Absorption of bicarbonate in sheep omasum.

Transport of bicarbonate across the isolated epithelium of sheep omasum was studied in vitro in Ussing chambers in combination with the pH-Stat method. The transport of HCO3- occurred in both directions, but Jms HCO3- was significant larger than Jsm. Reducing the activity of the apical Na/H exchanger by a low mucosal Na concentration caused a significant reduction of Jms HCO3-. Mucosal amiloride or short chain fatty acids (25 mmol l-1 SCFA) numerically decreased Jms HCO3-, but their combination (amiloride + SCFA) caused a significant reduction, which was also observed after addition of the carboanhydrase inhibitor ethoxyzolamide. Concentrations of 5 or 15 mmol·l-1 mucosal ammonia did not change transport rates. The obtained results indicate the importance of an undisturbed cytosolic pH for transcellular HCO3- transport, which is probably mediated by an anion exchanger in both the apical and basolateral membranes. Possible impairment of HCO3- transport appears to be an overlooked factor in the pathogenesis of displacement of the abomasum.

Entomological research on the vectors of bluetongue disease and the monitoring of activity of Culicoides in the Prishtinë region of Kosova.

Clinical bluetongue (BT) caused by BT virus serotype 9 (BTV-9) was observed in Kosova in 2001 and, although subsequently no further clinical cases was diagnosed, its continuing presence has been demonstrated by serological tests in cattle, sheep and goats. In this study, light traps were placed in stables near Prishtinë to identify possible vectors of BTV in Kosova. Samples were collected from October 2004 until the end of 2006. Culicoides were identified and speciated and results were plotted against temperature data. Samples contained Obsoletus and Pulicaris Complexes but not C. imicola. The first specimens of Culicoides were collected in April and they continued to be detected until November. Generally, Obsoletus Complex was present in the largest numbers, with the exception of the middle of the year when the Pulicaris Complex predominated. The number of Culicoides trapped was directly linked to temperature (p<0.05) and records indicated that Culicoides activity ceased when minimum temperatures fell below 0°C; activity recommenced when minimum temperatures rose to approximately 6°C. These results indicate that there was a lack of a vector for BTV during winter for a period lasting approximately five months.