Project Details
Projekt Print View

Effects of a lactation-induced and body condition-dependent mobilization of body reserves on steroid hormone and bile acid metabolism in high-yielding dairy cows

Subject Area Animal Breeding, Animal Nutrition, Animal Husbandry
Term from 2020 to 2024
Project identifier Deutsche Forschungsgemeinschaft (DFG) - Project number 451944681
 
Final Report Year 2025

Final Report Abstract

High-yielding dairy cows mobilize body fat reserves (lipolysis) in early lactation, while they build up fat reserves in late lactation and dry period. Cows that had a higher body fat condition before calving show increased lipolysis after calving compared to normally conditioned cows. Parallel to the increased release of lipids from adipose tissue into the blood, substances stored in the adipose tissue are released. Thus, lipophilic steroid hormones stored in the adipose tissue are also released into the bloodstream during lipolysis. As known from human studies, steroids and steroidogenic enzymes can also be relevant locally in adipose tissue during metabolic processes. Like steroids, bile acids are also formed from cholesterol, conjugated in the liver and stored in the gallbladder. In addition to supporting the digestion of dietary fats and fatsoluble vitamins, they can influence metabolic processes such as lipid and glucose metabolism as signaling molecules. This project investigated the influence of the body condition of highyielding dairy cows on steroid hormone and bile acid metabolism in adipose tissue and liver tissue during lactation . Two groups of cows - with high body condition score (HBCS; n = 19) and normal body condition score (NBCS; n = 19) - were studied. The results showed that HBCS cows exhibited increased lipolysis and a potential metabolic disorder - indicated by higher concentrations of free fatty acids and ketone bodies (beta-hydroxybutyrate). In addition to steroid concentrations, bile acid profiles in blood and subcutaneous adipose tissue as well as mRNA expression of steroidogenic enzymes and receptors and enzymes, transporters and receptors in bile acid metabolism in liver and adipose tissue were measured at different time points around calving. The steroid concentrations in the blood as well as in the adipose tissue were strongly influenced by the body condition of the cows. HBCS cows in particular showed an increased release of androgens and progestins after calving, as well as altered enzyme expression in adipose and liver tissue. Furthermore, HBCS cows showed lower serum bile acid concentrations and altered enzyme and receptor expression in adipose and liver tissue compared to NBCS cows. Overall, the results showed that both body condition and lactation have a major influence on steroid and bile acid metabolism in dairy cows.

Publications

 
 

Additional Information

Textvergrößerung und Kontrastanpassung