Location: Animal Genomics and Improvement Laboratory
Project Number: 8042-31310-114-006-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Sep 1, 2023
End Date: Aug 31, 2024
Objective:
The long-term goal is to identify how peripartal energy metabolism influences lactation performance and cow health during the peripartal transition from gestation to lactation. Specific objectives are: 1) to comprehensively characterize the nicotinamide adenine dinucleotide (NAD+) metabolome in the cellular fraction of blood, liver, and milk during the transition period. 2) Establish the associations between NAD+ metabolite pools in the different compartments and their relations to markers of metabolic status and immune function, as well as to lactation performance and efficiency.
Approach:
To test the central hypothesis, multiparous dairy cows (n =24) will be enrolled in a longitudinal observational study during the transition from late gestation (3-weeks prepartum) to early lactation (3 weeks postpartum). Blood samples will be collected at day -30 (enrollment), and -21, -14, -7, 0 (day of calving), 7, 14, 21, and 150 relative to parturition. Liver biopsies will be performed at day -21 and at day 7 postpartum, when near-maximal blood free fatty acids (FFA) and increased liver lipid accumulation are anticipated. Milk samples will be collected at day 7, 14, and 150 postpartum. Initial body weight and body condition (i.e., adiposity) will be recorded weekly during the study. Milk production will be recorded daily. The blood biomarkers glucose, FFA, ketones (betahydroxy buturate [BHB] and acetoacetate), and insulin, will be analyzed using colorimetry, as previously reported. Similarly, pro-, and anti-inflammatory cytokines (e.g., IL10, Il1B, TNF-a) will be measured using enzyme-linked immunoassay (ELISA). Blood and liver samples will be analyzed for components of the nicotinamide adenine dinucleotide (NAD+) metabolome using a targeted, quantitative assay of high-performance liquid chromatography (HPLC) coupled to mass spectrometry. Data will be analyzed under a mixed model that includes the random effects of cow and enrollment block, and the fixed effects of day relative to parturition and efficiency group (low vs high efficiency).
