Subclinical Ketosis Research Articles

Invited Review: Ketosis Diagnosis and Monitoring in High-Producing Dairy Cows

This work reviews the current impact and manifestation of ketosis (hyperketonemia) in dairy cattle, emphasizing the practical use of laboratory methods, field tests, and milk data to monitoring this disease. Ketosis is a major issue in high-producing cows, easily reaching a prevalence of 20% during early postpartum when the negative energy balance is well established. Its economic losses, mainly related to decreasing milk yield, fertility, and treatment costs, have been estimated up to €250 per case of ketosis/year, which can double if associated diseases are considered. A deep relationship between subclinical or clinical ketosis and negative energy balance and related production diseases can be observed mainly in the first two months postpartum. Fourier transform infrared spectrometry methods gradually take place in laboratory routine to evaluates body ketones (e.g., beta-hydroxybutyrate) and probably will accurately substitute cowside blood and milk tests at a farm in avenir. Fat to protein ratio and urea in milk are largely evaluated each month in dairy farms indicating animals at risk of hyperketonemia. At preventive levels, other than periodical evaluation of body condition score and controlling modifiable or identifying non-modifiable risk factors, the ruminatory activity assessment during the peripartum seems to be a valuable tool at farms. We conclude that a technological advance progressively takes place to mitigate the effects of these metabolic diseases, which challenge the high-yielding cows.

Genome-wide association study and functional analyses for clinical and subclinical ketosis in Holstein cattle

Ketosis is one of the most frequent metabolic diseases in high-yielding dairy cows and is characterized by high concentrations of ketone bodies in blood, urine, and milk, causing high economic losses. The search for polymorphic genes, whose alleles have different effects on resistance to developing the disease, is of extreme importance to help select less susceptible animals. The aims of this study were to identify genomic regions associated with clinical and subclinical ketosis (β-hydroxybutyrate concentration) in North American Holstein dairy cattle and to investigate these regions to identify candidate genes and metabolic pathways associated with these traits. To achieve this, a GWAS was performed for 4 traits: clinical ketosis lactation 1, clinical ketosis lactation 2 to 5, subclinical ketosis lactation 1, and subclinical ketosis lactation 2 to 5. The estimated breeding values from 77,277 cows and 7,704 bulls were deregressed and used as pseudophenotypes in the GWAS. The top-20 genomic regions explaining the largest proportion of the genetic variance were investigated for putative genes associated with the traits through functional analyses. Regions of interest were identified on chromosomes 2, 5, and 6 for clinical ketosis lactation 1; 3, 6, and 7 for clinical ketosis lactation 2 to 5; 1, 2, and 12 for subclinical ketosis lactation 1; and 20, 11, and 25 for subclinical ketosis lactation 2 to 5. The highlighted genes potentially related to clinical and subclinical ketosis included ACAT2 and IGF1. Enrichment analysis of the list of candidate genes for clinical and subclinical ketosis showed molecular functions and biological processes involved in fatty acid metabolism, lipid metabolism, and inflammatory response in dairy cattle. Several genomic regions and SNPs related to susceptibility to ketosis in dairy cattle that were previously described in other studies were confirmed. The novel genomic regions identified in this study aid to characterize the most important genes and pathways that explain the susceptibility to clinical and subclinical ketosis in dairy cattle.

Comparative evaluation of cytokine and acute-phase protein concentrations in sera of dairy cows with subclinical and clinical ketosis as a different view of the causes of the disease.

Background and Aim:Ketosis is a common disease occurring during the first stage of lactation in highly productive dairy cows. The aim of the present study was the comparative assessment of selected pro-inflammatory cytokines (including tumor necrosis factor-α [TNF-α] and interleukin 6 [IL-6]), anti-inflammatory cytokines (including IL-10), and acute-phase proteins (APPs) (including haptoglobin [Hp] and serum amyloid A [SAA]), in the sera of cows with subclinical ketosis (SCK), in those with clinical ketosis (CK), and in healthy cows.Materials and Methods:Thirty dairy cows of Holstein-Friesian breed were investigated. The cows were divided into three groups depending on the serum β-hydroxybutyric acid (βHBA) level. The control, SCK, and CK groups included healthy cows, cows with SCK, and cows with CK, respectively. BHBA concentration in blood serum was determined using colorimetric method. The blood serum was used for proper tests. Cytokine (TNF-α, IL-6, and IL-10) and APPs (SAA and Hp) concentrations in the investigated samples were determined by enzyme-linked immunosorbent assay method.Results:The SCK group had significantly higher TNF-α, IL-6; IL-10, and SAA values than had the CK group (p<0.01). The SCK group had a lower Hp concentration than had the CK group (p<0.05).Conclusion:This study showed that the inflammation intensity is higher in the initial phase of the disease and decreases during the advancement, probably due to active anti-inflammatory mechanisms (an increase of IL-10 concentration), which protect animal organism from self-destruction. On the basis of our study, it can be assumed that ketosis development in dairy cows was preceded by the systemic inflammation that may influence the progress of this disease.

Ketone bodies - causes and effects of their increased presence in cows' body fluids: A review.

Ketosis is the most common metabolic disease in high-performance dairy cows during the first 6-8 weeks of lactation. Its main symptoms include an excessive amount of so-called ketone bodies in a cow’s body fluids. Ketone bodies consist of β-hydroxybutyric acid (βHBA), acetoacetic acid, and acetone. βHBA is the main component with its share of the total volume of ketone bodies in the blood of about 70%. Clinical symptoms of ketosis in cows include loss of appetite, preference for forage to concentrated feed, and acetone odor in their mouth and urine. Those symptoms are accompanied by a production drop, an increase of concurrent illness (mastitis, metritis, and displaced abomasum), and poor reproductive performance. One of the ketosis characteristic effects is an increase in the level of fat in milk (>5%), while protein levels decrease (<2.9%). In the case of subclinical ketosis (SCK), the fat–protein ratio in milk is increased to above 1.4:1. The current consensus for SCK is to consider a cutoff point of βHBA to be at least 1.2 mmol/L in blood plasma. Ketosis prevention is based on keeping perinatal cows in good condition, that is, with around 3.5 points in the five-point body condition scoring, carefully balancing food doses during the first 2 months of lactation with the correct energy–protein ratio. Glucose precursor products should be administered orally, in particular to at-risk herds. Ketosis occurs in 7-14% on average of the total number of cows in a herd. In general, data on the prevalence of SCK vary considerably, depending on their source. Moreover, the problem is mostly observed in poorly-fed animals with high milk production potential. The objectives of this review are to reveal the current situation of ketosis prevalence, the possibility of diagnosis, consequences in dairy cows and to provide some recommendations for ketosis treatment and prevention.

Milk Fatty Acids Composition Changes According to β-Hydroxybutyrate Concentrations in Ewes during Early Lactation.

Simple SummaryKetosis can occur during the last six weeks of gestation and continue to the early weeks of lactation due to an increase in energy requirement. This condition can cause substantial economic issues because of the decrease in production, the cost of medical management, the loss of the mothers and the lambs. A better knowledge of this disorder and its early diagnosis could make treatment more effective and optimize productivity. The aims of this study were to understand the metabolic status of the early-lactating ewes and to identify biomarkers for precocious diagnosis of subclinical ketosis using gas chromatographic technique. Different relationships were found between milk fatty acids and metabolic status of the ewes. Furthermore, 8 potential biomarkers were determined.Ketosis is a metabolic disease of pregnant and lactating ewes linked to a negative energy balance which can cause different economic losses. The aims of this study were to understand the metabolic status of the early-lactating ewes and to identify biomarkers for early diagnosis of subclinical ketosis. Forty-six Sarda ewes were selected in the immediate post-partum for the collection of the biological samples. A blood sample from the jugular vein was used to determine β-Hydroxybutyrate (BHB) concentrations. Animals were divided into two groups: BHB 0 or healthy group (n = 28) with BHB concentration < 0.86 mmol/L; and BHB 1 or subclinical ketosis (n = 18) with a BHB concentration ≥ 0.86 mmol/L. Ten mL of pool milk were collected at the morning milking for the analyses. The concentration of 34 milk fatty acids was evaluated using gas chromatography. Two biochemical parameters and 11 milk fatty acids of the total lipid fraction presented a p-value ≤ 0.05. The study revealed different relationships with tricarboxylic acid cycle, blood flows, immune and nervous systems, cell functions, inflammatory response, and oxidative stress status. Eight parameters were significant for the receiver operating characteristic (ROC) analysis with an area under the curve greater than 0.70.

