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The effects of anti-lipopolysaccharide (LPS) antibody on rumen fermentation and LPS activity were investigated during subacute ruminal acidosis (SARA) challenge. Eleven Holstein cattle (164 ± 14 kg) were used in a 3 × 3 Latin square design. Cattle were fed a roughage diet on days -11 to -1 (pre-challenge) and day 2 (post-challenge), and a high-grain diet on days 0 and 1 (SARA challenge). For 14 days, 0-, 2-, or 4-g of anti-LPS antibody was administered once daily through a rumen fistula. Ruminal pH was measured continuously, and rumen fluid and blood samples were collected on days -1, 0, 1, and 2. Significantly lower ruminal LPS activity on day 1 was observed in the 2- and 4-g groups than those in the 0-g group. In addition, significantly higher 1-hr mean ruminal pH on SARA challenge period (days 0 and 1) was identified in the 4-g group than in the 0-g group. However, rumen fermentation measurements (total volatile fatty acid [VFA], VFA components, NH3-N and lactic acid) and peripheral blood metabolites (glucose, free fatty acid, beta-hydroxybutyrate, total cholesterol, blood urea nitrogen, aspartate aminotransferase and gamma-glutamyl transferase) were not different among the groups during the experimental periods. Therefore, anti-LPS antibody administration mitigates LPS release and pH depression without the depression of rumen fermentation and peripheral blood metabolites during SARA challenge in Holstein cattle. [ABSTRACT FROM AUTHOR]

Anti-lipopolysaccharide (LPS) antibody administration has the potential benefits of neutralizing and consequently controlling rumen-derived LPS during subacute ruminal acidosis. Four Holstein bulls were used in this crossover study with a 2-week wash-out period. Anti-LPS antibody (0 or 4 g) was administered once daily for 14 days. Significantly lower ruminal LPS and higher 1-h mean ruminal pH were identified in the 4 g group. However, blood metabolites, acute-phase proteins, cytokines, and hepatic transcriptomes were not different between the two groups. Therefore, anti-LPS antibody administration mitigated ruminal LPS release and pH depression without accompanying responses in acute-phase inflammation or hepatic transcriptomic expression. [ABSTRACT FROM AUTHOR]

Effects of a bacterial probiotic (BP) on ruminal fermentation and plasma metabolites were evaluated in four Holstein cattle (body weight, 645 ± 62 kg; mean ± SD) with induced subacute ruminal acidosis (SARA). SARA was induced by feeding a SARA-inducing diet, and thereafter, 20, 50 or 100 g per head of a commercial BP was administered for 7 consecutive days during the morning feeding. Cattle without BP served as the control. The 24-hr mean ruminal pH in the control was lower, whereas those in the BP groups administered 20 or 50 g were significantly higher compared to the control from days 2 to 7. Circadian patterns of the 1-hr mean ruminal pH were identical (6.4–6.8) among all cattle receiving BP. Although the mean minimum pH in the control on day –7 and day 0 was <5.8, the pH in the treatment groups on day 7 was >5.8 and significantly higher than that of the control group ( >5.2). Ruminal volatile fatty acid (VFA) concentrations were not affected by BP treatment; however, the BP groups had lower lactic acid levels compared with the control group at 20:00 on day 7. Additionally, non-esterified fatty acid levels decreased from 8:00 to 20:00 in all BP groups on day 7. These results suggest that administration of 20 to 50 g of a multi-strain BP for 7 days might improve the low pH and high lactic acid level of the ruminal fluid in SARA cattle. [ABSTRACT FROM AUTHOR]

The article discusses a study which investigated the relationship between pH and temperature in the ruminal bottom fluid by monitoring circadian changes in cows fed with a control diet (C) or a rumen acidosis-inducing diet (RAI). Topics discussed include the lower pH observed in cows fed wth the C and RAI diets, the higher ruminal temperature found in the cows and the negative correlation between the lowest ruminal pH and its corresponding ruminal temperature in cows fed the C and RAI diets.