticotropin (ACTH) intramuscular (i.m.) and the luteinizing hormone (LH) response to synthetic gonadotropin-releasing hormone (GnRH) i.m. were evaluated as well, during weeks 2 and 6 postpartum in exp. 2 During the first 16 wk of lactation, supplemental Cr tended to increase milk yields in PP cows by 13% (P = 0.06) and increased milk production by 7% (P &lt; 0.05) in exps. 1 and 2, respectively, but had no effect in MP cows. Despite increased milk yield, Cr supplementation had no adverse effect on milk composition, reproductive performance, or health status. Furthermore, Cr supplementation tended to increase the milk lactose content in PP cows. Supplemental Cr reduced serum β-hydroxybutyrate levels and may reduce subclinical ketosis in MP cows. In addition, in overconditioned, aged cows, Cr supplementation may reduce the incidence of certain other metabolic disorders. Peak values and production rates of cortisol in Cr-supplemented cows tended to be greater (P &lt; 0.10) than in control cows at week 6 Basal LH concentrations did not differ between the two treatments for either week However, the Cr-supplemented cows released less (P &lt; 0.05) LH than did control cows at week 6. Results from hormonestimulation tests suggest that the Cr-supplemented cows may have experienced a greater stress with their increased milk production. However the time in postpartum anestrus and the time to conception were similar, suggesting that Cr supplementation may have mitigated the slower return to fertility usually seen in higher producing PP dairy cows. Further study is needed to determine the effects of Cr supplementation on reproductive performance, health status, and metabolic disorders in dairy cows. Key words: Chromium, milk production, luteinizing hormone, cortisol, reproduction, dairy cows

Metabolic Profile in Beef Bulls under Conditions of Industrial Technologies

Jago§, P., IIlek, J., Doubek, J., Jurajdovli, Jana.:MetabolicProfileinBeef Bulls under Conditions of Industrial Technologies. Acta vet. Bmo, 54, 1985: 41-51. The development of health condition of animals was followed in 10 specialize-1 establishments of cattle fattening using the system of preventive diagnoses. Tre metabolic profile of healthy bulls and those suffering from disorders of the type of metabolic acidosis, alkalosis, rachitis, hyperphosphataemia and hypomagnesaemia was determined. Statistically significant differences of basic biochemical data between the group of healthy animals and those affected with individual metabolic disorders were found. The causes and the character of changes in the biochemical profile of individual animal groups and the possibilities of the application of new findings in an early diagnosis of metabolic disorders in beef bulls are discussed. Cattle fattening, metabolic acidosis, metabolic alkalosis, hyperphosphataemia, rachitis, hypomagnesaemia. The purpose of the intensive animal breeding is to increase the production of beef cattle. This goal is being achieved both by better utilization of potential growth capacity of our breeds and their crosses with beef types and by decrea~ing the losses caused by the lowered nutrient conversion, diseases and emergency slaughter of animals. The preferential task in solving of these problems has been attributed to the nutrition of animals reared under these technologies which is a limiting factor not only for the growth intensity but also for the morbidity and the resulting losses. New knowledge in the field of animal nutrition and the rapid development of clinical bioche­ mistry create favourable conditions for the investigation and influencing the growth capacity of young cattle, for its active production and health control. The main aim of these efforts has been to ensure optimal, economically effective production of wholesome and safe foodstuffs of high nutritional value for human consumption. The examination of biological fluids and tissues using modem laboratory techniques has already been commonly used in diagnosis of production and metabolic disorders in dairy cows and calves not only abroad (Payne 1977) but also in this country (Jagos et al. 1975, 1977, 1980). Lately, a system of preventive diagnosis for breeding of sheep and sows has also been worked out (J agos et al. 1980, 1981). Till now, no detailed findings have been published concerning hematological and biochemical parameters in healthy bulls compared with those suffering from metabolic dis­ orders.