Effects of Glycerol-Producing Yeast Supplementation on Production Performance, Biochemical Indexes, Subclinical Ketosis Incidence and Rumen Fermentation Performance of Dairy Cows

Glycerol could be used to alleviate negative energy balance in highproducing dairy cows as an important precursor participating of glucose synthesis. However, some industrial glycerol may do harm to cow health because of some mixed toxic chemicals. The purpose of this study was to investigate the effects of glycerol-producing yeast prepared in our laboratory on improving the production performance and reducing the subclinical ketosis incidence of transition dairy cows. The results showed that the concentrations of the β-Hydroxybutyric Acid (BHBA) and Non-Esterified Fatty Acid (NEFA) in the groups with glycerol-producing yeast were significantly decreased (P&lt;0.05), while the concentrations of glucose, TP and the production of propionic acid were significantly increased (P&lt;0.05) compared with the control groups on the 21st day. Moreover, the glycerol-producing yeast improved the milk quality by significantly increasing the rate of milk protein and milk fat (P&lt;0.05). Rumen fermentation performance was improved by supplementation of glycerol-producing yeast with significant increase in propionic acid and Microbial Crude Protein (MCP) concentrations (P&lt;0.05). Meanwhile, supplementation of glycerol-producing yeast reduced the incidence of subclinical ketosis by improving the blood glucose and NEFA concentration and decreasing the concentration of BHBA. In conclusion, glycerol-producing yeast supplementation benefits dairy cows on their production performance, some biochemical indexes, subclinical ketosis incidence and rumen fermentation performance. This study provided some supportive data for the application of glycerol-production yeast supplementation in dairy production.

130 Prediction of subclinical ketosis based on automated milking systems (AMS) in dairy cattle

130 Prediction of subclinical ketosis based on automated milking systems (AMS) in dairy cattle

EVALUATION OF DIAGNOSTIC METHODS FOR SUBCLINICAL KETOSIS IN DAIRY COWS

The article presents the results of a study of the sensitivity and specificity of two types of ketone test strips for detecting latent ketosis in dairy cows. During the experiment, test strips KetoPHAN and Keto-Test, showing the number of ketone bodies in milk and urine, were used in 108 Holstein-Friesian cows for 2-15 days after calving. Blood, urine and milk samples were taken simultaneously from the same cows. In general, subclinical ketosis in cows was determined by the level of beta-hydroxybutyrate in blood plasma by an enzymatic method («gold standard» method). The sensitivity and specificity of the test tests were evaluated at various levels of β-hydroxybutyrate. The maximum level of subclinical ketosis in cows was calculated as a β-hydroxybutyrate concentration of 1.2 mmol / L or higher. When evaluating test strips on urine and milk samples, the best results were obtained in the β-hydroxybutyrate range of 1.4 mmol / L and above. In this range, the sensitivity of the test strips to urine was high (95%), the specificity was moderate (70%). The sensitivity and specificity of milk tests were high (90% and 96%, respectively). The prevalence of subclinical ketosis in cows was studied using an electronic device (FreeStyle Optium). The prevalence of latent ketosis was different: FreeStyle - 25.0%, KetoPHAN - 48.1%, Keto-Test - 13.1%. The data obtained from the electronic device is close to the data obtained according to the "gold standard" (22.2%). Although milk and urine test strips are optimal for the diagnosis of subclinical ketosis at a plasma β-hydroxybutyrate level of 1.4 mmol / L, they can be used to predict and control ketosis in dairy cows due to their simplicity and availability.

Rumination time as an early predictor of metritis and subclinical ketosis in dairy cows at the beginning of lactation: Systematic review-meta-analysis

