Comparative Studies of Ruminal Fluid Collected by Oral Tube or by Puncture of the Caudoventral Ruminal Sac

Hofírek B. , D. Haas: Comparative Studies of Ruminal Fluid Collected by Oral Tube or by Puncture of the Caudoventral Ruminal Sac. Acta Vet. Brno 2001, 70: 27-33. Samples of ruminal fluid were collected in four groups of high-producing dairy cows simultaneously by an oral probe and by percutaneous puncture of the caudoventral ruminal sac. The samples were tested for basic indicators of the metabolic profile including pH, total acidity, ammonia, infusoria counts, and total and relative amounts of volatile fatty acids. Significant differences (P < 0.05) between the samples collected by oral probe (o) and by puncture (p) were observed for pH (o 6.74 vs. p 6.23), total acidity (o 17.1 vs. p 24.7), and total VFA (o 101.18 vs. p 131.70 mmol/l) in the group of cows with mean daily production of 18 l of milk. Highly significant (P < 0.01) differences between the samples collected by oral probe and by puncture were observed in the groups yielding daily 24 and 38 l of milk for pH (o -6.95 vs. p 6.24 and o 7.00 vs. 6.21, respectively), total acidity (o 13.2 vs. p 22.2 and o 12.6 vs. p 25.2, respectively), and total VFA (o 99.23 vs. p 136.25 mmol/l and o 89.66 vs. p 140.14 mmol/l, respectively). Buffering of the ration for the cows yielding 38 l of milk per day with 200 g of sodium hydrogen carbonate increased the above differences in pH, total acidity, and total VFA. Ruminal fluid samples collected by percutaneous puncture of the caudoventral ruminal sac better indicate the intensity of ruminal fermentation processes apparently because their composition is not influenced by the amount of saliva or buffer which is variable in the content of the cranial ruminal sacs where the oral samples are collected from. Although the sampling of ruminal fluid by percutaneous puncture is an easy method, it can be associated with some complications. Their risk can be minimised by strict adherence to the recommended procedure and observation of rules of aseptic work. Cattle, sampling methods, pH, total acidity, ammonia, infusoria, VFA Samples of ruminal fluid have been collected for diagnostic, therapeutic, and scientific purposes since the mid of the past century. Their examination has become a part of routine diagnostics of clinical and particularly subclinical forestomachal disorders (Pounden 1954; Hofírek et al. 1976; Dirksen 1981; Dvofiák et al. 1997). In the recent years, ruminal fluid tests have been used also for the control of nutrition and checks of ruminal fermentation in high-yielding dairy cows to obtain data for the elaboration of preventive measures against metabolic disorders and production diseases. Many factors must be considered in the calculation of daily rations and attempts to attain the optimal intensity of ruminal fermentation are not always fully successful owing to very complex interaction among the individual ration constituents. The composition of the ruminal fluid is very variable, depending on the sampling site and method and the intensity of ruminal fermentation. The latter factor is particularly important in herds where total mixture rations (TMR) are fed. To assess the results of the metabolic profile test of ruminal fluid correctly it is necessary to obtain standard samples even on repeated collections. This necessity has been encouraging attempts to improve the existing ruminal fluid sampling techniques. An alternative to the conventional oral tube method ACTA VET. BRNO 2001, 70: 27–33 Address for correspondence: Prof. MVDr. B. Hofírek, DrSc. Clinic for Diseases of Ruminants, Faculty of Veterinary University of Veterinary and Pharmaceutical Sciences Palackého 1-3, 612 42 Brno, Czech Republic Phone: +420 5 4256 2401 Fax: +420 5 748 841 E-mail: [email protected] http://www.vfu.cz/acta-vet/actavet.htm