Punkalaidun sonnit 2019

Rumen acidosis is a common digestive disorder in beef bulls fed with high-grain rations. It leads to altered ruminal microbiota and loss of bull performance. The condition develops when the rumen epithelium and the microbes are not able to take up and utilize organic acids of microbial origin at the rate the acids are produced. When the buffering capacity of rumen fluid is exceeded, the pH drops below the critical point of pH 5.8.

Besides lowering the amount of grains in the diet, the risk of ruminal acidosis can be decreased by dietary components which support the structure and function of gastrointestinal epithelium. The tall oil fatty acid -based feed material Progres® contains coniferous resin acids which support the gastrointestinal functions of farm animals.

In an experiment with 104 continental bulls, Prof. Alan Fahey from the University College Dublin, Ireland, showed that dietary Progres® decreases the risk of pH dropping below 5.8.

The bulls with a mean weight of 507 kg were individually penned and arranged in pen pairs. One pen pair was considered as one experimental unit. The study comprised of 52 pen pairs, half of which were fed the normal diet and the rest with the same diet plus Progres® at 7.5 grams/head/day. Both groups received 2 kg fresh weight of barley straw per day, and they had an ad-libitum access to water.  

The trial duration was 89 days. The mean body weight of the bulls at the end of the experiment was 678 kg, with no difference between the treatments. Both diet groups showed similar feed efficiency, feed intake as a percentage of bodyweight, slaughter weight or kill out percentage.

Six bulls per treatment were fitted with intraruminal bolus which measured pH, temperature and redox potential. No treatment-related differences were found for reticulorumen temperature, redox-value or mean pH, but rumen pH was significantly less often (-43%) at or below 5.8 in the Progres® group than in the Control group. In the Control group, the rumen pH was ≤ 5.8 for 11.86% of time, whereas in the Progres®-group, the rumen pH was ≤ 5.8 for 6.79% of time. This result was statistically highly significant (p < 0.01). 

Figure 1. Percentage of time with rumen pH ≤ 5.8

In conclusion, Progres® at 7.5 grams/head/day decreased the risk of rumen acidosis in beef bulls by reducing the time when the rumen pH was at or below the critical pH of 5.8. The result suggests a lower tendency for rumen acidosis and related gastrointestinal problems for beef bulls with Progres® in the diet.