Daily rumination time (RT; min/d) is recognized as an important tool for assessing the health of dairy cows, which may depend on the disease, lactation stage and individual cows. Using a systematic review-meta-analysis, this study evaluated whether the variation in RT is effective for early detection of metritis and subclinical ketosis (SCK) in dairy cows in the pre and post-partum periods (from three weeks before to three weeks after calving). The research was carried out in four electronic databases - Scopus, Science Direct, Pubmed and Web of Science. The main inclusion criteria were original research; evaluation of RT in dairy cows; and use of RT for early identification of metritis and/or SCK in post-partum dairy cows. A random effect meta-analysis (MA) was conducted for each disease (metritis and SCK) separately, with the RT means of healthy and sick groups, measured in the pre and post-partum. The effect size used was the mean difference (MD).Twenty-two trials from six studies were included in the MA, involving 1494 dairy cows. For metritis, four trials from three studies in the pre-partum period were considered as well as five trials from four studies in the post-partum. For SCK, six trials from four studies pre-partum and seven trials from five studies in the post-partum period were taken into consideration. The heterogeneity between studies for metritis was null (I2 = 0%) and low (I2 = 5.7 %) in the pre-partum and in the post-partum, respectively. The MD of RT between healthy cows and those with metritis was different in the pre (MD =0.411 min/d; P < 0.001) and in the post-partum (MD =0.279 min/d; P < 0.001). In SCK, heterogeneity was high in the pre (I2 = 69 %) and in the post-partum (I2 = 58.1 %), and the MD of RT was similar between healthy and sick cows (P> 0.05). In a meta-regression, RT from primiparous cows showed a lower predicted value for MD (0.48 min. d; P < 0.05) compared to multiparous cows, and the increment in each unit of milk production decreased the predicted MD value by 0.08 min. d (P < 0.001). Our MA demonstrates that RT is a good predictor for early detection of metritis in pre and post-partum; however, it is not an adequate predictor for SCK. Further investigations using more frequent blood sampling and the same threshold values for BHB are required to assess the adequacy of rumination time to predict SCK.

Hepatic autophagy and mitophagy status in dairy cows with subclinical and clinical ketosis

Severe negative energy balance around parturition is an important contributor to ketosis, a metabolic disorder that occurs most frequently in the peripartal period. Autophagy and mitophagy are important processes responsible for breaking down useless or toxic cellular material, and in particular damaged mitochondria. However, the role of autophagy and mitophagy during the occurrence and development of ketosis is unclear. The objective of this study was to investigate autophagy and mitophagy in the livers of cows with subclinical ketosis (SCK) and clinical ketosis (CK). We assessed autophagy by measuring the protein abundance of microtubule-associated protein 1 light chain 3-II (LC3-II; encoded by MAP1LC3) and sequestosome-1 (p62, encoded by SQSTM1), as well as the mRNA abundance of autophagy-related genes 5 (ATG5), 7 (ATG7), and 12 (ATG12), beclin1 (BECN1), and phosphatidylinositol 3-kinase catalytic subunit type 3 (PIK3C3). Mitophagy was evaluated by measuring the protein abundance of the mitophagy upstream regulators PTEN-induced putative kinase 1 (PINK1) and Parkin. Liver and blood samples were collected from healthy cows [n = 15; blood β-hydroxybutyrate (BHB) concentration <1.2 mM], cows with SCK (n = 15; blood BHB concentration 1.2 to 3.0 mM) and cows with CK (n = 15; blood BHB concentration >3.0 mM with clinical signs) with similar lactation numbers (median = 3, range = 2 to 4) and days in milk (median = 6, range = 3 to 9). The serum activity of aspartate aminotransferase and alanine aminotransferase was greater in cows with CK than in healthy cows. Levels of oxidative stress biomarkers malondialdehyde and hydrogen peroxide were also higher in liver tissue from ketotic cows (SCK and CK) than from healthy cows. Compared with cows with CK and healthy cows, the hepatic mRNA abundance of MAP1LC3, SQSTM1, ATG5, ATG7, ATG12, and PIK3C3 was upregulated in cows with SCK. Compared with healthy cows, cows with SCK had a lower abundance of p62 and a greater abundance of LC3-II, but levels of both were higher in cows with CK. The mRNA abundance of ATG12 was lower in cows with CK than in healthy cows. Furthermore, the hepatic protein abundance of PINK1 and Parkin was greater in cows with SCK and slightly lower in cows with CK than in healthy cows. These data demonstrated differences in the hepatic activities of autophagy and mitophagy in cows with SCK compared with cows with CK. Although the precise mechanisms for these differences could not be discerned, autophagy and mitophagy seem to be involved in ketosis.

