Peri-Parturient Rise in Faecal Nematode Egg Counts with Reference to Haemonchus contortus in Bulkhi Ewes in Northern Punjab, Pakistan

Abstract.- The occurrence of the peri-parturient rise (PPR) in fecal egg count (FEC) phenomena in Bulkhi ewes and its subsequent impact on naive lambs reared in a traditional semi-intensive husbandry system were monitored at the Small Ruminants Research Station, National Agricultural Research Centre, Islamabad, Pakistan. In this study, two ewe groups, pregnant/lactating (n=37) and open/non-pregnant (n=37), were observed for the PPR phenomena in the sub-tropical area of Pakistan. A significant difference (P< 0.01) was noted for FEC, individual larval culture, packed cell volume (PCV) and haemoglobin (Hb) level in the pregnant/lactating ewes as compared to the open ewes throughout the study. Faecal examination showed consistently higher, predominantly Haemonchus contortus, FEC with lower PCV and Hb level in the pregnant/lactating ewes. The sharp increase in FEC occurred two weeks before lambing and persisted for 12 weeks after lambing. The results showed that the PPR in FEC was associated with both gestation and lactation which provided a large number of third-stage infective larvae (L3) on pasture. These larvae were considered the primary source of infection for the lambs. Thus, infection in lambs showed an initial rise in FEC after four weeks when highly susceptible lambs were allowed to graze along with their dams on the same naturally contaminated pastures. A control measure to consider would be to deworm ewes before lambing or in early lactatio