Nature has blessed Pakistan with a large population of livestock which play an important role in the economy of the country. Parasitism adversely effects the growth and production of livestock. Great economic losses have been attributed to the sheep population in our country due to parasitic infections including gastro-intestinal parasitism. A study of gastro-intestinal parasitism with isolation and identification of the parasite species affecting sheep at different age groups in and around Lahore was conducted in the months of July, August, September and October, 1994.

For this purpose 200 G.I. tracts of sheep (One hundred each from below six months and above six months of age) were collected from Lahore Metropolitan Corporation, Abattoir.

The overall incidence of gastro-itestinal parasitism in sheep was found to be 68.5%. Age group wise incidence was found to be 71% and 66% in sheep below and above six months of age respectively. Classwise overall incidence was found to be Sporozoan (51%), Trematodes (21%), Cestodes (62%) and Nematodes (68%).

Age group wise incidence of Sporozoan, Trematodes, Cestodes and Nematodes was found to be 60% and 42%, 12% and 30%, 71% and 53%, 73% and 63% in sheep below and above six months of age.

Month-wise prevalence of gastro-intestinal parasitism was also carried out which was higher in the month of August and lowest in the month of October. Nineteen different species of Parasites were recorded which are detailed as under:

1. Eimeria arloingi
2. Eimeria ninakohlvakimovae
3. Eimerla parva
4. Elmerla intricata
5. Eimeria faurei
6. Paramphistomum cervi
7. Cotylophoron cotvlophorum
8. Moniezia. expansa
9. Moniezia benedeni
10. Avitellina centripunctata
11. Haemonchus contortus
12. Oesophagostomum colunThianum
13. Oesophagostonim venulosum
14. Trichuri
15. Ostertagia circumcincta
16. Ostertagia ostertagi
17. Chabertia ovina
18. Trichostrongvlus colubriformis
19. Nematodirus spathiger

The isolation and identification of various collected parasites was carried out. The relationship between the age of sheep and the occurrence of gestro-Intestinal parasitism was also studied. There was a Non Significant difference in the prevalence of gastro-intestinal parasites among the two groups.

The present project was also aimed to observe the effect of single or multiple parasitism on certain haematological parameters like, estimation of haemoglobin contents, total erythrocytic count, total leukocytic count, erythrocyte sedimentation Rate, packed cell volume and differential leukocytic count.

These heamatological studies were carried out on control (parasitic free) and parasitised sheep of below and above six months of age.

The findings of haematological studies showed that there was decrease in haemoglobin contents. total erythrocytic count, packed cell volume, total leukocytic count and increase in erythrocyte sedimentation rate in both sheep below and above six months of age under the effect of single or multiple gastrointestinal parasitism. The values of differential leukocytic count were variable in both age groups.

Most of the haematological disturbances on various blood parameters in both age group of sheep were proved to be statistically significant.

From the results of the presents study, it has been concluded that the incidence of gastro-intestinal parasitism in sheep below and above six months of age is on the higher side which warrants that certain essential preventive measures must be adopted to safeguard our valuable livestockfrom these serious parasitic infestations. It is also evident from the results that gastro-intestinal parasitism adversely affects the blood components in sheep which may lead to anaemia, loss of growth and loss of production.