Can Abomasal Oligofructose Infusions be Used as a Model to Study Post-Ruminal Acidosis?

Tanya F. GressleyExcessive microbial fermentation of carbohydrates in the large intestine of dairy cattle can result in post-ruminal acidosis and lead to laminitis, decreased reproductive success, and damage to the lining of the gastrointestinal tract. The objectives of the experiment were 1) to develop a model to study post-ruminal acidosis, and 2) to evaluate the potential for a dietary yeast supplement to alleviate post-ruminal acidosis. Six ruminally cannulated Holstein steers were used in a duplicated 3 x 3 Latin square experiment with 14-d treatment periods. Steers were randomly assigned to one of three treatments: (1) control, (2) oligofructose, and (3) oligofructose + yeast. Steers were fed a diet containing either 0 or 1 g/d Saccharomyces cerevisiae. On d 13 of each period, steers were abomasally infused with 1 L of water containing either 0 or 1 g/kg body weight of oligofructose. Fecal samples, blood samples, body temperature, heart rate, and respiratory rate were periodically collected for 48 hours after the abomasal infusion. The oligofructose infusion resulted in post-ruminal acidosis as indicated by a decrease in fecal pH and fecal score (P < 0.05). However, blood pH, temperature, heart rate, and respiratory rate were not affected, indicating that oligofructose-induced post-ruminal acidosis was likely sub-acute. Dietary yeast did not alleviate the oligofructose-induced decrease in fecal pH and fecal score. In conclusion, abomasal oligofructose infusion appears to be an effective model to study post-ruminal acidosis in dairy cattle.Animal Scienc