Given global warming and the growing dairy cow population, heat stress in dairy herds is of increasing concern. During heat stress, dairy cows suffer from compromised productivity and animal welfare in terms of reduced feed intake and milk production, decreased reproductive performance, and generally increased risk of health problems. These effects and their interactions are complex and are usually quantified separately; thus, a comprehensive understanding of the herd-level performance is missing. Moreover, compromised animal welfare and productivity may impact enteric methane (CH4) emission; however, these effects have rarely been investigated. Therefore, by performing herd simulation, this study aimed to model the impact of heat stress on dairy production and enteric CH4 emissions by aggregating its effects on milk production, reproduction, and health. Specifically, 10 scenarios (including baseline) were simulated in a conventional, high-yielding Danish herd by incorporating different combinations of effects on milk production, reproduction, and health of heat stress in different exposure durations (1, 2, and 4 mo). Sensitivity analyses were further conducted to account for the effects of different reduction rates in feed efficiency (kg ECM/kg DMI). Results showed that heat stress decreased the herd-level milk yield by up to 8.6% if all effects were combined in a duration of 4 mo, whereas a direct effect on milk yield only decreased herd-level yield by up to 6.9%. Heat stress increased the herd-level enteric CH4 intensity ranging from 0.8% to 6.6% across all 9 scenarios as compared with the baseline scenario. When a reduction in feed efficiency by 19.2% was assumed, the herd-level CH4 intensity increased by up to 4.4% during 2 mo. Overall, our results showed large impacts of heat stress on both dairy production and CH4 emissions and suggest the need to implement management mitigation strategies in heat-stressed dairy herds.

Heat stress compromises dairy production by decreasing feed intake and milk yield, and it may also alter milk composition and feed efficiency. However, little information is available for evaluating such effects across different levels of heat stress and cows enrolled in heat stress studies. The objectives of this study were to evaluate the effects of heat stress on dry matter intake (DMI), energy-corrected milk (ECM), milk composition, and feed efficiency (kg ECM/kg DMI) and to investigate the relationship between such effects and heat stress intervention and animal characteristics by using meta-analytical approaches. Data from 31 studies (34 trials) fulfilled the inclusion criteria and were used for analysis. Results showed that heat stress decreased DMI, ECM, and milk protein concentration, but did not alter milk fat concentration or feed efficiency. Meta-regression confirmed that such reductions in DMI and ECM were significantly associated with increasing temperature-humidity index (THI). Over the period of heat stress, for each unit increase in THI, DMI and ECM decreased by 4.13% and 3.25%, respectively, in mid-lactation cows. Regression models further revealed the existence of a strong interaction between THI and lactation stage, which partially explained the large heterogeneity in effect sizes of DMI and ECM. The results indicated a need for more research on the relationship between the effect of heat stress and animal characteristics. This study calls for the implementation of mitigation strategies in heat-stressed herds due to the substantial decrease in productivity.

With droughts becoming more frequent due to climate changes alternative feeding strategies are required. The aim of this study was to examine the effects of replacing all or part of the silage component with barley straw and concentrates for Holstein and Jersey cows. Forty-nine Holstein and 43 Jersey cows were fed either the C49 diet (Roughage-to-concentrate ratio [% of DM; dry matter] of 51:49), a diet where concentrate constituted 70% of DM (i.e., diet C70; 30:70), or the extreme diet (i.e., C91; 9:91), where 91% of DM was concentrate and 9% of DM was barley straw. Cows were allowed up to 2.65 kg DM per day from concentrate in the automatic milking system (AMS). Cows were fed their diets for 5 weeks. All diets were formulated to provide the same daily net energy intake. Daily feed intake and milk production responses were recorded. Volatile fatty acid profiles in rumen fluid were measured for Holstein cows. Impact on economy and carbon footprint were calculated. Data were analyzed using a general linear mixed model. For both breeds, total dry matter intake (i.e., AMS concentrate + partially mixed ration) decreased with increasing concentrate proportion. In neither Holstein nor Jersey, experimental diet affected milk yield. A decrease in fat percentage and ECM was observed for both breeds, when the level of concentrate was increased. However, there was an interaction between diet and breed for fat percentage and for energy-corrected milk yield (ECM), and there was an interaction for feed efficiency expressed as kg of ECM/kg of DM intake. For Holstein cows, acetate molar proportion in rumen liquid decreased and propionate molar proportion increased when silage was reduced. Regardless of breed, increasing concentrate in the ration did not affect carbon footprint per kg ECM, but caused a decrease per cow per day, and per kg DM intake. However, if the contribution from direct land use changes and soil C were taken into account, increasing concentrate in the ration reduced carbon footprint per kg ECM due to decreased proportion of soybean meal in C75 and C91 diets. Production of milk from predominantly concentrate based diets containing no grass silage reduced income over feed cost for both breeds but more for Holsteins. In conclusion, results showed that it is possible to keep dairy herds , produce milk even during extreme drought, when availability of silage is minimal, whereas such ration decreased income over feed cost.

