Effect of short-term abomasal corn starch infusions on postruminal fermentation and blood measures

It is possible that some of the systemic responses to sub-acute ruminal acidosis (SARA) may be caused by increased intestinal starch fermentation. The objective this experiment was evaluate effect abomasal infusion up 3 g/kg body weight corn (approximately 1.6 kg starch/d) on fecal measures fermentation, plasma acute phase proteins, and white blood cell populations. Six ruminally cannulated cows in late lactation were randomly assigned duplicate × Latin squares with 21-d periods. Cows fed a 20.6% TMR twice daily during last 7 d each period abomasally infused 0 (CON), 1 (ST1), or (ST3) split into 2 bolus infusions, provided every 12 h. Fecal samples collected at 0, 6, 12, 18 h following feeding 21 analyzed for pH, VFA, lactic acid, lipopolysaccharide (LPS). Composite used estimate apparent total-tract nutrient digestibility using undigested neutral detergent fiber as an internal marker. Blood 6 relative 14, 18, period. Concentrations haptoglobin serum amyloid A measured all samples, 14 measure populations, from flow cytometric analysis γδ T cells. Data SAS models included fixed effects treatment random cow square. For measures, before initiation infusions covariates. Time (d h) added repeated variables multiple contrast determine linear increasing starch. Abomasal linearly decreased pH total VFA LPS, but modest, LPS changing 6.96, 57.7 mM, 4.14 log10 EU/g CON 6.69, 64.1 4.58 ST3 treatment, respectively. This suggests we did not induce hindgut acidosis. There no content (mean 96.9 2.2%, respectively). Treatment affect proteins most circulating cells, proportion cells tended decrease 6.69% 4.61% ST3. Contrary our hypothesis, fermentation inflammatory response study.