Peri-parturient rise in faecal strongyle egg counts of different genotypes of sheep in North Sumatra, Indonesia.

Faecal strongyle egg counts were monitored in peri-parturient ewes and dry ewes grazing in a rubber plantation in North Sumatra, Indonesia. A significant rise in faecal egg counts was observed during the post-parturient period. Haemonchus contortus was the dominant species in the faecal cultures of the lactating ewes. The intensity of the peri-parturient rise was affected by the genotype of the sheep, which were the local Sumatra and its F1 crosses with St. Croix, Barbados Blackbelly and Java Fat-tail. The peri-parturient rise in egg counts was highest in Sumatra and lowest in the Barbados Blackbelly x Sumatra cross. A significant effect of litter size on the peri-parturient rise was also demonstrated. These findings are discussed in relation to the epidemiology and control of gastrointestinal nematodes in the humid tropics.