Oronasal administration of lipopolysaccharide prepartum modulated plasma metabolite patterns in periparturient dairy cows

The objective of this study was to evaluate whether repeated oronasal administration of LPS before parturition showed effects on metabolic and clinical responses in periparturient dairy cows. Hundred Holstein dairy cows were randomly allocated to two treatment groups (n = 50). Thirty cows out of 100 were randomly assigned for intensive sampling (n = 15) started at 28 d before the expected day of parturition. Cows received an oral and a nasal treatment of 2 mL and 1 mL of sterile saline solution (0.15 M of NaCl), respectively, alone (control), or containing 3 increasing doses of LPS from Escherichia coli 0111:B4 as follows: 1) 0.01 μg/kg body weight (BW) on d −28, 2) 0.05 μg/kg BW on d −25, and −21, and 3) 0.1 μg/kg BW on d −18 and −14. Blood samples were collected from coccygeal vein at different time points around parturition and analyzed for glucose, lactate, non-esterified fatty acids (NEFA), cholesterol, and betahydroxybutyrate (BHBA). Clinical monitoring of animals was done throughout the experiment at different time points for overall health status, udder edema (UE), manure score, and body condition score (BCS). Results showed that oronasal administration of LPS increased concentrations of glucose and cholesterol in the serum compared to the control group (P < 0.05). The administration of LPS had no effect on concentrations of NEFA, BHBA, and lactate in the serum (P > 0.05). Oronasal LPS did not influence BCS, manure score or the incidence of UE (P > 0.05). Overall, repeated oronasal administration of LPS modulated some serum metabolites related to energy metabolism around parturition in the treated cows. Further research is warranted to elucidate the mechanisms behind greater glucose and cholesterol status in the serum and their potential effects on long-term metabolic health status of dairy cows.