Background Individuals with mental illness may be particularly vulnerable to the negative impact that the coronavirus disease 2019 (COVID-19) pandemic seems to have on mental health. Most prior studies on this topic are however limited by non-random sampling, lack of information on non-respondents, and self-reported diagnoses. Here, we aimed at overcoming these limitations by means of random sampling in a population of clinically diagnosed patients, acquisition of clinical and socio-demographic data on non-respondents, and weighting of results informed by attrition. Methods We conducted a cross-sectional questionnaire-based online survey inviting six-thousand randomly drawn patients from the psychiatric services of the Central Denmark Region. They survey data were merged with sociodemographic- and clinical data from medical records on all invitees, which enabled analysis of attrition and weighting of results. The questionnaire included the 18-item Brief Symptom Inventory (BSI-18), the 5-item World Health Organization Well-Being Index (WHO-5), and 14 questions evaluating the perceived severity of symptoms during the four-week nationwide lockdown of Denmark in March/April 2020 – using the pre-pandemic period as reference. Reasons for worsening or improvement in mental health during lockdown were also reported. Results The preliminary results are as follows: The response rate was ≈20%. Approximately half the respondents reported that their mental health had deteriorated during lockdown, while the other half reported either no change (≈33%) or improvement (≈16%). The most commonly reported reasons for deterioration in mental health were disruption of routines and loneliness. Conclusion The final results will be shown at the conference. Disclosure No significant relationships.

The aim of this observational retrospective cohort study was to identify management procedures that are associated with herd-level eradication of Streptococcus agalactiae in dairy herds. The objective was to compare herds that recovered from Strep. agalactiae with herds that remained infected with Strep. agalactiae on the basis of specific management procedures. Data from the Danish surveillance program for Strep. agalactiae, where all milk delivering dairy herds are tested yearly, were used to identify study herds. One hundred ninety-six herds that were classified in the program as infected with Strep. agalactiae, in both January 2013 and January 2014, were identified as study herds. These were followed until January 2017. One hundred forty-four herds remained infected every year until January 2017. Forty-six herds recovered from Strep. agalactiae after January 2014 (were tested negative continuously after January 2015, January 2016, or January 2017 and remained noninfected in the program from recovery until January 2017). Herd characteristics and management procedures were obtained through the Danish Cattle Database. Herd characteristics included herd size, yield, milking system, and bulk milk somatic cell count (SCC). Management procedures included the proportion of cows culled within 100 d after calving due to mastitis, the extent of diagnoses relative to the extent of mastitis treatments, the proportion of cows treated for mastitis during lactation, the proportion of cows treated for mastitis early in lactation, the proportion of cows treated at dry-off, and the median length of the dry period for cows receiving dry cow treatment. All variables were calculated on herd level. Multivariable logistic regression was used to analyze the association between herd infection status and management procedures. A higher proportion of culling due to mastitis within 100 d from calving was associated with a higher probability of herd-level recovery from Strep. agalactiae in herds with conventional milking system. For example, herds with conventional milking, a bulk milk SCC of 260,000 cells/mL, and 10% early culling due to mastitis had a recovery probability of 0.13, whereas similar herds with 20% early culling due to mastitis had a recovery probability of 0.15. A higher proportion of mastitis treatments within 250 d postcalving was associated with a higher probability of herd-level recovery for herds with a relatively high bulk milk SCC. For example, herds with conventional milking, a bulk milk SCC of 260,000 cells/mL, and 10% lactational mastitis treatments had a recovery probability of 0.12, whereas similar herds with 20% lactational mastitis treatments had a recovery probability of 0.15. Herds with a low bulk milk SCC (<220,000 cells/mL) combined with a low proportion of lactational treatments (<0.2) had a relatively high probability of herd-level recovery (>0.2). Additional variables, including the proportion of dry cow treatments, were not associated with herd-level recovery from Strep. agalactiae.

