The relationship between the number and size of nematodes in the abomasum and the concentration of pepsinogen in ovine plasma.

Six-month-old lambs that had been naturally infected with predominantly Teladorsagia (Ostertagia) circumcincta were tested for plasma pepsinogen concentrations because pepsinogen concentrations may reflect the extent of damage to the abomasum. The distribution of pepsinogen concentrations among these lambs was positively skewed with most individuals having relatively low concentrations. Pepsinogen concentrations were more strongly associated with variation in the mean length of the adult female worms than with variation in the number of nematodes present. Previous trials have suggested that genetic variation in the growth of lambs is strongly influenced by genetic variation in worm length. Together these results imply that variation among lambs in the pathogenic effects of T. circumcincta depends upon the mean size of the worms as well as the number of worms present.

Pharmacokinetic studies of flunixin meglumine and phenylbutazone in plasma, exudate and transudate in sheep.

Flunixin meglumine (FM, 1.1 mg/kg) and phenylbutazone (PBZ, 4.4 mg/kg) were administered intravenously (i.v.) as a single dose to eight sheep prepared with subcutaneous (s.c.) tissue-cages in which an acute inflammatory reaction was stimulated with carrageenan. Pharmacokinetics of FM, PBZ and its active metabolite oxyphenbutazone (OPBZ) in plasma, exudate and transudate were investigated. Plasma kinetics showed that FM had an elimination half-life (t1/2beta) of 2.48 +/- 0.12 h and an area under the concentration - time curve (AUC) of 30.61 +/- 3.41 Lg/mL x h. Elimination of PBZ from plasma was slow (t1/2beta = 17.92 +/- 1.74 h, AUC = 968.04 +/- microg/mL x h). Both FM and PBZ distributed well into exudate and transudate although penetration was slow, indicated by maximal drug concentration (Cmax) for FM of 1.82 +/- 0.22 microg/mL at 5.50 +/- 0.73 h (exudate) and 1.58 +/- 0.30 microg/mL at 8.00 h (transudate), and Cmax for PBZ of 22.32 +/- 1.29 microg/mL at 9.50 +/- 0.73 h (exudate) and 22.07 +/- 1.57 microg/mL at 11.50 +/- 1.92 h (transudate), and a high mean tissue-cage fluids:plasma AUClast ratio obtained in the FM and PBZ groups (80-98%). These values are higher than previous reports in horses and calves using the same or higher dose rates. Elimination of FM and PBZ from exudate and transudate was slower than from plasma. Consequently the drug concentrations in plasma were initially higher and subsequently lower than in exudate and transudate.