Novel blood metabolites as pre-onset predictors of postpartum metabolic disease in overconditioned transition dairy cows

Novel blood metabolites as pre-onset predictors of postpartum metabolic disease in overconditioned transition dairy cows

Summary

Periparturient dairy cows lose weight due to reduced energy intake and increased energy expenditure. Overfeeding cows during late gestation results in excessive weight gain and adiposity (i.e. overconditioning) leading to the development of an “overnutrition syndrome”, similar to overweight monogastrics. Compared to lean cows, overconditioned cows exhibit greater insulin resistance and lipolysis resulting in elevated blood nonesterified fatty acid (NEFA) levels that predispose them to postpartum metabolic disease (PMD); compromising milk production, fertility, and health. Approaches to monitor pre-onset insulin resistance and hyperlipidemia represent a new means to prevent PMD, reduce economic losses, and ensure sustainability of the northeast dairy industry. The goal is to identify blood metabolites in overconditioned dry cows that could predict pre-onset PMD. Mass spectrometry has been employed to identify blood metabolites predicting pre-onset insulin resistance and hyperlipidemia in overweight monogastrics. Two such predictors are ceramides and fatty acylcarnitines, lipid mediators and biomarkers for the disease. Mass spectrometry will be utilized to identify whether these lipid mediators predict for pre-onset PMD. Using sixty transition cows in a commercial herd, blood will be collected at -45, -30, -15, -7, and +4 d relative to calving, and body condition scores (BCS) will be recorded. Prepartum physical activity, and postpartum disease incidence and reproductive success will also be monitored. Ceramide and fatty acylcarnitine levels during the far-off period will be correlated with physical activity, body condition at calving, and insulin sensitivity and NEFA mobilization postpartum. Identifying at risk far-off dry cows, using biomarker discovery, is an innovative approach to prevent the onset of PMD. This project will be completed by following a detailed outreach plan.

Objectives/Performance Targets

To date, we have followed our objectives precisely.

Objective 1: Identify prepartum blood biomarkers in overconditioned transition cows associated with reduced insulin sensitivity and elevated NEFA mobilization after calving. Employing cutting-edge mass spectrometry-based technologies, plasma collected from prepartum cows during the far-off period will be screened for unique metabolite signatures that can mark dairy cows at risk of developing greater reductions in insulin action and a greater magnitude of NEFA mobilization. Focus will be placed on ceramides and fatty acylcarnitines, adipose-derived lipid mediators associated with the development of insulin resistance and excessive lipolysis in overweight monogastrics. Monitoring biomarker levels prior to the onset of PMD might give dairy producers the ability to modify nutrition and management plans to maintain superior cow health through the transition from gestation to lactation.

To date, the experimental design has been implemented and samples have been collected.  Blood analysis has initiated.  Statistical analysis has initiated.  The remaining portions of this objective will be completed in 2014.

Objective 2: Inform and educate the dairy industry about approach, results, implications, and future direction. Approach specifics and results will be presented at the 2014 ADSA/ASAS joint annual meeting and a Dairy Cattle Nutrition Workshop for review and feedback by dairy researchers, producers, and industry representatives. In addition, a manuscript will be submitted to the Journal of Dairy Science for peer review. To address more dairy producers, an article communicating methodology, results, implications, and future direction will be submitted to DAIReXNET, the interactive cooperative extension on-line education platform.

To date, we’re preparing a minimum of two abstract submission to the 2014 ADSA/ASAS joint annual meeting.  The remaining portions of this objective will be completed in 2014.

Accomplishments/Milestones

At the present time, our research study progress is ahead of schedule.

Our accomplishments include:

1. 1. Establishing a strong working relationship with DoVan Farms, a 700 Holstein cow dairy farm in Berlin, PA. 

1. 1. During 2013, we started and completed our research trial at DoVan Farms.  We enrolled 70 Holstein dairy cows at -45 days prior to expected calving and followed them through 10 days in milk (DIM).  We collected plasma, serum, and urine samples at -45, -30, -15, -7, 1 and 4 relative to calving. Body weights and body condition scores were recorded at every sampling time.  Milk samples were collected at 4 and 10 DIM for milk composition and somatic cell count analysis.  Milk production was recorded daily.  Postpartum ketosis, milk fever, displaced abomasum, and retained placenta frequency were also recorded.  Prepartum and postpartum physical activity was also monitored using individual activity monitors.  Feed samples were collected from far-off, close-up, and lactation rations weekly, pooled bi-monthly, and analyzed for composition.

1. 1.  Laboratory analysis of plasma NEFA, glucose, and insulin was performed for all samples.  These data were used to calculate the revised quick insulin sensitivity index (RQUICKI) values for all cows at all sampling time points.  Plasma levels of beta-hydroxybutyric acid were also determined at -30 days prior to calving, and 1 and 4 DIM. Statistical analysis was performed on these data.

1. 1. Our initial data analysis validates current understanding.  We have confirmed that overweight dairy cattle mobilize more lipid and based on the RQUICKI, are more prone to insulin resistance. We also observed greater weight loss (as a percent of initial body weight, in overconditioned dairy cattle.  We were pleased to observe these responses because it reassures us that we have a suitable model to search for new biomarkers associated with pre-onset insulin resistance and metabolic disease in overconditioned dairy cattle.

1. 1. In preparation for novel biomarker discovery, laboratory methods for GC/MS/MS were developed to profile plasma free fatty acid, amino acid, sugar, and other potential biomarkers for insulin resistance and postpartum metabolic disease.

1. 1. Initiated compiling a comprehensive herd health report for DoVan farms.

1. 1. Modification from original plan include the additional enrollment of 10 Holstein dairy cows because of multiple premature calvings, and addition of +1 DIM blood sampling to ensure we monitor maximal NEFA mobilization.

Remaining work to be completed:

1. 1. Complete blood analysis of ceramides, fatty acylcarnitines, fatty acids, and other metabolites to demonstrate relationships between their relative levels and magnitude of insulin resistance (according to the RQUICK values) and NEFA mobilization.

1. 1. Analyze remaining blood marker data, body condition scores, body weight fluctuations, activity, milk production, milk composition, reproduction, and disease frequency data.

1. 1. Present a final report to DoVan farms reviewing their herd health and offering recommendations for improved cow health.

1. 1. Publish a dairy extension report focused on educating dairy producers about our technological approach and relevance to the dairy industry.

1. 1. Present our findings at the American Dairy Science Association and/or a regional dairy nutrition conference.

1. 1. Publish our findings in a peer-reviewed journal.

Submit re-imbursements.

Impacts and Contributions/Outcomes

Identifying prepartum dairy cows at risk of developing severe postpartum metabolic health would be a powerful method to improve dairy cow health, reduce economic loss, and improve the sustainability of the northeast dairy industry. Our analyses will provide new insights into prepartum dairy cow health and allow producers to manage dairy herds with the utmost efficiency.  Specifically, being able to identify novel relationships between metabolites and insulin resistance is an essential step in the development of a new diagnostic approach.  Our research will serve as a stepping stone to a follow-up study aimed at tracking newly discovered biomarkers and determine their efficacy at detecting cows susceptible to metabolic disease.  Such a diagnostic tool will allow producers to monitor disease progression in dairy cows with enhanced precision to improve cow health and production profits.  

Collaborators: