Effect of feeding of XTRACT(TM) on the acid-base metabolism and ruminal fermentation in high producing dairy cows

Abstract

In this experiment the administration of XTRACT™ resultet in an increase in the concentration of acetate. This is the opposite result of various experiments performed on the effect of plant extracts containing cinnamaldehyde and eugenol on ruminal fermentation. In the experiments done by Busquet et al. 2005a, and Busquet et al 2005b the concentration of acetate decreased. Acetate is important for the production of milk fat, but it is also necessary in the pathway for methane production which represents energy loss. The concentration of propionate increased in the experiment. This was also proven by the majority of the experiments mentioned in the literature review in this thesis. There are reasons to believe that the increase in propionate is a more consistent effect of XTRACT ™. It is a positive effect as propionate is a major source of blood glucose in the cow. This is beneficial in the high produing dairy cow, which is often in a negativ energy balance in the first month of lactation. The concentration of butyrate increased in this experiment, which is favorable since butyrate contributes to the energy supply for epithelial cells of rumen, and the general metabolism. In the experient performed by Busquet et al. (2005b) described in the literature review, there was also an increase in butyrate. This result was true for several of the experiments described. It is important to emphasise that the results of the experiments on the effect of plant extracts containing cinnamaldehyde and eugenol have been variable. The dose of plant extract administered, pH of the ruminal fluid, the diet of the cow, time period of experiments and experimental design have influence the effects. Pancosma suggested that amino acids and small peptides would be used more efficiently by rumen bacteria to produce metaboliseable protein. Hence XTRACT™ will slow deamination and reduce ammonia in the rumen. However, the results from the experiment showed that ammonia concentration generally increased. This is a negative effect according to Pancosma (Pancosma, Tektalk. XTTRACT, code 6965. Effects of the reduction of ruminal ammonia and milk urea nitrogen).