Seasonal density of trichostrongylid nematode larvae was investigated on a pasture used for communal grazing of livestock, using standard procedure of pasture larval count. For this purpose, herbage samples were collected from a posture near Faisalabad at fortnightly intervals over a 12 month period from July 2000 to June 2001. The larvae of Haemonchus (H) contortus, Trichostrongylus species, Ostertagia species and Cooperia (C) curticei were recorded from the pasture throughout the year. However, the nature and intensity of larval contamination varied among different months. H. contortus larvae were in the highest numbers, followed by those of Trichostrongylus species, C. curticei and Ostertagia species. A trend of higher contamination of pasture was found during February to April, which coincides with the lambing season of sheep and goats; and July to September which is normally monsoon in the study area. Standard pasture management integrated with strategic treatments of sheep and goats for nematode infections are suggested.  

Key words: Seasonal availability, pasture contamination, Trichostrongylids, sub-tropics.