Subclinical ketosis risk prediction in dairy cows based on prepartum metabolic indices

ABSTRACT Ketosis can seriously impair cow performance. This study detected changes in prepartum blood metabolic parameters for predicting postpartum ketosis occurrence in dairy cows. Body condition score (BCS) was assessed before and after delivery. Blood samples of 63 cows were collected from 10 days before calving to 10 days after calving to measure metabolic parameters including β-hydroxybutyric acid (BHBA), non-esterified fatty acid (NEFA), glucose (GLU), total bilirubin (TBIL), direct bilirubin (DBIL), indirect bilirubin (IBIL), total protein (TP), albumin (ALB), globulin (GLO), alanine aminotransferase (ALT), and aspartate aminotransferase (AST). There was a postpartum subclinical ketosis incidence of 42.25%. Compared with prepartum, plasma, levels of BHBA, AST, and NEFA significantly increased postpartum, and prepartum AST (R=0.57) and NEFA (R=0.45) showed a significant positive correlation with ketosis postpartum. Plasma GLU level significantly decreased postpartum and was significantly negatively correlated with ketosis (R=-0.21). Receiver operating characteristic curve analysis revealed prepartum BSC &lt; 2.88, and prepartum plasma AST &gt; 68.0 U/L, GLU &lt; 3.97mmol/L, NEFA &gt; 0.27mmol/L, and BHBA &gt; 0.43mmol/L, indicating a high risk of subclinical ketosis postpartum. These levels can be used as risk indicators to predict the occurrence of subclinical ketosis in postpartum cows.

Validation of a cow-side blood test for beta-hydroxybutyrate concentration in dairy cows

Clinical ketosis is common during the dairy cows' transition period and is responsible for considerable economic loss. Early identification of cows with subclinical ketosis is the first step for maintaining the health and productivity of dairy cows. The goals of the study were two-fold: The first was to examine the usefulness of a mobile test device as a cow-side test; and the second was to compare BHB concentrations measured by the ketometer using capillary blood and blood collected from the coccygeal vessels with values determined by a reference method in the laboratory using jugular blood. Blood samples were collected from a jugular vein or the coccygeal vessels in 81 dairy cows at 7 time points (14 and 7 days pre-partum and 7, 14, 21, 28, and 42 days post-partum) for kinetic enzymatic measurement of BHB concentration in the laboratory. Blood samples were concurrently collected from the coccygeal vessels or by pricking the vulvar lip at the transition of the skin to the mucosa (capillary blood) to determine BHB concentration using the WellionVet BELUA ketometer (MED TRUST GmbH, Marz, Austria). Initial errors in operating the ketometer were quickly eliminated with experience. BHB concentrations of jugular blood measured in the laboratory were 0.07 mmol/l lower than those measured in coccygeal blood. The mean BHB concentration measured in coccygeal and capillary blood using the WellionVet BELUA ketometer did not significantly differ but were 0.13 and 0.12 mmol/l respectively, lower than the mean jugular vein concentrations measured in the laboratory. The WellionVet BELUA ketometer is useful for determination of BHB concentration in cows provided that the manufacturer's specifications are followed. Capillary blood is best collected at the transition from the vulvar skin to its mucosa. The device generates rapid results that correlate well with BHB concentrations determined in the laboratory and with the results obtained from different blood collection sites. It is ideally suited for monitoring dairy cows for subclinical ketosis using capillary or coccygeal blood.

A Multi-Platform Metabolomics Approach Identifies Urinary Metabolite Signatures That Differentiate Ketotic From Healthy Dairy Cows.

Ketosis and subclinical ketosis are widespread among dairy cows especially after calving. Etiopathology of ketosis has been related to negative energy balance. The objective of this study was to investigate metabolite fingerprints in the urine of pre-ketotic, ketotic, and post-ketotic cows to identify potential metabolite alterations that can be used in the future to identify susceptible cows for ketosis and metabolic pathways involved in the development of disease. In this study, NMR, DI/LC-MS/MS, and GC-MS-based metabolomics were used to analyze urine samples from 6 cows diagnosed with ketosis and 20 healthy control (CON) cows at −8 and −4 weeks prepartum, the week (+1 to +3) of ketosis diagnosis, and at +4 and +8 weeks after parturition. Univariate and multivariate analyses were used to screen metabolite panels that can identify cows at their pre-ketotic stage. A total of 54, 42, 48, 16, and 31 differential metabolites between the ketotic and CON cows were identified at −8 and −4 weeks prepartum, ketosis week, and at +4, and +8 weeks postpartum, respectively. Variable importance in projection (VIP) plots ranked the most significant differential metabolites, which differentiated ketotic cows from the CON ones. Additionally, several metabolic pathways that are related to ketosis were identified. Moreover, two promising metabolite panels were identified which clearly separated ketotic from CON cows with excellent level of sensitivity and specificity. Overall, multiple urinary metabolite alterations were identified in pre-ketotic, ketotic, and post-ketotic cows. The metabolite panels identified need to be validated in the future in a larger cohort of animals.