Introduction Involuntary electroconvulsive therapy (ECT) can be a life-saving intervention for patients suffering from potentially lethal conditions who are unable to give informed consent. However, its use is not widespread, probably partly due to the scarce data on hard outcomes following involuntary ECT. In Denmark, involuntary ECT is only used when patients are at imminent/potential risk of dying if not receiving ECT. Objectives We aimed to assess the effectiveness of involuntary ECT by estimating the 1-year survival following its administration. Methods We conducted a register-based cohort study involving i) all patients receiving involuntary ECT in Denmark between 2008 and 2019, ii) age and sex-matched patients receiving voluntary ECT, and iii) age and sex-matched individuals from the general population. 1-year survival rates were compared via mortality rate ratios. Results We identified 618 patients receiving involuntary ECT, 547 patients receiving voluntary ECT, and 3,080 population-based controls. The survival rate in the year after involuntary ECT was 90%. For patients receiving involuntary ECT, the 1-year mortality rate ratios were 3.1 (95% confidence interval (CI)= 1.9-5.2) and 5.8 (95%CI = 4.0-8.2) compared to those receiving voluntarily ECT and to the population-based controls, respectively. Risk factors for early death among patients receiving involuntary ECT were male sex, being ≥70 years old and having organic mental disorder as the treatment indication. Conclusions Treatment with involuntary ECT is associated with a high survival rate, suggesting that the intervention is effective. However, patients receiving involuntary ECT constitute a high-risk population that should be monitored closely after this treatment. Disclosure No significant relationships.

Introduction The crisis caused by the ongoing COVID-19 pandemic is affecting the lives of billions of people across the world. Individuals with mental illness are suspected to be particularly affected by the societal consequences of the pandemic, but there is very limited data on this important aspect. Objectives The aim of this study is to gauge the longitudinal impact of the COVID-19 pandemic on the psychological well-being and symptom levels of individuals receiving treatment for mental disorder in psychiatric hospital services. Methods We are in the process of conducting a two-wave, questionnaire-based survey among patients with mental disorders receiving treatment in the psychiatric hospital services of the Central Denmark Region. The first wave was conducted in July 2020 and had 1180 respondents representing all major diagnostic categories. The main finding was that the majority of the respondents reported that their mental health had deteriorated during the COVID-19 pandemic. We are currently planning the second wave of the survey, which will be fielded in the fall of 2020. Here, we will reassess the mental health of the respondents from wave 1. Results Will be presented at the meeting. Conclusions Longitudinal studies of the impact of the COVID-19 pandemic of mental health are lacking. We therefore expect that the findings of this study will be of significant interest to the field. Disclosure No significant relationships.

