Some abstracts do not have video files because ASAS was denied recording rights.
1523
Effects of starch feeding on lipopolysaccharide (LPS) concentrations in rumen fluid and feces in fresh dairy cows
The objectives of this study were to determine 1) the effect of dietary starch content on the concentrations of lipopolysaccharide endotoxin (LPS) in rumen fluid and feces of lactating dairy cows during 21 d after calving, and 2) the correlation between rumen and fecal LPS concentrations. Multiparous ruminally-cannulated Holstein cows (n = 16) were fed a close-up diet (44% NDF, 16% starch, DM basis) diet for 21 d before expected calving. For the first 21 d after calving, cows were fed either a low starch diet [37% NDF, 21% starch, DM basis], or a high starch diet (32% NDF, 27% starch, DM basis). Rumen and fecal samples were collected at 6 h post feeding on day−14, 1, 2, 3, 4, 5, 6, 7, 9, 13, 17, and 21. Data were analyzed as a completely randomized design by ANOVA with the MIXED procedure of SAS with model effects of treatment, day, treatment x day, with day treated as a repeated measurement. Across days after calving, LPS concentrations in the rumen were higher (12,793 vs. 6592 EU/mL, p <0.01) for the cows on the high starch diet compared to on the low starch diet. Cows on the high starch diet also had a higher LPS concentration in feces during this period (11,885 vs. 7129 EU/mL, P <0.05). Day after calving did not affect the LPS concentration in rumen fluid. However, days after calving affected this concentration in feces (P < 0.01) due to a relatively low fecal LPS concentration at day 1 after calving. The concentrations of LPS in rumen fluid and in feces were positively correlated (r = 0.35, P< 0.001). Our results show that feeding higher starch during the first 3 wk of lactation increased LPS concentrations in rumen fluid and feces indicating a greater risk for compromised rumen health and inflammation.
Keywords: Lipopolysaccharide, starch, fresh cows