Addition of straw to the early-lactation diet: Effects on feed intake, milk yield, and subclinical ketosis in Holstein cows

This study evaluated feed intake, milk yield, and subclinical ketosis in dairy cows in early lactation fed 2 different diets postpartum. Cows are typically offered a high-energy ration immediately after calving. We compared a conventional high-energy total mixed ration (TMR) with a transition ration that contained chopped straw. We predicted that adding chopped straw would increase dry matter intake, milk production, and indicators of energy metabolism during the first 3 wk of lactation compared to cows fed a conventional high-energy TMR. We also predicted that carryover effects would be likely for at least 2 wk after treatment ended. A total of 68 mixed-age Holstein cows were enrolled in the study 3 wk before their expected calving. All cows were managed on a single high-forage diet during the dry period. At calving, cows were allocated to 1 of the 2 diets: half to the conventional high-energy TMR (CTMR; n = 34; net energy for lactation = 1.61 Mcal/kg; neutral detergent fiber = 31.7%), and the other half to a high-forage TMR containing chopped wheat straw, equivalent to 4.27% dry matter (STMR; n = 34; net energy for lactation = 1.59 Mcal/kg; neutral detergent fiber = 33.7%) for 3 wk after calving. Cows on STMR were then shifted to CTMR for the next 2 wk to study short-term residual effects on the performance of cows. Treatments were balanced for parity, body condition score, and body weight. Feed intake was measured daily from 2 wk before to 5 wk after calving using automatic feed bins. Blood was sampled twice weekly from 2 wk before to 5 wk after calving, and β-hydroxybutyrate and glucose were measured in serum samples. Subclinical ketosis was identified using a threshold of β-hydroxybutyrate ≥1.0 mmol/L in wk 1 after calving and ≥1.2 mmol/L in wk 2 to 5 after calving. Cows were milked twice daily, and weekly samples (composite samples of morning and afternoon milkings) were analyzed to determine total solids, fat, protein, lactose, and somatic cell count. Data were analyzed in 2 separate periods: the treatment phase (wk +1, +2, and +3) and the post-treatment phase (wk +4 and +5). The addition of straw to the TMR negatively affected the dry matter intake of STMR cows during wk 2 and 3 of lactation. Daily milk yield during the first 5 wk of lactation was lower in STMR cows than in CTMR cows. Concentrations of β-hydroxybutyrate were higher in CTMR cows than in STMR cows during wk 1, but this effect was reversed during wk 2 and 3 of lactation. By 21 d in milk, STMR cows had a greater risk of developing subclinical ketosis than CTMR cows. Adding chopped wheat straw to the TMR during the first 21 d after calving lowered dry matter intake and provided no metabolic or production benefits to lactating dairy cattle.

Expert opinion as priors for random effects in Bayesian prediction models: Subclinical ketosis in dairy cows as an example.