IntroductionThere is a lack of longitudinal studies of patients with bipolar disorder (BD) or unipolar depression (UD) in terms of psychological well-being as measured by the WHO-5 and the correlation to symptom scores. It is of interest to investigate whether the WHO-5 is useful in monitoring patients with mood disorders over time, as a tool in measurement-based care, and as a supplement to other psychometric measures.ObjectivesIn this study we investigate the correlation at baseline between the depressive symptom scores according to the 6-item Hamilton Depression Score (HDS-6) and the WHO-5 scores in outpatients treated for BD or UD. Furthermore, in patients with BD we investigate correlations between manic symptom scores according to the modified Bech-Rafaelsen Mania Scale (MAS-M) and the WHO-5 scores. Lastly, in patients with BD or UD, we investigate the correlations between endpoint-baseline change in WHO-5 and change in MAS-M and HDS-6.MethodsA longitudinal study of 200 outpatients diagnosed and treated for either BD or UD. Patients will be measured at baseline and at least four weeks later. Baseline data are presented as frequencies, means and standard deviations or medians with interquartile ranges as appropriate. All correlations are presented as scatter plots and a Spearman correlation analysisResultsThe study is ongoing, but the results will be available for presentation at the EPA in 2021.ConclusionsThe WHO-5 may represent a relevant outcome measure in the treatment of BD and UD.DisclosureNo significant relationships.

Improved animal health can reduce greenhouse gas (GHG) emissions intensity in livestock systems while increasing productivity. Integrated modelling of disease impacts on farm-scale emissions is important in identifying effective health strategies to reduce emissions. However, it requires that modellers understand the pathways linking animal health to emissions and how these might be incorporated into models. A key barrier to meeting this need has been the lack of a framework to facilitate effective exchange of knowledge and data between animal health experts and emissions modellers. Here, these two communities engaged in workshops, online exchanges and a survey to i) identify a comprehensive list of disease-related model parameters and ii) test its application to evaluating models. Fifty-six parameters were identified and proved effective in assessing the potential of farm-scale models to characterise livestock disease impacts on GHG emissions. Easy wins for the emissions models surveyed include characterising disease impacts related to feeding.

The objective of the study was to evaluate the effect of hygiene measures in automatic milking units on the transmission of 3 mastitis pathogens considered to be mainly or partly transmitted from cow to cow during milking events. Two studies were conducted as within-herd experimental trials in 2 Danish commercial dairy herds (A and B) with automatic milking systems. Interventions to enhance hygiene were implemented on the automatic milking units. The 2 studies evaluated separate interventions. In herd A, the hygiene interventions were manual wash with the Lely foam unit and adjustments on the brush-mediated teat cleaning procedure. In herd B, the hygiene intervention included automatic disinfection spray on the upper surface of the brush motor and daily change of brushes. Composite milk samples were collected longitudinally at 3- or 4-wk intervals from all lactating cows. Additional milk samples were taken from cows entering or leaving the study groups. Milk samples were analyzed with quantitative PCR. A hidden Markov model implemented within a Bayesian framework was used to estimate the transmission probability. For analysis, 701 samples from 156 cows were used for herd A, and 1,349 samples from 390 cows were used for herd B. In the intervention group in herd B, transmission of Streptococcus agalactiae was reduced to 19% (95% posterior credibility interval: 0.00-64%) of the transmission in the control group, whereas transmission of Streptococcus dysgalactiae was reduced to 17% (95% posterior credibility interval: 0.00-85%) of transmission in the control group. This suggests that automatic spray on the upper surface of the brush motor with disinfectant along with daily change of brushes collectively reduced transmission of Strep. agalactiae and Strep. dysgalactiae. Results on Staphylococcus aureus in herd B and results on manual foam cleaning and brush-mediated teat cleaning adjustments in herd A were inconclusive.

ABSTRACT Farmers play a key role in conserving native livestock breeds, but without economic support, farms with native breeds may not be viable. We hypothesized that terminal crossbreeding can improve herd economy and decrease the economic support needed from society. Three scenarios were simulated using SimHerd Crossbred: a herd of purebred Swedish Polled Cattle, a herd of purebred Swedish Red, and a herd of 75% Swedish Polled Cattle and 25% F1 crossbreds. The results showed annual contribution margin per cow in the herd can be increased by €181 by crossbreeding compared with pure-breeding with the native breed, giving a 13.6% growth in contribution margin. However, the needed cost in subsidies paid by the government will remain unchanged if the population size of the native breed is to be maintained. Combining a crossbreeding strategy with the marketing of niche products may facilitate the conservation of native cattle.

