Ruminal pH, short-chain fatty acid concentrations, and serum acute phase protein concentrations during finishing for steers with and without rumen and liver pathology

This study was carried out to determine whether ruminal fermentation and serum acute phase protein concentrations differed between steers with and without pathology at slaughter. Ruminally cannulated steers (n = 28) were housed with noncannulated steers (n = 250) and randomly assigned to one of eight pens. Steers were previously adapted to a diet containing 5% barley silage and 95% concentrate. Ruminal pH was measured continuously and ruminal fluid and blood samples were collected weekly. Steers were slaughtered and those with a liver score (A or A+) or a rumen score of 2 or 3 (ulceration or scarring) were classified as pathology (PATH) and compared with those with no pathology (NOPATH). Steers with PATH spent 182 min d−1 more with pH < 5.8 (P = 0.05) and 64 min d−1 more time with pH < 5.2 (P = 0.03) than NOPATH. The concentration of serum amyloid A was greater for steers with PATH than NOPATH (P = 0.02) and haptaglobin tended (P = 0.08) to be greater. Overall, results of the current study suggest that the duration of time that ruminal pH is