Random effects regression models are routinely used for clustered data in etiological and intervention research. However, in prediction models, the random effects are either neglected or conventionally substituted with zero for new clusters after model development. In this study, we applied a Bayesian prediction modelling method to the subclinical ketosis data previously collected by Van der Drift et al. (2012). Using a dataset of 118 randomly selected Dutch dairy farms participating in a regular milk recording system, the authors proposed a prediction model with milk measures as well as available test-day information as predictors for the diagnosis of subclinical ketosis in dairy cows. While their original model included random effects to correct for the clustering, the random effect term was removed for their final prediction model. With the Bayesian prediction modelling approach, we first used non-informative priors for the random effects for model development as well as for prediction. This approach was evaluated by comparing it to the original frequentist model. In addition, herd level expert opinion was elicited from a bovine health specialist using three different scales of precision and incorporated in the prediction as informative priors for the random effects, resulting in three more Bayesian prediction models. Results showed that the Bayesian approach could naturally take the clustering structure of clusters into account by keeping the random effects in the prediction model. Expert opinion could be explicitly combined with individual level data for prediction. However in this dataset, when elicited expert opinion was incorporated, little improvement was seen at the individual level as well as at the herd level. When the prediction models were applied to the 118 herds, at the individual cow level, with the original frequentist approach we obtained a sensitivity of 82.4% and a specificity of 83.8% at the optimal cutoff, while with the three Bayesian models with elicited expert opinion, we obtained sensitivities ranged from 78.7% to 84.6% and specificities ranged from 75.0% to 83.6%. At the herd level, 30 out of 118 within herd prevalences were correctly predicted by the original frequentist approach, and 31 to 44 herds were correctly predicted by the three Bayesian models with elicited expert opinion. Further investigation in expert opinion and distributional assumption for the random effects was carried out and discussed.

Effects of Energy Supply from Roughage and Concentrates and the Occurrence of Subclinical Ketosis on Blood Chemistry and Liver Health in Lactating Dairy Cows during Early Lactation

The objectives of this study were to examine the effects of varying dietary energy supply as well as the impacts of subclinical ketosis (SCK) on blood chemistry and liver health. A total 63 German-Holstein cows were housed from three weeks antepartum until sixteen weeks postpartum. After calving, cows were assigned to one of four treatment groups receiving either moderate or high energy concentrations in roughage and secondly moderate or high amounts of concentrates. Retrospectively, cows were additionally grouped according to their β-hydroxybutyrate concentration (SK: cows with SCK vs. CON: cows without SCK). The different energy supply of treatment groups had little effects on blood and liver variables; greater differences occurred between SK and CON cows. Liver fat content of SK cows was 34% higher compared to CON cows. Also, the activity of aspartate aminotransferase and γ-glutamyl transferase, bilirubin concentration, and percentage of granulocytes were increased in SK cows. The results indicate that cows were able to adjust their metabolism to different dietary energy supplies without having a clearly increased risks for metabolic disorders. However, individual animals of all groups developed a metabolic derailment during the postpartum period resulting in SCK, which is closely connected with impaired liver function, compromised immune-responsiveness, and elevated oxidative stress.

Disclosure of the Mechanisms of Metabolic Disorders in Highly Productive Cows as a Way to Improve Milk Production Technology

The aim of this study was to study the molecular mechanisms of metabolic disorders that develop in highly productive cows. It was found that in the blood serum of animals with subclinical ketosis (SCK), which are in the eighth month of pregnancy, the concentration of β-hydroxybutyrate is increased, the content of iron, calcium and phosphorus is reduced, its iron-binding capacity against the background of the absence of phenomena of hepatocellular insufficiency, violation of the integrity of hepatocytes, hypoplastic anemia. The aggravation of ketoacidosis in fresh cows with rumen acidosis is facilitated by the development of carbohydrate deficiency in them, due to their increased oxidation in the reactions of anaerobic glycolysis, accompanied by excessive catabolism of purine mononucleotides to uric acid. Excessive lipid peroxidation of membrane structures under conditions of increased catabolism of purine nucleotides, along with the accumulation of acylglycerols in the liver caused by cobalamin deficiency, leads to the development of syndromes of impaired hepatocyte integrity and hepatocellular insufficiency. A decrease in the liver's ability to store iron ions and synthesize proteins that provide an increase in the iron-binding capacity of blood plasma in conditions of cobalamin deficiency contributes to the development of hypoplastic anemia not only in cows, but also in calves born from them.

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The research aims to detect the possible cases of subclinical ketosis in the heavy milk producing cows bred in the regions of the RA and to provide professional support to the farmers. Clinical and laboratory tests of the animal blood, urine and milk were conducted in the farms by using Lestrade’s and Liben’s methods, as well as URIPATH-10 and SERVOTEST-KETOLAC tests. All cases of identified ketosis were induced by protein overfeeding and lack of digestible carbohydrates in the feed ration. For curative purposes it is recommended to supplement the food ration with easy digested carbohydrates and administer 5 % glucose solution, E-selenium and dexamethasone.

