Proteomics profiling of cow adipose tissue in relation to energy balance around calving

The genetic selection of cows for higher rates of milk production is negatively related to body condition score(BCS) and to reproductive performance. The major problem seems to be related to the increasing gap between milk yield and feed intake which turns in the occurrence of negative energy balance status (NEB). The worst period for cow NEB is experienced after parturition. In this period, proteins and fats are mobilized in order to compensate the energy requirements due to high amounts of milk production. The aim of this study was to analyze the differential proteomics profiling of adipose tissue from cows with different NEB scores. The analysis was performed in a total of 18 samples (3 per group), the first group was composed by cows with low NEB scores and the second group was composed by cows with high NEB scores (hNEB). Both groups were analyzed at three different time points, one month before calving, one week after calving and 16 weeks after calving. Four key proteins involved in adipocyte metabolism were differentially expressed between groups in all time points and, 22 other proteins were differentially expressed when considering each single comparison between the two groups in each time point. These differences highlighted the differentially regulated pathways among hNEB cows. The differential expression of proteins and pathways was consistent one month before calving suggesting that the individual variability in adipose tissue metabolism/mobilization/energy availability could be linked to the different levels of EB among dairy cows.