The development of breeding tools, such as genomic selection and sexed semen, has progressed rapidly in dairy cattle breeding during the past decades. In combination with beef semen, these tools are adopted increasingly at herd level. Dairy crossbreeding is emerging, but the economic and genetic consequences of combining it with the other breeding tools are relatively unknown. We investigated 5 different sexed semen schemes where 0, 50, and 90% of the heifers; 50% of the heifers + 25% of the first-parity cows; and 90% of the heifers + 45% of the first-parity cows were bred to sexed semen. The 5 schemes were combined in scenarios managing pure-breeding or terminal crossbreeding, including genomic testing of all newborn heifers or no testing, and keeping Swedish Red or Swedish Holstein as an initial breed. Thus, 40 scenarios were simulated, combining 2 stochastic simulation models: SimHerd Crossbred (operational returns) and ADAM (genetic returns). The sum of operational and genetic returns equaled the total economic return. Beef semen was used in all scenarios to limit the surplus of replacement heifers. Terminal crossbreeding implied having a nucleus of purebred females, where some were inseminated with semen of the opposite breed. The F1 crossbred females were inseminated with beef semen. The reproductive performance played a role in improving the benefit of any of the tools. The most considerable total economic returns were achieved when all 4 breeding tools were combined. For Swedish Holstein, the highest total economic return compared with a pure-breeding scenario, without sexed semen and genomic test, was achieved when 90% sexed semen was used in heifers and 45% sexed semen was used for first-parity cows combined with genomic test and crossbreeding (+€58, 33% crossbreds in the herd). The highest total economic return for Swedish Red compared with a pure-breeding scenario, without sexed semen and genomic test, was achieved when 90% sexed semen was used in heifers combined with genomic test and crossbreeding (+€94, 46% crossbreds in the herd). Terminal crossbreeding resulted in lower genetic returns across the herd compared with the corresponding pure-breeding scenarios but was compensated by a higher operational return.

The main objective of this study was to test the efficiency of a management system combining metabolic clustering of cows based on Fourier-transform mid-infrared (FT-MIR) spectra of milk and targeted treatment of metabolically imbalanced cows with propylene glycol drench. We hypothesized that cows identified in a metabolically imbalanced status during early lactation were associated with subsequent impaired health, reproduction, and production, and that treatment with propylene glycol treatment would improve health, reproduction, and production relatively more in these cows than in control cows. We completed a prospective, randomized controlled trial with 356 early-lactation cows in 2 private dairy herds in Denmark from December 2017 to April 2018. Milk samples of cows were collected before treatment, from 4 to 9 d in milk, and after treatment, from 22 to 27 d in milk. Milk samples were analyzed using FT-MIR spectroscopy. We also measured 4 milk metabolites (β-hydroxybutyrate, isocitrate, malate, and glutamate) and fat and protein contents. Based on FT-MIR spectra and cluster analyses, cows were clustered into groups of metabolically imbalanced and healthy cows. Within each group, cows were allocated randomly to treatment with propylene glycol (500 mL for 5 d) or no treatment. We analyzed the effect of the treatment on cow-level variables: metabolic cluster, milk metabolites, fat and protein contents, and fat-to-protein ratio at a milk sampling after the treatment. Furthermore, we analyzed daily milk yield, calving to first service interval, and disease occurrence. Results showed only a few effects of propylene glycol treatment and few interactions between treatment and metabolic clusters. We found no significant main effects of propylene glycol treatment in any of these analyses. A negative effect of the imbalanced metabolic cluster was found for the outcome of calving to first service interval for multiparous cows. In conclusion, we found a longer calving to first service interval in metabolically imbalanced cows, but we were not able to demonstrate overall benefits from the applied detection of cows in imbalanced metabolic status in early lactation and follow-up by treatment with propylene glycol.