Effect of supplementation of a mixture of gluconeogenic precursors during the transition period on performance, blood metabolites and insulin concentrations and hepatic gene expression of dairy cows

Clinical and subclinical ketosis are associated with low productivity and poor well-being of dairy cattle. Dietary supplementation of gluconeogenic precursors during the transition period is a strategy to prevent the occurrence of these diseases. However, there is a lack of information regarding the effect of feeding mixed gluconeogenic precursors on intake, and systemic and hepatic metabolism of transition dairy cows. Our objective was to examine the effect of supplementing a mixture of gluconeogenic precursors (Glucose Booster, GB) on intake, milk yield and composition, blood metabolites, and hepatic gene expression in transition dairy cows. Twenty-nine multiparous Holstein cows blocked by previous 305-d mature-equivalent milk yield were randomly assigned to one of the two treatments: GB supplementation or not (CTL). Cows received their respective dietary treatments from 28 d before expected calving to 21 d after parturition. Then, all cows were fed the CTL diet until d 56 of the lactation. Ambient temperature and relative humidity in the barn were assessed hourly. Vaginal temperature was determined weekly during the prepartum period from a subset of cows. Dry matter intake was recorded daily, and body condition score and body weight assessed every two weeks during the experiment. Milk yield was recorded daily and composition measured weekly in early lactation. Plasma samples were collected on d 28 and 10 before expected calving, calving, and 3, 7, 14, 21, 28 and 42 d after calving for analysis of metabolites and insulin. Liver biopsies were collected at 28 d before the expected calving and 14 d after calving to measure mRNA expression of genes related to gluconeogenesis, ketogenesis, and fatty acid oxidation. Data were analyzed using the PROC GLM or MIXED procedures of SAS. The temperature-humidity index averaged 74 and 65 in the pen for dry and lactating cows, and the vaginal temperature averaged 39.2 ○C before calving and was not different between treatments, suggesting that dry cows were exposed to heat stress. Treatment had no impact on intake, lactation performance, blood metabolites and insulin and hepatic gene expression. In conclusion, supplementation of GB did not affect performance or metabolism of transition dairy cows, indicating that exposure to heat stress may diminish the benefits of feeding gluconeogenic precursors during the transition period.

Subclinical hypocalcaemia follows specific time-related and severity patterns in post-partum Holstein cows

Hypocalcaemia is a common metabolic disorder of post-parturient dairy cows; enhancement of our knowledge regarding Ca dynamics would improve cow health and welfare. This study investigated the presence of time- and severity-related subclinical hypocalcaemia (SCHCa) patterns in Holstein cows after calving and their association with diseases during the first week of lactation. A total of 938 cows from nine herds were blood sampled on days 1, 2, 4 and 8 post-partum, and serum Ca concentration was measured with atomic absorption. Subclinical ketosis (serum β-hydroxybutyrate≥1.2 mmol/L) and cases of retained foetal membranes, metritis (MET), mastitis, ketosis and displaced abomasum (DA) were recorded. Using receiver operating characteristic (ROC) analysis, the SCHCa cut-off was identified at serum Ca ≤ 2.09 mmol/L. Hierarchical and two-step cluster analysis classified cows to seven clusters based on test day cow Ca records and overall SCHCa status. Two clusters (NORM and HIGH) included 318 normocalcaemic cows and five clusters (SCH-1 to −5) those that were at least once subclinically hypocalcaemic (n = 620). A second ROC analysis was performed in order to distinguish mild from severe cases of SCHCa in these 620 cows; this cut-off was identified at 1.93 mmol/L. The associated risk of disease with Ca clustership was assessed with generalized linear mixed models. Overall incidence of SCHCa was 66.1%. Clusters SCH-1 and SCH-2 included cows with short-term SCHCa of day 1 and day 2, respectively, while SCH-3 included cows with severe and prolonged SCHCa extending to day 4 and beyond. Clusters SCH-4 and SCH-5 included cows with delayed SCHCa, which culminated on days 4 and 8, respectively. Compared to NORM cows in HIGH had lower risk of MET and no cases of DA. Cows in SCH-3 had higher risk of being diagnosed with retained foetal membranes, DA or any disease during the study period. Cows in SCH-5 had higher risk of being diagnosed with ketosis, subclinical ketosis or any disease. In conclusion, there are multiple normocalcaemic and hypocalcaemic patterns that are differently associated with disease risk.