Potential association between trematode infections and development of pregnancy toxaemia in sheep

Objective of the work was to study a potential association between trematode infections in pregnant ewes and concentrations β-hydroxybutyrate, which is a ketone body found in animals with pregnancy toxaemia. After administration of a long-acting nematocide, 80 pregnant sheep, infected with trematodes, were allocated as follows; primigravidae ewes in group P-A remained untreated and in group P-B were given netobimin; multigravidae ewes in group M-A remained untreated, in group M-B were given netobimin and in group M-C were given rafoxanide. We collected faecal samples for trematode epg counting and blood samples for measurement of β-hydroxybutyrate concentrations. Mean faecal epg counts of D. dendriticum and F. hepatica decreased significantly after netobimin administration; mean faecal epg counts of F. hepatica, but not of D. dendriticum, decreased significantly after rafoxanide administration. Between P-A and P-B, the difference in mean blood β-hydroxybutyrate concentrations was significant (P = 0.036) immediately after lambing. Between M-A or M-C and M-B, it was significant (P ≤ 0.002) 28 days after trematocide administration and immediately after lambing; between M-A and M-C, no significant difference was evident. Immediately after lambing, mean blood β-hydroxybutyrate concentration in primiparous/multiparous ewes with Dicrocoelium faecal output ≤150 epg was 0.21/0.64 mmol L−1, respectively, and in primiparous/multiparous ewes with Dicrocoelium faecal output >150 epg was 0.40/0.93 mmol L−1, respectively (P = 0.704/<0.001, respectively). Mean blood β-hydroxybutyrate concentration in group P-C/M-C ewes with Fasciola faecal output of <16/<30 epg was 0.47/0.68 mmol L−1, respectively; that in group P-C/M-C ewes with Fasciola faecal output of ≥16/≥30 epg was 0.56/0.85 mmol L−1, respectively (P = 0.620/0.278, respectively). The results indicate that more trematode-infected adult ewes were found to have increased β-hydroxybutyrate blood concentrations and point out to a potential role of liver trematode infections in predisposing adult ewes to pregnancy toxaemia.