Abstract
The objective of this study was to determine presence of alterations in the urinary metabolite signatures related to amino acids (AAs), acylcarnitines (ACs), biogenic amines (BAs), glycerophospholipids, sphingolipids (SM) and hexose metabolism in cows that expelled fetal membranes normally and those with retained placenta (RP). Six cows that were diagnosed with RP and 20 healthy control cows (CON), similar in parity and body condition score were selected. Urine samples were collected at -8 and -4 wks prior to parturition, the week of RP as well as at +4 and +8 wks postpartum in Holstein dairy cows. AbsoluteIDQ 180 kit (BIOCRATES, Austria) was used to determine urinary metabolite signatures in RP and CON cows. Univariate analysis was performed using R (version 3.0.3; 2008). Metabolomic data were analyzed by MetaboAnalyst. Statistical significance was declared at P < 0.05. At -8 and -4 wks prepartum and the week of RP diagnosis, the urine of cows with RP was characterized by higher concentrations of 19 species of ACs, aspartate, asymmetric dimethylarginine (SDMA) and carnosine (PPPP<0.05). In conclusion, pre-RP and RP cows were characterized by higher excretion of ACs, ADMA, aspartate, and carnosine in the urine. Moreover, RP was preceded by lower concentrations of multiple species of phosphatidylcholines in the urine starting from -8 wks prior to parturition.