Continuous and long term measurement of reticuloruminal pH in crossbreed dairy cows in Brazil by an indwelling and wireless data transmitting unit

摘要

Subacute rumen acidosis (SARA) is a widespread disease in high yielding dairy cows, characterized by a persistent abnormally low rumen p H. In dairy cows, the negative effects on health associated with SARA are reduced dry matter intake (DMI), decreased body condition, diarrhoea, rumenitis and inflammation, caudal vena cava syndrome, displacement/ulceration of the abomasum, laminitis and immunosuppressive disorders (Plaizier et al., 2008). SARA is difficult to diagnose in the field. The evaluation of fermentation conditions in rumen fluid is the most meaningful criterion but the definitive test for SARA is the determination of the reticuloruminal p H (Krause and Oetzel, 2006). This p H can be measured in rumen fluid which is either collected with a stomach tube or by rumenocentesis, but the stomach tube technique overestimated the p H value by 0.5 p H-units when compared to rumenocentesis, as a result of saliva contamination (Seemann and Spohr, 2007). Recent techniques use indwelling p H probes placed in the rumen or in the reticulum (Gasteiner et al., 2009) for a continuous monitoring of reticuloruminal p H. This method is advantageous as it allows diurnal recording, but data collection requires either the removal of the chip (Penner et al., 2007) or the transmission by cable to an external unit, fixed onto the animal (Krause and Oetzel, 2006). Gasteiner et al. (2009) have described and evaluated a wireless data transmitting unit allowing continuous measurement of reticuloruminal p H and therefore long term investigation. The present study is the first time this indwelling p H probe has been tested in the field in Brazil. The aim was to study the variations of reticuloruminal p H and temperature in lactating dairy cows during a several week period and see how this method could be used in further research in rumen physiology and rumen pathology.