Physiological imbalance is an abnormal physiological condition that cannot be directly observed but is assumed to precede subclinical and clinical diseases in the beginning of lactation. Alert systems to detect the physiological imbalance in a cow using Fourier transform mid-infrared spectroscopy in milk have been developed. The objective of this study was to estimate the value of information provided from such system with different indicator accuracies, herd prevalence and prices. A decision tree was created to model the probabilities of detection and associated costs of test outcome, intervention and occurrence of disease. We assumed that the negative effect of physiological imbalance was the development of subclinical ketosis and that this negative effect was prevented by drenching the cows with propylene glycol for 5 days. We simulated the economic impact of subclinical ketosis mediated through physiological imbalance to be $194 per case. The results showed that if the alert system was highly accurate (Se = 0.99/Sp = 0.99), and the prevalence of physiological imbalance was 30 %, the value of information provided from the system is $19 per cow-year. In case the prevalence is 5 % or 50 %, the value of information is $3 and $13, respectively. These estimates for the value do not cover the capital costs and operational costs of the alert system. This study furthermore clearly demonstrated that in order to estimate the value of information correctly, it is important to consider that drenching all cows and not drenching any of the cows are the two relevant alternative options in the absence of the alert system. In conclusion, the decision tree and sensitivity analysis developed in this study show that final economic results are highly variable to the prevalence of physiological imbalance and highest at an intermediate prevalence. Other relevant factors are the costs associated with drenching and the cost associated with treating false positives and not treating false negatives. In addition, this study highlights the benefits of simulation to pinpoint where additional information is needed to further quantify the economic value and required accuracy of an indication-based intervention system.

Dairy farming is a complex production system involving biological, technological and human inputs. Therefore, `general knowledge of cause and effect' often seems inadequate to identify and implement optimal management procedures. To solve herd-specific problems, this paper explores the potential of planned experiments for internal use at the farm level to take advantage of local causal relationships. The shift towards larger dairy herds with access to automatic data recordings of a large number of relevant inputs and performance indicators supports the development of management tools that are able to estimate the effect of changes made in daily management on individual farms. The concept of EVolutionary OPeration (EVOP) implies making small systematic changes in production factors or procedures while running the production and continuously evaluating the results. The aim of this study was to develop and evaluate the feasibility of implementing EVOP in commercial dairy herds as an integral part of herd management. The concept of EVOP-Dairy is based on five principles: (1) farmer-driven identification of areas for improvement; (2) herd-specific goals for the interventions to be evaluated in EVOP trials; (3) a short EVOP trial period; (4) simple, but statistically sound, EVOP designs including data access and (5) regular estimation of intervention effects and frequent reporting to the farmer. The project involved three activities: first, visiting a number of dairy farms with the aim of identifying areas for management improvements and to define potential EVOP interventions and relevant designs of EVOP trials; second, conducting a series of EVOP trials to develop data registration, statistical models, analysis and reporting; third, interviewing the farmers to obtain their opinion of the conceptual idea and the process. These activities were documented for the twelve project farms, and five different EVOP trials are described in detail to illustrate the concept. In conclusion, the farmers found the concept a useful management improvement tool, although the EVOP trials created additional work. The EVOP-Dairy statistical models need to include dynamic multilevel data and control for confounding factors when estimating intervention effects, as design with randomization was not feasible in the majority of the identified EVOP trials. Therefore, future development for the EVOP-Dairy should focus on (i) easy to implement and execute interventions, (ii) guidelines to interpret intervention effect when practical conditions hinder fully randomized and well replicated interventions, and (iii) automation of the data analysis and reporting part of the concept.

