Effects of rumen-protected choline on the inflammatory and metabolic status and health of dairy cows during the transition period

摘要

The objectives of this study were to evaluate theeffects of rumen-protected choline (RPC) supplementationfrom 21 d pre- to 21 d postpartum on markersof metabolic status and inflammatory response, concentrationsof liposoluble vitamins, and plasma totalCa in parous Holstein cows. The hypotheses were thatsupplementing RPC during the transition period wouldreduce hepatic triacylglycerol accumulation postpartumand attenuate markers of inflammatory responsefollowing parturition, and collectively, such responseswere expected to benefit health of dairy cows. Parouscows at 241 d of gestation were blocked by parity groupand 305-d milk yield, and within block, they were assignedrandomly to receive either 0 g/d [no cholinein transition (NT), n = 55] or 12.9 g/d choline ion[choline in transition (CT), n = 58] from 21 d pre- to21 postpartum. The RPC product was individually topdressedonto the total mixed ration once daily. Prepartum,treatments were supplemented (mean ± standarddeviation) for the last 18.8 ± 5.7 and 19.2 ± 5.0 d ofgestation in NT and CT, respectively. SupplementingRPC prepartum did not affect concentrations of plasmametabolites and inflammatory markers during the last 3wk of gestation. Postpartum, cows fed RPC had greaterhepatic concentration of hepatic triacylglycerol (NT =3.4 vs. CT = 4.4%) and tended to have increased concentrationof β-hydroxybutyrate (NT = 0.48 vs. CT =0.53 mM) in plasma. In spite of the increased hepatictriacylglycerol in cows fed RPC, treatment did notaffect the concentrations of the inflammatory markertumor necrosis factor-α or of the positive acute phaseproteins, haptoglobin and fibrinogen. Supplementingcholine tended to increase the concentration of plasmatriacylglycerol by 0.69 mg/dL in the first 21 d postpartumand reduced the incidence of subclinical hypocalcemiaby 20.9 percentage units compared with NT.Supplementing transition cows with RPC did not affectthe concentrations of liposoluble vitamins in the first 7d postpartum or the incidence of individual diseases ormorbidity in early lactation. The inability of supplementalcholine to reduce hepatic triacylglycerol mighthave been a consequence of the increased productiveperformance without additional dry matter intake.