Automatic flushing of milking clusters between milking events is a control measure aimed at reducing transmission of mastitis pathogens from infectious milk to a subsequently milked cow. We evaluated the effect of flushing with cold water and flushing with water containing peracetic acid (PAA) on the concentration of Staphylococcus aureus in teat cup liners. Thirty-two clusters in a swing-over milking parlor (Dairymaster, Causeway, Ireland) were subjected to a simulated milking with S. aureus-contaminated milk. Sixteen clusters were not flushed (controls), whereas 8 clusters were flushed with cold water (966 ± 32 mL) and 8 clusters were flushed with water containing PAA (200 mL/mL). A random teat cup in each cluster was sampled by rinsing with a phosphate buffer. Teat cup samples were cultured on the day following collection on Baird-Parker plates to determine the concentration of S. aureus. In teat cup samples from control clusters, the mean concentration of S. aureus was 2.8 × 105 cfu/mL. The concentration of S. aureus was zero in teat cup samples from clusters flushed with cold water. In teat cup samples from clusters flushed with water containing PAA, the concentration of S. aureus was in general reduced compared with control clusters, but S. aureus was not removed completely. However, the automatic cluster flushing did not function properly when clusters were flushed with water containing PAA; thus, results reflected the effect of inadequate function rather than the effect of adding disinfectant to the flushing water. Before the main study, we conducted a pilot study to evaluate whether teat cup sampling with swabs and sample analysis with quantitative PCR were appropriate methods for the main study. Specifically, we evaluated the effect of swab sample mass on detection of S. aureus by quantitative PCR in the laboratory, Further, we compared PCR and bacterial culture on detection of S. aureus in a suspension following disinfection of the suspension with PAA. We sampled 20 identical S. aureus suspensions for culture and PCR by swabs before and after disinfection with PAA. Swab sample mass was determined by differential weighing and contributed to 46% of the variation observed in detection of S. aureus by PCR. Following disinfection with PAA, S. aureus remained detectable by PCR, although culturability ceased. Based on these results, we sampled teat cups in the main study with a buffer rinse and quantified S. aureus in the samples by bacterial culture. We concluded that automatic cluster flushing with cold water was effective in removing S. aureus from teat cup liners and that addition of PAA was therefore not necessary.

The aim of this study was to describe metabolism of early-lactation dairy cows by clustering cows based on glucose, insulin-like growth factor I (IGF-I), free fatty acid, and β-hydroxybutyrate (BHB) using the k-means method. Predictive models for metabolic clusters were created and validated using 3 sets of milk biomarkers (milk metabolites and enzymes, glycans on the immunogamma globulin fraction of milk, and Fourier-transform mid-infrared spectra of milk). Metabolic clusters are used to identify dairy cows with a balanced or imbalanced metabolic profile. Around 14 and 35 d in milk, serum or plasma concentrations of BHB, free fatty acids, glucose, and IGF-I were determined. Cows with a favorable metabolic profile were grouped together in what was referred to as the "balanced" group (n = 43) and were compared with cows in what was referred to as the "other balanced" group (n = 64). Cows with an unfavorable metabolic profile were grouped in what was referred to as the "imbalanced" group (n = 19) and compared with cows in what was referred to as the "other imbalanced" group (n = 88). Glucose and IGF-I were higher in balanced compared with other balanced cows. Free fatty acids and BHB were lower in balanced compared with other balanced cows. Glucose and IGF-I were lower in imbalanced compared with other imbalanced cows. Free fatty acids and BHB were higher in imbalanced cows. Metabolic clusters were related to production parameters. There was a trend for a higher daily increase in fat- and protein-corrected milk yield in balanced cows, whereas that of imbalanced cows was higher. Dry matter intake and the daily increase in dry matter intake were higher in balanced cows and lower in imbalanced cows. Energy balance was continuously higher in balanced cows and lower in imbalanced cows. Weekly or twice-weekly milk samples were taken and milk metabolites and enzymes (milk glucose, glucose-6-phosphate, BHB, lactate dehydrogenase, N-acetyl-β-d-glucosaminidase, isocitrate), immunogamma globulin glycans (19 peaks), and Fourier-transform mid-infrared spectra (1,060 wavelengths reduced to 15 principal components) were determined. Milk biomarkers with or without additional cow information (days in milk, parity, milk yield features) were used to create predictive models for the metabolic clusters. Accuracy for prediction of balanced (80%) and imbalanced (88%) cows was highest using milk metabolites and enzymes combined with days in milk and parity. The results and models of the present study are part of the GplusE project and identify novel milk-based phenotypes that may be used as predictors for metabolic and performance traits in early-lactation dairy cows.

•The unfavorable effect of extended lactation on genetic return is small.•Sexed semen can reduce the genetic lag caused by extended lactation.•Extended lactation and sexed semen combined increases total economic return.•There is synergy between sexed semen and extended lactation on the total return.